JPH0540869U - Rigid body pendulum for viscoelasticity measurement - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a rigid pendulum for viscoelasticity measurement, which can easily measure a wide range of viscoelasticity, is less affected by the viscous resistance of air, and has excellent measurement accuracy. [Structure] An edge portion 10 that is brought into contact with a film such as a coating film and vibrates, and a mass member (annular body 13) for securing an inertia moment in the vibration of the edge portion, and the mass member is an edge. The portions 10 are located on both the upper and lower sides of the plane perpendicular to the vertical plane including the tip 101 that contacts the film formation. A displacement piece 11 and a vibrating piece 12 are provided on the mass member. Further, the mass member may be arranged on both sides of a vertical plane including the center line of the tip.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a viscoelasticity measuring rigid pendulum used for measuring the viscoelasticity of a film of a viscoelastic substance such as a paint, an adhesive or a polymer structural material.

[0002]

[Prior art]

 Paints, adhesives, thermoplastic or thermosetting polymer structural materials, etc. are often applied to various mating materials to form a film. A rigid pendulum for measuring viscoelasticity has been conventionally used to measure the viscoelasticity in such film formation. Examples of such a rigid pendulum for viscoelasticity measurement are shown in FIGS. 12 to 14.

A rigid body pendulum for measuring viscoelasticity (hereinafter, also simply referred to as a rigid body pendulum) includes an edge portion 91, a frame portion 93, and a rod-shaped mass member 94 vertically provided below the edge portion 91, the frame portion 93, and the like. And becomes. As shown in FIG. 13, the edge portion 91 has a tip portion 910 that comes into contact with the film 70 having viscoelasticity, which is an object to be measured. Further, the mass member 94 is a portion for ensuring the moment of inertia in the vibration of the edge portion. The mass member 94 has a vibrating piece 95 near its lower end and a displacing piece 96 near its center. Then, in measuring the viscoelasticity, as shown in FIG. 13, first, the tip end portion 910 of the edge portion 90 is brought into contact with the film formation 70. Then, as shown in FIG. 14, vibration due to electromagnetic force is applied to the vibrating piece 95 of the mass member 94 by the control unit 8, the driving device 81, and the vibrating actuator 82. As a result, the rigid pendulum 9 oscillates in the left-right direction in FIG. 12B with the tip end 910 of the edge as a fulcrum.

Therefore, this vibration is measured by a displacement sensor 84 arranged near the displacement piece 96 as shown in FIG. The input signal of the displacement sensor is output as displacement data to the output device 86 via the displacement meter 83 and the control unit 8. At this time, when the film 70 has high viscoelasticity, the vibration damping is fast, and when it is low, the vibration damping is slow. Therefore, by measuring this, the viscoelasticity of the film can be measured (details). Is described later). In FIG. 13, reference numeral 72 is a base for forming a film, and 73 is a support for the same.

By the way, conventionally, as a viscoelasticity measuring device using a rigid pendulum, the one shown in FIG. 12 has been put on the market (for example, Orientec Co., former company name Toyo Baldwin: product name “rigid pendulum”). Viscoelasticity measuring instrument ", model" DDV-OPA "). Based on the rigid pendulum having the shape shown in FIG. 12, several variations are offered as standard or as an option. In addition, a lecture by Takeyuki Tanaka (Nippon Oil & Fats Co., Ltd.), who is a substantial developer of commercial machines, and a utility model gazette (Japanese Utility Model Publication No. 3-11725 gazette) jointly filed between Orientec and Nippon Oil & Fats Co., Ltd. A rigid pendulum with various features has also been introduced and proposed.

These rigid body pendulums are excellent, and the characteristic common to all of them is that the structure is that the edge part and its holding mechanism (the edge part may be made of the same material as the body part and integrated). As a member for adjusting the moment of inertia and the position of the center of gravity, the rod-shaped part is connected downward. Furthermore, it should be noted that most of the mass members, except for the supporting structure around the edges, are placed vertically below the edges, which was proposed by the associate professor of Seiji Ushimani, who proposed this principle. It can be said that it follows the design.

In these rigid pendulums, the inertia moment and the position of the center of gravity are adjusted depending on the shape, size, and material of the rod-shaped portion. In viscoelasticity measurement using a rigid pendulum, the magnitude of the inertial moment of the pendulum is an element that determines the range of viscoelastic response measured using the rigid pendulum. The viscoelastic response is the magnitude of the reaction from the film formation as a sample, and is a quantity determined by the viscoelastic value of the sample and the sample size. The larger the moment of inertia of the rigid pendulum, the smaller the influence of the viscoelastic response from the sample on the motion of the rigid pendulum.

Therefore, it is necessary to use a rigid pendulum having a small moment of inertia for a liquid having a low viscosity and a rigid pendulum having a large moment of inertia for a highly elastic solid. The dynamic range of viscoelastic response that can be measured with one rigid pendulum depends on the vibration measurement accuracy if the rigidity of the rigid pendulum is sufficient. On the other hand, when considering the measurement of vibrations, the observation time required to determine the vibration period and the damping of the amplitude is generally proportional to the period, so it is sufficient for changes in the sample state (hardening reaction and phase transition). There is an upper limit on the pendulum cycle in terms of design in order to shorten it. There is also a lower limit due to the request from the vibration measuring means side.

[0009]

[Problems to be solved]

 However, the conventional rigid pendulum for measuring viscoelasticity has the following problems. That is, as described above, the pendulum cycle (during free vibration) has a range that is allowed by design. As mentioned above, in order to secure a wide target range for viscoelasticity measurement, it is necessary to first set a wide variation of the moment of inertia of the rigid pendulum, but on the other hand, the free vibration period is adjusted to a certain range. I have to.

However, if the structure is one in which the moment of inertia and the position of the center of gravity are adjusted by a single member like the rigid pendulum used in the conventional device, the designable range of each is limited. In particular, conventional rigid pendulums cannot be designed with a high sensitivity to low viscoelastic responses, that is, rigid pendulums with a low moment of inertia cannot be designed with an appropriate period. In principle, the viscoelasticity measurement method using a rigid pendulum can cope with the viscosity of the coating film at the initial stage of baking, but it is difficult for conventional products to design a rigid pendulum corresponding to this as described above. .. Furthermore, with conventional rigid pendulums, the amount of viscous drag received from air during vibration cannot be ignored, and the effective measurement range is limited.

As described above, in the conventional rigid pendulum for measuring viscoelasticity, it is difficult to limit the vibration period of the rigid pendulum to an appropriate range and widen the design range of the moment of inertia. Is difficult to measure. When measuring a small viscoelastic response, the rigid pendulum is easily affected by the viscous resistance of air, making accurate viscoelastic measurement difficult. In view of such conventional problems, the present invention provides a rigid pendulum for viscoelasticity measurement that can easily measure a wide range of viscoelasticity, has little influence of viscous resistance of air, and has excellent measurement accuracy. Is what you are trying to do.

[0012]

[Means for solving the problem]

 The present invention provides a rigid pendulum for viscoelasticity measurement, which includes an edge part that is brought into contact with a viscoelastic film such as a coating film and vibrates, and a mass member that secures a moment of inertia in the vibration of the edge part. The mass member is a rigid pendulum for measuring viscoelasticity, characterized in that the mass member is arranged on each of the upper and lower sides of a plane perpendicular to the vertical plane including the tip portion in contact with the film formation.

In the present invention, the edge portion is a portion that is brought into contact with the film formation and gives vibration, and is the center portion of the viscoelasticity measurement. As the edge portion, there is one in which the tip portion has an acute angle shape (Fig. 3a), or one in which the tip portion has a circular shape (Fig. 3b). In the former case, the tip penetrates into the inside of the film, while in the latter case, the tip is placed on top of the film.

The edge portion is made of a material such as steel and ceramics that has a high elastic modulus in the measurement temperature range and does not cause a chemical reaction with the sample. In addition, at the above-mentioned edge portion, the cutting edge angle of the tip portion greatly affects the sensitivity of viscoelasticity measurement. That is, the larger the cutting edge angle, the greater the torque received from the sample, and the higher the sensitivity. However, when measuring the viscoelasticity of a coating film, etc., it is often measured in the process of volatilization of the solvent, so the larger the cutting edge angle, the more difficult the volatilization of these volatile components is, and the more inaccurate the measurement. When volatile components are present, the cutting edge angle is preferably within 60 degrees. If the cutting edge angle is small, the measurement sensitivity will decrease and the risk of damage to the edge will increase, so it is necessary to set it to 10 degrees or more for practical use.

On the other hand, in the case of a sample having no volatile component, a cutting edge angle within about 150 degrees can be used, but above this range, the sample strain with respect to the amplitude of the pendulum becomes too large and the sample may be destroyed. Further, the mass member has a function of ensuring the moment of inertia. Then, the mass members are respectively positioned on both sides (upper and lower sides) of a plane perpendicular to the vertical plane including the tip portion of the edge portion. As such means, there is a means for positioning the mass member on the upper and lower sides of the vertical plane by using a holder or a connecting member described later.

As the mass member, a material having a high density such as stainless steel, tungsten, or a platinum alloy is preferable. In terms of handling the equipment, it is desirable that it should not be easily deformed, so a material with high mechanical strength is also necessary. The shape of the mass member includes a torus (Figs. 1, 6, 7, and 11), a sphere (Figs. 8 and 10), and a disc (Fig. 9). In addition, it is preferable to provide a holder for holding the edge portion. Further, it is preferable to provide a connecting member between the holder and the mass member for connecting the both.

The holder is preferably made of a material such as bakelite or glass fiber reinforced epoxy resin that has sufficient mechanical strength in the measurement temperature range and has as low thermal conductivity as possible. If the heat dissipation from the edge is large, the temperature uniformity at the measurement site may be impaired and the measurement accuracy may be reduced. As the connecting member, a material having a low density and a high rigidity such as duralumin, titanium, magnesium alloy, carbon fiber reinforced resin is preferable. The connecting member does not have to be responsible for the inertia moment, and the holder and the mass member may be connected with desired rigidity.

However, in order to reduce the attenuation due to other than film formation due to the motion of the rigid pendulum, the cross-sectional area in the vibration direction is reduced to reduce the air resistance, and the weight is reduced to reduce the tip portion of the edge portion. Since it is necessary to reduce the friction at the above, a material having a high specific strength is preferable. Further, it is preferable that the mass member has an annular shape (FIGS. 1, 6, 7, and 11). When such an annular mass member is arranged on the left and right and the edge is arranged between them, the appropriate moment of inertia of the rigid pendulum when measuring the viscoelasticity of commonly used paints, adhesives, etc. It is considered to be in the range of 20 to 10,000 gcm ² .

The radius of the annulus for obtaining these moments of inertia depends on the allowable weight of the rigid pendulum, the density of the material used for the annulus, and the mechanical strength. It is not limited as long as it does not cause inconvenience. A torus suitable for typical measurement conditions can be made of stainless steel, for example, with a radius of 15 mm to 70 mm. Further, the essence of the present invention is that a part or all of the mass member that secures the moment of inertia exists at a position other than directly below the pendulum fulcrum. As a result, the weight of the rigid pendulum and the free vibration period can be fixed to appropriate values, and a rigid pendulum can be designed with the inertia moment selected in a wide range.

In addition, in the rigid pendulum, a vibrating piece for applying vibration to the edge part, a displacement piece for measuring the vibration state, to a part of the mass member or a holder that holds the edge part. Provide a piece. In the vicinity of the vibrating piece and the displacing piece, a vibrating device such as a solenoid and a displacement sensor are arranged in a non-contact manner as shown in the conventional example. The vibrator and displacement sensor are electrically connected to the control device. The control device performs the above-mentioned vibration and measures the free damping vibration by the signal from the displacement sensor. In addition, the controller controls the temperature of the sample film formation and measures the temperature as necessary. The measurement result is processed by the control unit and output from the output device.

Further, as another rigid pendulum for measuring viscoelasticity in the present invention, an edge part that is brought into contact with a viscoelastic film such as a coating film and vibrates, and an inertia moment in the vibration of the edge part are used. In the rigid pendulum for viscoelasticity measurement consisting of a mass member for securing, the mass member is placed on both sides of the vertical surface including the center line of the tip where the edge contacts the film formation. There is a rigid pendulum for measuring viscoelasticity. In the viscoelasticity measuring rigid pendulum, mass members for securing a moment of inertia are arranged on both sides of a vertical plane including the center line of the tip of the edge portion. Others are the same as the rigid pendulum for measuring viscoelasticity.

[0022]

[Action and effect]

 When measuring viscoelasticity using the rigid pendulum for measuring viscoelasticity of the present invention, the tip of the edge is first brought into contact with the film to be measured (see Fig. 3). Next, the rigid pendulum is vibrated with an appropriate amplitude by a vibrator. Next, the displacement sensor measures the vibration behavior of the rigid pendulum, that is, the vibration period and the damping rate of the amplitude. Then, a desired physical quantity is calculated based on the measured value (see Example 1).

Further, in the viscoelasticity measuring rigid pendulum of the present invention, as described above, the mass members are respectively positioned on the upper and lower sides of the plane perpendicular to the vertical plane including the tip of the edge portion. Therefore, the center of gravity of the pendulum can be adjusted by changing factors such as the distance from the vertical plane of the mass members on both sides, the mass, and the angle with the tip of the edge. It is high, and the moment of inertia can be changed freely without having to change the shape of the rigid pendulum significantly. Therefore, the moment of inertia can be set in a wide range, and viscoelasticity in a wide range can be easily measured.

Further, since the mass member for ensuring the moment of inertia is arranged at a position apart from the edge portion which is the vibration axis, the rigid pendulum is more rigorous than the conventional rigid pendulum having an equivalent moment of inertia. The overall size can be reduced. Therefore, even if the vibration period is common, the air velocity is small, and the viscous resistance of the air can be reduced. Therefore, the influence of the viscous resistance of air is small when measuring viscoelasticity.

Also, in the rigid pendulum for measuring viscoelasticity according to the second aspect, the mass members are located on both sides of the vertical plane including the center line of the tip portion of the edge portion. Therefore, similar to the above, there is a high degree of freedom in designing the position of the center of gravity, and it is not necessary to change the shape of the rigid pendulum significantly, and the moment of inertia can be changed freely. Also, as in the above case, the entire rigid pendulum can be made compact, so the viscous resistance of air is low. Therefore, according to the present invention, it is possible to easily measure a wide range of viscoelasticity, and to provide a viscoelasticity rigid pendulum which is less affected by the viscous resistance of air and has excellent measurement accuracy.

[0026]

【Example】

 Example 1 A rigid pendulum for measuring viscoelasticity according to an example of the present invention will be described with reference to FIGS. As shown in FIGS. 1 to 3, the rigid pendulum 1 of this example includes an edge portion 10 and an annular body 13 as a mass member for securing an inertia moment in the vibration of the edge portion 10. The torus 13 is located on each of the upper and lower sides of a plane perpendicular to the vertical plane including the tip portion 101 where the edge portion 10 contacts the film formation 70.

That is, as shown in FIGS. 2 and 3, the edge portion 10 is sandwiched by a pair of holders 15 and fixed by screws 151. The left and right sides of the holder 15 are fixed to a pair of connecting members 14 as shown in FIG. The connecting members 14 are fixed to the annular body 13 at the top and bottom thereof, respectively. A weight 16 is fixed to the lower end of the connecting member 14 with a screw 161. As described above, in the rigid pendulum of this example, as shown in FIGS. 1 and 2, the holder 15 is located above the tip 101 of the edge portion 10, and the holder 15 is circularly connected via the connecting member 14. A ring body 13 is provided. Therefore, the ring-shaped bodies 13 as the mass members are located on both sides (upper and lower sides, hereinafter the same) of the surface of the edge portion 10 that is perpendicular to the vertical plane including the tip portion 101.

As shown in FIG. 2B, the annular body 13 has a displacement piece 11 on the left side thereof for detecting the vibration displacement of the edge portion 10, and on the right side thereof, the annular body 13. A vibrating piece 12 for applying vibration to the edge portion is provided via 13, the connecting member 14, and the holder 15. Further, as shown in FIG. 1, a displacement sensor 24 is arranged in a non-contact manner on the displacement piece 11 and a vibration solenoid 22 is arranged in a non-contact manner on the vibration piece 12. The displacement sensor 24 is connected to the displacement meter 23 and the control device 2. The solenoid 22 is connected to the vibration power source 21 and the control device 2. An output device 26 is connected to the control device 2. Further, the shape of the tip portion 101 of the edge portion 10 may be an acute-angled protrusion as shown in FIG. 3 (a) or a circular shape as shown in FIG. 3 (b). good.

Next, when measuring the viscoelasticity of the film formation 70 using the above-mentioned rigid pendulum 1 for measuring viscoelasticity, first, as shown in FIGS. A film 70 is formed by applying a coating material or the like. Then, it is fixed on the support base 73 having the leg portions 74. Next, the edge portion 10 of the rigid pendulum 1 is brought into contact with the film formation 70. At this time, in the case of a fluid sample, the tip portion 101 of the edge portion 10 penetrates into the film formation 70 and comes into contact with the substrate 72, as shown in FIG. In the case of a non-fluid sample, the tip of the edge does not reach the substrate, but only contacts the sample surface.

Next, the solenoid 22 is operated by the control device 2 and the vibration power source 21. As a result, the vibrating piece 12 provided on the annular body 13 vibrates. Then, this vibration force is transmitted to the edge portion 10 through the connecting member 14 and the holder 15. Therefore, the annular body 13 rotates in the left-right direction of FIG. 2B (the paper surface direction of FIG. 1) around the tip portion 101 of the edge portion. The vibration is applied to the vibrating piece 12 for 1 to 2 seconds. Then, after the application of the vibration is stopped, the vibration behavior of the annular body 13, that is, the vibration period, the damping rate of the amplitude, and the like are measured by the displacement sensor 24 arranged opposite to the displacement piece 11. Then, a desired physical quantity is calculated based on the measured value (see later).

Then, in the rigid pendulum 1 of this example, as described above, the annular body 13 as the mass member is located on both sides of the plane perpendicular to the vertical plane including the tip 101 of the edge portion. There is. Therefore, there is a high degree of freedom in designing the position of the center of gravity, and it is not necessary to significantly change the shape of the rigid pendulum 1. Therefore, the moment of inertia can be changed freely. Therefore, the moment of inertia can be set in a wide range, and viscoelasticity in a wide range can be easily measured.

Further, since the annular body 13 as the mass member is provided at a position apart from the edge portion 10 which is the vibration axis, the entire rigid body pendulum is made more compact than the conventional rigid body pendulum having an equivalent moment of inertia. it can. Further, since the annular body 13 is used as the mass member, the viscous resistance of air can be reduced because the velocity of movement to air is small even if the vibration cycle is common. Therefore, when measuring viscoelasticity, the influence of the viscous resistance of air is small and the measurement accuracy is improved. Further, in the rigid pendulum 1 of this example, a pair of annular bodies 13 as mass members are arranged on both sides of the vertical plane including the center line of the tip portion 101 of the edge portion. Therefore, there is a high degree of freedom in designing the center of gravity, and it is not necessary to change the shape of the rigid pendulum significantly, and the moment of inertia can be changed freely. Therefore, according to this example, it is possible to provide a rigid pendulum for measuring viscoelasticity that can measure viscoelasticity over a wide range, has little effect of viscous resistance of air, and has excellent measurement accuracy.

Hereinafter, these will be described more specifically. First, the rigid pendulum for viscoelasticity measurement cannot be applied with the conventional moment of inertia when the viscoelasticity of the film to be measured is extremely large or small.

That is, when viscoelasticity is large, it is necessary to increase the moment of inertia. On the contrary, if the viscoelasticity is small, the moment of inertia must be small. This moment of inertia I is proportional to the distance d between the tip 101 of the edge and the center of gravity G of the pendulum as shown in FIGS. 4 and 5 and the following equation (1). , It is desirable to be constant in measurement, so it is proportional to only the distance d). T = 2π (I / Mgd) ^1/2 (1) In the above equation, T is the period, g is the acceleration of gravity, M is the mass of the pendulum, I is the moment of inertia, and d is the fulcrum and the center of gravity. It is a distance.

In the conventional rigid pendulum for measuring viscoelasticity, there is a mass member for ensuring the moment of inertia only vertically below the tip of the edge portion, so that there is a limit to the adjustment of d. For example, in order to reduce the above d, it is necessary to position the mass member near the fulcrum, resulting in a very short pendulum. On the other hand, in order to increase the above d, it is necessary to position the mass member farther than the fulcrum, resulting in a very long pendulum. On the other hand, as in the present invention, when the mass member is located on both sides of the vertical surface including the tip of the edge portion and the surface perpendicular to the vertical surface, the degree of freedom in designing the center of gravity is high, and It is possible to freely change d (inertia moment I) without having to change the shape of the pendulum largely.

Further, as in the present invention, when the mass member is on both sides of the vertical plane including the center line of the tip of the edge, the degree of freedom in designing the position of the center of gravity is high, and the shape of the pendulum is greatly changed. There is no need to change d (moment of inertia I) freely. As described above, in the present invention, since the pendulum has a large amount of change of the inertia moment I without largely changing the shape of the pendulum, the measurable width of the viscoelasticity of the film is large.

Next, the effect of air viscosity on the measurement results will be described. It is possible to observe that the rigid pendulum vibrates due to air viscosity and friction at the edge by the measurement operation without the sample (deposition). These resistance forces add to the viscous term of the sample and thus cause a decrease in measurement accuracy. The effects on the measurement results of air viscosity and friction force can be compared with the logarithmic attenuation rate Δ in the absence of the sample, the period T, and the D value calculated by the following equation (2) from the pendulum inertia moment I. D = I · Δ / T (2)

Next, Table 1 shows the measurement results of Example 1 and the comparative example (see FIG. 12). Each of these measured values is an average value of 99 measured values. From the D value in Table 1, it can be seen that the example is 23.6 times more sensitive than the comparative example. This difference in sensitivity is an important difference as to whether or not it can be applied to low-viscosity samples, such as automotive topcoats in the early stages of baking.

[0039]

[Table 1]

The moment of inertia will be described next. In the pendulum of the conventional example (FIG. 12), if the period of free vibration is limited to about 1 second, the value of the moment of inertia I is generally limited to the range of 2000 to 10000 gcm ^2. To be done. A high I value is required when the viscoelastic response from the sample is large, but a pendulum having an I value of 10000 gcm ² or more is not required for normal measurement due to the adjustment of the sample width.

However, when the viscoelastic response from the sample is small, a pendulum with a low I value is inevitably required. In the conventional pendulum, this is limited to about 2000 gcm ² , whereas in the pendulum of the present invention, a pendulum having an inertia moment I value of ²⁰ gcm ² can be put to practical use. This makes it possible to perform high-sensitivity measurements that are about 100 times higher than conventional pendulums.

Next, the theory and method for measuring viscoelasticity using the viscoelasticity pendulum of the present invention will be described. That is, as shown in FIGS. 4 and 5, the rigid pendulum having the knife edge as a fulcrum is supported by the coating film base and vibrates while receiving the force F ₁ due to the viscoelasticity of the coating film. The vibration displacement of the rigid pendulum is represented by the deflection angle θ with reference to the rest position. The vibration of the rigid pendulum is expressed by the following equation (3). I · d ² θ / dt ² + F ₁ · h / sin θ ₁ + Mgdθ = 0 (3) I: rotational inertia moment about the blade edge of the rigid pendulum θ: vibration displacement angle of the rigid pendulum t: time F ₁ : Force exerted by the coating film on one side of the blade h: Height of coating film in contact with the blade θ ₁ : Angle formed by the blade surface of a stationary rigid pendulum and the ground surface M: Mass of rigid pendulum g: Gravity acceleration d: Edge From the tip of the part to the center of gravity of the rigid pendulum

The first term on the left side of the above equation (3) represents the effect of inertia, the second term represents the effect of the force F ₁ received from the coating film, and the third term represents the effect of gravity. Since the forced vibration is not applied from the outside, the right side of the equation (3) is always zero. Here, to examine F ₁ , consider the case where the rigid pendulum swings from the equilibrium position by the angle θ. As shown in FIG. 5, a point P on the blade surface located at a distance a from the blade edge moves by a distance aθ with respect to a small θ. The thickness of the coating film as viewed in a direction perpendicular to the rake face from the point P is increased from Atanshita ₁ only A.theta., Or since decreasing the strain magnitude can be expressed as θ / tanθ _1. If the force exerted by the coating film on the blade surface is proportional to this strain, then F ₁ = E ^* Scot θ ₁ · θ ··· (4) S = bh / sin θ ₁ ··· (5) It S is the area of contact between the coating and one side of the blade, and b is the length of the coating contacting the blade.

Next, E ^* represents the complex elastic modulus of the coating film, and is a complex number expressed as E ^* = E ′ + iE ″ ... (6), where K = Scot θ _{When 1} · h / sin θ ₁ = bh ² cos θ ₁ / sin ³ θ ₁ (7), the equation (3) can be rewritten as follows.

I · d ² θ / dt ² + K (E ′ + iE ″) θ + Mgdθ = 0 (8) This equation has a solution of the following form when only θ is a function of t. = Θ ₀ exp (−αt + iωt) (9) θ ₀ , α and ω are constants, which represent the amplitude at zero time, the damping rate of the amplitude and the angular velocity of vibration, respectively, and differentiated with t. Then dθ / dt = (- α + iω) θ ··· (10) d 2 θ / dt 2 = (- α + iω) 2 θ ··· (11)

Therefore, the equation (8) is as follows, and E ′ and E ″ are obtained. I (−α + iω) ² + K (E ′ + iE ″) + Mgd = 0 ... (12) E ′ = − [(Α ² −ω ² ) I + Mgd] / K ... (13) E ″ = 2αωI / K ... (14) )

Generally, the logarithmic decay rate Δ is used to represent the relative change in viscosity. Δ = αT (dimensionless) (15) T = 2π / ω (16) Δ is the natural logarithmic value of the amplitude change per cycle, and is a chart that records vibration. It can be obtained by reading the amplitude from. From the comparison with the equation (14), there is a relation of Δ = [πK / ω ² I] · E ″ ... (17) between Δ and the loss elastic modulus E ″, and ω is constant, that is, the vibration period. It can be seen that Δ is proportional to E ″ when T is constant.

A method for evaluating the viscosity by obtaining a logarithmic decrement from a vibration phenomenon based on viscoelasticity of a sample is a common method that is also carried out by a vibrating rod hardness tester or a TBA (Tortional Braid Analysis). Generally, the viscosity of liquid or gas is expressed by viscosity η (poise = dyne · sec / cm ² = 0.1 Pa · sec). η It is obtained by dividing shear stress by shear rate, and steady shear state is often used for measurement.

For viscoelastic bodies, the following η ′ is used instead of η because it is necessary to measure the response to vibration displacement. η '= E "/ ω (definition) (18) η'is called the dynamic viscosity, and has the same dimension as η, that is, [mass] [length] ^-1 [time] ^-1 According to the equation (17), the logarithmic damping ratio Δ is expressed as follows: Δ∝η ′ / ω = E ″ / ω ² (19) That is, Δ is the dynamic viscosity and ω is , And is related to the loss elastic modulus by the coefficient of ω ² . When the sample is liquid and its elasticity can be ignored, ω can be treated as a constant, so either Δ, η ′ or E ″ can be used to express the viscosity change.

On the other hand, when the sample is handled as a viscoelastic body, it is appropriate to express the viscosity and the elasticity by the storage elastic modulus E ′ and the loss elastic modulus E ″ respectively. Therefore, here, E ′ and E ″. E′r and E ″ r are defined as variables that express the relative change of E′r = ω ² −α ² −ω ₀ ² (20) E ″ r = 2αω. ··· (21) ω ₀ = [Mgd / I] ^1/2 ··· (22) ω ₀ represents the angular velocity of the rigid pendulum vibration in the absence of the sample.

The relative storage elastic modulus E′r and the relative loss elastic modulus E ″ r are respectively proportional to E ′ and E ″ according to the equations (13) and (14), and E′r = (K / I) · E ′ (23) E ″ r = (K / I) · E ″ (24) tan δ = E ″ / E ′ = E ″ r / E′r (25) It is possible to obtain the tangent tan δ. The temperature at which tan δ reaches its maximum is considered to be one of the characteristic values derived from the microscopic structure of the coating film, and is conveniently called the glass transition temperature Tg. This can be obtained by measuring the viscoelasticity of the coating film cured with the rigid pendulum set while changing the temperature.

The viscoelasticity measurement method according to the present principle is based on the following procedure. [1] Vibrate the pendulum with an appropriate amplitude. Here, the method of vibration is arbitrary, but a non-contact method is preferable to reduce the force applied to the pendulum from other than the sample. The amplitude should also be in the range where this does not damage the sample. [2] Measure the vibration behavior of the pendulum. The measurement items are the period and amplitude attenuation rate. [3] A desired physical quantity is calculated according to the above theory.

Example 2 In this example, as shown in FIGS. 6A and 6B, in the rigid pendulum for measuring viscoelasticity of Example 1, the mass member is an elliptical annular body 13. .. Further, no weight is provided below the connecting member 14. Others are the same as in the first embodiment. Thus, the mass member may be a perfect circular body as in the first embodiment, an elliptical body as in this example, or an arcuate body.

Example 3 In this example, as shown in FIGS. 7A and 7B, in the rigid pendulum for measuring viscoelasticity of Example 1, the connecting member 14 was replaced with a wire 31. The wire 31 rigidly suspends and holds the holder 15 on the annular member 13 of the mass member. As the above wire, use a piano wire or a thin wire rope. Others are the same as in the first embodiment. Also in this example, the same effect as that of the first embodiment can be obtained. Moreover, in this example, since the wire 31 is used as the connecting member, the resistance of the air viscosity at the time of measurement is further reduced.

Embodiment 4 In this embodiment, as shown in FIGS. 8A and 8B, a holder 15 and a spherical body 131 as a mass member are connected by a connecting rod 14 as a connecting member. Further, a balance ball 41 as a mass member is provided below the holder 15 via a suspension rod 142. The spherical body 131 is located above the edge portion 10, and the balance sphere 41 is located below the edge portion 10. Then, the position of the center of gravity is set by changing the mass ratio between the spherical body 131 and the balance sphere 41 and the lengths of the connecting rod 14 and the suspension rod 142.

Further, the holder 15 is provided with a displacement piece 11 and a vibrating piece 12. As described above, the shape of the mass member is not limited to the ring shape, the arc shape, and may be the spherical body. In this example, the spherical body 131 as a mass member and the balance sphere 41 are located on both sides of a plane including the tip 101 of the edge portion 10 and perpendicular to the vertical plane. Therefore, with regard to such a configuration, it is possible to obtain the same effects as those shown in the first embodiment.

Example 5 In this example, as shown in FIGS. 9A and 9B, one connecting member 14 is erected on the upper part of the holder 15, and the connecting member 14 is provided with a metal plate 132 as a mass member. Are fixed by nuts 134 and 134. Further, a balance bar 144 is vertically provided on both sides of the holder 15, and a balance plate 42 as a mass member is provided at each lower end thereof. The balance plate 42 is fixed by nuts 134 and 134 screwed onto the threaded portion 140 of the balance rod 144. Others are the same as in the fourth embodiment.

In this example, by moving the nut 134 up and down, the metal plate 132 as a mass member and the balancing plates 42, 42 are moved up and down to set the center of gravity. In this example, since the mass member is located on both sides of the vertical surface including the tip of the edge portion 10 and the vertical surface, the same effect as the effect shown in the first embodiment can be obtained in this configuration. it can.

Example 6 In this example, as shown in FIGS. 10A and 10B, a connecting member 145 is provided below both sides of the holder 15, and a spherical body 135 as a mass member is fixed to the tip end thereof. Is. Others are the same as in the fourth embodiment. Further, in this example, the mass members are on both sides of the vertical plane including the center line of the tip portion 101 of the edge portion 10. Therefore, with respect to such a configuration, it is possible to obtain the same effects as the effects shown in the first embodiment.

Embodiment 7 In this embodiment, as shown in FIGS. 11 (a) and 11 (b), a holder 15 provided with an edge portion 10 and an annular body 13 as a mass member are connected by a horizontal connecting member 14. It is a connection. In this example, unlike the first example, only one annular member 13 is arranged in the central portion of the edge portion 10. Others are the same as in the first embodiment. In this example, the ring-shaped body 13 as a mass member is located on both sides of a plane perpendicular to the vertical plane including the tip portion 101 of the edge portion. Further, the annular body 13 is located on both sides of the vertical plane including the center line of the tip portion.

Therefore, the same effect as that of the first embodiment can be obtained. As is known from the above, Embodiments 1, 2, 3 and 7 are embodiments relating to Claims 1 and 2 of the present invention, and Embodiments 4 and 5 are embodiments relating to Claim 1. Example 6 is an example relating to claim 2.

[Brief description of drawings]

FIG. 1 is an overall explanatory view of a rigid pendulum for measuring viscoelasticity and viscoelasticity according to a first embodiment.

FIG. 2 is a front view of a rigid pendulum according to the first embodiment and its A.
-A line sectional view.

FIG. 3 is an explanatory diagram of a state in which an edge portion is placed on a film formation in Example 1.

FIG. 4 is an explanatory diagram of a rigid pendulum according to the first embodiment.

FIG. 5 is an explanatory diagram of displacement of a rigid pendulum and strain of film formation in Example 1.

6A and 6B are a front view and a side view of a rigid pendulum for measuring viscoelasticity in Example 2.

7A and 7B are a front view and a side view of a rigid pendulum for measuring viscoelasticity in Example 3.

8A and 8B are a front view and a side view of a rigid pendulum for measuring viscoelasticity in Example 4.

9A and 9B are a front view and a side view of a rigid pendulum for measuring viscoelasticity in Example 5.

FIG. 10 is a front view and a side view of a rigid pendulum for measuring viscoelasticity in Example 6.

FIG. 11 is a cross-sectional view taken along the line BB of FIG. 11B of the rigid pendulum for measuring viscoelasticity in Example 7 and a cross-sectional view taken along the line AA thereof.

FIG. 12 is a front view of a rigid pendulum for measuring viscoelasticity in a conventional example and a sectional view taken along line AA thereof.

FIG. 13 is an explanatory diagram of a contact state between the edge portion and the film formation in the conventional example.

FIG. 14 is an explanatory diagram of viscoelasticity measurement in a conventional example.

[Explanation of symbols]

 1. ． ． Rigid pendulum, 10. ． ． Edge part, 101. ． ． Tip, 11. ． ． Displacement piece, 12. ． ． Excitation piece, 13. ． ． Torus (mass member), 131, 135. ． ． Spherical body, 132. ． ． Metal plate, 14. ． ． Connection member, 15. ． ． Holder, 31. ． ． Wire, 41. ． ． Balance sphere, 42. ． ． Balancing plate, 70. ． ． Film formation,

Claims (2)

[Scope of utility model registration request] 1. A rigid pendulum for viscoelasticity measurement, comprising an edge part which is brought into contact with a viscoelastic film such as a coating film and vibrates, and a mass member for ensuring a moment of inertia in vibration of the edge part. A viscoelasticity measuring rigid pendulum, characterized in that the mass members are arranged on both upper and lower sides of a plane perpendicular to a vertical plane including a tip portion whose edge portion comes into contact with the film formation. 2. A rigid pendulum for viscoelasticity measurement, comprising: an edge part that is brought into contact with a viscoelastic film such as a coating film and vibrates, and a mass member for ensuring a moment of inertia in the vibration of the edge part. A rigid pendulum for viscoelasticity measurement, characterized in that the mass members are respectively arranged on both sides of a vertical plane including a center line of a tip portion whose edge portion comes into contact with the film formation.