JP3265704B2 - Evaluation method of adhesion of resin film applied on film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the adhesion of a resin film applied on a film in the fields of inks, adhesives, paints and the like.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed for the purpose of evaluating properties such as adhesion between a resin film coated on a base film and the film. For example, there is a method to compare the degree of peeling of the resin film when the adhesive tape is pressed on the resin film and the tape is peeled off. It is also affected by power. Therefore, a resin film having a high toughness has a large cohesive force, so that the measurement result tends to be poor even if the adhesive force is large. Strength has the drawback that it appears well.

[0003] In addition, by cutting continuously from the resin film surface to the interface using a sharp cutting edge, and measuring the force at that time, the shear strength from the cutting force in the resin film, cutting at the interface A method for determining the adhesive strength from the force in the middle has also been proposed. Further, there is a method in which an adhesive is applied on a resin film, an adherend is placed on the adhesive, and a force is measured when the whole is pulled up vertically. However, since these methods measure the force between the coating and the film, they do not provide any information on adhesion, ie, wettability, surface coverage, and in what form they adhere. In addition, there is a problem that measurement cannot be performed unless the sample is destroyed.

[0004]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies in view of the above problems, and as a result, have found that, by using a laser beam, a resin film coated on a substrate film as in the prior art was peeled off. The present invention has been found that the adhesion between the base film and the resin film can be measured without destruction without relying on such means.

[0005]

That is, the present invention provides a method of irradiating a laser beam from a cross-sectional direction of a resin-coated film to a direction perpendicular to the cross-section of the film so that the light entering the film passes through the film. Utilizing the fact that the amount of light leaking into the resin layer depends on the degree of adhesion of the resin applied above, a method is provided for evaluating the adhesion by measuring the amount of light emitted from the cross section on the opposite side I do.

Hereinafter, the present invention will be described with reference to FIGS. 1 to 4 which show the principle of the present invention in an exploded view. FIG. 1 shows a case where the adhesion between the base film and the resin film applied on the film is high. In this figure, A indicates a locus of a laser beam, and B indicates a film coated with a resin C.
When the adhesion between the base film and the resin film applied on the film is high, there is no air layer between the base film and the resin, and the resin is also oriented. Conceivable. Therefore, since light almost enters the resin film without being reflected between the base film and the resin film,
The amount of light remaining in the film is reduced.

On the other hand, FIG. 2 shows a case where the adhesion between the substrate film and the resin film applied on the film is low. In this figure, A represents the trajectory of the laser beam,
B shows a film coated with resin C. When the adhesion between the base film and the resin film applied on the film is low, there is an air layer D between the base film and the resin, and the resin is also oriented. It is thought that there is not. Accordingly, light is reflected between the base film and the resin film, and the amount of light that enters the resin film is small, so that the amount of light remaining in the film is large.

FIG. 3 shows a case where a light absorbing layer is provided on the resin film because of high adhesion between the base film and the resin film coated on the film. In this figure, A is the trajectory of the laser beam, B is the film coated with resin C,
E indicates a light absorbing layer. When the adhesion between the base film and the resin film applied on the film is high, there is no air layer between the base film and the resin, and the resin is also oriented. Conceivable. Therefore, light almost enters the resin film without being reflected between the base film and the resin film. Light that has entered the resin film travels through the resin layer.In this case, if the resin layer does not have the ability to absorb light, the light may be reflected on the surface of the resin film and return to the film. . Therefore, if the resin layer does not have the ability to absorb light, it is necessary to provide a light absorbing layer on the surface of the resin film in order to prevent this.

FIG. 4 shows a case where a light absorbing layer is provided on the resin film when the adhesion between the base film and the resin film coated on the film is high, and the film is further curved. In this figure, A is the trajectory of the laser beam, B
Denotes a film coated with resin C, and E denotes a light absorbing layer. When the adhesion between the base film and the resin film applied on the film is high, there is no air layer between the base film and the resin, and the resin is also oriented. Conceivable. Therefore, it is considered that light almost enters the resin film without being reflected between the base film and the resin film.

However, since the laser beam has high rectilinearity and travels substantially straight in the film, if the angle of incidence when entering the resin layer from the film cannot be made large (the film is not curved), the adhesion of the resin film will not occur. Irrespective of the properties, almost all of the incident laser light passes through the film, making it difficult to evaluate the adhesion of the resin film. When the refractive index of the base film is higher than the refractive index of the resin film, the total reflection condition is reached, and the strength may not be reduced even if the adhesion is high. Therefore,
Preferably, the film is curved so that the angle of incidence can be changed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to FIGS. FIGS. 5 and 6 are a plan view and a side view of a partial cross section showing one of the embodiments of the method for evaluating the adhesion of a resin film applied on a film according to the present invention. In this figure, reference numeral 2 denotes a film coated with a resin 3. The laser light emitted from the laser light emitting light source 1 enters the inside of the film from the cross section of the film 2 coated with the resin 3, and reaches the cross section on the opposite side through the inside of the film. The laser beam that has reached the cross section goes out of the cross section of the film, and this light is received by the photodiode 4.

More specifically, in order to accurately irradiate the laser light emitted from the laser light emitting light source 1 to the cross section of the film, the laser light emitting light source 1 is fixed on a table 7 which can move minutely right and left. ing. Further, holding jigs 5 and 6 are used to fix the film. The holding jig 6 is placed on a table 8 which can be finely moved in the front-rear direction in order to eliminate bending of the film. Further, the laser light emitting light source and the holding jigs 5 and 6 are placed on the tables 9, 10 and 11, respectively, in order to make the heights of the three equal. Photodiode 4
Is installed as close as possible from the film cross section in order to receive the light reaching the film cross section more accurately.

FIGS. 7 and 8 are a side view and a plan view, partly in section, showing an embodiment in which a mechanism capable of bending a film is incorporated in the embodiment shown in FIGS. 5 and 6. FIG. In this embodiment, a light absorbing layer 12 is provided on the surface of the resin film applied to the film, and a rotating stage 13 is incorporated under the holding jigs 5 and 6 so that the film can be curved. In this embodiment, the holding jig 5 is located on the rotary stage, but needs to be fixed outside the rotary stage so as not to rotate. The rotating stage 13 includes holding jigs 5 and 6
It is installed so as to rotate around the midpoint of. FIG. 9 shows a plan view in the case of several rotations. As shown in this figure, by rotating the rotary stage, the film is curved and the incident angle can be changed.

FIGS. 10 and 11 show the adhesion of urethane resin A and B coatings to a base material synthesized by a usual method using an adhesion measuring device equipped with a device capable of bending the film shown in FIGS. 7 and 8. It is the result of measuring the adhesion. In the figure, the vertical axis represents the output of the sensor, and the horizontal axis represents the bending angle of the film, that is, the angle between the jigs 5 and 6. In this case, when the holding jigs 5 and 6 are arranged in a straight line, that is, when the film is in a straight state, it is set to 0 °, when the light absorbing layer is bent inward, −90 °, and when it is bent outward, 90 °. Degree. FIG. 10 shows the measurement results of the urethane resin A having high adhesiveness. As shown in the figure, when the bending angle of the film is changed, the output of the sensor is greatly reduced to almost zero. This is probably because the laser light entered the resin film and was absorbed by the light absorbing layer provided on the resin film. Therefore, in this case, it is considered that the adhesion is high. On the other hand, FIG. 11 shows the measurement result of urethane resin B having low adhesiveness. In this case, the sensor output does not decrease when the bending angle of the film is changed as in the case of urethane A.

FIGS. 12 and 13 show the adhesion of the urethane resin C film to the substrate, which was synthesized by a usual method, using an adhesion measuring device equipped with a device capable of bending the film shown in FIGS. 7 and 8. 5 shows the results of measuring the change over time with respect to.
In the figure, the vertical and horizontal axes are the same as in FIG. FIG. 12 shows a state immediately after coating, and the adhesiveness at this time is low. FIG. 13 shows a state three days after the coating, and the adhesiveness at this time is high. From this, it can be seen that the adhesion is low immediately after coating, but the adhesion has increased over time.

Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. Some will be apparent to those skilled in the art.

[0017]

According to the present invention, the adhesion between the substrate film and the resin film can be measured without destruction.

[0018]

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention when the adhesion between a base film and a resin film is high.

FIG. 2 is a diagram illustrating the principle of the present invention when the adhesion between a base film and a resin film is low.

FIG. 3 is a principle diagram of the present invention in a case where the adhesion between a base film and a resin film is high and a light absorbing layer is provided on the resin film.

FIG. 4 is a principle diagram of the present invention in a case where the adhesion between a base film and a resin film is high, a light absorbing layer is provided on the resin film, and the film is further curved.

FIG. 5 is a plan view of a partial cross section showing one embodiment of the method for evaluating the adhesion of a resin film applied on a film of the present invention.

FIG. 6 is a side view of a partial cross section of the embodiment.

FIG. 7 is a partial cross-sectional plan view showing another embodiment of the method for evaluating the adhesion of a resin film applied on a film of the present invention.

FIG. 8 is a side view of a partial cross section of the other embodiment.

FIG. 9 is a partial cross-sectional plan view showing a case where a film is curved in another embodiment of the method for evaluating the adhesion of a resin film applied on a film according to the present invention.

FIG. 10 shows the results of evaluation of the adhesion of a urethane resin film having good adhesion measured using the resin film adhesion measuring device shown in FIGS. 7 and 8.

FIG. 11 shows the results of the evaluation of the adhesion of a urethane resin film having poor adhesion measured using the resin film adhesion measurement device shown in FIGS. 7 and 8.

FIG. 12 shows the results of the evaluation of the adhesion of the urethane resin film immediately after coating, measured using the resin film adhesion measuring device shown in FIGS. 7 and 8.

FIG. 13 shows the results of evaluation of the adhesion of the urethane resin film three days after application, which were measured using the resin film adhesion measurement device shown in FIGS. 7 and 8.

[Explanation of symbols]

 A: Trace of laser light B: Base film C: Resin film D: Air layer E: Light absorbing layer 1: Laser light emitting light source 2: Base film 3 ... Resin film 4 ... Photodiode 5 ... Holding jig 6 ... Holding jig 7 ... A table that can move minutely right and left 8 ... It can move minutely forward and backward Table 9 ... Table on which laser emitting light source is mounted 10 ... Table on which holding jig 5 is mounted 11 ... Table on which holding jig 6 is mounted 12 ... Light absorbing layer 13 ... Rotating stage

────────────────────────────────────────────────── (5) Continuation of the front page (56) References JP-A-2-228559 (JP, A) JP-A-5-29423 (JP, A) JP-A-3-12542 (JP, A) JP-A-61- 148345 (JP, A) JP-A-5-99840 (JP, A) JP-A-61-97551 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 33/44 G01N 21 / 84 G01N 19/04 JICST file (JOIS)

Claims (3)

(57) [Claims] A laser beam is irradiated from the cross-sectional direction of the resin-coated film to the film cross-section perpendicular to the film cross-section, and the adhesion of the resin coated on the film while the light entering the film passes through the film. A method of evaluating the adhesion by measuring the amount of light emitted from the cross section on the opposite side, utilizing the fact that the amount of light leaking into the resin layer varies depending on the degree. 2. The method for evaluating adhesion according to claim 1, wherein a light absorbing layer is provided on the surface of the resin film for absorbing light entering the resin layer. 3. The method for evaluating adhesion according to claim 1, wherein the angle of incidence when light enters the resin layer from the film is changed by bending the film.