JP2003014600A - Apparatus and method for evaluation of tearing property of film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for evaluation wherein the sticking strength, the tearing strength, the tearing property and the like of a film or a sheet can be evaluated and tested with a satisfactory correlation property with an actual hand tearing evaluation or a transplantation test and quantitatively. SOLUTION: The evaluation apparatus for the tearing property of a film is provided with a sample base which comprises a flat plate with a formed circular hole, a fixation means by which the film arranged so as to cover the circular hole is fixed onto the sample base, a conical sticking implement which comprises a tip movable toward the surface of the film on the central axis of the circular hole and a movement-stress measuring means by which the tip of the sticking implement is moved to the side of the film at a prescribed movement speed and which measures a movement amount and a stress applied to the sticking implement, the film is stuck and torn by the tip, and the tearing property of the film is evaluated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film tearability evaluation device and an evaluation method using the device, and more particularly to a multi-film used in the agricultural field, packaging, packing and decoration used in the commercial and industrial fields. Puncture strength of the film or sheet such as, an evaluation device and an evaluation method for quantitatively evaluating tear strength and tearability, etc., specifically,
The force when punching a hole in the film or a film with a notch in advance, the force to open the hole of the film when the tip is pierced and further, the hole of the film is widened,
The present invention relates to an evaluation device for quantitatively measuring and evaluating the relationship between the amount of movement of a tip when tearing and stress and an evaluation method for films and sheets using this device.

[0002]

2. Description of the Related Art Since the development of plastic materials, plastics have been said to be light and durable, have excellent solvent resistance, and can be easily molded by applying heat. Due to its advantages, the demand for plastics as a substitute material for metals, woods and papers has increased significantly. Even today, its demand is still high and its applications are becoming more diverse. At present, various products such as containers, sheets, and films using plastics having the required functions are on the market.
For example, the container is required to have impact strength, transparency, gas permeability, etc., depending on its application.

Further, as the applications of plastics and the shapes of products have become diverse, there are evaluation items and criteria required for each, and the evaluations are also becoming diverse. For example, films are generally evaluated for mechanical strength such as tensile strength and elongation, elastic modulus, tear strength, gas permeability of water vapor and carbon dioxide, transparency such as light transmittance and haze, and turbidity. These are JIS (Japanese Industrial Standards) and ASTM
Etc., the evaluation method is shown and standardized.
JIS K-7113 for tensile strength and elongation, JIS K-71 for tear strength
28, JIS K-7126 for gas permeation test. However, these are methods for evaluating and comparing general physical properties to the last, and in many cases, they are insufficient in comparison with a practical use situation or a practical evaluation.

Taking tear strength as an example, JIS K-7128 describes two test methods, the Elemendorff method and the trouser method. In both of these, a notch is made in the film in advance, and the stress is measured when both ends of the film are torn up and down at a constant speed so that the paper is torn by hand. However, the phenomenon of "tear" of the film in practical use is not limited to this, and in fact, there are many phenomena of "piercing" by pressing something on the film. Such a phenomenon has a problem that it cannot be fully evaluated by the evaluation of "tear" by the JIS test method described above.

For example, a mulch film used for agriculture can be pierced by a transplanter after being spread (covered) on a ridge of a field, and the piercing work at this time is just a "break through" work. is there. We collected several types of biodegradable agricultural mulch films, measured their tear strength in advance with the JIS K-7128 trouser method, and then conducted a practical test of spreading in the field and making holes with a transplanter. As described above, there is a problem that the practical test result and the JIS tear strength measurement result do not necessarily have a correlation.
From this result, it is understood that a new tearability evaluation method is required in addition to the existing tear test method.

In order to solve these problems, the present invention can reproduce phenomena that occur in practice, such as how to make a hole in a film, how to spread the hole after opening the hole, how to tear the hole, and the like. It is an object of the present invention to provide a new evaluation device and evaluation method that can be evaluated objectively.

[0007]

Therefore, the present inventors have investigated the tearing phenomenon of agricultural mulch film under various agricultural work conditions at various agricultural work sites by using various agricultural multifilms. Moreover, the tearing and tearing expansion phenomenon of various films and sheets for commercial and industrial use under various usage conditions were investigated. In addition, as the state of the film, there is a notch scratch in advance, and a tear phenomenon when there is no notch scratch, etc. Furthermore, after the film has a hole, "propagation" after the tear occurs, the phenomenon that the tear spreads. , Etc., from the aspect of strength, the spreading speed of the tearing part, stress at that time, etc., various evaluation test devices and evaluation methods for more accurate evaluation can be studied to obtain an evaluation device and evaluation method having high correlation. The present invention has been completed by finding out that these problems can be solved and the problems can be solved.

That is, the film tearability evaluation apparatus of the present invention comprises a sample table having a flat plate having circular holes, and a fixing means for fixing the film arranged so as to cover the circular holes on the sample table. A cone-shaped piercing tool having a tip movable on the central axis of the circular hole toward the surface of the film,
By moving the tip of the piercing tool to the film side at a predetermined moving speed and moving stress measuring means for measuring the amount of movement and the stress applied to the piercing tool, by piercing and tearing the film with the tip, It is characterized in that the tearability of the film is evaluated.

Further, the present invention is characterized in that the fixing means loads and fixes a weight on both ends of the film in one diametrical direction on the circle of the circular hole or in two diametrical directions orthogonal to each other. . Further, according to the present invention, the fixing means is 1
In both diametrical directions or in two diametrical directions orthogonal to each other, a weight is loaded and fixed at both ends of the film, and the film is fixed at the peripheral edge of the circular hole by an annular film fixing ring provided at the peripheral edge of the circular hole. It is characterized by that.

Further, the present invention is characterized in that the tip angle of the tip of the conical piercing tool is 30 to 150 degrees. Further, the present invention is characterized in that the tip shape of the tip of the conical piercing tool is R (R): 0 <R ≦ 20 mm.

Further, the film tearability evaluation method of the present invention uses one of the film tearability evaluation devices described above, the film is arranged so as to cover the circular hole, and the film is fixed by the fixing means. Fixed on top, moving the tip of the piercing tool to the film side at a predetermined moving speed, the tip pierces the film, opens a hole in the film, further spreads the hole of the film, and the tip when continuing to tear the film The moving stress measuring means measures the relationship between the moving amount and the stress.

Further, the film tearability evaluation method of the present invention uses one of the above-mentioned film tearability evaluation devices, wherein a notch is formed in the film so that the notch comes to the center of the circular hole. The film is arranged so as to cover the hole, the film is fixed on the sample table by the fixing means, the tip of the piercing tool is moved to the film side at a predetermined moving speed, the tip pierces the film, and a hole is opened in the film. Further, the moving stress measuring means measures the relationship between the amount of movement of the tip and the stress when the film hole is widened to continue tearing the film.

Further, the present invention is characterized in that the notch is formed in a shape elongated in the MD direction at the time of molding of the film or in a shape elongated in the TD direction orthogonal to the MD direction at the time of molding. It is a method of evaluating the tearability of. Further, the present invention is the film tearability evaluation method, wherein the notch is formed in a cross shape in both the MD direction and the TD direction orthogonal to the MD direction when the film is formed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The sample table having a flat plate of the tearability evaluation device of the present invention may have only a flat plate, and a trapezoidal sample table in which both ends of the flat plate are supported by two side plates perpendicular to the flat plate. Alternatively, it may be a desk-shaped sample stand that supports a flat plate with four legs. What has an appropriate space on the back side of the flat plate may be used. It is preferably a trapezoidal sample stage in which both ends of a flat plate are supported by side plates. Further, the flat plate may be placed horizontally, or the sample table may be arranged so that the plane of the flat plate is vertical. A sample table in which a flat plate is horizontal is preferable. When the plane of the flat plate is vertical, the tip of the piercing tool described later moves vertically to the flat plate, that is, in the horizontal direction, and the reaction force in the horizontal direction is measured.

The circular hole formed in the flat plate is formed substantially at the center of the flat plate, and the diameter of the circular hole is preferably such that the piercing tool can easily pass therethrough. That is, it is desirable that the diameter is larger than the diameter of the conical bottom surface of the piercing tool. It is desirable that the back portion of the circular hole forms a space having a diameter of the hole. When the side plate is provided on the sample table, it is desirable to make the height of the side plate larger than the diameter of the circular hole. That is, it is desirable that the flat plate be separated from the floor surface on which the sample table is installed by a distance larger than the diameter.

The piercing tool of the tearability evaluation apparatus of the present invention has a conical shape, and the tip of the cone can be moved vertically toward the film surface toward the film side on the flat plate. The apex angle of the line of intersection between the cone, which is the tip angle of the conical piercing tool, and the surface including the axis is preferably 30 degrees to 150 degrees, and preferably 90 degrees. The minimum vertical angle is 30 degrees is 3
If the angle is less than 0 degrees, the tip angle is too small, and if it exceeds 150 degrees, the angle is too large and the correlation with the actual case becomes low. Further, the size of R at the tip of the tip angle is 0
<R ≦ 20 mm is desirable, preferably 0 <R ≦ 10 m
m. The reason for limiting the radius R of the tip to a certain range is that the above-mentioned correlation becomes low when the radius R of the tip exceeds 20 mm.

The fixing means of the tear evaluation apparatus of the present invention fixes the film so as to cover the circular hole on the flat plate of the sample table, and the fixing may be performed near the circular hole or at a distance or both. For example, a weight is attached to both ends of the film covering the circular hole in the longitudinal direction, that is, both ends of the film in the diameter direction of the circle of the circular hole, tension is applied to the film, and the peripheral portion of the circular hole is covered. You may fix with. Further, weights may be attached to both ends of the film both in the longitudinal direction and in the width direction orthogonal to the longitudinal direction, and tension may be applied to the film in both directions to fix the film.
At this time, if the flat plate is horizontal, the weight may be attached to both ends of the film and vertically lowered. In addition, if the flat plate is vertical, a pulley or an engaging body is provided so that the film is in close contact with the flat plate, and both ends of the film are positioned on the back side of the flat plate, and the pulley is attached to the chuck that holds both ends of the film. You may apply tension with the passed weight.

Further, as shown in FIG. 5, the fixing means of the tear evaluation apparatus of the present invention is such that the peripheral edge portion 13a forming the circular hole 12 of the flat plate 13 is formed of the magnetic body 24b so as to be in close contact with the magnetic body. A ring-shaped magnetic body 24a may be provided to fix the film 11 on the flat plate 13 by magnetic force. Further, an annular pressing ring may be pressed onto the peripheral edge of the circular hole 12 of the flat plate from above the film 11 by a method not shown. Furthermore, a plurality of pin holes penetrating the flat plate are provided in the peripheral portion forming the circular hole, and a pressing ring having a pin penetrating the pin hole is provided, and the film is sandwiched by the pressing ring and the pin tip is fixed on the back surface of the flat plate. The film may be fixed by pressure.

The moving stress measuring means of the tear evaluation apparatus of the present invention is capable of adjusting and changing the moving speed of the tip of the piercing tool moving toward the film, measuring the amount of movement, and applying a stress to the tip of the piercing tool. Anything that can measure The stress applied to the tip of the piercing tool is the stress applied to the tip when the tip pushes the film after the tip touches the film, that is, the stress that the film pushes back the tip, and further when the hole of the film is opened and teared. It is the stress applied to the tip. For example, a vertical type or a horizontal type in which a crosshead with a fixed load cell is moved at a constant speed can be used.

The moving speed of the tip of the piercing tool of the present invention depends on the type and thickness of the film, but is preferably 20 to 2000 mm / min, and preferably 500 mm / min. The amount of movement may be one that measures and records the amount of movement of the crosshead. Although the stress is measured by a load cell, a load cell having an appropriate measurement sensitivity, for example, a capacity of 10 kgf
Alternatively, 5 kgf may be used, and the measurement range may be switched when measuring the stress, such as 10% of the capacity or 20% of the full range.

[0021]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. Figure 1
5A to 5C are views showing a film tearability evaluation device of the present invention. In FIG. 1, reference numeral 10 denotes a film tearability evaluation apparatus, and the film tearability evaluation apparatus 10 includes a sample table 15 having a horizontal flat plate 13 on which a circular hole 12 is provided substantially at the center and a test film 11 is placed. , A fixing means 16 for fixing the film 11 on the flat plate 13, a piercing tool 17 arranged directly above the center of the circular hole 12, a piercing tool 17 supporting the piercing tool 17 and vertically moving the piercing tool 17, and the amount of movement thereof. It has a moving stress measuring means 20 for measuring and displaying the stress applied to the tip 17a of the piercing tool.

As shown in FIGS. 1, 2, 3, and 5, the sample table 15 has a circular hole 12 in the center and a horizontal flat plate 13,
It is composed of vertical side plates 14 integrally formed at both ends of the flat plate, and is fixed on the floor surface 22. The diameter of the circular hole 12 is 120 mmφ, the width of the flat plate is 200 mm, and the length is 300.
mm, the height of the side plate is about 200 mm. As shown in FIGS. 1 and 6, the film 11 on the flat plate is a film that is formed by the method described below and is conditioned by a constant temperature and humidity machine described later, and has a width of 150 mm and a length of 500 mm. The hole 12 is covered and the flat plate 13 and the both side plates 14 are laid across.

The fixing means 16 uses the film 11 for the sample table 1
5, the weight 18 is attached to both ends 11a in the longitudinal direction of the film so that tension is applied between both ends 11a, and a weight 18 having a total load of 700 gf is attached. Weight 18 here
Although the description has been given of the case where the film is applied only in the longitudinal direction of the film 11, it may be applied in the width direction or may be applied in both the longitudinal direction and the width direction to give tension to the film in both directions. In this embodiment, the film 1 on the flat plate 13
After the tension is applied in the longitudinal direction of the film 1, the entire circumference of the film is fixed at the peripheral edge of the circular hole 12.

That is, as shown in FIGS.
A film fixing ring 24 made of a pair of upper and lower magnetically detachable annular magnetic members is provided on the peripheral edge portion 13a of the circular hole 12 of FIG.
a and 24b are disposed, and the lower lower film fixed ring 24b on the lower side is disposed.
Is fitted into a recess formed in the peripheral edge portion 13a of the circular hole of the flat plate, and the upper film fixing ring 24a on the upper side is magnetically pressure-bonded onto the lower film fixing ring 24b via the film 11 to fix the film 11 It is adapted to be fixed on the flat plate 13 at the entire peripheral edge of the circular hole. The weight 18 and the upper and lower film fixing rings 24a and 24b constitute fixing means.

As shown in FIGS. 1 and 4, the piercing tool 17 has an inverted conical shape, and a tip 17a, which is an apex, is movable on the central axis of the circular hole 12 toward the surface of the film 11. . In the cone-shaped piercing tool 17, the diameter of the circle of the bottom surface 17b is 100 mm, the apex angle of the surface including the axis of the cone is 90 degrees, and the radius R of the tip 17a is 0.1 mm. Bottom 17b of piercing tool
Is fixed to the lower surface of a load cell 28 fixed to a beam-shaped crosshead 26 of a moving stress measuring means 20 described later via a support rod 29.

The moving stress measuring means 20 is ORIENTE.
The product name is UCT-5 manufactured by Company C, and as shown in FIG.
A beam-shaped crosshead 26 that is held by two pillar-shaped screws (not shown) and moves up and down with high precision by the rotation of the screws, a load cell 28 attached to the lower center of the crosshead, and a load cell 28. A support rod 29 fixed to the lower surface of the support for supporting the piercing tool 17 at the lower end, the amount of movement of the crosshead and the stress applied to the load cell 28 are sensed in a movement sensor and a load cell 28, respectively, which are not shown,
It has the measurement indicator 30 which measures and displays with high precision.
As the load cell, 10 kgf was used, and 10% thereof was measured as a full range. Crosshead moving speed is 50
It was set to 0 mm / min.

Next, Examples 1 to 10 and Comparative Examples 1 to 8
Table 1 below shows the names of the resin raw materials used in the films and their compounding ratios.

[Table 1]

The details of the symbols of the resin raw materials shown in Table 1, the material names and the names of the manufacturers are shown below. PE: Sumikasen (Sumitomo Chemical Co., Ltd.) PCL H7: Polycaprolactone (Daicel Chemical Co., Ltd.)
# 1001: Bionolle # 1001 (Showa High Polymer Co., Ltd.) # 1903: Bionolle # 1903 (Showa High Polymer Co., Ltd.) # 3001: Bionolle # 3001 (Showa High Polymer Co., Ltd.) Perprene S1002: PCL / PBT random copolymer (manufactured by Toyoho Co., Ltd.) Hytron A: Talc (manufactured by Takehara Chemical Co., Ltd.)

Next, blending and pelletization of the above resin raw materials will be described. First, the resin raw material is 10 at 60 ° C.
After drying for an hour, each was blended using a tumbler. Then, the mixture was heated and kneaded using a twin-screw extruder, and then pelletized. In each of Examples 1 and 6 and Comparative Examples 1 and 5, a single resin raw material was used, but the extrusion work was performed in the same manner as above in order to match the heat history. The temperature conditions of each part of the extruder are as follows. C1: 100 ° C, C2: 180 ° C, C3: 200 ° C, C4: 200
℃, C5: 200 ℃, C6: 210 ℃, C7: 210 ℃, AD: 2
10 ℃, D: 200 ℃

Film formation was carried out using the pelletized resin thus obtained. The film forming method is not particularly limited, such as inflation molding and T-die extrusion, but this time the film was formed using the inflation molding method. The resin used in this case is also
The thing which pre-dried at the temperature of 60 degreeC for 10 hours or more was used. The temperature conditions and inflation molding conditions of each part of the inflation molding machine are as follows. C1: 100 ° C, C2: 140 ° C, C3: 150 ° C, C4: 170
℃, C5: 170 ℃, C6: 170 ℃, AD: 150 ℃, D1: 1
50 ℃, D2: 150 ℃ Film take-up speed: 20-30m / min Lip width: 1.0mm Film width: 1350mm Film thickness: 20μm Each film molded product obtained by molding by inflation molding method is used Then, various evaluation tests shown below were performed.

(Example 3) First, a sample film was prepared from a film molded product using the resin raw material shown in Example 3 of Table 1, and the evaluation method of the present invention was carried out using the film tearability evaluation apparatus of the present invention. A tearability evaluation test was conducted according to. (1) Tearability evaluation test The sample film was cut to a width of 150 mm and a length of 500 mm shown in FIG.
What was conditioned at a constant temperature and humidity of 50% RH for 24 hours was used. Then, the film tearability evaluation apparatus 10 shown in FIG. 1 was used to perform the evaluation method of the present invention. Specifically, it is as follows.

First, the sample film 11 of Example 3 is arranged so as to cover the circular hole 12 of the flat plate 13 of the sample stand, and the side plate 1
4, the weight 18 is attached to both ends 11a of the film, and tension is applied to the film 11 to fix the film 11 on the sample table 15. Then, on the lower film fixing ring 24b of the peripheral portion of the circular hole, the upper film of the magnetic material is attached. The fixing ring 24a is fixed by magnetic force, and the entire circumference of the film 11 on the circular hole is fixed on the flat plate 13.

Next, the crosshead 26 is moved downward at a moving speed of 500 mm / min, and after the tip 17a of the piercing tool contacts the film 11, the tip 17a extends the film to push down the surface of the film 11, and finally the film is pierced. The amount of movement of the tip 17a up to when a hole was formed and the stress at that time were detected by a movement sensor (not shown) of the crosshead 26 and the load cell 28, and measured and displayed by the measurement display 30. Further, the leading end 17a is further lowered and the film 11
The movement amount of the tip 17a and the stress at that time when the hole spreads while tearing the hole of
It was sensed by and was measured and displayed on the measurement display unit 30. Then, while piercing a piercing hole and then pushing open, the amount of movement until the film tears and the load decreases and the stress at that time are measured respectively, and the maximum load is defined as the puncture strength (kgf), and the amount of movement (displacement at that time) The amount) was defined as the sticking elongation (mm). The above test was carried out using 5 sample films, and the average values were taken and shown in Table 2. The puncture elongation was 60 mm and the puncture strength was 7.2 kgf.

(Examples 1, 2, 4) In addition, Example 1,
The sample films of Nos. 2 and 4 were measured and displayed in the same manner as in Example 3, and are shown in Table 2. Then, the numerical values of these Examples 1 to 4 were compared and the results were displayed in a 10-grade evaluation. The tearability evaluation criteria are as follows.
When there is no difference in tear strength, the size of tear elongation was taken into consideration. 10: Tear does not easily propagate and stretches well, and the load at that time is relatively large. 9 to 7: Tear does not easily propagate, but the load at that time is relatively small. 6 to 4: Tear propagates, but the load at that time is relatively large. 3 to 1: Tear easily propagates.

(Embodiment 5) In the tearability evaluation test of Embodiment 3, when the tip 17a of the piercing tool 17 shown in FIG. 1 has a piercing hole in the film and the hole continues to spread while being ruptured. 10 is a graph 1 in which the amount of movement of the tip 17a is plotted on the horizontal axis as the elongation of the film and the stress applied to the tip 17a is plotted on the vertical axis.
It was shown to. The measurement was performed 3 times.

(Comparative Examples 1 to 4) As shown in Table 1, sample film for JIS test was prepared by using film molded products molded from the same resin raw materials as in Examples 1 to 4, and JIS tear evaluation was performed. The test (JIS K-7128) was tested and compared.

(2) JIS Tear Evaluation Test First, a film formed by inflation molding was cut into a width of 25 mm and a length of 100 mm, and then, as shown in FIG. 9, at the center in the width direction, the longitudinal direction (MD direction). A test film for the JIS test, in which a notch 33 of 30 mm was made, was prepared. This test film is 5 at 23 ° C
After controlling the humidity for 24 hours with a thermo-hygrostat at 0RH, the tear strength (unit: / 20 μm) was measured under the following measurement conditions. (Measurement conditions) Test film chuck attachment distance: 30 mm Tester used: OLIENTEC, trade name RTA-5
00 load cell: 5 kgf, full range: 20% Crosshead speed: 500 mm / min In the test, five test films were measured under the above-mentioned measurement conditions, and the average values were taken. Then, the numerical values of Comparative Examples 1 to 4 were set as 10 in Comparative Example 1 and comparatively evaluated in 10-point evaluation and displayed. The evaluation standard depends on the value of tear strength.

(Comparative Examples 5 to 8) Next, a long film (thickness: 20) formed by the above-mentioned inflation molding was processed.
(1 μm, width 1350 mm) was used to actually spread the film on the ridges of the field, and then the hole formation and tearing at the time of transplantation were evaluated. (3) [Transplantation Test] (Field Test) As an evaluation criterion, a hole hole when transplanted to a polyethylene film (used in Example 1) which is widely used as agricultural mulch film at present, The tearing method was set to 10 on a 10-point scale, and the hole opening and tearing of each film of Comparative Examples 5 to 8 were evaluated by the following 10-point evaluation, and shown in Table 2. 10: The hole at the time of transplantation is almost circular and no notch or corner is visible in the hole. 9 to 7: The hole at the time of transplantation is almost round, but it is partially angular. 6 to 4: The holes at the time of transplantation are not round and are square. 3 to 1: The hole at the time of transplantation is not round, and it tears like a notch in the MD direction.

Next, using the film (thickness 20 μm) formed by the above-mentioned inflation molding, each film was torn by hand from the notch and evaluated by a sensory test based on the feeling of hand tearing. (4) [Evaluation of hand tearing] (Evaluation of longitudinal tearability in MD direction by sensory test) A polyethylene film (used in Example 1), which is widely used as a general-purpose film at present, is cut, and then the following criteria The feeling when tearing by hand like 10
A score of 10 was given for the score evaluation, and a sensory evaluation (maximum score of 10) was made for each film of Comparative Examples 5 to 8 according to the sense of hand tearing. As the criteria for judgment at this time, not only the strength but also the overall tearability such as the resistance transmitted to the hand when tearing by hand, the way of tearing, that is, the presence or absence of linearity, and the waviness of the tearing surface were sensory evaluated. 10: No vertical tear and large load at that time. 9 to 7: No vertical tear, but a small load at that time. 6 to 4: Vertical tearing, but the resistance applied to the hand at that time is relatively large. 3 to 1: Vertically torn, with little resistance to the hand at that time.

[0040]

[Table 2]

As can be seen from the results in Table 2, the results of the tearability evaluation, which is the quantitative evaluation of the present invention, have a very good correlation with the transplantation test which is the field test. Also, the correlation with the hand tear evaluation is quite good. On the other hand, the JIS evaluation results are inconsistent with the practical evaluations of the transplantation test and the hand tearing evaluation, and it is difficult to make a practical evaluation method.

(Example 6) Next, in order to evaluate the tear propagation of the film, a notch was made in a sample film using a film molded product of the same resin raw material as in Example 3 shown in Table 1 and the test was carried out. The same test and evaluation as in Example 1 were carried out. As shown in FIG. 7, the sample used for the test is a film molded product having a width of 1 mm.
A sample film A36 cut into 50 mm and a length of 500 mm and having a notch 35 of 10 mm in the longitudinal direction at the center of the film, and as shown in FIG. 8, a 10 mm cross shape in both the longitudinal direction and the width direction at the center of the film. Two types of sample films, a sample film B38 having a notch 37, were prepared.

As the sample films A and B used in the test, those which were conditioned at a temperature of 23 ° C. and a humidity of 50% RH for 24 hours were used. The test is performed by using two types of notched sample films A and B, using the film tearability evaluation apparatus 10 of the present invention, and by the evaluation method of the present invention, as in Example 3, "Tearability Evaluation". A test (quantitative test) was performed. The test results are shown in Table 3. (Examples 7 to 9) Sample films using the film-formed products of the resin raw materials shown in Table 1 were tested in the same manner as in Example 6 and shown in Table 3. In Table 2, (2) Tearability Evaluation and (3) Tearability Evaluation, the evaluation results of Examples 6 to 9 of the sample film A and the sample film B are the test results of Example 6, respectively.
A score of 0 was shown in a 10-point scale. The evaluation was first performed based on the magnitude of tear strength, and when there was no difference, the magnitude of tear elongation was considered.

[0044]

[Table 3]

Results of Table 3 and (2) Tear strength of Table 2, JIS
As can be seen by comparison with the results of the evaluation, (3) transplantation test, and (4) hand tear evaluation, the results of the “tearability evaluation test”, which is the quantitative evaluation of the present invention, also in the sample films A and B with notches. Has a very good correlation with the field test “transplantation test”. Also, the correlation with the hand tear evaluation is quite good. On the other hand, the JIS evaluation result does not always have a good correlation with the hand tear evaluation and the transplant test.

[0046]

As described above, according to the present invention,
Whether the sample film has a notch or not, the results of the “tearability evaluation test”, which is the quantitative evaluation of the present invention, have a very good correlation with the “implantation test” which is a field test. have. Also, the correlation with the hand tear evaluation is quite good.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a film tearability evaluation device of the present invention.

FIG. 2 is a schematic perspective view of a sample table.

FIG. 3 is a schematic perspective view showing a fixed state of the film on the sample table.

FIG. 4 is a front view of the piercing tool.

FIG. 5 is a sectional view showing a fixed state of a film on a flat plate.

FIG. 6 is a plan view of a sample film.

7A and 7B are views showing a sample film A having one notch, in which FIG. 7A is a plan view thereof, and FIG. 7B is a partially enlarged plan view thereof.

8A and 8B are views showing a sample film B having two notches, FIG. 8A is a plan view thereof, and FIG. 8B is a partially enlarged plan view thereof.

FIG. 9 is a plan view of a sample film for JIS tear evaluation.

FIG. 10 is a graph showing the elongation and strength of the film in Example 5.

[Explanation of symbols]

10 Film tearability evaluation device 11 films 12 round holes 13 flat plate 14 Side plate 15 sample table 16 Fixing means 17 piercing tools 17a tip 18 weights (fixing means) 20 Moving stress measuring means 24a, 24b Upper and lower film fixed rings 26 Cross head (moving stress measuring means) 28 load cell (moving stress measuring means) 29 Support bar (moving stress measuring means) 30 Measuring indicator (moving stress measuring means) 35,37 Notch

Claims (9)

[Claims] 1. A sample table having a flat plate having a circular hole, fixing means for fixing a film arranged so as to cover the circular hole on the sample table, and a central axis of the circular hole of the film. A conical piercing tool having a tip movable toward the surface, and a moving stress measuring means for moving the tip of the piercing tool to the film side at a predetermined moving speed and measuring the amount of movement and the stress applied to the piercing tool. A film tearability evaluation apparatus, comprising: piercing and tearing the film with the tip to evaluate the tearability of the film. 2. The film according to claim 1, wherein the fixing means applies a weight to both ends of the film in one diametrical direction on the circle of the circular hole or in two diametrical directions orthogonal to each other to fix the film. Tearability evaluation device. 3. The fixing means applies a weight to both ends of the film in one diametrical direction on the circle of the circular hole or in two diametrical directions orthogonal to each other so as to fix the film, and an annular shape provided on the peripheral portion of the circular hole. The film tearability evaluation device according to claim 1, wherein the film is fixed at the peripheral portion of the circular hole by the film fixing ring. 4. The film tearability evaluation device according to claim 1, wherein a tip angle of the tip of the conical sticker is 30 degrees to 150 degrees. 5. The tip shape of the tip of the conical piercing tool is R:
0 <R ≦ 20 mm, 5.
A film tearability evaluation device as described in any one of the above. 6. The film tearability evaluation device according to claim 1, wherein the film is arranged so as to cover the circular hole, and the film is fixed on the sample table by the fixing means, The tip of the piercing tool is moved to the film side at a predetermined moving speed, the tip pierces the film, a hole is opened in the film, the hole of the film is further widened, and the amount of movement and stress of the tip when continuing to tear the film The film tearability evaluation method is characterized in that the relationship with the above is measured by the moving stress measuring means. 7. The film tearability evaluation apparatus according to claim 1, wherein a film having a pre-notch is formed so that the notch comes to the center of the circular hole and covers the circular hole. Arranged, the film is fixed on the sample table by the fixing means, the tip of the piercing tool is moved to the film side at a predetermined moving speed, the tip pierces the film, and a hole is further formed in the film. A film tearability evaluation method, characterized in that the moving stress measuring means measures the relationship between the amount of movement of the tip and the stress when the film is spread and continued to tear. 8. The film according to claim 7, wherein the notch is formed in a shape long in the MD direction at the time of forming the film or in a shape long in the TD direction orthogonal to the MD direction at the time of forming. Tearability evaluation method. 9. The film tearability evaluation method according to claim 7, wherein the notches are formed in a cross shape in both the MD direction and the TD direction orthogonal to the MD direction when the film is formed.