JP6909720B2 - Method for evaluating crack followability of multi-layer film - Google Patents

Description

The present invention relates to a method for evaluating the crack followability of a multilayer film.

Non-Patent Document 1 discloses a technique relating to the overall durability performance of an stretchable finish coating material. Specifically, in Non-Patent Document 1, a test piece obtained by applying an extendable finish coating material as a top coat on an extendable finish coating material as a main material is prepared, exposed to various environments, and then subjected to a tensile test. As a result, the results of confirming the overall durability performance of the stretchable finish coating material are shown. In Non-Patent Document 1, elongation rate performance (crack followability) is used as the performance of a multi-layer coating film having a main material (intermediate coating) and a top coat (top coating). Non-Patent Document 1 suggests that the topcoat affects the crack followability of the multi-layer coating film. In particular, when the flexibility of the top coat is smaller than the flexibility of the middle coat, it is pointed out that cracks of the multi-layer coating film and cracks of the top coat may occur due to cracks smaller than those of the middle coat alone.

Terugo Inoue et al., "Study on Durability Test Method (Part 29) Effect of Heat on Durability of Extendable Multilayer Finishing Coating Material", Architectural Institute of Japan Conference Academic Lecture Abstract, Japan, Architectural Institute of Japan, 1986 August, 355-356 pages.

The above-mentioned Non-Patent Document 1 merely shows a qualitative relationship that the performance of the multi-layer coating film is affected by the performance of the top coating. Therefore, in this field, a method for quantitatively evaluating the performance of a multi-layer film has been desired.

Therefore, an object of the present invention is to provide a method for quantitatively evaluating the crack followability of a multilayer film.

One embodiment of the present invention is a crack in a multi-layer film having a first film portion formed of a polymer material on a substrate and a second film portion formed of a polymer material on the first film portion. This is a method for evaluating the followability. The crack followability (Z _{N ) possessed by the first film portion is compared with the crack followability (Z X} ) required for the multi-layer film, and the crack followability (Z _N ) is compared. Gahibiware followability when (Z _X) smaller, due to the first membrane unit determines that multilayer film is not satisfactory cracking followability the (Z _X), or, cracking followability (Z _N) Gahibiware When the followability (Z _X ) is larger than the first judgment step for shifting to the second judgment step, and when the crack followability (Z _N ) is larger than the crack followability (Z _{X), the crack followability of the multi-layer film} Comparing the properties (Z _F ) and the crack followability (Z _N ), when the crack follow property (Z _F ) is smaller than the crack follow property (Z N), the crack follow property (Z _N ) is caused by the second film portion. It determines that Z _F) Gahibiware followability _{(Z X)} is not satisfied, or when it is cracked followability _{(Z F)} Gahibiware followability _{(Z N)} or more, cracking followability _{(Z F)} is cracked It has a second determination step of determining that the _{followability (Z X) is satisfied.}

In this method, the crack followability (Z _{N ) of the first film portion and the crack followability (Z X} ) required for the multi-layer film are quantitatively compared to evaluate the first film portion. .. _{Furthermore, the crack followability (Z F} ) of the multi-layer film and the crack followability _{(Z N} ) of the first film portion are quantitatively compared. Therefore, the crack followability of the multi-layer film can be quantitatively evaluated.

In one form, the second determination step is a step of _{obtaining the elongation rate (ETX} ) required for the second film portion by utilizing _{the crack followability (Z N} ), and the elongation rate (ETX) possessed by the second film portion. obtaining a E _T), compared elongation _{(E T)} and elongation and _{(E TX),} elongation _{(E T)} is elongation _{(when E TX)} is smaller than, crack follow-up property _{(Z F} ) Gahibiware followability _{(Z N)} is determined as less than or elongation _{(E T)} is elongation _{(when E TX)} larger, crack follow-up property _{(Z F)} Gahibiware followability _(Z N) It may have a third determination step for determining the above.

According to this form, the crack followability (Z _F ) and the crack followability (Z _N ) in the second determination step can be compared well and quantitatively.

In one embodiment, the method of evaluating the crack followability of the multilayer film includes a _{first measurement step of obtaining the crack followability (Z N} ) of the first film portion by measurement before the first determination step, and a first measurement step. In the first determination step, when it is determined that the multi-layer film _{does not satisfy the crack followability (Z X} ) due to the first film portion, the first repair determination step for determining that the first film portion is to be repaired, and the first 2 In the determination step, when it is determined that the crack followability (Z _F ) does not satisfy the crack followability (Z _X ) due to the second film portion, the second repair determination is determined to repair the second film portion. It may further have steps.

According to this embodiment, it is possible to cause that does not satisfy cracking trackability required for the multi-layer film (Z _F) is either a first film section, to quantitatively determine whether the second membrane unit ..

In one aspect, a method for evaluating the cracking followability of the multilayer film, before the first determining step, further comprising a first setting step of setting cracking followability of the multilayer film has a (Z _F), The first setting step and the first determination step are performed while changing the crack followability set in the first setting step until the condition that the crack followability (Z _N ) becomes larger than the crack followability (Z _{X) is satisfied.} repetition, in the step of obtaining elongation rate _{(E T),} may be set to a value that is a rate elongation elongation rate _{(E T) (E TX)} above.

According to this embodiment, cracking trackability required for the multi-layer film (Z _F) first film portion cracking following capability capable of satisfying the with (Z _N), elongation of the second film portion and (E _T) Can be set quantitatively.

In one embodiment, in the first measurement step, the crack followability (Z _N ) in the first film portion may be obtained by utilizing the actually measured value obtained by using the nano indenter. The measurement using the nano indenter can be easily performed. Therefore, the crack followability (Z _N ) can be easily obtained.

In one form, in the first measurement step, the crack followability (Z _N ) in the first film portion _{increases as the thickness (TN} ) of the first film portion increases, and the crack followability (Z _N ). When the relationship between the thickness (T _N) of the first membrane unit utilizes the relation indicated by the elongation of the first film portion thickness coefficients obtained from _{(E N) (Δ T)} , the nano The measured value obtained by using the indenter may be converted into the _{crack followability (Z N).} According to this form, the crack followability (Z _N ) can be suitably calculated by using the actually measured value obtained by the nano indenter.

In one embodiment, the first measurement step includes the steps of obtaining a measured value in the first layer portion using a nano indenter, a step of converting the elongation ratio of the measured value (E _N), the elongation rate (E _N) Using, the step of obtaining the film thickness coefficient (Δ _T ), the step of obtaining the thickness of the first film portion ( _TN ), the film thickness coefficient (Δ _T ), and the thickness of the first film portion ( _TN ) are used. Then, it may have a step of obtaining the crack followability (Z _N). According to these steps, the crack followability (Z _N ) can be suitably derived by utilizing the measured value obtained by the nano indenter.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a method capable of quantitatively evaluating the crack followability of a multilayer film.

FIG. 1 is a cross-sectional view showing a multi-layer film. FIG. 2 is a flow chart showing an evaluation method according to the first embodiment. FIG. 3 is a flow chart showing an evaluation method according to the second embodiment. FIG. 4 is a table summarizing the results of Experimental Example 1 and Experimental Example 2. FIG. 5 is a graph showing the results according to Experimental Example 1. FIG. 6 is a graph showing the results according to Experimental Example 2. FIG. 7 is a table summarizing the results of Experimental Example 3 and Experimental Example 4. FIG. 8 is a graph showing the results according to Experimental Example 3. FIG. 9 is a graph showing the results according to Experimental Example 4. FIG. 10 is a table summarizing the results according to Experimental Example 5. FIG. 11 is a graph showing the results according to Experimental Example 5. FIG. 12 is a table summarizing the results according to Experimental Example 6. Part (a) of FIG. 13 and part (b) of FIG. 13 are graphs showing the results of Experimental Example 6.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

First, an object evaluated by a method for evaluating the crack followability of a multilayer film according to the present embodiment (hereinafter, also simply referred to as an “evaluation method”) will be described. Then, as the first embodiment, an example of applying the evaluation method to the repair work of the multi-layer film will be described. Further, as a second embodiment, an example of applying the evaluation method to the design of the multilayer film will be described. Then, some experimental examples 1 to 6 will be described.

The "crack followability" in the present embodiment is a numerical value obtained based on the test method shown in the following standards. According to the standard, "crack followability" is the amount of elongation when a through hole is formed in the coating film. Here, the amount of elongation is set until a through hole is formed in the multilayer film 2 or a crack or a hole is formed in the upper layer film 4. The evaluation value of the crack followability is indicated by the amount of elongation (mm).
・ Architectural Institute of Japan, Polymer Cement Waterproofing Work Guideline (Draft) ・ Explanation, Reference Material 2 Quality Test Method for Polymer Cement Waterproofing Material, 4. Zero span tension elongation test.

<Evaluation target>
The object evaluated by the method for evaluating the crack followability of a multi-layer film is a multi-layer film used for a building. The multi-layer film (for example, a coating film) covers a base such as concrete or a panel. The multi-layer film structure has a lower layer film (for example, an intermediate coating) and an upper layer film (for example, an upper coating). Organic coatings used on concrete and panels may crack due to cracks in the base and behavior of the joints. Since cracks create the possibility of deteriorating aesthetics, deteriorating the protective ability of the internal skeleton, or overwhelming water leakage, it is necessary to suppress the occurrence. Therefore, the exterior coating film and the coating film waterproofing (multi-layer film) are composed of an intermediate coating film (underlayer film) having a thickness and flexibility of about 0.1 mm to 3 mm, such as a finishing coating material for the purpose of ensuring crack followability. It includes a thin topcoat (upper layer film) of about 0.03 mm to 0.1 mm formed by a paint for the purpose of weather resistance, aesthetics, and stain resistance.

FIG. 1 shows a cross section of a sample 1 to be evaluated by a method for evaluating the crack followability of a multi-layer film. Sample 1 is a cutout of a part of the wall or floor of the building to be repaired. Sample 1 has, for example, a substantially square shape in a plan view having a side length of 1 cm or more and 2 cm or less. Sample 1 has a multi-layer film 2. The multi-layer film 2 has a lower layer film 3 (first film portion) and an upper layer film 4 (second film portion). The multi-layer film 2 is formed of a material specified in the following standards and a material similar to these, and is formed of a polymer material used as a building material. For example, a coating film, a sheet, or the like.
-JIS-A-6909 "Architectural finish coating material".
-JIS-A-6021 "Building coating film waterproofing material".
-JIS-K-5658 "Weather-resistant topcoat paint for construction".
・ JASS (Architectural Institute of Japan, Standard Specifications for Building Construction: Japanese Architectural Standard Specialization) -8 “Waterproofing”.

The underlayer film 3 is formed on the base material 5 (base material). The upper layer film 4 is formed on the lower layer film 3. In sample 1, the upper layer film 4 is provided on a part of the lower layer film 3. That is, in the sample 1, a part of the upper layer film 4 is peeled off from the lower layer film 3. This part is, for example, about half the area of the lower layer film 3 in a plan view. That is, in the multilayer film 2, a part of the lower layer film 3 is exposed. The base 5 is formed of, for example, concrete.

_{The thickness (TN} ) of the lower layer film 3 is the length in the stacking direction of the multi-layer film 2. _{The thickness (TN} ) of the underlayer film 3 may be, for example, 0.25 mm or more and 3.0 mm or less. The thickness ( _TN ) of the underlayer film 3 may be 1.0 mm. The thickness of the upper layer 4 (T _U) is the length in the stacking direction of Fukusomaku 2. The thickness of the upper layer 4 _{(T U)} is, for example, may be 0.05mm or 0.1mm or less. The thickness of the upper layer 4 _{(T U)} may be 0.1 mm. The thickness _{(T N), (T U} ) is not limited to the above numerical ranges.

A coating material shown in the following standards and a coating material similar thereto may be applied to the underlayer film 3.
-JIS-A-6909 "Architectural finish coating material".
-JIS-A-6021 "Building coating film waterproofing material".
-JIS-A-6916 "Architectural base adjustment coating material".
-Polymer cement-based coating film waterproofing material.

A coating material shown in the following standards and a coating material similar thereto may be applied to the upper layer film 4.
-JIS-K-5658 "Weather-resistant topcoat paint for construction".

<First Embodiment>
Hereinafter, a method for evaluating the crack followability of the multilayer film (hereinafter, also referred to as “evaluation method”) will be described. The term "evaluation" as used herein means that when a predetermined crack followability is required for the multilayer film 2, the crack followability of the multilayer film 2 affected by the crack followability of the lower layer film 3 is a required value. Is to judge whether or not to satisfy. Further, it is to determine whether or not the crack followability of the multilayer film 2 affected by the crack followability of the upper layer film 4 satisfies the required value. That is, based on the crack followability of the lower layer film 3 and the upper layer film 4, it is quantitatively determined whether or not the crack followability of the multilayer film 2 satisfies the required value. Further, the "evaluation" can be said to determine whether or not the crack followability of the lower layer film 3 and the upper layer film 4 can satisfy the required value.

Now, it is assumed that the multi-layer film 2 is formed on a surface such as a floor or a wall of an existing building. These multi-layer films 2 deteriorate over time. Therefore, the degree of deterioration will be checked regularly and repairs will be made as necessary. Here, the degree of deterioration is confirmed by using the crack followability. Then, when the crack followability of the multilayer film 2 does not satisfy the required value, it is determined that repair is necessary. When the crack followability of the multilayer film 2 does not satisfy the required value, the following three factors can be assumed. The first factor is that the deterioration of the multilayer film 2 is caused by the deterioration of the crack followability of the lower layer film 3. The second factor is that the deterioration of the multilayer film 2 is caused by the deterioration of the crack followability of the upper layer film 4. The third factor is that the deterioration of the multilayer film 2 is caused by the deterioration of the crack followability of both the lower layer film 3 and the upper layer film 4.

In addition, a dedicated test piece is required for the crack followability test for evaluating the crack followability. Therefore, it is generally difficult to evaluate cracks in the multilayer film 2 already constructed on the floor or wall of an existing building.

For example, when the factor of deterioration of the multilayer film 2 is due to the deterioration of the upper layer film 4 (second factor), if only the upper layer film 4 is repaired, the repaired multilayer film 2 satisfies the required value. obtain. Therefore, if it is possible to determine whether the cause of deterioration of the multilayer film 2 is the upper layer film 4 or the lower layer film 3, it is not necessary to perform unnecessary repair work.

Therefore, a method of evaluating the crack followability of the multi-layer film is applied to determine whether the cause of deterioration of the multi-layer film 2 is the upper layer film 4 or the lower layer film 3.

FIG. 2 shows an example in which an evaluation method is used to determine whether the cause of deterioration of the multilayer film 2 is the upper layer film 4 or the lower layer film 3 and to assist in determining which film should be repaired. It is a flow chart which shows. This flow consists of a required value setting step (step S1), a lower layer film crack followability acquisition step (step S10) (first measurement step), a first evaluation step (step S20), and a first repair determination step (step). It has S21), a second evaluation step (step S30), a second repair determination step (step S34), and a third repair determination step (step S35).

[Required value setting step]
In step S1, the crack followability (Z _X ) required for the multilayer film 2 is set. The crack followability (Z _X ) is appropriately set based on the location of the building in which the multilayer film 2 is formed, the number of years elapsed, and the like. Further, the crack followability (Z _X ) may be expected to have a safety factor with respect to the crack width assumed on the actual wall surface. This takes into consideration that the crack width is not constant on the actual wall surface, the crack width fluctuates and the effect of repetition occurs, the physical property value of the multi-layer film 2 fluctuates due to temperature, and the construction error of the multi-layer film 2 is taken into consideration. To do.

[Step to acquire crack followability of lower layer film]
Next, in step S10, the crack followability (Z _N ) of the underlayer film 3 is obtained. Step S10, and step S11 of measuring the underlayer film 3 with a nano indenter, a step S12 to obtain the parametric _{(N N),} and step S13 to obtain elongation rate _{(E N),} cracking followability of the standard value having a _{(Z N0)} step S14 to obtain a step S15 to actually measure the thickness _{(T N),} the step S16 to obtain a thickness factor (delta _T), a step S17 to obtain cracking trackability the _{(Z N),} the ..

In step S11, first, the underlayer film 3 is actually measured using a nanoindenter. Specifically, by pressing the indenter 6 (see FIG. 1) against the underlayer film 3, some actually measured values are obtained. Examples of this measured value include Martens hardness (HM), indentation creep (C _IT ), indentation hardness (H _IT ), elastic return deformation work of a depression ( _Welast ), and the like. Then, by converting these actually measured values, the crack followability (Z _N ) is obtained.

Here, the nanoindenter refers to an apparatus used for a nanoindentation test. The measurement method and material parameters for nanoindenters conform to the following standards.
-ISO14577-1 "METALLICTENIALS-InstrumETted indETtion test for hardness and parameters parameters-".

In this embodiment, obtained as a result of step S11, Martens hardness of the underlayer film 3 (HM) and indentation creep _{(C IT).} In the actual measurement by the nano indenter, the indenter 6 (see FIG. 1), which is a Berkovich indenter, is pressed against the surface of the underlayer film 3. In this pressing, the depth of pushing the indenter 6 into the underlayer film 3 (maximum pushing depth) is controlled. Further, in the measurement of the lower layer film 3, the material parameters of the lower layer film 3 are not affected by the base 5. Therefore, the indenter 6 is pushed from the exposed region of the underlayer film 3 toward the base 5 so that the maximum pushing depth of the indenter 6 is _{1/6 or less of the thickness (TN).}

In step S12, the parameter ( _NN ) is obtained. Specifically, dividing indentation creep _{(C IT)} in Martens Hardness (HM). As a result, the parameter ( _NN = C _IT / HM) is acquired.

Ｅ_Ｎ：下層膜の伸び率。
Ｎ_Ｎ：媒介変数。
Ａ１，Ｂ１，Ｃ１：係数。 In step S13, by using the material parameters of the lower film 3 to obtain elongation of the lower film 3 (E _N). Specifically, by utilizing the parametric calculated in step S12 _{(N N),} to obtain the elongation rate _{(E N).} As shown in equation (1), mediating variables _{(N N)} as independent variables, by utilizing the function _{(f 1)} containing the constants A1, B1, C1 as a coefficient to obtain elongation rate _{(E N).}

E _N: growth rate of the lower film.
_N N: mediating variable.
A1, B1, C1: Coefficient.

In step S14, a standard value (Z _N0 ) of the crack followability of the underlayer film 3 is obtained. Here, the standard value (Z _N0 ) of the crack followability of the lower layer film 3 is the crack followability of the lower layer film 3 having the reference thickness (T _0). The reference thickness (T ₀ ) is a reference dimension (thickness) in the stacking direction of the multi-layer film with respect to the underlayer film 3.

Ｚ_Ｎ０：基準厚みである下層膜のひび割れ追従性。
Ｎ_Ｎ：媒介変数。
Ａ２，Ｂ２，Ｃ２：係数。 Parametric obtained in step S12 the _{(N N)} using, get cracking followability the _{(Z N0).} Specifically, as shown in equation (2), a parametric _{(N N)} independent variables, by utilizing the function _{(f 2)} containing the constants A2, B2 as a coefficient, crack follow-up property _{(Z N0} ).

Z _N0 : Crack followability of the underlayer film, which is the reference thickness.
_N N: mediating variable.
A2, B2, C2: Coefficient.

In step S15, the thickness ( _TN ) of the underlayer film 3 is obtained. Specifically, the dimensions of the underlayer film 3 are actually measured by observing a cross section with a micrometer or a microscope. As a result, the thickness ( _TN ) is obtained. When a plurality of values are obtained by performing the actual measurement a plurality of times with respect to the thickness of the underlayer film 3, the minimum value among the plurality of values is defined as the thickness ( _TN ).

Here, according to the findings of the present inventor, the crack followability (Z _N ) is affected by the _{thickness (TN).} For example, the _{larger the thickness (TN} ), the larger the crack followability (Z _N ). The degree of influence of the thickness _{(T N)} to crack followability _{(Z N)} has a correlation with elongation _{(E N).} That is, as the elongation (E _N) is large, the degree of influence is large. Therefore, elongation and _{(E N),} the thickness _{(T N)} as a coefficient showing a correlation between the Gahibiware followability _{(Z N)} to exert influence level, thickness coefficient based on elongation _{(E N)} (Δ _T ) Is introduced. Then, the crack followability (Z _N ) is obtained from the thickness ( _TN ) by using the film thickness coefficient (Δ _T).

Δ_Ｔ：膜厚係数。
Ｅ_Ｎ：下層膜の伸び率。
Ａ３，Ｂ３：係数。 In step S16, obtaining a thickness factor (delta _T) by using obtained elongation in step S13 the _{(E N).} Specifically, as shown in equation (3), and elongation rate _{(E N)} as independent variables, by utilizing the function _{(f 3)} which includes a constant A3, B3 as a coefficient, thickness coefficient (delta _T ).

Δ _T : Film thickness coefficient.
E _N: growth rate of the lower film.
A3, B3: Coefficient.

Ｚ_Ｎ：下層膜のひび割れ追従性。
Ｚ_Ｎ０：基準厚みである下層膜のひび割れ追従性。
Ｔ_Ｎ：下層膜の厚み。
Δ_Ｔ：膜厚係数。
Ｔ_０：基準厚み（１ｍｍ）。 In step S17, the crack followability (Z _N ) is obtained by using the film thickness coefficient (Δ _{T) obtained in step S16.} Specifically, as shown in Equation (4), as independent variables the thickness (T _N), as well as cracking followability the (Z _N) as the dependent variable, the thickness factor (delta _T) as a proportional coefficient Obtained using the included function (f _4).

Z _N : Crack followability of the underlayer film.
Z _N0 : Crack followability of the underlayer film, which is the reference thickness.
_TN : Thickness of the underlayer film.
Δ _T : Film thickness coefficient.
T ₀ : Reference thickness (1 mm).

By the above step S10, the crack followability (Z _N ) of the underlayer film 3 is obtained.

[First determination step]
In the first determination step (step S20), the crack followability (Z _X ) and the crack followability (Z _N ) are compared. Specifically, it is determined whether or not the crack followability (Z _N ) is larger than the crack followability (Z _X). When the crack followability (Z _N ) is smaller than the crack followability (Z _X ) (step S20: NO), the process proceeds to the first repair determination step (step S21). When the crack followability (Z _N ) is _{larger than the crack followability (Z X} ) (step S20: YES), the process proceeds to the second determination step (step S30).

[1st repair judgment step]
In step S21, based on the result of step S20, _{it is determined that the factor that the crack followability (Z F} ) of the multilayer _{film 2 does not satisfy the crack followability (Z X} ) is the deterioration of the lower layer film 3. Therefore, it is determined that the underlayer film 3 should be repaired in the repair work. In this case, since the lower layer film 3 is under the upper layer film 4, the lower layer film 3 and the upper layer film 4 are repaired as a result.

[Second judgment step]
In step S30, the crack followability (Z _F ) and the crack followability (Z _N ) are compared. That is, although the crack followability (Z _N ) satisfies the crack followability (Z _X ), the crack followability (Z _F ) does not satisfy the crack followability (Z _X ). It can be qualitatively estimated that the upper layer film 4 is deteriorated. In step S30, it is quantitatively determined that the factor that the crack followability (Z _F ) does not satisfy the crack followability (Z _X ) is the deterioration of the upper layer film 4. In this judgment, the crack followability (Z _F ) and the crack followability (Z _N ) are not directly compared, but an indirect comparison is performed using another evaluation value.

Specifically, comparing the growth rate of the upper layer 4 (E _T) and elongation required for the upper layer film 4 (E _TX). Here, the elongation rate is the ratio of the length in the initial state, the length at break, and the difference in the tensile test to the length in the initial state. The required elongation ( _ETX ) is the smallest value that does not impair _{the crack followability (Z N} ) of the lower layer film 3 when the upper layer film 4 is formed on the lower layer film 3. That is, larger than elongation elongation of the upper layer 4 _{(E T)} is required _{(E TX),} it does not impair cracking followability of the underlayer film 3 _{(Z N).}

Ｅ_ＴＸ：要求される伸び率。
Ｚ_Ｎ：下層膜のひび割れ追従性。
Ａ５，Ｂ５：係数。 First, the required elongation rate ( _ETX ) is obtained (step S31). The elongation rate ( _ETX ) is obtained by, for example, the formula (5). As shown in the equation (5), the elongation rate ( _{ETX ) is a linear function in which the crack followability (Z N} ) of the underlayer film 3 is an independent variable and the elongation rate ( _ETX ) is a dependent variable. The formula for obtaining the elongation rate ( _ETX ) from the crack followability (Z _N ) of the underlayer film 3 is not limited to the following formula (5).

_ETX : Required growth rate.
Z _N : Crack followability of the underlayer film.
A5, B5: Coefficient.

Ｅ_Ｔ：上層膜の伸び率。
Ｎ_Ｎ：媒介変数。
Ａ６，Ｂ６：係数。 Next, to obtain the growth rate of the upper layer 4 _{(E T)} (step S32). Elongation of the upper layer 4 (E _T), similar to the cracking followability of the underlayer film 3 (Z _F), may be obtained using a nano indenter. For example, separating the upper layer 4 Fukusomaku 2, only as step S11 upper layer film 4, obtained indentation creep (C _IT) and Martens hardness and (HM) using a nano indenter. Next, the nanoindenter physical property value ( _NN = C _IT / HM) is obtained. The obtained nano indenter physical data _{(N N)} By substituting the equation (6), elongation of the upper layer 4 _{(E T).}

E _T: the growth rate of the upper layer film.
_N N: mediating variable.
A6, B6: Coefficient.

Then, comparing the elongation percentage _{(E T)} and elongation _{(E TX)} (step S33: third determination step). When the elongation percentage _{(E T)} is elongation than _{(E TX)} small cracks followability of Fukusomaku 2 _{(Z F)} is smaller than the cracking followability of the underlayer film 3 _{(Z N).} In this case, the process proceeds to the second repair determination step (step S34). On the other hand, the elongation percentage _{(E T)} is elongation when _{(E TX)} larger, cracking followability of Fukusomaku 2 _{(Z F)} is greater than the cracking followability of the lower film 3 _{(Z N).} In this case, the process proceeds to the third repair determination step (step S35).

[Second repair judgment step]
In step S34, it is determined that the factor that the crack followability (Z _F ) of the multilayer _{film 2 does not satisfy the crack followability (Z X} ) is the deterioration of the upper layer film 4. Therefore, it is determined that the upper layer film 4 should be repaired in the repair work. In this case, the upper layer film 4 is peeled off, and the lower layer film 3 is maintained as it is. Then, a new upper layer film 4 is formed on the lower layer film 3. Alternatively, the multi-layer film 2 may be peeled off and a new multi-layer film 2 may be formed on the base 5.

[Third repair judgment step]
In step S35, it is determined that the crack followability (Z _F ) of the multilayer film 2 satisfies the crack followability (Z _X). Therefore, in this case, there is no need for repair.

According to this method, it is possible to evaluate cracking followability of the Fukusomaku 2 (Z _F) quantitatively. Further, according to this method, the crack followability (Z _F ) in step S30 and the crack followability (Z _N ) of the underlayer film 3 can be compared well and quantitatively. Further, according to this method, it is possible to quantitatively determine whether the factor that does not satisfy the _{crack followability (Z F) required for the multilayer film 2 is the lower layer film 3 or the upper layer film 4.} can.

<Second Embodiment>
Next, as a second embodiment, an example of applying the evaluation method to the design of the multilayer film will be described. That is, the evaluation method is applied to determine the configurations of the lower layer film 3 and the upper layer film 4 capable of satisfying the _{crack followability (Z X) required for the multilayer film 2.} Specifically, the material and thickness of the lower layer film 3 and the material of the upper layer film 4 are determined.

In other words, with respect to the multi-layer film 2 (organic multi-layer coating film) having the lower layer film 3 (intermediate coating film) and the upper layer film 4 (top coating film), the lower layer film 3 sufficiently satisfies the crack width to be followed. By the design process of the above and the selection process of the upper layer film 4 that does not reduce the crack followability of the lower layer film 3, the multilayer film 2 having high crack followability is rationally (quantitatively) designed.

For example, in order to determine the composition of the underlayer film 3, the material and thickness of the underlayer film 3 are first assumed. Next, crack followability is obtained based on the assumed material and thickness. Then, it is determined whether or not the crack followability can satisfy the crack followability required for the multilayer film 2. The method for evaluating the crack followability of the multi-layer film determines whether or not the crack followability based on the hypothetical conditions can satisfy the required crack followability. Therefore, by repeating the assumption of the configuration of the underlayer film 3 and the determination based on the assumption, the multilayer film 2 having the required crack followability can be quantitatively designed.

FIG. 3 is a flow chart showing an example of applying the evaluation method to the design of the multi-layer film. This flow includes a crack followability setting step (step S1), a first setting step (step S10A), a first determination step (step S20A), and a second determination step (step S30A). Hereinafter, steps S10A, S20A, and S30A will be described.

In step S10A, the crack followability (Z _N ) of the underlayer film 3 is obtained. Step S10A includes a step S18 of selecting the material, and step S13A of obtaining elongation rate _{(E N),} the step S15A to set the thickness, and Step S16 to obtain a thickness factor (delta _T), crack follow-up property (Z _N ) is obtained with step S17.

In step S18, the material constituting the underlayer film 3 is selected. Materials, because it has a specific growth rate _{(E N),} obtained by selection of the material, the elongation rate _{(E N)} (step S13A). Next, in step S15A, the thickness ( _TN ) of the underlayer film 3 is set. Next, in step S16, the film thickness coefficient (Δ _T ) is obtained, and in step S17, the crack followability (Z _F ) is obtained.

That is, in the first embodiment, obtained by measuring the elongation of the lower film 3 (E _N) and the thickness (T _N). On the other hand, in the second embodiment, the elongation of the lower film 3 (E _N) and the thickness (T _N) as the designed value, the designer in that appropriately setting differs from the first embodiment. Therefore, step S16, S17 to obtain elongation _{(E N)} and the thickness factor by utilizing the thickness _{(T N)} (Δ _T) and cracking trackability the _{(Z N)} is the first embodiment and the second embodiment Is common in.

By the way, in steps S13A, S16 and S17, it is assumed that the material is new. The term "new" as used herein means that the properties of the material have not changed due to the passage of time or the influence of the surrounding environment. _{In step S10A, the crack followability (Z N} ) may be set not only at the time of construction but also in consideration of deterioration. That is, the material and thickness of the underlayer film 3 are set based on the material properties that have not deteriorated and based on the material properties after deterioration. According to this configuration, the crack followability (Z _F ) of the multilayer _{film 2 can satisfy the crack followability (Z X} ) even after a lapse of a predetermined period.

In step S20A, it is determined whether or not the crack followability (Z _F ) obtained in step S10A satisfies the required crack followability (Z _X). That is, in step S20A, the crack followability (Z _X ) and the crack followability (Z _N ) are compared. Specifically, it is determined whether or not the crack followability (Z _N ) is equal to _{or higher than the crack followability (Z X).} When the crack followability (Z _N ) is smaller than the crack followability (Z _X ) (S20A: NO), it indicates that the assumed design condition of the underlayer film 3 is not appropriate. Therefore, the process returns to step S10A again, and another material, thickness, and the like are set. On the other hand, when the crack followability (Z _N ) is larger than the crack followability (Z _X ) (S20A: YES), it indicates that the assumed design conditions of the underlayer film 3 are appropriate. Therefore, the process proceeds to step S30A for designing the upper layer film 4.

As described above, step S10A and step S20A are repeated while changing the design conditions in step S10A until the result of step S20A becomes YES.

[Second judgment step]
In step S30A, comparing the growth rate of the upper layer 4 _{(E T)} and elongation required for the upper layer film 4 _{(E TX).} First, the required elongation rate ( _ETX ) is obtained using the formula (5) (step S31).

Then, set the growth rate of the upper layer 4 _{(E T)} (step S32A). Specifically, the material constituting the upper layer film 4 is selected. The selection of the material, obtaining elongation rate _{(E T).} Here, in the selection of the material (i.e. elongation (selection of E _T)), selecting the material for the elongation (E _TX) or more values to be the required. Incidentally, when setting the elongation percentage (E _T), similarly to the lower film 3 may set in consideration of deterioration.

Then compared elongation _{(E T)} and elongation and _{(E TX)} (step S33). In step S33, since the elongation percentage _{(E T)} is set to a value that is a growth rate _{(E TX)} above, as a result of the determination in the step S33 is YES. By the above steps S20A and S30A, the material and thickness of the lower layer film 3 and the material of the upper layer film 4 that satisfy the _{crack followability (Z X) required for the multilayer film 2 are selected.}

By the way, Reference 1 shows that the crack followability (Z _F ) of the multilayer film 2 is ensured by _{the crack followability (Z N} ) of the lower layer film 3 (intermediate coating). Crack followability of the underlayer film 3 (Z _N) is generally affected by the elongation of the material forming the underlayer film 3 and (E _N) and the thickness (T _N). Thus, taking into account the interaction of the elongation rate and (E _N) and the thickness (T _N), it is necessary to evaluate the cracking followability. Therefore, the evaluation method according to the present embodiment, based on the growth rate of the underlayer film 3 and (E _N) and the thickness (T _N), to allow quantitative design of cracking followability of the underlayer film 3.
Reference 1: Masashi Achinami et al., "Study on Crack Followability of Acrylic Rubber Polymer Cement-based Waterproofing Material", Architectural Institute of Japan Academic Lecture Abstract, Japan, Architectural Institute of Japan, September 1996, pp. 925-926.

Further, the lower layer film 3 (intermediate coat) and the upper layer film 4 (top coat) are deteriorated by sunlight, heat, or the like, so that the flexibility is lowered. Reference 2 shows that as the flexibility decreases, so does the crack followability.
Reference 2: Masahide Tileya et al., "Study on Photodegradation of Coating Films", Color Materials, Japan, 2000, pp. 594-600.

On the other hand, the crack followability test is generally performed in the initial state and does not consider the influence of deterioration. When evaluating the crack followability by deteriorating the multi-layer film 2 using an accelerated weather resistance tester or the like, a plurality of parameters such as _{the material of the upper layer film 4, the material of the lower layer film 3, and the thickness (TN) of the lower layer film 3} Therefore, it is necessary to test with a large number of combinations. Since the crack followability is a fracture test, it is necessary to prepare a large number of test samples. Therefore, in the evaluation method of the present embodiment, the deterioration test of the lower layer film 3 and the upper layer film 4 is performed by itself. By evaluating elongation rate _{(E N)} (E _T) in advance in each, to allow cracking followability of design considering performance variation degradation.

Further, Patent Documents 1 and 2 are known as techniques related to crack followability.
Patent Document 1: Japanese Unexamined Patent Publication No. 9-177259.
Patent Document 2: Japanese Unexamined Patent Publication No. 2005-35527.

In Patent Document 1, the elongation rate of the lower waterproof layer is made larger than the elongation rate of the upper waterproof layer by 50% or more. This design ensures high crack followability, surface toughness and trauma resistance. Example 3 in Patent Document 1 discloses an example in which the crack followability is 4.5 mm on the lower side, 1.5 mm on the upper side, and 3.6 mm in the multilayer layer. In the third embodiment, the crack followability of the lower waterproof layer is reduced as a whole (multilayer film) due to the influence of the upper waterproof layer.

In Patent Document 2, the intermediate coating is a flexible coating film having a crack followability of 0.5 mm or more, and the top coat is a hard coating film having a crack followability of 0.2 mm or less. Then, when the base material fluctuates by about 0.2 mm, cracks occur in the topcoat coating film, and cracks in the base material are detected. This is because the topcoat is hard, so that the coating film is broken at a value smaller than the original crack followability of the intermediate coat. On the other hand, the composite coating film protects the intermediate coating having low weather resistance by the top coating having high weather resistance. Then, when the top coat is cracked, the intermediate coat is rapidly deteriorated and cracks are generated. Therefore, it is necessary to prevent the topcoat from cracking. Further, in Patent Document 2, when a crack of 0.2 mm occurs in the base, a crack is generated in the top coat. Therefore, it is not intended to design a multi-layer coating film that does not cause cracks in the topcoat when a crack of 0.5 mm occurs in the base.

For these prior art, a method for evaluating the cracking followability of the multilayer film according to the second embodiment, can be evaluated cracking followability of the Fukusomaku 2 (Z _F) quantitatively. Further, according to this method, the crack followability (Z _F ) in step S30A and the crack followability (Z _N ) of the underlayer film 3 can be compared well and quantitatively. Furthermore, according to this method, cracking followability of the underlayer film 3 capable of satisfying crack trackability required for the multi-layer film (Z _F) and (Z _N), elongation of the upper layer 4 and (E _T) Can be set quantitatively.

<Example>
As described above, the design method of the multilayer film 2 using the evaluation method includes the elongation rate (EN) of the lower layer film 3 in the _{initial state, the thickness (TN} ) of the lower layer film 3, and the elongation rate of the upper layer film 4 _(TN). E _T) not only cracking followability of the multilayer film 2 (Z _F) by, elongation of the lower film 3 after degradation (E _N promoting '), elongation of the upper layer 4 (E _T' a) in advance _{The crack followability (Z F} ') of the multilayer film 2 in consideration of deterioration may be evaluated by evaluating it by a deterioration test or the like. Hereinafter, examples of a design method in consideration of deterioration will be shown. In the following examples, the description will be given while showing specific numerical values, but the evaluation method according to the embodiment is not limited to those specific numerical values.

Now, it is assumed that the lower layer film is forcibly heat-deteriorated at 80 ° C. for 1000 hours, and the upper layer film is subjected to the accelerated weathering test for 1000 hours as a deteriorated state.

_{The crack followability (Z X} ) required for the multilayer film 2 is 1.3 mm. _{The thickness (TN} ) of the underlayer film 3 is 1 mm. The material of the underlayer film 3 is the same as that of the test piece 1E in the table of FIG. Then, the initial elongation of the lower film 3 _{(E N)} is 296%. Then, after degradation of the lower film 3 (80 ° C., 1000 hours thermal aging) elongation _{(E N} ') is 257% (specimen 2L).

The elongation _(E N), according equation (2) and _{(E N} '), cracking trackability in the initial state _{(Z N0)} (standard thickness 1mm) is 1.54 mm. Further, the crack followability (Z _N0 ') (standard thickness 1 mm) in the deteriorated state is 1.38 mm. Subsequently, the above-mentioned crack followability (Z _N0 ) (Z _N0 ') and the thickness ( _TN ) are substituted into the equation (4). As a result, the actual thickness cracking followability of the underlayer film 3 in _{(T N) (Z N)} is 1.58mm in the initial state. _{Further, the crack followability (Z N} ') of the underlayer film 3 at the actual thickness ( _TN ) is 1.34 mm in the deteriorated state.

When the comparison specified in step S20A is performed, both the initial state and the deteriorated state satisfy the _{determination formula (Z X} <Z _N).
Initial state: Z _X (1.3) <Z _N (1.54).
Deterioration state: Z _X (1.3) <Z _N (1.38).

Next, in step S31, elongation of the upper layer 4 which is required based on the equation ₍₅₎ (E T), obtain _{(E T} '). _{Substitute the crack followability (Z N} = 1.54) and (Z _N = 1.38) into Eq. (5), respectively. As a result, the required elongation rate ( _ETX ) of the upper layer film 4 in the initial state is 55.3%. _{The required elongation rate (ETX} ') of the upper layer film 4 in the deteriorated state is 49.7%.

Select a material that allows the _{multi-layer film 2 to ensure crack followability (Z X} ) even after 1000 hours of accelerated deterioration. That _is, to select a material satisfying E _{T> E TX} and _{E T '> E TX'.}

For example, suppose that "fluorine b" (see the table in FIG. 10) is selected as the material for the upper layer film 4. Fluorine b is the growth rate of the initial state _{(E T)} 167% (specimen _5K), satisfies _{E T>} E _TX. On the other hand, fluorine b is an elongation of the deteriorated state _{(E T} ') is 46% (specimen 5N). This number does not satisfy the _{E T '> E TX'.} Therefore, fluorine b is not suitable as a material for the upper film 4.

Further, for example, it is assumed that "urethane b" (see the table of FIG. 10) is selected as the material of the upper layer film 4. Urethane b is the growth rate of the initial state _{(E T)} is 101% (specimen _5I), satisfies _{E T>} E _TX. Further, urethane b is' is also 69% (specimen 5M), _{E T} elongation deteriorated state _{(E T) 'satisfies> E TX'.} Therefore, it can be seen that urethane b is suitable as a material for the upper layer film 4 in the design of the multi-layer film 2 in consideration of deterioration.

Hereinafter, Experimental Examples 1 to 6 corresponding to some of the above-mentioned steps will be described. That is, in Experimental Examples 1 to 6, the validity of the evaluation in the above steps is confirmed by experiments.

<Experimental example 1>
In Experimental Example 1, the validity of the formula (1) was confirmed. In other words, in Example 1, to confirm the validity of the method of calculating elongation ratio from the measured values by Nano Indenter the (E _N). That is, Experimental Example 1 corresponds to steps S11, S12, and S13 in the embodiment. In Experimental Example 1, test bodies 1A to 1L were prepared. The test bodies 1A to 1F were made of different materials as described below.
Specimen 1A: JIS-A-6909 Flexible shape repair coating material E.
Specimen 1B: JIS-A-6909 Flexible shape repair coating material E.
Specimen 1C: JIS-A-6909 Flexible shape repair coating material RE.
Specimen 1D: JIS-A-6909 waterproof multi-layer coating material E.
Specimen 1F: JIS-A-6021 Acrylic rubber type for outer wall.

Further, the test body 1D was subjected to a heat deterioration treatment to prepare test bodies 1G to 1I. Further, the test body 1E was subjected to a heat deterioration treatment to prepare test bodies 1J to 1L. The heat deterioration treatment is to leave it in an environment of predetermined temperatures (60 ° C., 80 ° C., 100 ° C.) for 1000 hours. The table shown in FIG. 4 summarizes the test specimen numbers, materials, and conditions, as well as some measured and calculated values.

In Example 1, for each of the specimens 1a1l, to obtain a constant elongation as measured values (E _N) and nano-indenter property value calculated from the measured value (N _N). Elongation _{(E N)} is based on the elongation test prescribed in 7.29 of JIS-A6909. Specifically, the underlayer film 3 was uniformly applied to a vinyl chloride plate or a glass plate coated with a release agent so that the dry thickness was 1 mm. Then, the test body was dried and cured in an environment of 50 ° C. for 3 days, and cured under the conditions of 20 ° C. and 60% RH for 7 days or more to prepare a test body. After curing, the coating film was peeled off, and a dumbbell-shaped No. 2 mold was punched to complete the test piece. Then, for each of the test bodies 1A to 1L, the distance between the gauge points was set to 20 mm, and a tensile test was performed at a tensile speed of 50 mm per minute under the condition of 20 ° C. E _N) was obtained.

Further, the measured value for the nanoindenter physical properties _{(N N)} was the Martens hardness (HM) and indentation creep _{(C IT).} Nanoindenter physical properties _{(N N)} corresponds to the parametric _{(N N)} in the embodiment. Furthermore, in Example 1, a nano indenter physical properties _{(N N)} is a push-creep _{(C IT)} and Martens hardness (HM) ratio of _(C IT / HM).

In Experimental Example 1, as a conversion formula for converting the first nanoindenter physical properties (N _N) elongation (E _N), it was used equation (7). The formula (7) corresponds to the formula (1) shown in the first embodiment.

Figure 5 shows the calculated values of elongation percentage in the transverse axis (E _N). The calculated value is a value based on the equation (7). The vertical axis shows the measured values of elongation of the specimen 1A~1L _{(E N).} 5, plot P5a represented by black diamonds show the elongation in the initial state (E _N). On the other hand, the plot P5b indicated by white triangles indicate elongation rate (E _N ') in the heating deterioration state. Further, graph G5 is a linear approximate straight line. As shown in FIG. 5, calculated value and R-squared value that indicates the association degree between the actual measurement value of the elongation _{(E N)} ^was R 2 = 0.8314. Therefore, there is a strong association between the calculated and measured values of the elongation (E _N), elongation was obtained by equation ₍₇₎ (E N) is the elongation obtained by actual measurement (E _N) On the other hand, it turned out to be a reasonable value. Further, when confirming in detail, the equation calculated value using (7), the first nano indenter physical properties in both the initial and heated deteriorated state (N _N) elongation (E _N or E _N It was confirmed that it can be converted well to'). Therefore, a conversion formula for converting the first nanoindenter physical properties (N _N) elongation (E _N or E _N '), using the equation (7), in any of the initial and heat deteriorated state Turned out to be valid.

According to Example 1, step S11, S12, it is found that can satisfactorily convert the nano indenter physical properties by the process of S13 _{(N N)} elongation _{(E N).}

<Experimental example 2>
In Experimental Example 2, the validity of the formula (2) was confirmed. That is, Experimental Example 2 corresponds to step S14 in the embodiment. Specifically, to prepare a test body 1a1l, respectively of elongation _{(E N)} and cracking trackability the _{(Z N0)} was measured. That is, the test body used in Experimental Example 2 was prepared based on the same conditions as in Experimental Example 1. Then, elongation rate _{(E N)} is introduced into the formula (8) was calculated cracked followability the _{(Z N0).} Equation (8) corresponds to Equation (2). The cracking followability is found values (Z _N0), to evaluate the relationship between the crack follow-up property is a calculated value (Z _N0).

Elongation _{(E N),} as well as in Experimental Example 1, based on elongation test prescribed in 7.29 of JIS-A6909.

Figure 6 is a graph showing the relationship between the calculated value of the measured values and crack follow-up of cracking followability _{(Z N0) (Z N0)} . 6, the horizontal axis represents the calculated values of the crack follow-up property (Z _N0), the vertical axis represents measured values of cracking followability (Z _N0). In FIG. 6, the plot P6a shown in black rhombus shows the crack followability (Z _N0 ) in the initial state. On the other hand, the plot P6b shown by the white triangle shows the crack followability (Z _N0 ') in the heat-deteriorated state. Further, graph G6 is a linear approximate straight line.

As shown in FIG. 6, the correlation coefficient between the calculated value of the measured values of the crack follow-up property _{(Z N0)} and cracking trackability _{(Z N0)} ^was R 2 = 0.944. Therefore, it was found that the calculation of the crack followability using the equation (2) corresponds well with the measured value. Also, be either in the initial state and the deteriorated state, was found to be satisfactorily converted into elongation (E _N) cracking followability (Z _N0). Thus, it as a conversion formula for converting the elongation (E _N) cracking followability (Z _N0 or Z _N0 '), using the equation (8) is also valid in both the initial state and heating the deteriorated state I understood.

<Experimental example 3>
In Experimental Example 3, _{the relationship between the thickness (TN} ) of the underlayer film 3 and the crack followability (Z _N ) was confirmed. That is, Experimental Example 3 corresponds to steps S15, S16, and S17 in the embodiment. In Experimental Example 3, a plurality of test specimens 3A to 3I made of _{the same material and having different thicknesses (TN) were prepared.} Then, the test bodies 3A to 3I were composed of different materials as described below.
Specimens 3A, 3B, 3C: JIS-A-6909 Flexible shape repair coating material RE.
Specimens 3D, 3E, 3F, 3G: JIS-A-6909 waterproof multi-layer coating material E.
Specimen 3H, 3I: Acrylic rubber type for outer wall of JIS-A-6021.

_{The thickness (TN} ) of the test bodies 3A to 3I was measured using a micrometer. _{Further, the crack followability (Z N} ) of the test bodies 3A to 3I was measured by the same configuration as in Experimental Example 1.

Table shown in FIG. 7, elongation of the lower layer film in which the measured values specimen 3A to 3I _{(E N)} and cracking followability of the lower film (standard thickness) _{(Z N0)} and the thickness factor (delta _T) The thickness ( _TN ) and the crack followability (Z _N ) of the underlying film are shown. Further, the table shown in FIG. 7 shows the film thickness coefficient (Δ _T ), the thickness ( _TN ), and the crack followability (Z _N ) of the underlayer film in the test bodies 3A to 3I, which are the calculated values. Further, FIG. 8 _{shows a graph in which the thickness (TN} ) is shown on the horizontal axis and the crack followability (Z _N ) is shown on the vertical axis. In FIG. 8, plot P3a corresponds to specimens 3A-3C. Plot P3b corresponds to specimens 3D-3G. Plot P3c corresponds to specimens 3H, 3I. The graph G3a is an approximate straight line of the plot P3a. Graph G3b is an approximate straight line of plot P3b. Graph G3c is an approximate straight line of plot P3c.

These approximate line a is graph G3a, G3b, the slope of G3c is the thickness factor (delta _T). Graph G3a, G3b, as shown in G3c, thickness coefficient (delta _T) in each material were found to be taken the same numbers. In other words, cracking followability of the underlayer film 3 (Z _N) is influenced by the thickness of the lower film 3 (T _N), and the thickness (T _N) the larger the cracks followability (Z _N) that increases I understood.

Furthermore, the proportion of as the thickness _{(T N)} is large crack followability (Z _N) is large has a correlation with elongation _{(E N),} the thickness factor (delta _T) growth rate of the _{(E N)} It was found that it can be shown as a function (Equation (4)) that is an independent variable.

<Experimental Example 4>
In Example 4, check cracking trackability by calculation using equation (4) and (Z _N), compares the cracking followability by actual measurement (Z _N), the validity of the calculation using equation (4) did. That is, Experimental Example 4 corresponds to step S17 in the embodiment.

In Experimental Example 4, test bodies 3A to 3I were used. That is, the test body used in Experimental Example 4 was prepared based on the same conditions as in Experimental Example 3.

FIG. 9 shows a graph in which the calculated value of crack followability (Z _N ) is on the horizontal axis and the measured value of crack followability (Z _N ) is on the vertical axis. The R-squared value indicating the degree of correspondence between the calculated value of crack followability (Z _F ) and the measured value of crack followability (Z _N ^{) was R 2} = 0.937. Therefore, there is a high correlation between the calculated crack followability (Z _N ) and the measured crack followability (Z _N ), and it was confirmed that the calculation using Eq. (4) is appropriate. ..

<Experimental Example 5>
In Example 5, the elongation rate by calculation using the equation (6) and (E _T), compared with the growth rate actually measured (E _T), to confirm the validity of the calculation using the equation (6). That is, Experimental Example 5 corresponds to step S32 in the embodiment.

In Experimental Example 5, test bodies 5A to 5N were prepared. Then, the test bodies 5A to 5K were composed of different materials as shown in the table of FIG. Further, the test body 5E was deteriorated to obtain a test body 5L. Further, the test body 5M was obtained by deteriorating the test body 5I. Then, the test body 5K was deteriorated to obtain a test body 5N. Each deterioration treatment was based on the accelerated weathering test xenon lamp method cycle (A) specified in JIS K5600-7-7.

In Experimental Example 5, a nanoindenter physical property value ( _NN ) was obtained using a nanoindenter. Nanoindenter physical properties _{(N N)} were indentation creep and _{(C IT)} Martens hardness and the ratio of _{(HM) (C IT / HM} ). Further, elongation of the measured value (E _T) was obtained in the same manner as in Experimental Example 1. The growth rate of the calculated value (E _T) is obtained using the equation (9).

Further, FIG. 11, elongation is calculated value (E _T) and the horizontal axis shows a graph elongation of (E _T) and the vertical axis is a measured value. 11, plot P11a represented by black diamonds show the elongation in the initial state _{(E T).} On the other hand, the plot P11b represented by white triangles indicate elongation rate _{(E T)} in the accelerated aging condition. Further, graph G11 is a linear approximate straight line. R-squared value indicating the degree of correspondence between the elongation is a calculated value _{(E T)} and elongation is measured value _{(E T)} ^was R 2 = .8216. Accordingly, elongation is calculated values (E _T), between the elongation is measured value (E _T), there is a high correlation, confirmed that a calculation using the equation (6) is reasonable did it. Further, when confirming in detail, the equation calculated value using (9), can be satisfactorily converted into a nano indenter physical properties in both the initial state and accelerated aging conditions (N _N) elongation (E _T) Was confirmed. Therefore, a conversion formula for converting the elongation ratio Nano Indenter physical data (N _N) (E _T), the use of the equation (9) is also found to be valid in either of the initial state and accelerated aging conditions rice field.

<Experimental example 6>
In Experimental Example 6, the confirmation regarding step S30 was performed. Specifically, with showing the derivation of equation (5), according to the settings of the formula (5) elongation by elongation of the upper layer film 4 using (E _TX) (E _T), the Fukusomaku 2 It was confirmed that the condition that the crack followability (Z _F ) is larger than the crack followability (Z _{N) of the underlayer film 3 can be satisfied.}

When the lower layer film 3 has a predetermined crack followability (Z _{N ), the crack followability (Z F} ) of the multilayer film 2 including the lower layer film 3 is affected by the upper layer film 4. For example, if elongation of the upper layer 4 _{(E T)} is relatively large, crack follow-up of Fukusomaku 2 _{(Z N)} is equivalent to cracking followability of the underlayer film 3 _{(Z N),} or, It is expected that it can be higher than that. On the other hand, when the elongation of the upper layer 4 (E _T) is relatively small, cracks followability of Fukusomaku 2 (Z _N) is expected to be less than the cracking followability of the underlayer film 3 (Z _N) NS. Then, cracking followability of the underlayer film 3 (Z _N) and Fukusomaku 2 cracks followability (Z _F) and that is equal, the growth rate of the upper layer 4 (E _T) may be present.

Therefore, with respect to the lower film 3 having a predetermined cracking followability (Z _N), to prepare a multi-layer film 2 which is a combination of upper layer 4 having different elongation of the (E _T) from one another, of the multi-layer film 2 Measure the crack followability (Z _F). Example, (a) portion of FIG. 13, the growth rate of the upper layer film 4 on the horizontal axis indicates the _{(E T),} showing cracking followability of Fukusomaku 2 _{(Z F)} on the vertical axis. According to this graph, when the elongation of the upper layer 4 (E _T) are different, it can be seen that the cracking followability of Fukusomaku 2 (Z _F) is changed. _{The crack followability (Z N} ) of the lower layer film 3 in this test body was a predetermined value (4.65). Then, a linear G15b showing cracking followability of the approximate line G15a and lower film 3 _{(Z N),} having an intersection K. X-coordinate values indicating the intersection point K, i.e. elongation of the upper layer 4 (E _TX) is cracked followability of the underlayer film 3 (Z _N) and Fukusomaku 2 of cracking followability and (Z _F) is equal It is a boundary value. In other words, by increasing elongation of the upper layer 4 (E _T) than elongation indicating the boundary value (E _TX), cracking followability of Fukusomaku 2 (Z _F) is cracked follow the lower film 3 The condition that it is larger than the sex (Z _{N) can be satisfied.} Further, as for the boundary value, when the crack followability (Z _{N ) of the lower layer film 3 is determined, one elongation rate (ETX} ) of the upper layer film 4 indicating the boundary value is also determined. _{That is, the elongation rate (ETX} ) of the upper layer film 4 indicating the boundary value can be shown as a function with the crack followability (Z _{N) of the lower layer film 3 as a variable.}

Seen from another side, in the crack followability test (crack follow width evaluation test method), the test piece is observed from the front side while pulling the test piece, and the length when cracks or pinholes occur in the coating film is determined. It is defined as crack followability. With only the intermediate coating (underlayer film), when cracks occur in the intermediate coating, it is evaluated as _{crack followability (Z N).} Now, in the case of elongation ratio in a multilayer coating film _(E T) <elongation _{(E TX),} topcoat is broken first. In the case of this elongation ratio in a multilayer coating film (E _{T) <elongation} (E _TX) is a crack in intercoat occurs when the crack reaches the cracking followability (Z _N), from the outside Cannot be observed. Further, when the crack width is widened, cracks are generated in the top coat (upper layer film), and crack followability (Z _F ) can be obtained. Then, in the overcoating elongation _(E T)> elongation _{(E TX),} even cracking followability _(Z F)> Crack followability _{(Z N),} has reached a crack followability _{(Z N)} At that point, the middle coat (inside) may have cracks. Therefore, it is meaningless that the crack followability (Z _{F ) of the multi-layer film is larger than the crack followability (Z N} ) of the lower layer film, and it is regarded as the actual crack followability (Z _N). Therefore, there is "crack follow-up width of the middle _{coat (Z N} )> crack follow-up width required for the multi-layer coating film (Z _X )" and "crack follow-up property of the multi-layer (Z _F )> crack follow-up property of the middle coat (Z F). Z _N ) ”must be satisfied.

Therefore, the confirmation as shown in FIG. 12 was carried out under various conditions, _{and a function in which the crack followability (Z N} ) of the underlayer film 3 was used as a variable was derived. The function is Eq. (5).

(B) portion of FIG. 13, the horizontal axis indicates cracking followability of the underlayer film 3 (Z _N), which is a graph showing the longitudinal axis elongation of the upper layer 4 (E _T). The graph G15c is a straight line represented by the equation (5). Then, elongation of the upper layer 4 _{(E T),} is made greater than the growth rate of the upper layer 4 shown in this graph G15c _{(E T),} cracking followability of Fukusomaku 2 _{(Z F)} is The condition that it is larger than the crack followability (Z _{N) of the lower layer film 3 can be satisfied.}

In this regard, as shown in the table of FIG. 12, and providing a plurality of lower layer film 3 having different cracking trackability the (Z _N), different elongation with respect to each of the lower film 3 (E _T) The upper layer film 4 to have was formed, and test bodies 6A to 6M were obtained. Then, for each of cracking followability of the underlayer film 3 and _{(Z N),} elongation of the upper layer 4 and _{(E T),} were measured and the crack follow-up of Fukusomaku 2 _{(Z F).} As a result, for the test bodies 6A, 6B, 6C, 6D, 6F, 6G, 6I, 6J, 6L, 6M, the crack followability (Z _F ) of the multilayer film 2 is the crack followability (Z _{N) of the lower layer film 3.} ) Satisfied with the condition that it is larger than. On the other hand, the test body 6E, 6H, 6K (Fig. 13 (b) section: Plot of white triangles (6E, 6H, 6K)) for cracking followability of Fukusomaku 2 _{(Z F)} is lower film 3 It did not satisfy the condition that it was larger than the crack followability (Z _{N) of.}

Then, the actually measured values were plotted on the graph shown in part (b) of FIG. Then, the test specimens 6A, 6B, 6C, 6D, 6F, 6G, 6I, 6J, 6L, and 6M satisfying the conditions were all plotted in the region above the graph G15c. Furthermore, the specimens 6E, 6H, and 6K that did not satisfy the conditions were all plotted in the region below the graph G15c. Thus, elongation of the upper layer 4 (E _T), is made larger than the value obtained by equation (5), crack follow-up of Fukusomaku 2 (Z _F) is cracked followability of the underlayer film 3 ( It was found that the condition that it was larger than Z _{N) could be satisfied.}

Although the embodiment of the present invention has been described, the present invention is not limited to the above embodiment.

For example, in the above embodiment, as a material parameter relating underlayer film 3, Martens hardness (HM), and were used indentation creep _{(C IT).} Further, as a material parameter relating Fukusomaku 2, Martens hardness (HM), and were used indentation creep _{(C IT).} However, the material parameters of the standard material parameters in ISO14577-1, indentation hardness _{(H IT),} and may be an elastic return deformation work of the depression _{(W elast).}

Further, in the above embodiment, the maximum indentation depth of the indenter 6 which is a Berkovich indenter is used as a control parameter in the measurement by the nano indenter. However, the indenter is not limited to the Berkovich indenter and may be another indenter. Further, the control parameter in the measurement by the nano indenter is not limited to the maximum indentation depth, and another control element such as the maximum indentation load may be used.

1 ... sample, 2 ... multi-layer film, 3 ... lower layer film (first film part), 4 ... upper layer film (second film part), 5 ... base, 6 ... indenter.

Claims (2)

A method for evaluating the crack followability of a multi-layer film having a first film portion formed of a polymer material on a substrate and a second film portion formed of a polymer material on the first film portion. And
Comparing the crack follow-up property (Z _X) required cracking followability having said first film portion and (Z _N) to the multi-layer film, cracking followability to the first film portion has (Z _N) is If the crack follow-up performance required for the multi-layer film (Z _X) smaller than the cracking followability of the multilayer film is required to the multi-layer film due to the first film portion (Z _X) If it is determined that the first film portion is not satisfied, or if the crack followability (Z _N ) of the first film portion is larger than the crack followability (Z _X ) required for the multilayer film, the process proceeds to the second determination step. The first judgment step and
When the crack followability (Z _N ) of the first film portion is larger than the crack followability (Z _X ) required for the multilayer film, the _{crack followability (Z F} ) of the multilayer film and the first film . Comparing with the crack followability (Z _N ) possessed by the one film portion, when the crack follow property (Z _F ) possessed by the multi-layer film is smaller than the crack follow property (Z _N ) possessed by the first film portion, determines not to satisfy the second due to the film portion cracking followability with the multilayer film (Z _F) is cracked trackability required for the multilayered film (Z _X), or the double layer If cracking followability the membrane having (Z _F) is the crack follow-up property of the first film portion has (Z _N) or more, cracking followability of the multilayer film has (Z _F) is in the multi-layer film A method for evaluating the crack followability of a multi-layer film having a second determination step for determining that the required crack followability (Z _{X) is satisfied.} The second determination step is
Using the crack follow-up property with said first layer portion (Z _N), and obtaining the elongation (E _TX) required for the second film portion,
And obtaining elongation rate (E _T) to the second film portion has,
Comparing the elongation percentage (E _T) and elongation required for the second layer portion in which the second film portion has (E _TX), elongation second film portion has (E _T) is the first When it is smaller than the elongation rate ( _ETX ) required for the two film portions, it is determined that the crack followability (Z _F ) of the multi-layer film is smaller than the crack followability (Z _N ) of the first film portion. and, or, the second film section elongation having elongation (E _T) is required in the second film portion when (E _TX) larger, crack follow-up property of the multilayer film has (Z _F The method for evaluating the crack followability of the multilayer film according to claim 1, further comprising a third determination step of determining that) is equal to or higher than the crack followability (Z _N ) possessed by the first film portion.

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