JP2019109202A - Method of evaluating crack followability of multilayer film - Google Patents

Abstract

To provide a method of quantitatively evaluating the crack followability of a multilayer film.SOLUTION: The method of evaluating the crack followability of a multilayer film 2 includes: a step S20 of comparing the crack followability (Z) included in a lower layer film 3 with the crack followability (Z) required by the multilayer film 2; and a step S30 of comparing the crack followability (Z) included in the multilayer film 2 with the crack followability (Z) when the crack followability (Z) is higher than the crack followability (Z).SELECTED DRAWING: Figure 2

Description

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

  Non-Patent Document 1 discloses a technology relating to the overall durability performance of a stretch-type finish material. Specifically, Non-Patent Document 1 prepares a test body in which an elongating finish is applied as a top coat on an elongating finish as a main material, and is subjected to a tensile test after exposure to various environments. The results show that the overall durability of the stretchable finish is confirmed. In Non-Patent Document 1, elongation percentage performance (crack followability) is used as the performance of a multilayer coating film having a main material (middle coat) and a top coat (upper coat). Non-Patent Document 1 suggests that the overcoating affects the crack followability of the multilayer coating. In particular, it is pointed out that if the flexibility of the top coat is small relative to the flexibility of the middle coat, cracks smaller than that of the middle coat alone may cause cracks in the multilayer coating or cracks in the top coat.

Teruga Inoue, et al., "Studies on endurance performance test method (Part 29) Influence of heat on durability performance of stretched multi-layer finish coating material", Proceedings of Annual Conference of the Architectural Institute of Japan, Architectural Institute of Japan, Showa 61 August, 355-356 pages.

  The above-mentioned Non-patent Document 1 only shows a qualitative relationship that the performance of the multilayer coating is affected by the performance of the topcoat. Therefore, in the art, a method for quantitatively evaluating the performance of a multilayer 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 aspect of the present invention is a crack in a multilayer film having a first film portion formed of a polymer material on a base material and a second film portion formed of a polymer material on the first film portion. a method of evaluating the follow-up property, cracking trackability of the first film portion has (Z _N) and cracking trackability required for the multi-layer film (Z _X) and compares the cracking followability (Z _N) It is judged that the multilayer film does not satisfy the crack followability (Z _X ) due to the first film part when the crack followability (Z _X ) is smaller, or the crack followability (Z _N ) is cracked The first determination step to shift to the second determination step when larger than the followability (Z _X ), and the crack followability possessed by the multilayer film when the crack followability (Z _N ) is larger than the crack followability (Z _X ) (Z _F ) and crack followability (Z _N ) Comparison, cracking followability (Z _F) Gahibiware followability when (Z _N) is less than, due to the second film portion Crack followability (Z _F) Gahibiware followability when (Z _X) does not satisfy the determined, or, in the case where crack followability _{(Z F)} Gahibiware followability _{(Z N)} or more, a second determination step of determining that cracking followability _{(Z F)} is satisfactory cracking followability the _{(Z X)} And.

In this method, the first film portion is evaluated by quantitatively comparing the crack followability (Z _N ) of the first film portion with the crack followability (Z _X ) required of the multilayer film. . Furthermore, the crack followability (Z _F ) of the multilayer film and the crack followability (Z _N ) of the first film portion are compared quantitatively. Therefore, the crack followability of the multilayer film can be quantitatively evaluated.

In one form, the second determination step uses the crack followability (Z _N ) to obtain an elongation percentage (E _TX ) required for the second film portion, and an elongation percentage of 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} ) Is judged to be smaller than the crack followability (Z _N ), or when the elongation rate (E _T ) is larger than the elongation rate (E _TX ), the crack followability (Z _F ) is the crack followability (Z _N ) And a third determination step of determining that the above is true.

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

In one form, the method for evaluating the crack followability of a multilayer film includes a first measurement step of obtaining a crack followability (Z _N ) of the first film portion by measurement before the first determination step; In the first determination step, when it is determined that the multilayer film does not satisfy the crack followability (Z _X ) due to the first film portion, a first modification determination step of determining that the first film portion is to be repaired; The second modification determination that the second film portion is to be repaired when it is determined in the 2 determination step that the crack followability (Z _F ) does not satisfy the crack followability (Z _X ) due to the second film portion The method may further include the steps of

According to this embodiment, it can be quantitatively determined whether the factor not satisfying the crack followability (Z _F ) required for the multilayer film is the first film part or the second film part. .

In one form, the method of evaluating the crack followability of the multilayer film further includes a first setting step of setting the crack followability (Z _F ) of the multilayer film before the first determination step, The first setting step and the first determination step are performed while changing the crack followability set in the first setting step until the crack followability (Z _N ) satisfies the condition that the crack followability (Z _X ) is larger than the crack followability (Z _X ). 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, the crack followability (Z _N ) of the first film portion that can satisfy the crack followability (Z _F ) required for the multilayer film, and the elongation rate (E _T ) of the second film portion Can be set quantitatively.

In one form, in the first measurement step, the crack followability (Z _N ) in the first film portion may be obtained using an actual measurement value obtained using a nanoindenter. The measurement using a nanoindenter can be easily performed. Therefore, the crack followability (Z _N ) can be easily obtained.

In one embodiment, in the first measurement step, the crack followability (Z _N ) in the first film portion is larger as the thickness (T _N ) of the first film portion is larger, and the crack followability (Z _N ) And the thickness (T _N ) of the first film portion is expressed by a film thickness coefficient (Δ _T ) obtained from the elongation percentage (E _N ) of the first film portion, The measured value obtained using the indenter may be converted to the crack followability (Z _N ). According to this aspect, the crack followability (Z _N ) can be suitably calculated using the actual measurement 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 (T _N ) of the first film portion, and using the film thickness coefficient (Δ _T ) and the thickness (T _N ) of the first film portion And the step of obtaining the crack followability (Z _N ). According to these steps, the crack followability (Z _N ) can be suitably derived using the measured values obtained by the nano indenter.

  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 multilayer 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 according to 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 according to 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 according to Experimental Example 6.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description.

  First, an object to be evaluated by a method for evaluating the crack followability of the 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 in which the evaluation method is applied to the repair work of the multilayer film will be described. Furthermore, as a second embodiment, an example in which the evaluation method is applied to the design of a multilayer film will be described. Then, several 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 described in the following standard. According to the said standard, "crack following property" is taken as the amount of elongation when a through-hole arises in a coating film. Here, the amount of elongation until a through hole is generated in the multilayer film 2 or a crack / hole is generated in the upper layer film 4 is used. The evaluation value of the crack followability is indicated by the amount of elongation (mm).
・ Japan Architectural Institute, Polymer cement based waterproofing work construction guidelines (draft) ・ The same explanation, reference materials 2 Quality test method of polymer cement based waterproofing material, 4. Zero span tension elongation test.

<Evaluation object>
The target evaluated by the method of evaluating the crack followability of a multilayer film is a multilayer film used in a building. A multilayer film (for example, a coating film) covers a base such as concrete, a panel or the like. The multilayer film structure has a lower layer film (eg, an intermediate coating) and an upper layer film (eg, an upper coating). Organic coating films used on concrete and panels may be cracked due to the cracking of the substrate and the behavior of joints. It is necessary to suppress the occurrence of cracking, as it causes a decrease in aesthetic appearance, a decrease in the ability to protect the inner casing, or a possibility of over-water leakage. Therefore, the outer coating film and the coating film waterproof (multilayer film) is a middle coating (lower layer film) having a thickness of about 0.1 mm to 3 mm and flexibility such as a finish coating material for the purpose of securing crack followability. It includes a thin top coat (upper layer film) of about 0.03 mm to 0.1 mm, which is formed of a paint for the purpose of weatherability, aesthetics and stain resistance.

FIG. 1 shows a cross section of a sample 1 to be evaluated by the method for evaluating the crack followability of a multilayer film. Sample 1 is a part of a wall or floor of a building to be subjected to a repair work. The sample 1 has, for example, a substantially square shape in plan view in which the length of one side is 1 cm or more and 2 cm or less. Sample 1 has a multilayer film 2. The multilayer film 2 has a lower layer film 3 (first film portion) and an upper layer film 4 (second film portion). The multilayer film 2 is formed of a material described in the following standard, and materials similar thereto, and is formed of a polymeric material used as a construction material. For example, a coating film, a sheet or the like.
-JIS-A-6909 "Finish for architectural coatings".
・ JIS-A-6021 "coating waterproofing material for building".
・ JIS-K-5658 "Weather-resistant top coat for construction".
-JASS (Architectural Construction Standard Building Construction Specifications: Japanese Architectural Standard Specification)-8 "waterproof construction".

  The lower layer film 3 is formed on the base 5 (base material). The upper layer film 4 is formed on the lower layer film 3. In the 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. The 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 foundation 5 is formed of, for example, concrete.

The thickness (T _N ) of the lower layer film 3 is a length in the stacking direction of the multilayer film 2. The thickness (T _N ) of the lower layer film 3 may be, for example, 0.25 mm or more and 3.0 mm or less. The thickness (T _N ) of the lower layer film 3 may be 1.0 mm. The thickness (T _U ) of the upper layer film 4 is a length in the stacking direction of the multilayer film 2. The thickness (T _U ) of the upper layer film 4 may be, for example, 0.05 mm or more and 0.1 mm or less. The thickness (T _U ) of the upper layer film 4 may be 0.1 mm. The thicknesses (T _N ) and (T _U ) are not limited to the above numerical range.

The lower layer film 3 may be coated with a coating material described in the following standard and a coating material similar thereto.
-JIS-A-6909 "Finish for architectural coatings".
・ JIS-A-6021 "coating waterproofing material for building".
・ JIS-A-6916 "Base adjustment paint for construction".
-Polymer cement based waterproofing material.

The upper layer film 4 may be coated with a coating material described in the following standard and a coating material similar thereto.
・ JIS-K-5658 "Weather-resistant top coat 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. Here, “evaluation” means that when the multilayer film 2 is required to have a predetermined crack followability, the crack followability of the multilayer film 2 affected by the crack followability of the lower layer film 3 is a required value It is to judge whether it is satisfied or not. Furthermore, it is to judge whether 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 judged quantitatively whether the crack followability of the multilayer film 2 satisfies the required value. In addition, “evaluation” can also be said to determine whether 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 multilayer film 2 is formed on the floor or wall of an existing building. These multilayer films 2 deteriorate with time. Therefore, while regularly checking the degree of deterioration, repair as necessary. Here, the degree of deterioration is confirmed using the crack followability. Then, when the crack followability of the multilayer film 2 does not satisfy the required value, it is determined that the 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 as the factor. As a first factor, the deterioration of the multilayer film 2 is attributed to the deterioration of the crack followability of the lower layer film 3. As a second factor, the deterioration of the multilayer film 2 may be attributed to 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 film 3 and the upper film 4.

  In addition, a crack followability test for evaluating the crack followability requires a dedicated test body. Therefore, it is generally difficult to evaluate the cracking of the multilayer film 2 already applied to the floor or wall of an existing building.

  For example, if the cause 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 multilayer film 2 after modification satisfies the required value. obtain. Therefore, if it can be determined whether the cause of the deterioration of the multilayer film 2 is the upper film 4 or the lower film 3, it is not necessary to carry out unnecessary repair work.

  Therefore, in order to determine whether the cause of deterioration of the multilayer film 2 is either the upper film 4 or the lower film 3, a method of evaluating the crack followability of the multilayer film is applied.

  FIG. 2 shows an example of using an evaluation method to determine whether the cause of deterioration of the multilayer film 2 is the upper film 4 or the lower film 3 and to determine which film should be repaired. It is a flowchart which shows. This flow includes 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 modification determination step (step). S21), a second evaluation step (step S30), a second modification determination step (step S34), and a third modification 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 configured, the number of years elapsed, and the like. Also, the crack followability (Z _X ) may be based on a safety factor with respect to the crack width assumed on the actual wall surface. This means that in an actual wall surface, the crack width is not constant, the crack width varies, and the effect of repetition occurs, the physical property variation of the multilayer film 2 due to temperature, and the application error of the multilayer film 2 In order to

[Lower layer film crack followability acquisition step]
Next, in step S10, the crack followability (Z _N ) of the lower layer film 3 is obtained. The step S10 is a step S11 of measuring the lower layer film 3 using a nano indenter, a step S12 of obtaining a parameter (N _N ), a step S13 of obtaining an elongation rate (E _N ), and a standard value of crack followability. Step S14 of obtaining (Z _N0 ), step S15 of measuring thickness (T _N ), step S16 of obtaining film thickness coefficient (Δ _T ), and step S17 of obtaining crack followability (Z _N ) .

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

Here, a nano indenter refers to an apparatus used for a nano indentation test. The measurement method and material parameters of the nanoindenter conform to the following standards.
-ISO14577-1 "METallicmatics-InstrumETted indETtation test for hardness and materials paramETers-".

In the present embodiment, Martens hardness (HM) and indentation creep (C _IT ) of the lower layer film 3 are obtained as a result of step S11. In the measurement by the nanoindenter, an indenter 6 (see FIG. 1), which is a Berkovich indenter, is pressed against the surface of the lower layer film 3. In this pressing, the depth (maximum pressing depth) of pressing the indenter 6 into the lower layer film 3 is controlled. Furthermore, in the measurement of the lower layer film 3, the material parameters of the lower layer film 3 are not influenced by the base 5. Therefore, the indenter 6 is pressed toward the base 5 from the exposed region of the lower layer film 3 so that the maximum pressing depth of the indenter 6 is 1/6 or less of the thickness (T _N ).

At step S12, a parameter (N _N ) is obtained. Specifically, indentation creep (C _IT ) is divided by Martens hardness (HM). As a result, the parameter (N _N = 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, using the parameter (N _N ) calculated in step S12, the elongation rate (E _N ) is obtained. 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 : Elongation rate of lower layer film.
N _N : parameter.
A1, B1, C1: coefficients.

In step S14, a standard value (Z _N0 ) of the crack followability of the lower layer 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 multilayer film with respect to the lower layer 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。 Crack tracking (Z _N0 ) is obtained using the parameter (N _N ) obtained in step S12. Specifically, as shown in the equation (2), the crack followability (Z _N0 ) is made using a function (f ₂ ) with the parameter (N _N ) as an independent variable and the constants A 2 and B 2 as coefficients. Get).

Z _N0 : Crack followability of the lower layer film which is a standard thickness.
N _N : parameter.
A2, B2, C2: coefficients.

In step S15, the thickness (T _N ) of the lower layer film 3 is obtained. Specifically, the dimensions of the lower layer film 3 are measured by cross-sectional observation with a micrometer or a microscope. As a result, a thickness (T _N ) is obtained. Regarding the thickness of the lower layer film 3, when a plurality of actual measurements are performed to obtain a plurality of values, the minimum value of the plurality of values is taken as the thickness (T _N ).

Here, according to the findings of the present inventor, the crack followability (Z _N ) is influenced by the thickness (T _N ). For example, as the thickness (T _N ) increases, the crack followability (Z _N ) increases. And the influence degree of the thickness (T _N ) on the crack followability (Z _N ) has a correlation with the elongation rate (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 Introduce). Then, by utilizing the thickness factor (delta _T), obtained thickness _{(T N)} Karahibiware trackability the _{(Z N).}

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 Get).

Δ _T : Film thickness coefficient.
E _N : Elongation rate of lower layer film.
A3, B3: coefficients.

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, crack followability (Z _N ) is obtained using the film thickness coefficient (Δ _T ) obtained in step S16. Specifically, as shown in the equation (4), the thickness (T _N ) is an independent variable, the crack followability (Z _N ) is a dependent variable, and the film thickness coefficient (Δ _T ) is a proportional coefficient. Obtained using the function (f ₄ ) that contains

Z _N : Crack followability of lower layer film.
Z _N0 : Crack followability of the lower layer film which is a standard thickness.
T _N : Thickness of lower layer film.
Δ _T : Film thickness coefficient.
T ₀ : Reference thickness (1 mm).

The crack followability (Z _N ) of the lower layer film 3 is obtained by the above step S10.

[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 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 modification 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).

[First Modification Determination Step]
In step S21, based on the result of step S20, it is determined that deterioration of the lower layer film 3 is a factor that the crack followability (Z _F ) of the multilayer film 2 does not satisfy the crack followability (Z _X ). Therefore, in the repair work, it is determined that the lower layer film 3 should be repaired. 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 consequently repaired.

[Second determination step]
In step S30, the crack followability (Z _F ) and the crack followability (Z _N ) are compared. In other words, despite the satisfactory cracking followability (Z _N) Gahibiware trackability the (Z _X), it is that it does not satisfy the crack follow-up property (Z _F) Gahibiware followability (Z _X), its source It can be qualitatively estimated that the upper layer film 4 is deteriorated. Step S30 quantitatively determines 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 compared directly but an indirect comparison is performed using another evaluation value.

Specifically, the elongation rate (E _T ) of the upper layer film 4 and the elongation rate (E _TX ) required for the upper layer film 4 are compared. Here, the elongation percentage is the ratio of the length in the initial state, the length at break, and the difference in the tensile test, and the length in the initial state. Further, the required elongation percentage (E _TX ) means 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, if the elongation rate (E _T ) of the upper layer film 4 is larger than the required elongation rate (E _TX ), the crack followability (Z _N ) of the lower layer film 3 is not impaired.

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 (E _TX ) is obtained (step S31). The elongation rate (E _TX ) is obtained, for example, by equation (5). As shown in the equation (5), the elongation (E _TX ) is a linear function having the crack followability (Z _N ) of the lower layer 3 as an independent variable and the elongation (E _TX ) as a dependent variable. The equation for obtaining the elongation percentage (E _TX ) from the crack followability (Z _N ) of the lower layer film 3 is not limited to the following equation (5).

E _TX : Required growth rate.
Z _N : Crack followability of lower layer film.
A5, B5: coefficients.

Ｅ_Ｔ：上層膜の伸び率。
Ｎ_Ｎ：媒介変数。
Ａ６，Ｂ６：係数。 Next, the elongation percentage (E _T ) of the upper layer film 4 is obtained (step S32). The elongation percentage (E _T ) of the upper layer film 4 may also be obtained using a nanoindenter, as with the crack followability (Z _F ) of the lower layer film 3. For example, the upper layer film 4 is separated from the multilayer film 2, and only the upper layer film 4 is subjected to indentation creep (C _IT ) and Martens hardness (HM) using a nanoindenter as in step S11. Next, the nanoindenter physical property value (N _N = C _IT / HM) is obtained. Then, by substituting the nanoindenter physical property value (N _N ) into the equation (6), the elongation percentage (E _T ) of the upper layer film 4 is obtained.

E _T : Elongation rate of upper layer film.
N _N : parameter.
A6, B6: coefficients.

Next, the expansion rate (E _T ) and the expansion rate (E _TX ) are compared (step S33: third determination step). When the elongation percentage (E _T ) is smaller than the elongation percentage (E _TX ), the crack followability (Z _F ) of the multilayer film 2 becomes smaller than the crack followability (Z _N ) of the lower layer film 3. In this case, the process proceeds to the second modification 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 modification determination step (step S35).

[Second Modification Determination Step]
In step S34, it is determined that the upper layer film 4 is deteriorated due to the crack followability (Z _F ) of the multilayer film 2 not satisfying the crack followability (Z _X ). Therefore, in the repair work, it is determined that the upper layer film 4 should be repaired. 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 film 4 is formed on the lower film 3. Alternatively, the multilayer film 2 may be peeled off, and the multilayer film 2 may be newly formed on the base 5.

[Third Modification Determination 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, there is no need for modification in this case.

According to this method, the crack followability (Z _F ) of the multilayer film 2 can be quantitatively evaluated. Further, according to this method, the crack followability (Z _F ) in step S30 and the crack followability (Z _N ) of the lower layer film 3 can be favorably and quantitatively compared. Furthermore, according to this method, quantitatively determining whether the factor not satisfying the crack followability (Z _F ) required for the multilayer film 2 is the lower layer film 3 or the upper layer film 4 it can.

Second Embodiment
Next, as a second embodiment, an example in which the evaluation method is applied to the design of a 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 that can satisfy 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, for the multilayer film 2 (organic multilayer coating film) having the lower layer film 3 (intermediate coating) and the upper layer film 4 (upper coating), the underlayer film 3 sufficiently fills the crack width to be followed. The multi-layer film 2 having a high crack followability is rationally (quantitatively) designed by the design process of (1) and the selection process of the upper layer 4 that does not reduce the crack followability of the lower layer 3.

  For example, in order to determine the configuration of the lower layer film 3, first, the material and thickness of the lower layer film 3 are 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 of the multilayer film 2. The evaluation method of the crack followability of the multilayer film determines whether the crack followability based on the assumption can satisfy the required crack followability. Therefore, the multilayer film 2 having the required crack followability can be quantitatively designed by repeating the assumption of the configuration of the lower layer film 3 and the determination based on the assumption.

  FIG. 3 is a flow chart showing an example of applying the evaluation method to the design of a multilayer film. This flow has a crack tracking property 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 lower layer 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 _{And N} ) obtaining step S17.

In step S18, the material forming the lower layer 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 (T _N ) of the lower layer 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, steps S16 and S17 of obtaining the film thickness coefficient (Δ _T ) and the crack followability (Z _N ) using the elongation percentage (E _N ) and the thickness (T _N ) are the first embodiment and the second embodiment. In common.

By the way, in steps S13A, S16 and S17, it is assumed that the material is new. Here, "new" means that the property of the material has 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 in consideration of deterioration as well as at the time of construction. That is, the material and thickness of the lower layer film 3 are set based on the material characteristics that are not degraded, and are set based on the material characteristics after degradation. According to this configuration, the crack followability (Z _F ) of the multilayer film 2 can satisfy the crack followability (Z _X ) even after the predetermined period has elapsed.

In step S20A, it is determined whether 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 the crack followability (Z _N ) is equal to or more 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 lower layer film 3 is not appropriate. Therefore, the process returns to step S10A again to set another material, thickness, and the like. 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 condition of the lower layer film 3 is appropriate. Therefore, the process proceeds to step S30A for designing the upper layer film 4.

  As described above, steps S10A and S20A are repeatedly performed while changing the design conditions in step S10A until the result of step S20A is YES.

[Second determination step]
In step S30A, the elongation rate (E _T ) of the upper layer film 4 is compared with the elongation rate (E _TX ) required for the upper layer film 4. First, the required elongation rate (E _TX ) is obtained using the equation (5) (step S31).

Next, the elongation percentage (E _T ) of the upper layer film 4 is set (step S32A). Specifically, the material forming the upper layer film 4 is selected. Elongation (E _T ) is obtained by the choice of materials. Here, in the selection of the material (that is, the selection of the elongation rate (E _T )), a material having a value equal to or more than the required elongation rate (E _TX ) is selected. In addition, in setting the elongation percentage (E _T ), similarly to the lower layer film 3, setting may be performed in consideration of deterioration.

Then compared elongation _{(E T)} and elongation and _{(E TX)} (step S33). Since the expansion rate (E _T ) is set to a value that is equal to or higher than the expansion rate (E _TX ) in step S33, the determination result in this step S33 is YES. By the above steps S20A and S30A, the material and thickness of the lower layer film 3 satisfying the crack followability (Z _X ) required of the multilayer film 2 and the material of the upper layer film 4 are selected.

Incidentally, it is shown in Reference 1 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 coat). Generally, the crack followability (Z _N ) of the lower layer film 3 is affected by the elongation percentage (E _N ) and the thickness (T _N ) of the material forming the lower layer film 3. 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: Masafumi Achnami et al., "Study on crack followability of acrylic rubber polymer cement-based film waterproofing material", Abstracts of Annual Conference of Architectural Institute of Japan, Japan Architectural Institute of Japan, September, 1996, pp. 925-926.

Furthermore, since the lower layer film 3 (middle coat) and the upper layer film 4 (upper coat) are deteriorated by solar radiation, heat or the like, the flexibility is reduced. It is shown in Reference 2 that when the flexibility decreases, the crack followability also decreases.
Reference 2: Kawahara Masahide et al., "Study on photodeterioration of coating film", Color material, Japan, pp. 594-600, 2000.

On the other hand, the crack followability test is generally performed in the initial state, and does not take into consideration the influence of deterioration. When the multilayer film 2 is degraded by using an accelerated weathering tester or the like to evaluate the crack followability, a plurality of parameters such as the material of the upper film 4, the material of the lower film 3, and the thickness (T _N ) of the lower film 3 Because of that, it requires a lot of tests in combination. Since crack compliance is a destructive test, it is necessary to prepare a large number of test samples. Therefore, in the evaluation method of the present embodiment, a deterioration test with the lower layer film 3 and the upper layer film 4 alone is performed. And, by evaluating the elongation rate (E _N ) (E _T ) in each of them, it is possible to design the crack followability in consideration of the change in deterioration performance.

Moreover, patent documents 1 and 2 are known as art about crack flattery nature.
Patent document 1: Unexamined-Japanese-Patent No. 9-177259.
Patent document 2: Unexamined-Japanese-Patent No. 2005-35827.

  In Patent Document 1, the elongation of the lower waterproof layer is made 50% or more larger than the elongation of the upper waterproof layer. This design ensures high crack followability and secures surface toughness and trauma resistance. Example 3 in Patent Document 1 discloses an example in which the crack followability is lower 4.5 mm, upper 1.5 mm, and multilayer 3.6 mm. In Example 3, 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 middle coat is a soft coating having a crack followability of 0.5 mm or more, and the top coat is a hard coating having a crack followability of 0.2 mm or less. When the base changes about 0.2 mm, cracks occur in the top coating film, and the cracks in the base are detected. This is because the hard coating causes breakage of the coating at a value smaller than the inherent crack followability of the middle coating. On the other hand, the composite coating film protects the low weather resistant intermediate coating by the highly weather resistant top coating. Then, if a crack is generated in the top coat, the inner coat is rapidly deteriorated to cause the crack. Therefore, it is necessary to make the top coat not crack. Furthermore, in patent document 2, when a crack of 0.2 mm generate | occur | produces in a base | substrate, a crack is generated in a top coat. Therefore, it is not intended to design a multilayer coating that does not cause a crack in the top coat when a crack of 0.5 mm occurs in the substrate.

With respect to these prior arts, the method for evaluating the crack followability of the multilayer film according to the second embodiment can quantitatively evaluate the crack followability (Z _F ) of the multilayer film 2. Further, according to this method, the crack followability (Z _F ) in step S30A and the crack followability (Z _N ) of the lower layer film 3 can be favorably and quantitatively compared. Furthermore, according to this method, the crack followability (Z _N ) of the lower layer film 3 capable of satisfying the crack followability (Z _F ) required for the multilayer film and the elongation rate (E _T ) of the upper layer film 4 Can be set quantitatively.

<Example>
As described above, the design method of Fukusomaku 2 using the evaluation method, elongation of the lower film 3 in the initial state (E _N), the thickness of the lower film 3 (T _N), the elongation rate of the upper layer 4 ( Not only the crack followability (Z _F ) of the multilayer film 2 by E _T ) but also the elongation rate (E _N ') of the lower layer film 3 after degradation and the elongation rate (E _T ') of the upper layer film 4 in advance The crack followability (Z _F ′) of the multilayer film 2 in consideration of deterioration may be evaluated by evaluating the deterioration test or the like. Hereinafter, an embodiment of a design method in consideration of deterioration will be shown. In addition, in the following examples, although it demonstrates, showing a concrete numerical value, the evaluation method which concerns on embodiment is not limited to those specific numerical values.

  Now, when the lower layer film is forcibly heat-deteriorated at 80 ° C. for 1000 hours, the case where the upper layer film is treated for 1000 hours for accelerated weathering test is assumed to be a deteriorated state.

And, the crack followability (Z _x ) required for the multilayer film 2 is 1.3 mm. The thickness (T _N ) of the lower layer film 3 is 1 mm. The material of the lower layer film 3 is the same as the sample 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. In addition, the crack followability (Z _N0 ′) (standard thickness 1 mm) in the deteriorated state is 1.38 mm. Subsequently, the crack followability (Z _N0 ) (Z _N0 ′) and the thickness (T _N ) are substituted into the equation (4). As a result, the crack followability (Z _N ) of the lower layer film 3 at the actual thickness (T _N ) is 1.58 mm in the initial state. Further, the crack followability (Z _N ′) of the lower layer film 3 in the actual thickness (T _N ) is 1.34 mm in the deteriorated state.

When the comparison defined in step S20A is performed, both the initial state and the deterioration state satisfy the judgment 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, the required elongation rates (E _T ) and (E _T ′) of the upper layer film 4 based on the equation (5) are obtained. The crack followability (Z _N = 1.54) and (Z _N = 1.38) are respectively substituted into the equation (5). As a result, the required elongation (E _TX ) of the upper layer film 4 in the initial state is 55.3%. Also, the required elongation (E _TX ′) of the upper layer film 4 in the deteriorated state is 49.7%.

A material is selected from which the multilayer film 2 can maintain the crack followability (Z _X ) even after 1000 hours of accelerated deterioration. That is, a material satisfying E _T > E _TX and E _T '> E _TX ' is selected.

For example, it is assumed that “fluorine b” (see the table of FIG. 10) is selected as the material of the upper layer film 4. The fluorine b has an initial state elongation rate (E _T ) of 167% (specimen 5K), and satisfies E _T > E _TX . On the other hand, fluorine b has an elongation rate (E _T ′) in the deteriorated state of 46% (specimen 5N). This number does not satisfy E _T '> E _TX '. Therefore, fluorine b is not suitable as the material of the upper layer 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. Furthermore, urethane b is also 69% (test sample 5M) in the elongation rate (E _T ′) in the deteriorated state, and satisfies E _T ′> E _TX ′. Therefore, it is understood that urethane b is suitable as a material of the upper layer film 4 in the design of the multilayer film 2 in consideration of deterioration.

  Hereinafter, experimental examples 1 to 6 corresponding to the above-described several steps will be described. That is, Experimental Examples 1 to 6 confirm the validity of the evaluation in the above-described steps by experiments.

Experimental Example 1
In Experimental Example 1, the validity of the equation (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). In other words, Experimental Example 1 corresponds to steps S11, S12, and S13 in the embodiment. In Experimental Example 1, test bodies 1A to 1L were prepared. And the test bodies 1A-1F were comprised with the mutually different material as follows.
Test sample 1A: JIS-A-6909 flexible repair paint E.
Test sample 1B: JIS-A-6909 flexible repair paint E.
Test Sample 1C: JIS-A-6909 Flexible Modified Coating Material RE.
Test body 1D: JIS-A-6909 waterproof multi-layer coating material E.
Test body 1F: Acrylic rubber system for JIS-A-6021 outer wall.

  Furthermore, heat degradation processing was performed with respect to test body 1D, and test bodies 1G-1I were prepared. Moreover, the heat deterioration process was performed with respect to the test object 1E, and test object 1J-1L were prepared. The heat deterioration treatment is left in an environment of a predetermined temperature (60 ° C., 80 ° C., 100 ° C.) for 1000 hours. The table shown in FIG. 4 is a summary of the specimen number, the material, the state, and some actual measured values and calculated values.

In Experimental Example 1, the nanoindenter physical property value (N _N ) calculated from the elongation percentage (E _N ) and the actual measurement value was obtained as the actual measurement value for each of the test bodies 1A to 1L. Elongation _{(E N)} is based on the elongation test prescribed in 7.29 of JIS-A6909. Specifically, the lower layer 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 dry-cured for 3 days in an environment of 50 ° C., and cured for 7 days or more under conditions of 20 ° C., 60% RH to prepare a test body. After curing, the coating was peeled off, and a dumbbell-like No. 2 die was punched out to complete a test specimen. Then, with respect to each of the test bodies 1A to 1L, the distance between marks is 20 mm, and a tensile test is performed at a tensile speed of 50 mm for 1 minute under the condition of 20 ° C. Got E _N ).

The measured values for the nano indenter physical property value (N _N ) were Martens hardness (HM) and indentation creep (C _IT ). The nanoindenter physical property value (N _N ) corresponds to the parameter (N _N ) in the embodiment. Furthermore, in Experimental Example 1, the nanoindenter physical property value (N _N ) is a ratio (C _IT / HM) of indentation creep (C _IT ) to Martens hardness (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). Formula (7) corresponds to 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 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. Furthermore, the graph G5 is a linear approximate straight line. As shown in FIG. 5, the R-squared value indicating the degree of association between the calculated value of the elongation rate (E _N ) and the actual value 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) It turned out that it is 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 has been confirmed that it can be converted well into '). 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 Also proved to be appropriate.

According to Experimental Example 1, it was found that the nanoindenter physical property value (N _N ) can be favorably converted into the elongation percentage (E _N ) by the processing of steps S11, S12, and S13.

<Experimental Example 2>
In Experimental Example 2, the validity of Formula (2) was confirmed. In other words, 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 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, a plot P6a indicated by a solid diamond indicates the crack followability (Z _N0 ) in the initial state. On the other hand, a plot P6b indicated by an open triangle indicates the crack followability (Z _N0 ') in the heat-deteriorated state. Furthermore, the 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 equation (2) corresponds well to 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 understand.

<Experimental Example 3>
In Experimental Example 3, the relationship between the thickness (T _N ) of the lower layer 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 pieces 3A to 3I made of the same material and different in thickness (T _N ) were prepared. And test body 3A-3I was comprised with the mutually different material as follows.
Specimens 3A, 3B, 3C: JIS-A-6909 flexible modified coating material RE.
Test bodies 3D, 3E, 3F, 3G: JIS-A-6909 waterproof multi-layer coating material E.
Specimens 3H, 3I: Acrylic rubber system for JIS-A-6021 outer wall.

The thickness (T _N ) of each of the test specimens 3A to 3I was measured using a micrometer. Further, for the test body 3A to 3I, measured cracked followability the _{(Z N)} in the same configuration as in Experimental Example 1.

The table shown in FIG. 7 shows the measured values of the elongation of the lower layer film (E _N ) and the crack followability of the lower layer film (standard thickness) (Z _{N 0} ) and the film thickness coefficient (Δ _T ) in the test pieces 3A to 3I And thickness (T _N ) and crack followability (Z _N ) of the lower layer film. Moreover, the table shown in FIG. 7 shows the film thickness coefficient (Δ _T ), the thickness (T _N ) and the crack followability (Z _N ) of the lower layer film in the test bodies 3A to 3I which are calculated values. Furthermore, FIG. 8 shows a graph in which the thickness (T _N ) is taken as the abscissa and the crack followability (Z _N ) is taken as the ordinate. In FIG. 8, the plot P3a corresponds to the test objects 3A to 3C. The plot P3b corresponds to the test specimens 3D to 3G. The plot P3c corresponds to the test specimens 3H and 3I. The graph G3a is an approximate straight line of the plot P3a. The graph G3b is an approximate straight line of the plot P3b. The graph G3c is an approximate straight line of the plot P3c.

The slopes of the graphs G3a, G3b, and G3c, which are approximate straight lines, are film thickness coefficients (Δ _T ). As shown in the graphs G3a, G3b, and G3c, it was found that the film thickness coefficient (Δ _T ) can take the same numerical value for each material. That is, the crack followability (Z _N ) of the lower layer film 3 is affected by the thickness (T _N ) of the lower layer film 3, and the crack followability (Z _N ) increases as the thickness (T _N ) increases. I understand.

Furthermore, the rate at which the crack followability (Z _N ) increases as the thickness (T _N ) increases has a correlation with the elongation rate (E _N ), and the film thickness coefficient (Δ _T ) indicates the elongation rate (E _N ) It turned out that it is possible to show as a function (formula (4)) made into an independent variable.

<Experimental Example 4>
In Experimental Example 4, the crack followability (Z _N ) calculated by using the equation (4) is compared with the crack followability (Z _N ) by measurement, and the validity of the calculation using the equation (4) is confirmed. did. That is, Experimental Example 4 corresponds to step S17 in the embodiment.

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

FIG. 9 shows a graph in which the crack followability (Z _N ), which is a calculated value, is taken on the horizontal axis, and the crack followability (Z _N ), which is an actually measured value, on the vertical axis. The R-square value indicating the degree of correspondence between the calculated crack followability (Z _F ) and the actually measured crack followability (Z _N ) was R ² = 0.937. Therefore, there is a high correlation between the calculated crack followability (Z _N ) and the actually measured crack followability (Z _N ), and it was confirmed that the calculation using equation (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, the test bodies 5A to 5N were prepared. And, as shown in the table of FIG. 10, the test bodies 5A to 5K were made of materials different from each other. Moreover, 5 L of test objects were obtained by carrying out the deterioration process of the test object 5E. Moreover, the test object 5M was obtained by carrying out the deterioration process of the test object 5I. And test object 5N was obtained by carrying out degradation processing of test object 5K. The respective deterioration treatments were based on the accelerated weathering test xenon lamp cycle (A) defined in JIS K 5600-7-7.

In Experimental Example 5, the nanoindenter physical property value (N _N ) was obtained using a nanoindenter. The nanoindenter physical property value (N _N ) was taken as the ratio of indentation creep (C _IT ) to Martens hardness (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).

Furthermore, FIG. 11 shows a graph in which the calculated elongation value (E _T ) is taken on the horizontal axis and the measured elongation value (E _T ) is taken on the vertical axis. In FIG. 11, a plot P11a indicated by a filled diamond indicates the elongation percentage (E _T ) in the initial state. On the other hand, a plot P11b indicated by an open triangle indicates an elongation rate (E _T ) in the accelerated deterioration state. Furthermore, the 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 = 0.8216. Therefore, there is a high correlation between the calculated elongation value (E _T ) and the actually measured elongation rate (E _T ), confirming that the calculation using equation (6) is appropriate. did it. Further, as confirmed in detail, the calculated value using the above equation (9) is capable of favorably converting the nanoindenter physical property value (N _N ) into the elongation rate (E _T ) in both the initial state and the accelerated deterioration state. Was confirmed. Therefore, using equation (9) as a conversion equation to convert the nanoindenter physical property value (N _N ) to the elongation rate (E _T ) was found to be appropriate in both the initial state and the accelerated deterioration state. The

Experimental Example 6
In Experimental Example 6, confirmation regarding step S30 was performed. Specifically, according to the setting of the elongation percentage (E _T ) of the upper layer film 4 using the elongation percentage (E _TX ) according to the equation (5) while showing the derivation of the equation (5), It was confirmed that the condition that the crack followability (Z _F ) was larger than the crack followability (Z _N ) of the lower layer film 3 could 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 influenced 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 to be more 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) Ru. Then, there may be an elongation rate (E _T ) of the upper layer film 4 such that the crack followability (Z _N ) of the lower layer film 3 and the crack followability (Z _F ) of the multilayer film 2 become equal.

Therefore, the multilayer film 2 is prepared by combining the upper layer film 4 having different elongation rates (E _T ) with the lower layer film 3 having a predetermined crack followability (Z _N ). 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, it can be understood that the crack followability (Z _F ) of the multilayer film 2 changes when the elongation rate (E _T ) of the upper layer film 4 is different. The crack followability (Z _N ) of the lower layer film 3 in this test body was a predetermined value (4.65). Then, the approximate straight line G15a and the straight line G15b indicating the crack followability (Z _N ) of the lower layer film 3 have an intersection point K. The X coordinate value indicating the intersection point K, that is, the elongation (E _TX ) of the upper layer film 4 is such that the crack followability (Z _N ) of the lower layer 3 and the crack followability (Z _F ) of the multilayer film 2 are equal. It is a boundary value. In other words, if the elongation (E _T ) of the upper layer film 4 is made larger than the elongation (E _TX ) indicating the boundary value, the crack followability (Z _F ) of the multilayer film 2 will follow the crack of the lower layer 3 It is possible to satisfy the condition of being larger than the sex (Z _N ). Further, when the crack followability (Z _N ) of the lower layer film 3 is determined, the boundary value also determines one elongation rate (E _TX ) of the upper layer film 4 indicating the boundary value. That is, the elongation percentage (E _TX ) 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.

Viewed from another aspect, the crack followability test (the evaluation test method for crack follow width) observes the test body from the front side while pulling the test body, and the length when crack or pinhole is generated in the coating film It defines as a crack followability. In the case of the middle coat (lower layer film) alone, the crack followability (Z _N ) is evaluated when a crack occurs in the middle coat. Now, in the case of elongation ratio in a multilayer coating film _(E T) <elongation _{(E TX),} topcoat is broken first. In this multilayer coating film, if elongation rate (E _T ) <elongation rate (E _TX ), a crack occurs in the intermediate coating when the crack reaches the crack followability (Z _N ), but from the outside Can not be observed. Furthermore, when the crack width opens, a crack occurs in the top coat (upper layer film), and the crack followability (Z _F ) is obtained. Then, the top coat reached the crack followability (Z _N ) even if the crack followability (Z _F )> the crack followability (Z _N ) when the elongation rate (E _T )> the elongation rate (E _TX ) There is a possibility that a crack has occurred in the inner coating (internal) at the time. Therefore, it is meaningless that the crack followability (Z _F ) of the multilayer film is larger than the crack followability (Z _N ) of the lower layer film, and it is regarded as a substantial crack followability (Z _N ). Therefore, there is “crack follow width of inner coating (Z _N )> crack follow width required for multilayer coating (Z _X )” and “crack followability of multilayer (Z _F )> crack followability of inner coating (Z It is necessary to satisfy “Z _N )”.

Therefore, the confirmation as shown in FIG. 12 was carried out under various conditions, and a function having the crack followability (Z _N ) of the lower layer film 3 as a variable was derived. The function is equation (5).

Part (b) of FIG. 13 is a graph in which the horizontal axis indicates the crack followability (Z _N ) of the lower layer film 3 and the vertical axis indicates the elongation (E _T ) of the upper layer film 4. And the graph G15c is a straight line shown by Formula (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 the crack followability (Z _N ) of the lower layer film 3 is larger can be satisfied.

In this regard, as shown in the table of FIG. 12, a plurality of lower layer films 3 having different crack followability (Z _N ) are prepared, and different elongation rates (E _T ) for the respective lower layer films 3 are obtained. The upper layer film 4 having the above was formed to obtain test pieces 6A to 6M. 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 and 6M, the crack followability (Z _F ) of the multilayer film 2 is the crack followability (Z _{N of the} lower layer film 3) Satisfying the condition of being larger than). On the other hand, in the test bodies 6E, 6H, 6K (part (b) in FIG. 13: plots of white triangles (6E, 6H, 6K)), the crack followability (Z _F ) of the multilayer film 2 is lower layer film 3 It did not satisfy the condition of being larger than the crack followability (Z _N ) of

Then, the actual measurement values were plotted on the graph shown in part (b) of FIG. Then, the test bodies 6A, 6B, 6C, 6D, 6F, 6G, 6I, 6J, 6L, 6M, which satisfied the conditions, were all plotted in the area above the graph G15c. Furthermore, the test bodies 6E, 6H and 6K which did not satisfy the conditions were all plotted in the area below the graph G15c. Therefore, by setting the elongation percentage (E _T ) of the upper layer film 4 larger than the value obtained by the equation (5), the crack followability (Z _F ) of the multilayer film 2 corresponds to the crack followability of the lower layer film 3 It has been found that the condition of being larger than Z _N ) can 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, Martens hardness (HM) and indentation creep (C _IT ) were used as material parameters for the lower layer film 3. In addition, Martens hardness (HM) and indentation creep (C _IT ) were used as material parameters for the multilayer film 2. However, as material parameters, among material parameters standardized in ISO14577-1, indentation hardness (H _IT ) and elastic return deformation work (W _elast ) of a recess may be used.

  Moreover, in the said embodiment, in measurement by a nano indenter, the maximum indentation depth of the indenter 6 which is a Berkovich indenter was used as a control parameter. However, the indenter is not limited to the Berkovich indenter but may be another indenter. In addition, 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.

DESCRIPTION OF SYMBOLS 1 ... sample, 2 ... multilayer film, 3 ... lower layer film (1st film part), 4 ... upper layer film (2nd film part), 5 ... foundation | substrate, 6 ... indenter.

Claims (7)

A method of evaluating the crack followability of a multilayer 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
The crack followability (Z _N ) of the first film part is compared with the crack followability (Z _X ) required of the multilayer film, and the crack followability (Z _N ) is the crack followability (Z _If smaller than _X, it is determined that the multilayer film does not satisfy the crack followability (Z _X ) due to the first film portion, or the crack followability (Z _N ) is the crack follow A first determination step to shift to a second determination step if the polarity (Z _X ) is larger;
When the crack followability (Z _N ) is larger than the crack followability (Z _X ), the crack followability (Z _F ) possessed by the multilayer film is compared with the crack followability (Z _N ), and the crack follows When the followability (Z _F ) is smaller than the crack followability (Z _N ), the crack followability (Z _F ) must not satisfy the crack followability (Z _X ) due to the second film portion. judgment, or determines that the crack follow-up property (Z _F) is the case where the crack follow-up property (Z _N) or more, the crack follow-up property (Z _F) satisfies the crack follow-up property (Z _X) A method of evaluating the crack followability of a multilayer film having a second determination step. In the second determination step,
Obtaining an elongation rate (E _TX ) required for the second film portion using the crack followability (Z _N );
Obtaining an elongation rate (E _T ) of the second film portion;
The elongation (E _T ) and the elongation (E _TX ) are compared, and when the elongation (E _T ) is smaller than the elongation (E _TX ), the crack followability (Z _F ) is the same as the elongation (E _T ). The crack followability (Z _F ) is determined to be smaller than the crack followability (Z _N ) or when the elongation rate (E _T ) is larger than the elongation rate (E _TX ), the crack followability (Z _F ) The crack followability of the multilayer film according to claim 1, further comprising: a third determination step of determining that _N is _N or more. Prior to the first determination step, a first measurement step for obtaining a crack followability (Z _N ) of the first film portion;
In the first determination step, when it is determined that the multilayer film does not satisfy the crack followability (Z _X ) due to the first film portion, it is determined that the first film portion is to be repaired Repair determination step,
In the second 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 film portion is repaired The method for evaluating the crack followability of a multilayer film according to claim 2, further comprising: a second modification determination step of determining. Before the first determination step, the method further includes a first setting step of setting the crack followability (Z _F ) of the multilayer film,
While changing the crack followability (Z _F ) set in the first setting step until the crack followability (Z _N ) satisfies the condition that the crack followability (Z _X ) becomes larger, the first Repeating the setting step and the first determination step;
In the step of obtaining the elongation ratio (E _T), it sets the elongation rate (E _T) to a value to be the elongation (E _TX) above, evaluate the cracking followability of the multilayer film according to claim 2 how to. The crack of the multilayer film according to claim 3, wherein in the first measurement step, the crack followability (Z _N ) in the first film portion is obtained using an actual measurement value obtained using a nano indenter. How to assess followability. In the first measurement step,
Wherein the crack follow-up property of the first film portion (Z _N) is a relationship that increases the higher the first film of a thickness (T _N) is large, the crack follow-up property (Z _N) and said first film portion The nano indenter is formed by using the relationship between the thickness (T _N ) of the first film portion and the thickness coefficient (Δ _T ) obtained from the elongation percentage (E _N ) of the first film portion. The method for evaluating the crack followability of a multilayer film according to claim 5, wherein an actual measurement value obtained by using is converted into the crack followability (Z _N ). The first measurement step is
Obtaining an actual measurement value in the first film unit using the nanoindenter;
Converting the measured value to the elongation rate (E _N );
Obtaining the film thickness coefficient (Δ _T ) using the elongation percentage (E _N );
Obtaining a thickness (T _N ) of the first film portion;
Obtaining the crack followability (Z _N ) by using the film thickness coefficient (Δ _T ) and the thickness (T _N ) of the first film portion. To assess the crack followability of

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