JP2018096734A - Method and device for testing accelerated weathering resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for evaluating a sample which reproduces deterioration phenomena including chalking well in an outdoor environment.SOLUTION: Water is sprayed to a front surface of a sample 300, and a temperature gradient where the front surface is hotter than the back surface is generated in a plate's thickness direction. More specifically, hot water is sprayed to the front surface of the sample 300 by a water spraying unit 12 and the back surface is cooled by a sample coolant 18.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for evaluating long-term reliability of a polymer material in an outdoor environment.

Typical standards for the accelerated weather resistance test for evaluating the weather resistance of polymer materials are “JIS K 7350-1” to “JIS K 7350-4” which are plastic test methods, and “ JIS K 5600-7-7 "and" JIS K 5600-7-8 ". For example, “JIS K 5600-7-7” uses a test apparatus using a xenon lamp as a light source to irradiate a sample with light (60 W / m ² between 300 nm and 400 nm) and a drying period ( This test method repeats a black panel temperature of 63 ± 2 ° C. and a relative humidity of 40 to 60% and a wetting period (18 minutes) by water spraying.

Junji Iida, “Accelerated Weatherability Test (Part 3)”, Paint Research, No.147 Mar. 2007 "Accelerated Exposure Test Handbook, [I] Accelerated Weatherability Test", Japan Weathering Test Center, April 1, 2009

  However, in the conventional accelerated weather resistance test, it cannot be said that the deterioration of the polymer material in the actual outdoor environment can be sufficiently reproduced, and the reliability of the test result is inferior to the outdoor exposure test (Non-patent Document 1). ). In particular, the deterioration phenomenon such as chalking that occurs when an outdoor exposure test is conducted in a salt-damaged area cannot be reproduced.

  The influence of moisture on the degradation of polymer materials can be caused by hydrolysis, extraction of low molecular weight additives by moisture, plasticizing effect by moisture, etc., and loading with moisture changes more than the test without loading. Is known to be large (Non-Patent Document 2).

  Chalkification, which is one of the deterioration phenomena of polymer materials, is a phenomenon in which the resin on the surface layer of the material deteriorates and the pigment contained in the material becomes powdery, and greatly impairs the appearance of the material. The progress of chalking is considered to be mainly affected by ultraviolet rays and water. However, when a sample with chalking in an outdoor exposure test is evaluated by a conventional accelerated weathering test, the chalking is sufficiently reproduced. There was a problem that it was not possible.

  In other words, the accelerated weathering test that is now widely used is merely spraying water at room temperature, so that moisture does not penetrate deeper into the polymer material than in the real environment, and chalking in the real environment. Has not been reproduced. When water at room temperature is sprayed, the temperature of the sample surface decreases when wet, and the water absorption of the sample is hindered by the following two points. One is that the decrease in the temperature of the sample itself decreases the water absorption rate of the polymer material. The other is that the temperature of the sample surface becomes lower than the temperature of the back surface of the sample (the temperature of the back surface of the sample is about the same as the temperature in the tank) by spraying, and a temperature gradient in the direction opposite to the water penetration occurs. It is a point that the invasion of is prevented.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sample (polymer material) evaluation method and apparatus that well reproduce deterioration phenomena such as chalking in an outdoor environment.

  In order to solve the above-mentioned problems, an accelerated weathering test method according to claim 1 is an accelerated weathering test method for a sample performed by an accelerated weathering test apparatus, wherein a spraying step of spraying water on the sample surface, and the sample surface And a temperature gradient generating step of generating a temperature gradient in the sample that is higher than the back surface of the sample.

  According to the present invention, water is sprayed on the sample surface, and a temperature gradient is generated in the sample so that the sample surface is hotter than the back surface of the sample. Therefore, it is possible to reproduce well the deterioration phenomenon such as chalking caused by the irradiation of ultraviolet rays in a state where water generated in the indoor environment penetrates into the deep part of the sample.

  The accelerated weather resistance test method according to claim 2 is the accelerated weather resistance test method according to claim 1, wherein the temperature gradient is generated by cooling the back surface of the sample with cooling water or a Peltier element in the temperature gradient generation step. It is characterized by generating.

  The accelerated weathering test method according to claim 3 is the accelerated weathering test method according to claim 1 or 2, wherein, in the spraying step, water having a temperature equal to or higher than a bath temperature is sprayed on the sample surface. Features.

  The accelerated weather resistance test method according to claim 4 is the accelerated weather resistance test method according to claim 1, wherein in the spraying step, water having a temperature equal to or higher than the temperature in the tank is sprayed on the sample surface, and the temperature gradient In the generating step, the temperature gradient is generated by cooling the back surface of the sample with a heat sink.

  The accelerated weathering test apparatus according to claim 5 is the accelerated weathering test apparatus for a sample, wherein a water spray portion that sprays water on the sample surface and a temperature gradient that causes the sample surface to be higher in temperature than the sample back surface are generated in the sample. And a temperature gradient generating section.

  The accelerated weather resistance test apparatus according to claim 6 is the accelerated weather resistance test apparatus according to claim 5, wherein the temperature gradient generating section is a spray water temperature adjusting section for heating the water temperature, or the back surface of the sample. And a sample cooling body for cooling the sample.

  The accelerated weather resistance test apparatus according to claim 7 is the accelerated weather resistance test apparatus according to claim 6, wherein the sample cooling body is one of cooling water, a Peltier element, and a heat sink.

  ADVANTAGE OF THE INVENTION According to this invention, the evaluation method and apparatus of a sample which reproduce well the deterioration phenomena, such as chalking, in an outdoor environment can be provided.

It is a figure which shows the structure of the accelerated weathering test apparatus which concerns on this Embodiment.

  The present invention relates to a test method and apparatus for a polymer material that well reproduces deterioration phenomena such as chalking in outdoor environments including salt damage areas. In the present invention, attention is paid to the fact that moisture does not penetrate deeper into the polymer material than in the actual environment.

  Therefore, in the present invention, the sample surface is sprayed with water having a temperature equal to or higher than the temperature in the tank, and the sample back surface (the back surface opposite to the sample surface) is cooled with cooling water or the like. By providing a temperature gradient that is higher than that in the thickness direction of the sample, moisture can penetrate into the deep part of the sample as efficiently as possible in the same time as the actual environment, and the deterioration behavior in the outdoor environment is well reproduced. This makes it possible to more appropriately evaluate the long-term reliability of the polymer material (sample) in the outdoor environment.

[Conventional accelerated weather resistance test]
First, the conventional accelerated weather resistance test will be described.

  An accelerated weather resistance test was conducted using a sample in which a polyurethane resin paint was applied to a 7 cm × 15 cm steel material at a thickness of 50 μm. This polyurethane resin paint has been chalked in an outdoor exposure test for 1.5 years.

Based on the test conditions of the conventional accelerated weather resistance test (JIS K 5600-7-7), a drying step (102 minutes, under a temperature of 60 W / m ² at a dose of 300 to 400 nm of a xenon light source and an internal temperature of 38 ° C. (Black panel temperature 63 ± 2 ° C., relative humidity 40-60%) and room temperature water spraying step (18 minutes) are repeated.

  The accelerated weathering test was conducted for 2000 hours, but no chalking occurred in the sample. The specific heat of the polymer material as the sample is approximately 1 to 2 J / g · K, which is lower than the specific heat of water (4.2 J / g · K). Decrease nearby. On the other hand, the back surface of the sample has a temperature close to the bath temperature of 38 ° C. It is considered that moisture was hardly invaded into the sample due to the low temperature of the sample surface and a temperature gradient in the direction opposite to the direction of moisture penetration in the thickness direction of the sample.

[About accelerated weathering test of the present invention]
Therefore, the test was carried out for 4 hours at 60 W / m ² at an irradiation amount of 300 to 400 nm of a xenon light source, a bath temperature of 38 ° C., a black panel temperature of 63 ± 2 ° C., and a relative humidity of 40 to 60%. The test cycle of taking out the test sample and immersing it in hot water at 50 ° C. for 4 hours was repeated for 2000 hours. As a result, it was found that the sample surface became chalky, and chalking occurred by irradiating the sample with light containing ultraviolet rays in a state where moisture was permeated.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an accelerated weathering test apparatus 100 according to the present embodiment. As illustrated in FIG. 1, the accelerated weathering test apparatus 100 according to the present embodiment includes a light source 11, a water spray unit 12, a spray water temperature control unit 13, a tank humidity control unit 14, and a tank temperature control unit 15. The refrigerator 16 and the black panel 17 are provided in the tank. In the tank, a sample 300 as a polymer material is disposed close to the black panel 17, and the sample cooling body 18 is disposed on the back surface of the sample 300.

  The light source 11 is used to irradiate the sample 300 and the black panel 17 in the tank with light including ultraviolet rays. The water spray unit 12 is used for spraying (spraying) water on the surface of the sample 300. The spray water temperature adjusting unit 13 is used for heating the temperature of water sprayed by the water spray unit 12. The tank humidity adjustment unit 14 is used to adjust the humidity in the tank. The tank temperature adjustment unit 15 is used to adjust the temperature in the tank. The refrigerator 16 is used to lower the temperature in the tank. The black panel 17 is used for quasi-observing the surface temperature of the sample 300. The sample cooling body 18 is fixed to the back surface of the removable sample holder, and is used to cool the back surface of the sample 300. For example, one or more of cooling water, a Peltier element, and a heat sink are used as the sample cooling body 18.

  The accelerated weather resistance test apparatus 100 further includes a control unit 19 and a test condition input unit 20. The control unit 19 is a device that remotely controls the irradiation amount of the light source 11, the water spray amount of the water spray unit 12, the in-tank humidity by the in-tank humidity adjustment unit 14, and the in-tank temperature by the in-tank temperature adjustment unit 15. The existing control unit of the accelerated weathering test apparatus may be used, or an information processing apparatus including a CPU and a memory may be newly used. The test condition input unit 20 is a device that inputs a set value such as an irradiation amount used by the control target (11, 12, 14, 15) of the control unit 19 to the control unit 19. For example, a control monitor with a touch panel function is used.

  The accelerated weathering test apparatus 100 according to the present embodiment is similar to the existing accelerated weathering test apparatus, but differs in that it includes a spray water temperature adjusting unit 13 and a sample cooling body 18. Either one or both of the spray water temperature adjusting unit 13 and the sample cooling body 18 may be used. The spray water temperature adjusting unit 13 and the sample cooling body 18 are temperature gradient generating units in the claims. The spray water temperature adjusting unit 13 is used for heating the temperature of water sprayed on the surface of the sample 300, and the sample cooling body 18 is used for cooling the back surface of the sample 300. Therefore, a temperature gradient generating unit is used. Has a function of generating a temperature gradient in the sample plate thickness direction in which the sample surface is hotter than the sample back surface.

<Example>
Next, the accelerated weathering test method performed in this embodiment will be described.

First, the sample 300 is installed in the tank of the accelerated weathering test apparatus 100. As the light source 11 of the accelerated weathering test apparatus 100, for example, a xenon arc lamp, an ultraviolet fluorescent lamp, a carbon arc lamp, a metal halide lamp and the like are suitable. In this embodiment, a light source 11 of a xenon lamp is used, and the irradiation amount is set to 60 W / m ^{2 at} 300 to 400 nm.

  Next, a test cycle is defined. The test cycle may be a test cycle in which a drying step (drying period) performed while irradiating light including ultraviolet rays and a wetting step (wetting period) performed without irradiating light are alternately repeated. Moreover, it is good also as a test cycle which repeats alternately the drying step and wet step performed while irradiating the light containing an ultraviolet-ray. In addition, it is good also as a test cycle which repeats three steps which added the wetting step or wetness step performed without irradiating light to the drying step and wetness step performed while irradiating the light containing an ultraviolet-ray. A test cycle in which other steps are combined with these can be easily inferred. In the present embodiment, the test cycle is a test cycle in which two steps of a drying step (102 minutes) and a wetting step (18 minutes) performed while always irradiating light including ultraviolet rays are alternately repeated.

(Specific example 1)
Specific Example 1 describes a case where water having a temperature equal to or higher than the tank temperature is sprayed on the surface of the sample 300 using the water spray unit 12 and the spray water temperature adjusting unit 13. A light source 11 irradiation amount of 300 to 400 nm, 60 W / m ² , a bath temperature of 38 ° C., a drying step (102 minutes, black panel temperature 63 ± 2 ° C., relative humidity 40 to 60%), and warm water of 58 ° C. The spraying wetting step (18 minutes) is repeated alternately. When this repeated test was carried out for 2000 hours, chalking could be reproduced.

  At this time, the water temperature to be sprayed is higher than the temperature in the tank so that the sample surface is higher than the sample back surface. At this time, a heat sink may be provided on the back surface of the sample to cool the back surface of the sample. By making the water temperature sprayed on the sample surface higher than the temperature in the tank, a temperature gradient is generated between the sample surface and the sample back surface, which makes the sample 300 easy to absorb water, and UV light is emitted while moisture penetrates into the sample 300. It is considered that the deterioration of the sample has progressed due to irradiation with the contained light.

Note that when the glass transition point of the polymer material as a sample is T _G ° C, the temperature T _W of the hot water to be sprayed is preferably less than T _G. Although the water absorption of the polymer material is accelerated as the temperature is increased, the property of the polymer material changes when the temperature exceeds _TG , and if the accelerated weather resistance test is performed at a temperature higher than _TG , the degradation differs from the actual environment. Because. _TG is desirably measured by DSC (Differential Scanning Calorimetry), and reference values of polymer materials having a composition similar to that of the sample may be referred to. In the present embodiment, it is confirmed by DSC measurement that the _{TG of the} polyurethane resin paint is 72 ° C.

(Specific example 2)
In specific example 2, a case where the back surface of the sample 300 is cooled using the sample cooling body 18 will be described. The sample back surface is cooled using one or more of cooling water or Peltier elements. In Example 2, the back surface of the sample was cooled with a Peltier element. A light source 11 irradiation amount of 300 to 400 nm, 60 W / m ² , a bath temperature of 38 ° C., a drying step (102 minutes, black panel temperature 63 ± 2 ° C., relative humidity 40 to 60%) and a wetting step (18 minutes) , Normal temperature water spraying, and cooling the back of the sample to 8 ° C. with a Peltier device. When this repeated test was conducted for 2000 hours, the chalking observed in the outdoor exposure test could be reproduced. This is because when the back surface of the sample is cooled, a temperature gradient is generated between the surface of the sample and the back surface of the sample, thereby making it easy for the sample 300 to absorb water and irradiating the sample 300 with light containing ultraviolet rays. It is considered that the deterioration of the sample has progressed.

(Specific example 3)
In Specific Example 3, a case will be described in which hot water is sprayed on the surface of the sample 300 and the back surface thereof is cooled using both the water spray unit 12 and the spray water temperature control unit 13 and the sample cooling body 18. . The sample back surface is cooled using one or more of cooling water or Peltier elements. In Specific Example 3, the back surface of the sample was cooled with a Peltier element.

Here, the temperature in the tank is T _C ° C., the spray water temperature is T _W ° C., and the Peltier element temperature is T _P ° C. T _{W, T P is, T G> T W> T} C> T P is preferred. A light source 11 irradiation amount of 300 to 400 nm, 60 W / m ² , a bath temperature of 38 ° C., a drying step (102 minutes, black panel temperature 63 ± 2 ° C., relative humidity 40 to 60%) and a wetting step (18 minutes) , 58 ° C. warm water spray, and the sample back surface is cooled to T _P ° C. by a Peltier device). When carried out at T _P = 28,18,8, chalking observed in the outdoor exposure test could be reproduced. Table 1 shows the test time required to reproduce the back surface cooling temperature and chalking.

  From Table 1, it can be understood that the temperature gradient between the front surface and the back surface of the sample 300 is increased by increasing the temperature of the sample surface and cooling the back surface of the sample, thereby shortening the time required to reproduce chalking.

  According to the present embodiment, water is sprayed on the surface of the sample 300 and a temperature gradient in which the surface is higher than the back surface is generated in the plate thickness direction, so that the sample 300 can absorb water efficiently in a short time. it can. As a result, moisture can penetrate into the deep part of the sample 300 in a short time and the accelerated weather resistance test can be carried out, so that the water generated in the outdoor environment penetrates the deep part of the sample and is irradiated with ultraviolet rays, etc. The deterioration phenomenon can be reproduced well. As a result, it is possible to more appropriately evaluate the long-term reliability of the polymer material in outdoor areas including salt damage areas.

DESCRIPTION OF SYMBOLS 100 ... Accelerated weathering test apparatus 11 ... Light source 12 ... Water spray part 13 ... Spray water temperature control part (temperature gradient generation part)
DESCRIPTION OF SYMBOLS 14 ... Humidity adjustment part in a tank 15 ... Temperature control part in a tank 16 ... Freezer 17 ... Black panel 18 ... Sample cooling body (temperature gradient generation part)
19 ... Control unit 20 ... Test condition input unit

Claims (7)

In the accelerated weathering test method of a sample performed by the accelerated weathering test apparatus,
A spraying step of spraying water on the sample surface;
A temperature gradient generation step for causing the sample to generate a temperature gradient in which the sample surface is hotter than the sample back surface;
An accelerated weathering test method comprising: In the temperature gradient generation step,
The accelerated weathering test method according to claim 1, wherein the temperature gradient is generated by cooling the back surface of the sample with cooling water or a Peltier element. In the spraying step,
3. The accelerated weathering test method according to claim 1 or 2, wherein water having a temperature equal to or higher than the temperature in the tank is sprayed on the surface of the sample. In the spraying step, water having a temperature equal to or higher than the temperature in the tank is sprayed on the sample surface,
In the temperature gradient generation step,
The accelerated weathering test method according to claim 1, wherein the temperature gradient is generated by cooling the back surface of the sample with a heat sink. In the accelerated weathering test apparatus of the sample,
A water spray section for spraying water on the sample surface;
A temperature gradient generating section for generating a temperature gradient in the sample such that the sample surface is hotter than the sample back surface;
An accelerated weather resistance test apparatus comprising: The temperature gradient generator is
The accelerated weathering test apparatus according to claim 5, wherein the accelerated weathering test apparatus is a spray water temperature adjusting unit that heats the temperature of the water, or a sample cooling body that cools the sample on the back surface of the sample. The sample cooling body is:
The accelerated weathering test apparatus according to claim 6, wherein the accelerated weathering test apparatus is one of cooling water, a Peltier element, and a heat sink.

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