から 53509 “ゴムの試験 – オゾンクラッキングに対する耐性の測定 – 一部 1: 静的応力” is used to determine the resistance of synthetic rubber to cracking by exposing specimens to a specified ozone concentration and to elongation stress.
Introduction to DIN 53509
から 53509 was developed by the Working Committee NMP 434 “Testing of the Physical Properties of Rubber and synthetic Rubber” under the German Committee for Testing Standards for Materials (NMP) with reference to the international standard ISO 1431-1:1989. In addition to reference to Part 1 of the above standard, ISO 1431-2:1982 with dynamic stress determination content and ISO 1431-3:2000 with reference method for ozone concentration determination were adopted. The preferred method of determination of ozone concentration recommended in this standard is not the chemical method as DIN 52509-2, but a ultraviolet photometric method.

から 53509-0 “ゴムの試験 – オゾンクラッキングに対する安定性の測定 – 一部 1: 静的応力”

から 53509 differs from ISO 1431-1:1989 in the following ways:

– Relative air humidity should be less than 65% under normal conditions, only limit the upper limit. しかし, if the product will be used in humid conditions, it should be tested at 80~ 90% 相対湿度.

– In order to ensure sufficient supply of ozone, the ratio of the sample surface to ozone flow rate shall not exceed a value of 25 s x m-1,

– In Method A, the trial time is proposed to be 72 hours instead of 48 時間,

– In Method B, no limit is required for 96 時間,

– In method A, the use of a crack table to determine the rating is no longer specified. しかし, it is necessary to explain whether cracks are generated or not after the test. If a film (photograph) is required,

– 必要であれば, a T50-dumbbell sheet specimen of only 2 mm width is allowed to determine whether cracks have begun to form,

-It is also allowed to test specimens that are subjected to a number of different tensile stresses at the same time, つまり, リング状に曲げられた年輪標本と長方形標本.

から 53509-0 “ゴムの試験 – オゾンクラッキングに対する安定性の測定 – 一部 1: 静的応力”

1. 適用範囲と目的
この規格で指定された試験方法は、サンプルを指定されたオゾン濃度下に置き、伸び応力にさらすことによって合成ゴムの耐亀裂性を測定するために使用されます。. オゾンは、一定期間自然大気にさらされた後の合成ゴムの損傷の主な原因です. しかし、オゾンは屋内でも発生する可能性があります, 特に放電や紫外線源のある地域では. 材料の耐亀裂性は、オゾン濃度と材料の伸び応力に関係します。. その他の要因には温度が含まれます, 空気の湿度, 日光, 空気中の不純物や沈殿物, 等.

All secondary factors related to material exposure to the atmosphere are not considered when static tests are performed in accordance with this standard, only constant elongation and constant ozone concentration, temperature and air humidity are considered. It is only desirable that the specimen can be tested under static stress.

It is only desirable that the specimen can be tested under static stress.

This test method is not suitable for determining the light resistance of synthetic rubber materials.

から 53509-0 “ゴムの試験 – オゾンクラッキングに対する安定性の測定 – 一部 1: 静的応力”

2. References to this standard
The various references used in this standard are either dated or undated. These references, which are cited in the standard text, are indicated. A citation standard with a publication date is a later modified or revised version of the standard. Undated standard version refers only to the last version (including modified version) of the relevant standard

から 7716 Rubber and gum products – Requirements for storage, cleaning and maintenance.

から 50014? Air conditioning and its technical application-standard air conditioning equipment

から 53502? Tests on synthetic rubber and fabrics with a synthetic rubber layer — test specimens — manufacturing practice

DIN 53509–2? Tests on rubber and synthetic rubbies-Accelerated ageing of synthetic rubbies-Determination of ozone concentration (recommended method)

から 53509-0 “ゴムの試験 – オゾンクラッキングに対する安定性の測定 – 一部 1: 静的応力”

ステップ 3: 用語
1. Critical elongation

The so-called critical elongation rate refers to the maximum elongation rate that can be subjected to ozone under specified conditions without cracking.

4. Basis of this test method
Put the sample into the fixture of the laboratory to lengthen it to the specified size, stay at the specified temperature and air humidity for a certain time, 指定されたオゾン濃度の空気を使用して、試験中にサンプルの表面を循環させます。. ついに, 亀裂が評価される.

テストの実施には次の方法が使用できます。:

方法A

所定の伸び率で所定の応力時間をかけた後に亀裂パターンを評価します.

方法B

所定の伸び率で亀裂発生時の応力時間を測定.

方法C

亀裂形成時の応力時間を決定するために、少なくとも 4 つの異なる伸び率が使用されました。.

一定の応力時間における臨界伸びのデータ

5. 試験装置 (楽器)
5.1 サンプル治具

治具の材質はオゾン濃度の測定に影響を与えないものとする. アルミニウムやステンレス鋼の製造に最適. 治具では鋭利で鈍いエッジを避ける必要があります. The fixture should be shaped to ensure that the surface of the synthetic rubber sample can be in contact with the ozone-containing air in the laboratory to allow air flow over the surface of the sample. Use a threaded vise to clamp the strip specimen and use it to elongate the specimen to 80%. The unclamped length of the specimen should be at least 40 mm in the unstretched state.

The dumbbell sheet specimen needs to be applied such a fixture, the chuck is in the shape of a claw, the width of the specimen used for elongation is 5 んん, this part is 50 mm long before elongation, can be stretched to 90 んん (80% 伸長). The maximum elongation of the annular specimen is about 20% when the fixture shown in Figure 1 is applied.

The corresponding fixture shall be applied to the finished product. 仕上がりの硬度が大きく、生地の強度が高まるため, ストリップサンプルでは必要な伸びを達成できない. 完成品のセクションをマンドレルに巻き付けることができます, 満足のいく伸びが得られるように. 伸びはデバイス上のあらかじめ作成された目盛線によって制御できます。.

注記: 完成品サンプルの加工面はオゾンから保護する必要があります.

1. 試験室

試験室の内壁はオゾン濃度の測定に悪影響を及ぼさない材質で作られていること。, ステンレス鋼など.

テストチャンバーでは、温度が±2°C、相対湿度が 200 ℃であることを保証する必要があります。 (55±10) % サンプルを持ち出すとき. 試験室に観察穴があり、試験室を開けずに試料を観察できます。 (途切れることのないオゾン供給).

日光や紫外線の直接的な影響から標本を保護します。.

試験チャンバーは最小限の条件に従って設計する必要があります。 10 cm3の空き容量 (音量) 1cm2あたりの試験室の面積. フリースペース (音量) ここでのテストチャンバーの体積とは、チャックと固定具を取り外した後のテストチャンバー内の容積を指します。.

試験チャンバーを通過するオゾン含有空気の流量は、次の計算要件に達する必要があります。 12 ～ 16 mm/s, 最小流体速度は次の値に達する必要があります 8 mm/s. この計算された流体速度は体積流量の商に等しい (音量/時間) 空気流の有効断面積で割った値.

In order to ensure that the ozone concentration tolerance, temperature and relative air humidity specified in sections 7.1 そして 7.2 of this standard are met throughout the chamber, a filter plate is required to distribute the inlet air or other equipment with the same function is used.

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It is recommended to install an auxiliary fan in the test box to strengthen the circulation of air, so that the surface of the sample can be significantly accelerated by (600±100) mm/s, so as to better distribute the air in the test box.

注記 1 When auxiliary fan is not used, the test results may be different, which should be explained in the test report.

述べる 2 It is critical to ensure the uniformity of ozone distribution in the test chamber and to avoid the jig blocking the flow of air flow. In order to better solve the problem, other methods can be used, 例えば, the fixture can be installed on a rotary table, so that the test process is periodically exposed to a certain area of the test box. Similar information and data can be found in the ISO /DIS1431-1:1986 標準.

In addition to using fresh air into the test chamber, you can also use circulating air plus part of the fresh air, the recommended amount of fresh air is not less than 3 x the volume of the test chamber/hour.

In order to prevent the disturbance of the established test conditions, it is required to extract 1 ～ 3 liters of air volume flow rate (LUft-volume EndurchFluss) per minute at the outlet of the test chamber and conduct ozone analysis according to DIN53509-2.

1. Ozone generation equipment can use ultraviolet lamp or discharge tube as ozone source, in the discharge tube to produce static discharge. Air or oxygen can be supplied. Especially when the discharge tube is used to inject air to produce ozone, it needs to be kept very dry (up to 0.3 grams of water per cubic meter of air). Ozone generating equipment shall ensure that the ozone concentration, temperature and relative humidity of the air flow before entering the test chamber meet the relevant test conditions specified in Section 8 of this standard and can maintain these test conditions during the test. The ozone concentration can also be adjusted by changing the voltage of the UV lamp or discharge tube and the amount of fresh air fed.

The ozone source used is required to have sufficient power. Because it is hoped that each time in the opening of the test box door, replace the new sample or observe whether the crack occurs above the sample, after closing the box door, at the latest, the ozone concentration should be adjusted again within half an hour.

The ozonated air from such ozonating equipment shall not contain carbon oxide, 油, dust and other impurities.

Ozone concentration control equipment

The e fluctuating ozone concentration in the test chamber can be recorded at any time and anywhere using suitable equipment operating on the basis of electrochemical or photometric methods. Test such equipment according to the method recommended by DIN 53509-2.

から 53509-0 “ゴムの試験 – オゾンクラッキングに対する安定性の測定 – 一部 1: 静的応力”

6. サンプル
Sections 6.1.1 に 6.1.3 of this standard specify the specimens to be applied. The most commonly used sample is Streifenproben.

The strip specimens and dumbbell sheet specimens can adjust the elongation more accurately than the annular specimens.

6.1 Shape and size of the specimen

6.1.1 Strip sample

The thickness is (2±0.2) んん, and the length is not less than 10 んん; The length is not specified. If the clamping length is not specified, it should be ensured that the length is not less than 40 mm in the unextended state.

6.1.2 Dumbbell sheet sample size is shown in the figure.

Picture is missing

イチジク. 2 dumbbell sheet

6.1.3 環状試験片

The thickness was (6±0.3) mm and the side length or diameter was (60±0.3) んん.

Such annular specimens require a special fixture (セクションを参照 5.1) with a maximum elongation of about 20%.

6.2 Manufacture of the sample

Manufacture specimens according to standard DIN 53502. Can be processed from vulcanized rubber sheet or by the product of the appropriate size of the sample, especially for the latter directly from the product of the sample need to pay attention to the processing shall not damage the vulcanized surface layer (vulcanized film).

注記: IF THE sample of the product cannot be manufactured according to Section 6.1 of this standard, the test can also be carried out directly with the product.

6.3 The number of samples. At least three samples should be used each time.

6.4 Pretreatment of sample test

6.4.1 Pretreatment of the sample without elongation

から 53509-0 “ゴムの試験 – オゾンクラッキングに対する安定性の測定 – 一部 1: 静的応力”

から 53509-0 “ゴムの試験 – オゾンクラッキングに対する安定性の測定 – 一部 1: 静的応力”

Test specimens should wait at least 16 hours after vulcanization and no longer than 4 weeks at the latest. The period between vulcanization and the start of testing should not exceed three months as far as possible. 一方で, the trial shall be started no later than two months after the supply to users. If the test is conducted at a different time, a separate contract shall be signed and indicated in the test report.

If it is necessary to place vulcanized rubber with different mixed structures together, it should be noted that in contact with another vulcanized rubber, the mixing additive should be replaced as much as possible (first, ozone protective agent), which can affect the performance of ozone resistance. このために, aluminum foil can be padded between the various synthetic rubber parts.

When storing, attention should be paid to DIN 7716, which stipulates that the storage temperature should be controlled to better maintain the temperature at (23±2) ℃.

6.4.2 Pretreatment under tensile condition

The surface to be evaluated shall be intact and clean. Requires the removal of weathered skin from the surface.

Such a part of the specimen will produce severe deformation after being clamped through the clamp mouth (セクションを参照 5.1 of this standard). したがって, the part should be coated with a coating of ozone-resistant paint (such as a polyester based on chlorinated chloride) before clamping. The dividing line between the painted surface and the non-painted surface should not be perpendicular to the tensile direction of the specimen, but should be inclined, さもないと, serious cracks will occur on the dividing line. Ozone-protective coatings such as silicone grease (Silikonfett) that may adversely affect the properties of synthetic rubber should be avoided

Before the sample is exposed to ozone, it should be clamped in the jig to reach the tensile state specified in this standard (see Sections 7.4 そして 8 of this standard) のために 48 に 72 時間. In the case of arbitration (in Schiedsf? lle) should be adjusted according to DIN50014-2350-2 to handle tensile state (70-72) 時間 (pre-elongation) under standard ambient conditions.

Hand contact with the specimen should be avoided both during conditioning and subsequent testing.

The test results of samples under the same conditioning conditions and stress conditions need to be comparable.

から 53509-0 “ゴムの試験 – オゾンクラッキングに対する安定性の測定 – 一部 1: 静的応力”

7. Stress conditions
7.1 Ozone concentration

This standard specifies that the ozone concentration used in the test is mainly (50±5) pphm (pphm is the abbreviation of part perhundred millions). 1pphm is equal to 1 volume share of ozone in 108 volume shares of air). 加えて, ozone concentrations of (25±5) pphm, (100±10) pphm and (200±20)pphm can be applied to perform the test.

The unit of ozone concentration can also be used in mg/m 3. The conversion relationship between the two units is as follows:

The unit of the pressure p in the formula is pa. The unit of temperature is K(thermodynamic temperature). The following simple conversion relationship can be used at standard ambient pressure and temperature of 20°C:

50 pphm(V/V) =1 mg/m 3.

注記: Because the ozone concentration in the natural atmosphere is much lower than that actually used in the test, the product is exposed to a lower ozone concentration in the practical application, and the actual interaction is better. Ozone concentration units can be referred to in the introduction to this standard.

7.2 Temperature and relative air humidity

The main test temperature was (40±2) ℃. Temperatures of (23±2) °C and (30±2) °C are also recommended.

The relative air humidity in the test chamber recommended by this standard should reach (55±10) % テスト中に. If you want to use other relative air humidity, you need to sign the contract and indicate it in the test report.

7.3 Stress time

The crack generation diagram (Rissbild) is evaluated after one or more of the following stresses have been applied for hours:

(1.9 2), (3.9 4), (7.8 8), (15.5-16), (23.5-24), (47-48), (71-72), (95-96),

For test method A(セクションを参照 9 of this standard), the main stress action time is (47 に 48) 時間.

The longest stress action time (95-96 時間) should be selected for test methods B and C.

One of the main stresses used for test method C critical elongation is (95-96) hours..

7.4 Elongation of the sample

One or more of the following elongation % may be selected during the strip specimen test:

(5 + 1), (10 + 1), 15 + / – 2), (20-2), (30 + 2), (40 + 2), (50 + 2), (60 + 2), (80 + 2).

For test method A and test Method B, 20% is recommended if only one elongation is selected.

The maximum selected elongation when bending the annular specimen on the fixture of FIG. 2 is about 20%.

There is a great relationship between the crack tendency and the elongation of the specimen. It is hoped that the elongation of the actual application can be used as much as possible for the test of the product.

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8. Implementation of the test
形 3 shows the system diagram of equipment layout when the test is actually carried out.

Start the test chamber is empty, has not yet loaded the sample, first close the switch, make it to meet the requirements of section 7 of this standard stress conditions such as ozone concentration, temperature and relative air humidity. Then put the samples in the fixture treated before section 6.4.2 into the test chamber.

It is necessary to return to the aforementioned test conditions at the latest half hour (30 分).

As far as possible, the peephole installed in the test chamber is used to evaluate the specimen. Only at this time, artificial light is allowed to facilitate the evaluation of the specimen. Test interruption and unnecessary opening of the test chamber should be avoided as far as possible, and the opening time should be shortened as much as possible when it is unavoidable. Other test results are obtained because the specimen is subjected to frequent stress reduction and relaxation processes that can lead to prolonged interruption of ozonation. When opening the test chamber, the loss of ozone and the interruption of ozone generator work should be avoided. Because almost every time the test chamber is opened, あれは, it takes 30 minutes after each interruption of the test to resume the test conditions required by the regulations again.

The test can be conducted by any of the following three methods:

方法A

According to the sample macro grinding observation evaluation. The strip specimens shall reach the specified elongation, 主に 20%, in accordance with Section 7.4 of this standard. The maximum elongation of annular specimens is about 20%. This method requires the stress time specified in Section 7.3 of this standard to be achieved, 主に 48 時間.

方法B

This approach allows the adoption of one or more of the elongation rates given in Section 7.4. If you only use one, 使用 20%. The maximum elongation of annular specimens is about 20%. Stress time was selected as specified in Section 7.3. After the action time, to determine whether the sample cracks. The intermediate time is usually used to evaluate the elongation data according to the period of priority crack detection.

方法C

At a minimum, this method uses the four elongation rates specified in Section 7.4. After the stress time is determined according to Section 7.3, the sample is checked for cracks. For each specimen, the stress time at which the initial crack was detected, the elongation data related to the critical elongation range, and the intermediate time can also be used for evaluation.

For all the above measurement methods, the sample was clamped on the fixture when the observation was made.

から 53509-0 “ゴムの試験 – オゾンクラッキングに対する安定性の測定 – 一部 1: 静的応力”

9. Assessment
The evaluation work requires that the surface to be evaluated be unprocessed and unprotected. Cracks at the edge of the specimen are not considered in the evaluation.

The method of assessment depends on which method (あ,B, またはC) given in Section 8 is applied. These three test methods

Methods can be used 6-8 times of magnifying glass to observe, to see whether the sample surface cracks. Method A can determine the degree and grade of crack without magnifying glass.

Method A is to check the specified elongation after the specified stress time (主に 48 hours and 20%) to see whether cracks occur. If so, the cracks are evaluated according to the crack map automatically drawn by the equipment, so it is not necessary to use a magnifier. It is divided into the following assessment levels:

学年 0: no crack

クラス 1: short and narrow cracks

クラス 2: Long, slightly wider crack

クラス 3: Long, wide crack

It can also be divided into several intermediate levels. 形 4 shows the typical crack distribution diagram of strip samples divided into grades 1-3.

から 53509-0 “ゴムの試験 – オゾンクラッキングに対する安定性の測定 – 一部 1: 静的応力”

The length and width of the crack should be measured during the evaluation. It is also necessary to measure the depth of the crack in annular specimens.

In order to evaluate the crack map more accurately and study the effect of ozone protective agent, the cracks can be evaluated by referring to the following crack class-crack number and crack class-crack length tables.

ここ, the strip sample is selected according to Section 6.1.1, and the length of the sample is 60 んん.
For Method B, the required stress time is obtained at the beginning of crack generation with the elongation specified in the standard (20% more). Both data need to be filled in the test report.

Method C is based on finding the elongation range at which the critical elongation is located. あれは, the maximum elongation ε1% and minimum elongation ε2? Are measured within the specified stress time. %. No crack has been found in all tested samples at ε1. Cracks appear in all tested samples at ε2.

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形 5 shows an example of a graphical solution (line diagram) for the critical elongation of method C. The results of the experiment can be seen at a glance without the need for explanation. In the figure, the ordinate represents the elongation, and the abscissa represents the stress action time (縦軸と横軸の両方で対数スケールを使用して数値を表します. 図中の斜線の上部は亀裂が観察されてからの試験時間を表す。. あれは, 亀裂が発生している領域. しかし, 斜線の下側と破線の上側は小さな亀裂が見つかった場合の試験時間を示す, あれは, 亀裂が発生していない部分. 破線内の領域は、応力時間が到達した後に測定された臨界伸びを表します。 96 時間. 図１に示される種類の折れ線グラフを使用する利点. 5 関連する臨界伸びは、任意に選択した応力時間を使用して簡単に推定できるということです。. しかし, この直線計算にも限界があります. 曲線は合成ゴムの品質に関係します, あれは, this line calculation cannot be applied to all synthetic rubber. If there are no other requirements, the critical elongation should be determined according to the maximum stress time (最大 96 時間).

Method C Line calculation of critical elongation Graphical legislation

Method C Line calculation of critical elongation Graphical legislation

Dehnung in %: 伸長 %; Beansprungungsdauer in h: stress action time (時間); Gebiet mit Rissbildung: areas where cracks occur; Prufzeit, nach der erste Risse beobachtet wurden: test time after the discovery of the first crack; Prufzeit, bis zu der keine Risse beobachtet wurden: test time when no cracks are found; Gebiet ohne Rissbildung: areas where no cracks occur; Kritische Dehnung ε=4% fur 96 h Beansprungsdauer: critical elongation ε=4% after 96 h stress action time

1. 試験報告書

In accordance with this standard, the test report needs to state:

– タイプ, name and shape of the product;

– Where the sample is sampled on the finished product, if from the finished product;

– Shape and size of the specimen;

– Clamping method during finished product testing;

-Specific test method chosen (あ, B or C).

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If the main test conditions for application are not the same, it should also be given:

– ozone concentration;

– temperature under stress;

– Time of stress action:

– Elongation when strip test and dumbbell sheet specimens are used;

– Maximum elongation of annular specimens and products;

– pre-stretch time;

– No auxiliary fan shall be applied;

– Methods for the determination of ozone concentration;

– The crack diagram is evaluated according to grade 0-4 or grade 0-6. For method A, the grade of A-D is used to evaluate;

– Stress time of the first crack in method B;

– Range of critical elongation (ε1,ε2) for method C at specified stress time;

– Existing line diagrams;

– この基準と違うところは;

– 試験日.
D > 8