Interpretation of ISO 2115: The Core Standard for Film-Forming Properties of Plastic Polymer Dispersions

In the chemical industry such as plastics and coatings, the film-forming properties of polymer dispersions directly determine the quality, stability and application effect of products. As a core standard developed by the International Organization for Standardization (ISO), ISO 2115 specifically specifies the determination methods of white point temperature and minimum film-forming temperature of polymer dispersions, providing a unified technical basis for industrial production, quality control and product research and development. This article will comprehensively interpret ISO 2115 from the aspects of basic standard information, core definitions, determination principles, implementation points and application value, helping industry practitioners deeply understand its core connotation and practical significance.

IO. Basic Information of ISO 2115 Standard

ISO 2115 is fully named “Plastics — Polymer dispersions — Determination of white point temperature and minimum film-forming temperature”. It is formulated and maintained by ISO/TC 61/SC 9 (Plastics Technical Committee/Dispersions and Latices Subcommittee). The current valid version is ISO 2115:1996, which was released in February 1996 and confirmed valid after the last review in 2021. It is in the international standard confirmation stage (90.93) and will undergo a systematic review every 5 years to ensure its applicability.
The International Standard Classification Number (ICS) of this standard is 83.040.10 E 83.080.01, covering the field of plastic dispersions and related materials. As a method standard, ISO 2115 is not directly used for product quality determination, but ensures the comparability of film-forming performance data measured by different laboratories and enterprises through a unified test method, providing technical support for product quality control and international trade. It is worth noting that China has equivalently adopted this standard and formulated the national standard GB/T 9267-2008, expanding its application scope to coatings emulsions, coatings and plastic polymer dispersions, which is more in line with domestic industry needs.
ISO 2115:1996 replaces the second edition standard released in 1976. On the basis of the original version, it has been expanded and coordinated to make the test method more scientific and operable. The full text has 5 pages, mainly including core contents such as test principle, instrument requirements, operation steps, result expression and precision.

II. Core Definitions and Test Objects of ISO 2115

To understand ISO 2115, it is first necessary to clarify the definitions of two key terms in the standard, which are also the core objectives of the test, and clarify its scope of application to avoid misuse.
(IO) Core Definitions
1.Polymer dispersion: A dispersion system formed by uniformly dispersing polymer materials in a liquid medium (usually water). During the drying process, with the evaporation of the liquid, polymer particles will interact and combine closely, and finally form a film. Its film-forming effect is affected by many factors such as temperature and dispersion type.
2.White point temperature: The boundary temperature at which an opaque film turns into a transparent film. When the temperature is insufficient, polymer particles cannot coalesce effectively, forming discontinuous and opaque white lumps; when the temperature reaches the white point temperature, the particles start to coalesce, and the film gradually becomes transparent.
3.Minimum film-forming temperature: The minimum temperature at which a continuous, uniform and crack-free transparent film is formed, which is the core index of the film-forming performance of polymer dispersions. Usually, the white point temperature is several degrees lower than the minimum film-forming temperature, and both reflect the film-forming characteristics of the dispersion together.
(II) Test Objects
The core test object of ISO 2115 is polymer dispersions for plastics. Allo stesso tempo, according to the expansion of China’s GB/T 9267-2008 (equivalent to ISO 2115:1996), its application scope also includes coatings emulsions and coatings polymer dispersions. Inoltre, similar products in other industrial fields such as rubber can also be tested with reference to this standard.

III. Test Principle and Instrument Requirements of ISO 2115

The core of ISO 2115 test is to simulate the actual drying conditions, construct a temperature gradient, observe the film-forming process of polymer dispersions, so as to determine the white point temperature and minimum film-forming temperature. The entire test process must follow rigorous principles and instrument specifications.
(IO) Test Principle
A linear temperature gradient (temperature difference set between 20℃ and 40℃, kept constant during the test) is constructed on a metal plate (alluminio, stainless steel or steel) located between a heat source and a cold source. The polymer dispersion is uniformly coated on the metal plate, starting from the high-temperature end. Then, a constant low-speed dry air stream is introduced from the cold end to the hot end to gradually dry the dispersion. By observing the change of the film state, the boundary point between opaque and transparent (white point temperature) and the minimum temperature for forming a continuous and crack-free transparent film (minimum film-forming temperature) are determined. If the temperature gradient is linear, the result can be directly read through the temperature measuring device; if it is non-linear, the test result must be determined by the graphing method (with the distance of the temperature measuring point as the abscissa and the temperature as the ordinate).
(II) Instrument Requirements
To ensure the accuracy and repeatability of test results, ISO 2115 puts forward clear requirements for test instruments. The core instruments and specifications are as follows:
1.Main test instrument: Composed of a rectangular metal plate, the surface can be smooth or grooved with several 0.3mm deep grooves (easy to clean, and can be covered with a thin anti-adhesive material), which can stably form a linear temperature gradient.
2.Temperature measuring device: Used to accurately measure the temperature at different positions on the metal plate to ensure that the temperature gradient meets the requirements. A surface thermometer or other high-precision temperature measuring instruments can be selected.
3.Film coater: Divided into grooved plate coater and flat plate coater. The flat plate coater must ensure a coating thickness of about 0.1mm and a coating width of 20mm~25mm; the grooved plate coater must be used with the groove body to ensure uniform coating of the sample.
4.Equipaggiamento ausiliario: Including a glass cover (used to maintain a dry environment), a dry air supply device (to ensure constant air flow rate), eccetera.

IV. Test Process and Result Requirements of ISO 2115

ISO 2115 specifies a detailed test process, and each step must be strictly followed to ensure the reliability and comparability of test results. The specific process and result requirements are as follows:
(IO) Test Process
1.Formation of temperature gradient: Place the temperature measuring device at the designated position, adjust the temperature of the heat source and cold source, and construct a suitable linear temperature gradient to ensure that the white point temperature is measured in the middle of the metal plate, and the upper and lower limits of the temperature gradient are within the range of the measuring device.
2.Sample coating: After the temperature is balanced, uniformly apply the sample on the metal plate. When using a grooved plate, inject a little more sample than the groove capacity into the groove from the high-temperature end, coat along the groove with a coater and remove the excess sample; when using a flat plate, start coating from the high-temperature end to form a narrow strip of specified thickness and width.
3.Drying and observation: Cover the glass cover, introduce a constant low-speed dry air stream from the cold end to the hot end, observe the change of the film state, record the reading of the temperature measuring device, or determine the white point temperature and minimum film-forming temperature by the graphing method.
4.Repeat test: At least two determinations shall be carried out. If the difference between the two results is greater than 2℃, the test shall be re-conducted to ensure the repeatability of the results.
(II) Result Expression and Precision
The test results are expressed as integers in degrees Celsius (℃), which can be obtained by the graphing method or directly reading the data of the surface thermometer, and finally take the average value of multiple determination results. According to the requirements of ISO 2115, the test results must meet the following precision requirements:
•Repeatability: When multiple tests are carried out in the same laboratory, by the same operator and with the same instrument under the same conditions, the result deviation shall not exceed 2℃;
•Reproducibility: When tests are carried out in different laboratories, by different operators and with different instruments under the same conditions, the result deviation shall not exceed 4℃.
The test report shall include at least the following contents: standard number (ISO 2115:1996 or corresponding national standard number), complete identification information of the tested product, model of test equipment and test conditions, laboratory temperature, test results and average value, eccetera.

V. Application Value and Industrial Significance of ISO 2115

As an international standard for testing the film-forming properties of polymer dispersions, ISO 2115 has irreplaceable application value in the plastics, rivestimenti e altre industrie, and its core significance is reflected in the following aspects:
(IO) Standardize Quality Control and Ensure Product Consistency
The film-forming properties of polymer dispersions directly affect the quality of the final product, such as the adhesion of coatings and the flexibility of plastic films. ISO 2115 provides a unified test method, enabling enterprises to accurately control the film-forming characteristics of products, avoid product defects (such as cracking, Chalking, poor adhesion, eccetera.) caused by inconsistent film-forming temperature, and ensure the consistent quality of mass-produced products.
(II) Support Product R&D and Optimize Formula Design
In the process of product R&D, through the test method of ISO 2115, R&D personnel can quickly evaluate the film-forming properties of polymer dispersions under different formulas and processes, optimize the formula composition, adjust the production process, and develop products more in line with application needs. Per esempio, for coatings used in low-temperature environments, the minimum film-forming temperature can be tested to optimize the formula so that it can still form a good film at low temperatures.
(III) Promote International Trade and Eliminate Technical Barriers
As a globally recognized technical criterion, the application of ISO 2115 makes the test data of different countries and enterprises comparable, avoiding trade barriers caused by differences in test methods. By following this standard, imprese’ product quality is more likely to be recognized by the international market, which helps expand overseas business and enhance international competitiveness.
(IV) Improve the Standard System and Promote Industrial Upgrading
ISO 2115 is connected with relevant industry standards (such as China’s GB/T 9267-2008) to form a standard system for quality control of polymer dispersions. Its implementation has promoted the improvement of the industry’s technical level, guided enterprises to standardize production processes, improved quality management level, and promoted the standardized and high-quality development of the entire plastics and coatings industry.

VI. Precautions and Common Misunderstandings of ISO 2115

(IO) Precautions
•During the test, the temperature gradient must be kept constant and as linear as possible, otherwise the accuracy of the test results will be affected;
•The sample coating must be uniform, and the thickness must strictly follow the standard requirements (0.1mm for flat plate coating) to avoid abnormal film-forming state caused by uneven coating;
•The speed of the dry air stream must be constant and introduced from the cold end to the hot end to ensure that the drying process meets the standard requirements;
•Test instruments must be calibrated regularly to ensure the accuracy of temperature measurement and avoid instrument errors affecting the test results.
(II) Common Misunderstandings
•Confusing white point temperature with minimum film-forming temperature: Both are film-forming performance indicators, but the white point temperature is the “boundary temperature between transparent and opaque”, and the minimum film-forming temperature is the “minimum temperature for forming a qualified film”, which cannot be regarded as equivalent;
•Ignoring the test environment temperature: The laboratory temperature will affect the drying speed and film-forming state of the sample, which must be clearly recorded in the test report;
•Failing to conduct repeat tests: Conducting only one test is likely to lead to result deviation. It is necessary to strictly conduct at least two tests in accordance with the standard requirements to ensure the repeatability of the results.

VII. Conclusion

As the core international standard for testing the film-forming properties of plastic polymer dispersions, ISO 2115:1996 provides a unified technical basis for the industry by clarifying test methods, instrument requirements and result specifications, and plays a key role in quality control, product R&D and international trade. Its core value lies in standardizing the test process, ensuring product consistency, eliminating technical barriers, and promoting the high-quality development of the plastics, rivestimenti e altre industrie.
For enterprises, strictly following the requirements of ISO 2115 can not only improve product quality and market competitiveness, but also realize the standardization of production processes; for the industry, the wide application of this standard helps improve the standard system, promote technological upgrading, and promote the sustainable development of the industry. With the continuous progress of the chemical industry, ISO 2115 will also be regularly reviewed to continuously adapt to the needs of industry development, providing continuous support for the technical unification and quality improvement of the global polymer dispersion field.

Our product GA-6021 Film-Forming Temperature Tester meets this standard.

Tester della temperatura di formazione del film

Norma di prova:
It isaccordance with ISO 2115, ASTM D 2354 standard, e può testare la temperatura minima della pellicola del polimero in emulsione in modo semplice e accurato.

Descrizione：
As the most important component–emulsions for coatings and polymer dispersions for coatings and plastics polymer, la sua proprietà filmogena ha un'influenza importante sulle proprietà di essiccazione dei prodotti finali. Così, knowing its MFT is very necessary.
Ad una certa temperatura, emulsioni o dispersioni polimeriche, se la temperatura non è abbastanza alta, quindi non è possibile lasciare che le particelle polimeriche polimerizzino. Ora, tutte le particelle del polimero non riescono più ad unirsi e quindi formano una massa bianca incontinua e non trasparente; Se la temperatura è sufficientemente alta, lasciare che le particelle si uniscano, quindi può formare una pellicola continua e trasparente.
Temperatura del punto bianco：La temperatura di divisione quando la pellicola non trasparente passa alla pellicola trasparente.
Temperatura minima di formazione del film：La temperatura più bassa durante la formazione continua, uniform and no-crack film（Generally speaking, White Point Temperature has serval degrees lower than MFFT）
Minimum Film-Forming Temperature（MFFT）Tester is the newest instruments which is developed by Biuged lately, La sua struttura principale è una piastra di metallo (rame) con un gradiente di temperatura imposto elettronicamente. Built in temperature sensors monitor the temperatureacross the platen, sul touch screen viene visualizzato un grafico del gradiente. Acooling source and a heating source are located separately on the two ends of platen to produce different temperature gradient through metal heat conduction theory.
Applicate a continuous and uniform thickness wet film of emulsion ordispersions on the temperature gradient platen, quindi asciugarlo con aria secca, con la temperatura di influenza della piastra, l'acqua del campione evaporerebbe e formerebbe una pellicola. A causa della diversa temperatura sulla piastra, anche la posizione di formazione del film è diversa. Trova il punto di divisione tra la pellicola trasparente continua e la pellicola bianca non trasparente, thus this point which also can be read from touch screen of tester is MFT.

Caratteristiche：
◆ Initiated in China, Prodotto ad alta tecnologia,combinano molti brevetti con diritti di proprietà intellettuale indipendenti.
◆ Small size, alta precisione, funzionamento intelligente, facile da usare e da mantenere.
◆ Color touch screen+ menu operation system, tutti i parametri possono essere visualizzati in tempo reale
◆ High precision digital temperature sensor, ensure the temperature error is less than 0.1℃
◆ Come with chiller
◆ Removable scale is convenient for operator to read any point temperature on the gradient platen. L'operatore può spostare la bilancia liberamente, quindi il tester può identificare automaticamente la posizione corrente e mostrare la temperatura rilevante di questa posizione.
◆ Monitor automatically cooling water temperature and flow, il tester smetterebbe di funzionare automaticamente in caso di condizioni eccezionali.
◆ Platen（Temperature gradient）is made of copper with special process, conduzione veloce del calore e forte stabilità.
◆ System reminder operator automatically about the testing progress.
◆ Seven work conditions for selection,conveniente per misurare diversi campioni di temperatura di formazione del film.
◆ 13 high temperature sensors isdistributed on the gradient platen.
◆ Come with cube applicator which can get the 100 micron continuous and uniform wet film with 25mm width

Principali parametri tecnici
■ Working temperature range of gradient platen：-10℃～+70℃
■ Number of inspection points of gradient platen：13 punti
■ Interval distance of gradient：25mm
■ Test channels：7 pcs（width is25mm）
■ Gradient platen size：447mm×210 mm
■ Alimentazione：220Ampia tensione CA V/50 Hz (alimentazione trifase con buona terra)
■ Tester Size：528mm（L）×430mm（W）× 184mm（H）
■ Chiller Size：460mm（L）×200mm（W）× 160mm（H）
■ Weight：20Kg

Product link:

https://www.gonoava.com/product/ga-6021-minimum-film-forming-temperature-tester/

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