ASTM D1622 Apparent Density of Rigid Cellular Plastics

Introduction

The ASTM D1622 test method determines the properties of cellular materials by providing measures of their apparent overall density (including the skins formed in the manufacturing process) and apparent core density (after removing the skins formed in the manufacturing process). This method mainly applies to expanded plastics. The units of final results are in SI systems.

Scope

The ASTM D1622 test method determines the density of cellular plastics with or without forming skins. Spray foam materials can also be tested using this test. This test method provides data for research, aids in development and quality control, and specifies the applications of these materials. In this way, it defines the standard for preparing and testing rigid cellular plastics. 

Apparatus used for ASTM D1622

The table below provides insights into the apparatus used in the process.

Procedure

In the ASTM D1622 test method, the analytical balance, micrometer dial gauge, and dual component spray equipment are set up. Weigh the specimen on a balance and measure its dimensions using a gauge. Check the specimen’s weight to ±0.1 % precision. Measure the specimen using a caliper or dial gauge with a minimum area of 6.5 cm2. Maintain the dial foot pressure to 2.7±0.7kPa [0.4±0.1 psi] until the specimen undergoes indentation. Reduce the pressure if there is any indentation. The experimenter should ensure that the caliper gauge jaws are not compressing the sample. Take three measurements for every dimension. Take the measurements thrice to avoid any errors.

Specimen Size

The specimen size and number should be as the ASTM D1622 standard requires. Three specimens are taken such that their volumes can be accurately calculated and are not less than 16.4 cm³ (1.0 in.³) in volume.

Data

For ASTM D1622, the density is calculated up to three significant figures as follows:

D = Wₛ/V

Where,

D = density of the specimen 

Wₛ = weight of the specimen, kg (lb)

V = volume of the specimen

The estimated standard deviation is reported up to two significant figures.

Result

The apparent density of rigid cellular is reported in three significant figures.

Applications of ASTM D1622

1. Research and Development: ASTM D1622 provides the basic information that facilitates research and development in cellular plastics. This knowledge helps to assess material characteristics for innovation in various applications and formulations.
2. Quality Control: The test method’s major application involves quality control processes. It helps ensure that a manufacturer’s products have met specific stipulated density requirements critical to performance and industry-standard conformance. 
3. Material Specification: The test results inform material specification, which advises engineers and designers on the materials that should be utilized for a particular application. Such specification plays a critical role in industries like construction, automotive, and aerospace, where the characteristics of materials significantly contribute to performance and safety.
4.  Versatility in Applications: Methods under ASTM D1622 can be applied to materials that form a skin and those that do not. Further, even spray foam materials can be tested using this method. Thus, they extend their usefulness across various industries and into several applications.
5. Interlaboratory Comparisons: Interlaboratory studies have also used this method for developing precision statements, further establishing it as one of the standardized test methods for multiple laboratories.

Conclusion

ASTM D1622 covers the determination of density in rigid cellular plastics, both with surface skins and spray foam material. The procedure includes a precise weighing and dimensional measurement to ensure precision in both apparent overall and core densities. This is a significant method for research, development, and quality control in that it serves as crucial information for material properties and performance evaluation. More so, the industry will be in a better position regarding improving product quality and consistency, making better decisions on appropriate applications of the material, and improving general product reliability due to the specifications of ASTM D1622.

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