This part of YY/T 0681 describes the evaluation procedures of chemical contact bearing capacity of printed inks, finishing varnish or coatings on the upper layer of printing. Typical chemicals that may come into contact with packaging include water, ethanol, acid, etc. For special chemicals, the methods shall be selected and measurement results shall be determined through discussion and negotiation with users. The methods listed in this part provide suggestions for test methods and information collection.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2918 Plastics — Standard atmospheres for conditioning and testing
3 Significance and use
3.1 Packaging materials may come into contact with chemicals such as water, ethanol and acid during their life cycle. If the packaging material is expected to come into contact with chemicals, it is important that the inks or coatings do not degrade, soften or dissolve after contact.
3.2 The tests included in this part are applicable to surfaces with printing and coating materials designed to be stable to a specific chemical.
3.3 The test chemicals should be compatible with printed and/or coated substrates (i.e., not damaged or degraded).
3.4 This part details four methods. These methods are gradually stricter from Method A to Method D. The method should be selected according to the expected contact type. For example, pouring method (Method A) is expected to be used for accidental contact (e.g., pouring chemicals on the surface of materials). When the desired chemical resistance depends on the expected contact level (B) or wiping level (C), Method B or C is used respectively. Method D indicates that materials are in constant contact with chemicals and need to be chemically resistant (e.g., the package is soaked in chemicals for a certain period and wiped).
Foreword i 1 Scope 2 Normative references 3 Significance and use 4 Apparatus 5 Sampling 6 Conditioning 7 Procedure 8 Report
