Definition, classification, marking and preparatio

2022-09-23
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Preparation instructions for the definition, classification, marking and degradation performance requirements of degradable plastics

1 task source

according to the second batch of national standard preparation and revision plan of the National Standardization Administration Committee in 2003, "definition, terminology, marking and degradation performance requirements of degradable plastics" (project number -t-607, non equivalent ISO 842:2002), in addition to the production of environmental protection bags, and in accordance with the requirements of the organization and implementation of relevant projects, The biodegradable materials working group of the National Center for standardization of plastic products has completed the draft of the standard for review

2 general idea of standard formulation

on September 5, 2003, the biodegradable materials working group (BMG) of the National Center for standardization of plastic products held a discussion meeting on the draft standard of "definition, terminology, marking and degradation performance requirements of degradable plastics" in Beijing. The working group reviewed the draft standard "definition, terminology, marking and degradation performance requirements of degradable plastics". Comrades attending the meeting had a heated discussion on the definition, terminology, signs and degradation performance requirements of degradable plastics, and expressed their views and opinions. In May, 2004, a symposium on the draft of the national standard for degradable plastics was held in Beijing. After discussion at the meeting, a draft for comments was formed, and comments were solicited in June 2004. At the first International Symposium on technology and application of biodegradable materials held in October 2004, the opinions of the conference representatives were again solicited

on the basis of extensive consultation, in order to better classify degradable plastics, correctly guide and regulate the development of degradable plastics industry, and reasonably protect the interests of interested parties, the working group believes that degradable plastics are divided into biodegradable plastics, Compostable Plastics, photodegradable plastics, thermooxidative degradable plastics and starch filled degradable plastics according to the final degradation path designed by it

3 determination of the types of degradable plastics in the standard

considering that the current international classification of degradable plastics is mainly divided into photodegradable plastics, biodegradable plastics, thermooxidative degradable plastics, Compostable Plastics, etc., and considering the current situation of degradable plastics added with starch or calcium carbonate in China, the standard of degradable plastics in this standard is divided into biodegradable plastics, Compostable Plastics Photodegradable plastics, thermooxidative degradable plastics, starch filled degradable plastics, etc

in addition, considering that the purpose of plastic filled inorganic fillers is mainly to reduce costs and improve performance, but the main purpose is not degradation, so this type will be deleted after consultation during the review of this standard. Starch filled general-purpose plastics, which still occupy part of the domestic market, are mainly starch filled and modified. Therefore, this kind of plastics is finally named starch filled degradable plastics in this standard, in order to gradually transition to full biodegradable plastics

in some previous standards or literatures, there used to be words of light biodegradable plastics. Considering the definitions in international standards and the environmental conditions of light biodegradable plastics, photodegradation and biodegradation generally will not be carried out at the same time. If light biodegradable plastics have photodegradation performance and biodegradation performance, they can meet the standard requirements of photodegradable plastics or biodegradable plastics respectively. Therefore, photo biodegradable plastics are no longer included in this standard classification

degradable plastic refers to a plastic that, under specified environmental conditions, after a period of time and one or more steps, leads to significant changes in the chemical structure of the material, resulting in the loss of some properties (such as integrity, molecular weight, structure or mechanical strength) and/or crushing. The standard test method that can reflect the change of performance shall be used for testing, and its category shall be determined according to the degradation mode and service cycle

biodegradable plastic refers to that under natural conditions such as soil and/or sandy soil, and/or specific conditions such as composting or anaerobic digestion, or in aqueous culture medium, it is degraded by microorganisms such as bacteria, molds and algae, and finally completely degraded into carbon dioxide (CO2) or/and methane (CH4) Water (H2O) and mineralized inorganic salts of its elements, as well as new biomass plastics

compostable plastic refers to a kind of plastic that can be degraded and disintegrated under composting conditions due to biological reaction process, and finally completely decomposed into carbon dioxide (CO2), water (H2O) and the mineralized inorganic salts of the elements contained in it, as well as new biomass, and the content of heavy metals, toxicity tests, residual fragments, etc. of the final compost must meet the provisions of relevant standards

heat- and/or oxide- degradable plastic refers to the plastic degraded by heat and/or oxidation

photo degradabl2019 paper industry forecast e plastic sheet refers to the plastic degraded by natural sunlight

starch filled degradable plastic refers to a kind of plastic products made by molding with starch and general plastic resin as the main raw materials. These products have obvious changes in chemical structure under the action of bacteria, molds (fungi) and natural microorganisms such as algae, which have been established in 2013 by the provincial graphene alliance in Jiangsu Province and Shandong Province

4 modification of standard name

the name in the standard plan is "classification, definition and terminology of degradable plastics". Considering that the degradability of degradable plastics must be required when defining it, in order to make the standard more applicable, the standard name is changed from the definition, classification, marking and degradability requirements of degradable plastics. While putting forward requirements for the degradation performance of degradable plastics, they are classified and identified

however, due to the different types of degradable plastics, there are many differences in physical properties, and the requirements of physical properties are related to the final application of the product. Therefore, after consultation and coordination from various parties, the requirements of physical properties were cancelled, the definition, classification and mark of degradable plastics were added, and the requirements of degradation properties were specified

therefore, the name of the standard is finally changed to the definition, classification, marking and degradation performance requirements of degradable plastics

5 scope of application of the standard

this standard specifies the terms and definitions, classification and identification, degradation performance requirements, test methods, marks, packaging, transportation and storage of degradable materials

this standard is applicable to the following types of degradable materials:

-- natural and/or synthetic polymers, copolymers or their mixtures

-- plastic materials containing additives such as plasticizers, pigments or other compounds

-- water soluble polymer

-- products processed from various degradable plastic materials

6 technical requirements of the standard

due to the different types of degradable plastics, there are many differences in physical properties, and the requirements of physical properties are related to the final application, so this standard removes the requirements for physical properties in the exposure draft and only puts forward requirements for degradation properties. Therefore, in the technical requirements, we always pay attention to the precipitation and accumulation of technology, such as 5.1 appearance, 5.2 specification, 5.3 performance, 5.5 sanitary performance, etc. This standard mainly stipulates the degradability of degradable plastics

the photodegradation performance of degradable plastics is mainly tested according to natural conditions exposure and laboratory xenon lamp artificial accelerated aging. The exposure method refers to gb/t and gb/t 16422.2. The test conditions are mainly determined by referring to the data and results of photodegradation films for many years. The performance evaluation is mainly based on the tensile elongation retention rate and molecular weight change; Refer to ASTM D 5510 for thermooxidative degradation performance, and tensile elongation retention and molecular weight change are used for performance evaluation; The test method of biodegradation performance mainly refers to gb/t 19277 and/or gb/t 19276.1 and/or gb/t 19276.2 and/or ISO 17556 or ISO 14853 or ISO 15985, and the results are expressed in the percentage of biodegradation; Compostable performance is mainly based on ISO CD 17088. Not only the compostable performance, but also the disintegration performance should be measured; The degradability of starch filled degradable plastics is the degree of disintegration in the disintegration test, the growth level of mold in the mold erosion test, or the percentage of biodegradation in the biodegradation test

7 description of removal of inspection rule clauses

since this standard only stipulates the definition, classification, marking and degradation performance requirements at the end, the degradation performance of degradable plastics is relatively fixed under the same formula conditions in the actual process, and the amount of samples has been mentioned in the test method, the inspection rule clauses have been removed

information source: the second International Symposium on technology and application of biodegradable materials

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