Resource Intensity Analysis of Producing 21 Types of Plastic in Terms of Mining Activity

Round 1

Reviewer 1 Report

The authors have tried to perform a Resource Intensity Analysis for 21 types of plastics. At the moment, the paper lacks cohesiveness. The goal is quite demanding. In order to tackle the goal, the manuscript needs more detailed data and a more detailed discussion. The authors mention that the numbers depend on the location of plastic production (and use), and the authors should expand more on this aspect. It would be good, if the authors "work through the numbers" for 2-3 plastic types (for the location Japan, for instance), so that the reader can understand which processes lead to the overall TMR and GWP. Plastic types can be chosen, where more than one dominant process of production exists. This would include numbers (eg., for Japan) for the end-of-life streams vs. recycling streams. That would be better than simply stating that the inventory data have been gleaned from MiLCA. MiLCA and IDEA should be introduced to readers who have not worked with them. Also, it must be noted that many plastic products are made of composite materials, and it should be mentioned how this fact reflects on the calculations. 

The English needs to be revised extensively.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript deals with theoretical studies on the resource consumption of various plastics. The results are of practical and scientific interest. However, the following points should be reworked before publication:

(1) Lines 138 ff.: The equation for determining the specific TMR needs to be better explained. For the theoretical case that incoming and outgoing quantities are equal, this equation gives the result 0 = 1

(2) Lines 186 ff: It must be explained why only 19 and not 21 plastics were analysed for the consideration of TMR per tensile strength. And, is the unit “kg-TMR/kg x MPa” in Fig. 3 correct?

(3) It must be stated more precisely how “natural resources” and “greenhouse gas emission” can be compared with each other to draw the line in Fig. 5

(4) Lines 18 ff. and line 320: The expression “positive correlation” needs to be better explained

(5) Line 257: It should read Fig. 5 instead of Fig. 6

(6) Some of the sources need to be better provided in the References section in order to be found, e.g. [31], [32] and [58]

Sentence structure can be improved in some places.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The authors present the data from different sources and analyze 21 different plastics on account of sustainability and resource expenses. The article can be accepted for publication as it gives an idea about the cost of natural resource usage and greenhouse gas emission contribution of 21 different plastics. 

Why the biodegradable plastics not included in the study?

line 257: figure number should be 6, not 5.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have addressed most of the concerns of the reviewer. It is important to edit the English of the article, as in its current form it is not publishable. The citations should be in a uniform format (the journal's names should be given in full, not abbreviated). Typos may need to be fixed - such as the heading "input materials" in the supplementary material. It is not clear why the three plastics/polymers detailed in the supplementary material were chosen to show the calculations for.

The English needs to be edited extensively.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf