Before you can export plastic and or other scrap material to China, foreign enterprises must first register with the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, or AQSIQ for short.
This is the governmental department established to ensure that all cargo entering China complies with rules, laws and regulations.
The largest issue companies face when registering for AQSIQ certification is that all submitted information must be written in Chinese.
If you're not familiar with the Chinese language, the best way is to get assistance from a third-party AQSIQ registration company.
There are a total of 17 documents needed for the AQSIQ registration process:

1. The Provisional Registration of Overseas Supplier Enterprises of Imported Scrap Materials application form.
   
2. Copy of your business registration.
   
3. Document on environmental management system or certified certificate on environmental management system.
   
4. Document on source of supply and environment protection control measures.
   
5. A general description and relevant certificating documents on the safety, hygiene, environmental protection, and quality of scrap materials exported to China within the past three years.
   
6. Organizational structure, responsibilities of departments and job positions.
   
7. An undertaking to abide by the technical regulations on environmental protection, applicable environmental protection controls standards and the relevant laws and regulations of China.
   
8. Information on permanent office and processing locations (must show floor plans).
   
9. Certificates relating to type, quantity, and environmental quality of commodity.
   
10. Quality control management system and relevant technical personnel (including control over dangerous waste, contaminated waste and arrangement on discarded waste).
    
11. Verification and acceptance system for raw materials.
    
12. Measurement and equipment calibration system.
    
13. Rules on control over substandard commodity.
    
14. Staff training program.
    
15. Undertaking on control over environmental quality of goods.
    
16. Undertaking on bearing the cost incurred in the disposal of goods failing to meet environmental quality requirements.
    
17. Text of Chinese environmental control standards, directories on items prohibited from import and directories of hazardous waste materials

Looking to purchase plastic scrap to export to China? The first thing you need to ask is if the seller has an AQSIQ certificate.
If the seller is AQSIQ certified, you won't have to worry about renting one.
Yes, there are AQSIQ certificates out for rent for a small fee.
While the Chinese government forbids renting out the AQSIQ certificate, it's part of the plastic scrap trade and happens on a daily basis.
Please note that AQSIQ certified sellers are usually very established in selling to Chinese buyers.
Most of the time, they have an email list of Chinese buyers and manufacturers waiting to bid on their plastics (which means high prices!).
An alternative to shipping to China is Hong Kong.
Hong Kong is an open port which requires no documentation for importing or exporting.
Plus, there is no customs duty.
In fact, most of my business has now moved to Hong Kong.
Buyers in Hong Kong typically do not process recycled plastics (due to high wages), it usually ends up being resold to buyers or manufacturers in Guang Dong (a neighboring province in China).
If China is your final destination, there are logistic companies in Hong Kong that can forward your containers into China.
They will take care of the AQSIQ rental and CCIC inspection for you.