国内外生物降解塑料现状与发展趋势

目前全球塑料年消耗量约为2亿吨，而生物可降解塑料的市场份额还不到0.5%。近些年来由于石油价格的长期上涨，全球气候的暖化问题日益严重，世界各国政府出于资源战略、环境和经济的考虑，出台了一系列支持生物可降解塑料的政策法规，促使生物可降解塑料市场需求保持在年均增长20-30%的水平。 根据日本生物降解塑料研究会的资料，2002年日本生物降解塑料生产量约1万吨，2003年约2万吨，2005年约4万吨，到2010年预计达到10～20万吨左右。 欧洲生物塑料协会资料，2001年的数字显示，欧盟可生物降解产品的消费量为2.5～3万吨，而传统聚合物的用量高达3500万吨。截至2007年8月，全球生物降解塑料的年生产能力已达31．5万吨；欧洲生物塑料协会预计2010年生物降解塑料的用量会达到100万吨左右。第二届国际生物塑料市场会议上也有专家预测，全球生物可降解塑料市场需求年增长预计为30%，到2010年，全球生物可降解塑料的需求将达到130万吨，而届时生物可降解塑料的产能预计只有100万吨。

美国Freedonia市场研究集团研究报告预计最具有“最佳发展机会”的品种是聚乳酸材料，其次为淀粉改性塑料树脂。Freedoma集团认为，由于聚酯类生物降解塑料价格下降，应用范围宽，加上其在薄膜和纤维领域中的新应用，将是一种需求“增长性”的生物降解塑料品种。预测今后几年北美生物降解聚合物市场需求强劲。
图1.世界生物降解材料的增长及未来发展预测
在中国，最初的可降解塑料是PP或PE与淀粉的简单共混物，只能分裂成小碎片或部分降解，不但不能从根本上解决白色污染问题，而且造成了回收困难和二次污染，因此没有得到广泛应用。按照中国塑协降解塑料专业委员会的统计，中国2003年生物降解材料的用量大概是15000吨，其中不添加淀粉的生物降解聚合物约1000吨。2005年从事生物降解塑料的企业约30家，生产能力6万吨/年，实际生产约3万吨，国内市场需求约5万吨，国外进口1万吨，出口2万吨。预计2010年产能将达到25万吨左右。
目前，全球研发的生物降解塑料品种已有几十种，可批量生产的品种主要有：微生物发酵合成的聚羟基脂肪酸酯（PHA, PHB, PHBV等）、化学合成的聚乳酸（PLA）、聚己内酯（PCL）、二元醇二羧酸脂肪族聚酯（PBS）、脂肪族/芳香族共聚酯（Ecoflex）、二氧化碳/环氧化合物共聚物（APC）和聚乙烯醇（PVA）等，天然高分子淀粉基塑料及其生物降解塑料共混物、塑料合金等（详见表1）。其中聚己内酯（PCL）和聚乙烯醇（PVA）工业化技术最成熟，聚乳酸（PLA）、二元醇二羧酸脂肪族聚酯（PBS）、脂肪族/芳香族共聚酯（Ecoflex）工业化技术也渐趋完善，而微生物发酵合成的聚羟基脂肪酸酯（PHA, PHB, PHBV等）和二氧化碳/环氧化合物共聚物（APC）还处于大规模工业化的前期阶段。

上述生物降解高分子中，聚羟基脂肪酸酯类，聚乳酸和淀粉属于生物基高分子，它们的生产原料来自生物资源----淀粉，所以不依赖石油的价格波动，且整个过程更加环保，不会造成进一步的环境污染问题。以市场规模统计，生物基高分子大约占了生物降解高分子的80~90%。在生物基高分子中，生产1公斤的聚羟基脂肪酸酯类材料大概需要5公斤的玉米，而聚乳酸则只需要2.6公斤的玉米。从原料成本上看，聚羟基脂肪酸酯类的成本就增加了大约一倍，且目前的聚羟基脂肪酸酯类生产技术还不是很完善，大多处于中试阶段，生产成本在5000~7000之间。淀粉基生物降解塑料真正的工业化大生产的是意大利Novamont的Mater-Bi。产品仍有不足之处，且产品的价格高达7000多美元／吨。

An overview of Certification Bodies

Biodegradability & Compostability

1. What is difference between Biodegradability and Degradation?

Degradation/Fragmentation
- Heat, moisture, oxygen, sunlight and/or enzymes shorten & weaken polymer chains, resulting in fragmentation

Biodegradation
- Only if the fragmented residues consumed by microorganisms as a food source and energy source and become to CO2 and H2O.

2. Four basic criteria for assessing compostability

a. Chemical Testing/ Characterization
- To ensure neither harmful organic substances (e.g. polychlorinated biphenyl (PCB) and dioxins), nor heavy metals (e.g. Pb, Hg, Cd) pass into the soil vial the compost.

b. Testing of ultimate biodegradability
- To verify the complete degradation of the materials within the processing period of normal composting plants.

c. Testing of compostability (Disintegration)
- To determine the max. compostable layer thickness; To ensure the ability to fragment into non-distinguishable pieces after screening and safely support bio-assimilation and microbial growth.

d. Compost Quality Analysis (Ecotoxicity)
- To ensure that the materials used have no adverse effect on the quality of the compost; To ensure the finished compost can support plant growth.

3. Standards - Basic criteria for assessing compostability

• EN 13432 1. Chemical Testing: Amounts of specified elements are not to exceed the upper limits as defined in the German bio-waste regulation. 2. Testing of ultimate biodegradability: ISO 14851/14852/14855; at least 90% conversion to CO2 with respect to a suitable reference material; within 180 days (6 mths). 3. Testing of compostability (Disintegration): ISO 16929; <>

• ASTM D6400 1. Chemical Testing: The product shall have concentrations of regulated heavy metals less than 50 % of those prescribed for sludges or composts in the country where the product is sold. 2. Testing of ultimate biodegradability: ASTM D5338-98(02); At least 60% conversion to CO2 for homopolymers; at least 90% conversion to CO2 for blends and copolymers; within 180 days (6 mths)). 3. Testing of compostability (Disintegration): ASTM D5338-98(02);

• GleenPla Scheme 1. Chemical Testing: Amounts of specified elements are not to exceed the upper limits as defined by GreenPla Certification Scheme. 2. Testing of ultimate biodegradability: ISO 14851/14852/14855; at least 60% conversion to CO2 with respect to a suitable reference material; max duration: NOT SPECIFIED. 3. Testing of compostability (Disintegration): NOT SPECIFIED. 4. Compost Quality Analysis (Ecotoxicity): NOT SPECIFIED. 5. Oral Acute Toxicity Test for material: Rats - LD50 Test. 6. Environmental Safety Test for material: Algae - Growth Inhibitor Test (OECD 201); Daphnia – EC50 Test & Reproduction Test (OECD 202); Fish - Acute Toxicity Test (OECD 203)

• China National Standard (Similar to GleenPla)

4.International certification bodies – Overview, Registration Flow chart, Estimated Cost and Duration

(i) DIN CERTCO – Europe
(ii) BPI – USA
(iii) BPS – Japan
(iv) BMG – China
(v) EBPA – Taiwan

DIN CERTCO operates a certification scheme for compostable products made of biodegradable materials and licenses the use of the corresponding Mark developed by European Bioplastics (the former IBAW Interest Group for Biodegradable Materials). Certification body located at Berlin, Germany. Review and approve certification scheme for compostable products made of biodegradable materials; Review and approve registration scheme of compostable materials and additives; Licenses the use of corresponding Mark/ Logo. More … http://www.dincertco.de/en/index.html

BPI Biodegradable Products Institute, located at New York, United States. Multi-stakeholder group (people & organization). Promotes the use, and recycling of biodegradable polymeric materials. Compostable Logo awarded to any product (includes resin material) which meet the stringent test requirements based on ASTM D-6400-99 (Independent Test Laboratory). More… http://www.bpiworld.org/

BPS Biodegradable Plastic Society, located at Tokyo, Japan. Establish technology of biodegradable plastic. Lead commercial use of the GreenPla. Review and approve certification scheme for compostable products made of biodegradable materials. Review and approve registration scheme of compostable resin material in Positive List. Licenses the use of corresponding Mark/ Logo. More… http://www.jbpaweb.net/english/e-jbpa.htm

BMG Biodegradable Materials Group, located at Beijing, China. Review and approve certification scheme for compostable products made of biodegradable materials and resin material. Licenses the use of corresponding Mark/ Logo.