Analysis of Patent Application of Corn Plastic (Polylactic Acid) (I)

“Environmental protection” is the topic of common concern of people of all countries in the world today. The introduction of environmentally friendly materials with excellent performance has always been extremely satisfying. In recent years, with the advent of corn plastics, this environmentally friendly material that is biodegradable, environmentally friendly, and harmless to the human body has become popular with people; corn plastics have entered practical applications in many fields and have entered people's Everyday life. Many large companies are optimistic about this new environmentally friendly material. For example, the 500,000 disposable cups that Coca-Cola used at the Winter Olympics in Salt Lake City were all made of corn plastic. The cups disappeared in open air in just 40 days. Another example is that McDonald's used cornware made from NatureWorks de Corn Cups to hold soda water; another example is that many American families are eating Del Monte's corn and plastic canned fruits and vegetables and listening to Sony's portable use of corn plastics. Listen and drink Biota's mineral water in a corn plastic bottle. In China, with corn plastic instead of traditional plastics made of agricultural mulch, vests, lunch boxes, disposable tableware, etc., but also to bid farewell to a hundred years can not degrade, harm the environment "white pollution" took a substantial step.

At present, a few producers in China have begun to produce corn plastics, but the specific application of corn plastics remains to be developed. Here, through the search, screening, and analysis of domestic and foreign patent databases, the author made a detailed analysis of the patented technology of corn plastic (polylactic acid) bags at home and abroad. At the same time, the author introduced the main products made from various raw materials and patented technologies. Uses, hope to provide relevant assistance to China's relevant research institutions and enterprises to develop the application of polylactic acid.

On August 4, 2005, in the patent database of DERWENT WPI, the author retrieved a total of 44 patents based on the strategy of “(biodegradable(s)bag??)/ti and (polylactic or lactic)”. The analysis found that there are more than ten patents for the preparation of biodegradable bags made of polylactic acid, and the rest are patents for materials (such as films) that can be used to make biodegradable bags.

1. Title: Biodegradable bag

Source: US2004241359 (filing date: 2003.06.02, public date: 2004.12.02)

Inventor: MIKSIC BORIS A [US]; VELA PASKO [US]; BERG ROBERT [US]; BOYLE ROBERT [US]

The novelty of the invention lies in that: the biodegradable bag is made of a biodegradable film; the film comprises polylactic acid and a biodegradable polymer resin, wherein the polylactic acid accounts for 5%-50% by weight of the mixture of the two; Biodegradable bags have a thickness of less than or equal to 2 mils (thousandths of an inch).

Uses: This biodegradable bag is used to package and store compostable materials. The bag can be in the form of a drawstring or hand bag.

Advantages: The biodegradable bag uses less resin than conventional biodegradable bags, but has better toughness and strength and can carry heavier loads. And it is durable and more economical to manufacture.

2. Title: BIODEGRADABLE RESIN BAG

Source: JP2004155460 (Application Date: 2002.11.07, Public Day: 2004.06.03)

Applicant: SHOWA PACKS KK

The novelty of the invention is that the biodegradable resin bag comprises the following resin components: 50-90 wt% of biodegradable polylactic acid resin and 50-10 wt% of biodegradable aliphatic polyester resin.

The object of the present invention is to provide a biodegradable resin bag having a higher strength, and even if the bag filled with the contents is dropped, the creases are hardly broken.

Uses: The bag can be used as fertilizer bags, rice bags, compost bags, garbage, shopping bags and heavy bags.

Advantages: The resin bag has excellent biodegradability and strength, and can prevent the content placed inside the bag from falling off; because the resin bag has biodegradability, it can prevent environmental pollution.

3. Title: BIODEGRADABLE BAG-SHAPED ARTICLE

Source: JP2004142766 (filing date: 2002.10.23, publication date: 2004.05.20)

Applicant: UNITIKA LTD

The biodegradable pouches disclosed in this invention are made of non-woven textiles of blended fibers. The blend fiber includes a polylactic acid polymer (ingredient A), and a mixture of polylactic acid and a biodegradable aliphatic-aromatic copolyester (ingredient B). The bag-shaped article has a heat seal portion.

Uses: Used as drainage bags (installed in kitchen and waste water pool filters), storage bags such as coolant bags, liquid absorption bags, pest control bags, packaging bags and as agricultural materials.

Advantages: The biodegradable pouch material has excellent heat seal strength and good thermal stability.

4. Title: Biodegradable Film and BIODEGRADABLE FILM AND BIODEGRADABLE BAG FORMED OF THIS FILM

Source: JP2004082512 (Application Date: 2002.08.27, Public Day: 2004.03.18)

Applicant: MITSUBISHI PLASTICS IND LTD

The biodegradable film is mainly composed of lactic acid resin, the longitudinal F2 value is adjusted to 30-55 MPa, and the ratio of F2 value/F1 value is set to ≤170%. In addition, one layer on the upper and lower sides of the film contains 0.02-0.5 wt% of inert particles with an average particle size of 0.5-8 μ. The biodegradable bag is made by using a sealing film.

The film obtained in this invention has similar physical properties as OPP and has excellent heat resistance and strong wet/heat durability.

5. Title: BIODEGRADABLE FERTILIZER BAG

Source: JP2003183483 (application date, publication date: 2003-07-03)

Applicant: UNITIKA LTD

The biodegradable fertilizer bag disclosed in the present invention is obtained by heat-sealing one side of the film, wherein the heat-sealing temperature is 260-285° C., the heat-sealing time is 0.1-1 second, and the heat-sealing strength is 15 N/15 mm or more. The film comprises: (A) polylactic acid; (B) a biodegradable aliphatic-aromatic copolyester having a glass transition point of 0°C or less; (C) a plasticizer; (D) an inorganic filler.

Uses: The biodegradable bags prepared by the invention are used for agriculture and horticulture;

Advantages: The biodegradable fertilizer bag has excellent softness, plasticizer anti-leaking performance, heat seal strength and biodegradability. The bag can be naturally degraded without the need for waste treatment and does not produce harmful gases when incinerated.