Here is some information about High Tensile Bags
Common materials used for 'High Tensile'(HT) bags:
Low density polythene (LDPE)
Linear low density polythene (LLDPE)
Medium density polythene (MDPE)
Recycled polythene
Available Thickness:
80 Gauge(20microns) to 250 Gauge(62.5microns)

Tolerances:
Normally, 'High Tensile(HT) bags' in Great Britain should follow widely accepted industrial standards according to British Standard - see BS7344, 1990 Width: Plus or minus 3mm (0.125") or 2% whichever is greater
Length: Plus or minus 6mm (0.25") or 2% whichever is greater
Gauge: Plus or minus 10%
Standards for 'High Tensile(HT) bags' to use for food contact and medical application:
Food Contact – To use High Tensile(HT) bags inside European Union, in contact with food should comply with the relevant legislation on food contact including Great Britain.
Great Britain: Statutory Instrument, 1998 No. 1376 and BPF-BIBRA (1995), Polymer Specification 4, Polyethylene
EU: Commission Directive 90/128/EEC, 92/39/EEC, 93/9/EEC, 95/3/EEC and 96/11/EC, Section A.
Example of a company comply with food contact: Polybags Limited
Medical use – Similarly, to use High Tensile(HT) bags inside European Union, to produce containers for preparations for medico-pharmaceutical purposes should comply with the following regulation:
European Pharmacopoeia - Monograph 3.1.3 "Polyolefin's" for medico-pharmaceutical purposes.
The final responsibility for the decision of whether a material is fit for a particular application lies with the pharmaceutical firm.
Example of a company comply with medical use: Polybags Limited

In modern international trade, technical barriers to trade protectionists frequently used means, in particular for developing countries are developed countries, the existence of technological advantages, developed countries can make use of this privileged position to protect its related industries. Technical Barriers to have its hidden nature, especially in food, livestock and poultry products, the developed countries more and more and more to security, hygiene, health, citing more and more high formulate technical regulations and standards, set up all sorts of technical trade measures.

     China's exports of food and other products usually by the importing country under various pretexts and closed customs, detain, return, destruction, or even a complete embargo. At present, the food labeling system has become our country food exports insurmountable technical barriers. Major countries food labeling system is as follows:
     EU
     In 2006, the European Union published on Food and Nutrition and Health Regulation No. 1924/2006 statement. The Ordinance was July 1, 2007 formally implemented, apply to the EU market for sale for human consumption any food or drinks. The new regulations aimed at ensuring that the food packaging to consumers provided by the nutritional information more accurate and reliable, in order to avoid misleading consumers.
     USA
     The United States Department of Agriculture for organic food labeling system provides: the extent of any organic reached or exceeded 95% of the food, can be affixed with a printed English word "organic" and "The United States Department of Agriculture" in the green circle markers. Organic extent at 70% ~ 95% of the food, should not paste special markings, but can be specified on the label on the product "contains organic ingredients." Whether or not foods have organic food add tag qualifications, subject to the approval of the United States Department of Agriculture certification of the specialized agencies.
     Russia
     Russian State Committee for Standardization to re-formulate and implement "TOCTP51014-2003 / food consumption indicate the general requirements," one of the relevant contents of the new food labeling standards, we must note in the consumer (food labeling) marked on the origin of the name and address of manufacturer, product name, product composition, capacity, food value, use and storage conditions, the application period, the storage period, production and packaging date code as well as important information, such as food ingredients, the consumer should be using the Russian label, ask the food and food additives name must be in line with the Russia National standards.
     The new labeling system for food export enterprises of China's main impact has two aspects:
     (1) new labeling system for the implementation of an increase of China's food export enterprises the cost of exports
To complete the composition of the new labeling requirements for detection, required companies to pay an extra fee Detected, but these new labeling requirements Detect demanding, difficult to improve the detection, which further increased the detection of costs, and increase China's food export enterprises the cost of exports.
     (2) the new tag system allows the export customs clearance inspection resulted in a lot of uncertainties
     For our country enterprises, not strictly because of domestic demands, enterprises rarely exposed to Detect Food and Nutrition program, and unfamiliar, and therefore the production of food labeling, when inefficient, and the quality is not high, coupled with the foreign requirements for the tag Strict, a short period of time to China's food export enterprises in full compliance with the requirements of the new labeling system must exist more difficult.
     Rare in our country because of the domestic authority of the nutrition labeling inspection agencies, so the production of our country or not qualified at the tag on to some extent depend on the importing country related to Detect Department, which will enable our country food enterprises in a very passive position. Imports of Congress in accordance with their own interests to consider, in the event of Chinese exports to the country's food is not conducive to the domestic industry when they can, through approval of the importing country at the time, looking for an excuse to refuse to endorse it for approval, which will allow enterprises in China's food exports to suffer huge losses.
     The new food labeling system for the implementation of, for our country's food export enterprises further increased access to international market risk and increase the cost of exports of enterprises. Because enterprises do not timely respond to the importing country has been caused by a variety of pretexts, customs, detain, return, destruction, food enterprises of our country caused great loss, but also on China's export of food caused a lot of adverse effects.

Great Moments in Plastic Bag History

• 1957 The first baggies and sandwich bags on a roll are introduced.
• 1958 Poly dry cleaning bags compete with traditional brown paper.
• 1966 Plastic bag use in bread packaging takes over 25 to 30 percent of the market.
• 1966 Plastic produce bags on a roll are introduced in grocery stores.
• 1969 The New York City Sanitation Department's "New York City Experiment" demonstrates that plastic refuse bag kerbside pickup is cleaner, safer and quieter than metal trash can pick-up, beginning a shift to plastic can liners among consumers.
• 1974/75 Retailing giants such as Sears, J.C. Penney, Montgomery Ward, Jordan Marsh, Allied, Federated and Hills make the switch to plastic merchandise bags.
• 1973 The first commercial system for manufacturing plastic grocery bags becomes operational
• 1977 The plastic grocery bag is introduced to the supermarket industry as an alternative to paper sacks.
• 1982 Kroger and Safeway start to replace traditional craft sacks with polyethylene "t-shirt" bags.
• 1990 The first blue bag recycling program begins with kerbside collection.
• 1990 Consumer plastic bag recycling begins through a supermarket collection-site network.
• 1992 Nearly half of U.S. supermarkets have recycling available for plastic bags.
• 1996 Four of five grocery bags used are plastic.
   

1.Food Contact – To use Polythene film or bags inside European Union, in contact with food should comply with the relevant legislation on food contact including Great Britain. Great Britain: Statutory Instrument, 1998 No. 1376 and BPF-BIBRA (1995), Polymer Specification 4, Polyethylene

• EU: Commission Directive 90/128/EEC, 92/39/EEC, 93/9/EEC, 95/3/EEC and 96/11/EC, Section A.
• Example of a company comply with food contact: Polybags Limited

2.Medical use – Similarly, to use Polythene film or bags inside European Union, to produce containers for preparations for medico-pharmaceutical purposes should comply with the following regulation:

• European Pharmacopoeia - Monograph 3.1.3 "Polyolefin's" for medico-pharmaceutical purposes.
• The final responsibility for the decision of whether a material is fit for a particular application lies with the pharmaceutical firm.
• Example of a company comply with medical use: Polybags Limited

1. Low density polythene (LDPE): Ethylene polymer with densities ranging from about 0.916 to 0.925 grams per cubic centimeter
2. High density polythene (HDPE): Ethylene polymer with densities ranging from 0.941 to 0.965 grams per cubic centimeter
3. Liner low density polythene (LLDPE): Ethylene polymer with densities ranging from 0.900 to 0.939 grams per cubic centimeter
4. Medium density polyethylene (MDPE): Ethylene polymer with densities ranging from 0.926 to 0.940 grams per cubic centimeter
5. Polypropylene (PP): A thermoplastic resin made by the polymerization of high-purity propylene gas in the presence of catalyst at relatively low pressures and temperatures. It is used to make film, fibers, rope and moulded articles
6. Ethylene Vinyl Acetate (EVA): EVA compounded with LDPE is widely used to prevent plastic film/bags from cracking down to -30 degrees centigrade
7. Polyvinyl chloride (PVC): Thermoplastic resin produced by the polymerization of the gas vinyl chloride [CH2CHCl]. Used in soft, flexible films for food packing. Also used in rigid products such as pipes or window profile.
    

The real star of the plastics industry in the 1930s was "polyamide" (PA), far better known by its trade name "nylon."  Nylon was the first purely synthetic fiber, introduced by Du Pont Corporation at the 1939 World's Fair in New York City.

In 1927, Du Pont had begun a secret development project designated "Fiber66," under the direction of a Harvard chemist named Wallace Carothers.  Carothers had been hired to perform pure research, and not only investigated new materials, but worked to understand their molecular structure and how it related to material properties.  He took some of the first steps on the road to "molecular design" of materials.

His work led to the discovery of synthetic nylon fiber, which was very strong but also very flexible.  The first application was for bristles for toothbrushes.  However, Du Pont's real target was silk, particularly silk stockings.

It took Du Pont twelve years and $27 million USD to refine nylon and develop the industrial processes for bulk manufacture.  With such a major investment, it was no surprise that Du Pont spared little expense to promote nylon after its introduction, creating a public sensation, or "nylon mania."  Nylon mania came to an abrupt stop at the end of 1941, when America entered World War II.  The production capacity that had been built up to produce nylon stockings, or just "nylons" for American women, was taken over to manufacture vast numbers of parachutes for fliers and paratroopers.  After the war ended, Du Pont went back to selling nylon to the public, engaging in another promotional campaign in 1946 that resulted in an even bigger craze triggering off "nylon riots."

Nylon still remains an important plastic, and not just for use in fabrics.  In its bulk form, it is very wear-resistant, and so is

  
To assist recycling of disposable items, the Plastic Bottle Institute of the Society of the Plastics Industry devised the now-familiar scheme to mark plastic bottles by plastic type.  A recyclable plastic container using this scheme is marked with a triangle with three "chasing arrows" inside of it, which enclose a number giving the plastic type: PETE, HDPE, PVC, LDPE, PP, PS, and OTHER.