Author: MakerPRO／蔡松寰
According to their characteristics, plastics can be roughly divided into two categories-thermoplastics and thermosets. The ones we use on vacuum forming machines are thermoplastics. This is because the basic principle of vacuum forming machines is to heat and soften the plastic. , Utilize the suction of the vacuum to shape the plastic sheet, and the shape will be set after cooling.
However, there are many common types of plastics. What should I pay attention to when choosing a plastic for thermoforming? What are the types and characteristics of plastic sheets? I believe that many people have similar questions in their mind. Thus, we will introduce the plastics with common recycling codes No. 1~7, and share some knowledge about plastic materials.
Recognize the classification of recyclable plastics
Seven categories of plastic recycling（Source：KS Environmental Group）
1. PET/PETE（Polyethylene terephthalate）
- Tg temperature：60~85 °C
- Characteristics：Acid and alkali resistance, good hardness and toughness, light weight and none volatile
- Applications：The most common application of PET is te PET bottles. If it is used above Tg temperature, it will release a regular chemical agent. Besides that, PET will not release harmful substances.
2. HDPE（High-density polyethylene）
- Tg temperature：90~110 °C
- Characteristics：Corrosion resistance, acid and alkali resistance
- Applications：It is the most widely used plastic in life, such as shopping bags and milk bottles.
3. PVC（Polyvinyl chloride）
- Tg temperature：60~80 °C
- Characteristics：Chlorine-containing plastics are mostly used in industrial products. From production, use to disposal, toxic substances are generated
- Applications：Common gray water pipes and some seasoning bottles are made of PVC. Many plasticizers must be added to improve some of their properties. The high temperature easily releases plasticizers. Therefore, the Environmental Protection Agency is gradually banning them in use.
PVC is widely used around our lives because of its cost and convenient to manufacture, but the process releases a large amount of plasticizer, which is called "poisonous plastic" by the International Greenpeace Organization.（Source：bob vila）
4. LDPE（Low density polyethylene）
- Tg temperature：70~90 °C
- Characteristics：Corrosion resistance, acid and alkali resistance, overheating is easy to produce carcinogens
- Applications：Plastic bags and various laboratory bottles, washing bottles or plastic wrap, etc.
5. PP（Polypropylene）
- Tg temperature：100~140 °C
- Characteristics：Acid and alkali resistance, chemical resistance, high temperature resistance, collision resistance
- Applications：Food containers, tableware, water cups, etc. It is the most commonly used plastics for food applications, because they do not release harmful substances within the temperature range of general food processing, and their impact resistance characteristics are also widely used in industry.
6. PS（Polystyrene）
- Tg temperature：70~90 °C
- Characteristics：Low water absorption, good stability
- Applications：Yakult bottles, instant noodle bowls, etc.
Common Yakult bottles are made of polystyrene（Source：bloomberg）
7. Other
Others that do not fall into the above categories are directly classified as No. 7
Plastics selected by FORMART
FORMART attaches great importance to the environmental protection requirements of using plastic sheets（Source：MY YARD）
MY YARD, the developer of FORMART, attaches great importance to environmental issues. Although most of the various thermoplastics can be used in the vacuum forming process, the team selected from a large number of sheets to prevent the product from causing too much impact on the environment. Thermoplastic and environmentally friendly plastic sheets require non-toxic and environmentally friendly characteristics that are easy to recycle. In addition, each plastic sheet that MY YARD sells will also come with recycling labels affixed to its corners, so that the recycling staff can see it at a glance, and not treat it as general trash to burn it or bury it
The following are the types, characteristics and applications of the 4 environmentally friendly plastics selected by FORMART：
1. Food grade plastic –PP
Non-toxic, odorless food grade plastic sheet – PP
Non-toxic, odorless PP (Polypropylene Polypropylene) sheet has excellent chemical resistance and bending resistance, and can withstand 120 ℃ for a long time. It is an excellent choice for various food applications.
- Applications：Chocolate or fudge molds, food stampers, pudding boxes, food containers (microwave available)
- Recycling classification：No.5
- Color：White
- Size：50 cm x 30 cm；A4
- Thickness：0.5 mm、1.0 mm
2. Impact resistant plastic – PET
Plastic sheet with high transparency and impact resistance – PET
Impact-resistant PET (Polyethylene terephthalate) board has high transparency and impact resistance, and is especially suitable for product applications that require high transparency and high impact strength.
- Applications：Packaging blister, toy shell, tray, food packaging, low temperature food container
- Recycling classification：No.1
- Color： Transparent, White
- Size：50 cm x 30 cm；A4
- Thickness：0.3 mm、0.5 mm
3. General-purpose plastic – HIPS
High-strength, general-purpose plastic sheet – HIPS
High-strength HIPS (High impact polystyrene) sheet is particularly easy to shape, has excellent dimensional stability, and is easy to color on the surface. It is suitable for various of molds or product applications that require coloring.
- Applications：Turn over molds, soap molds, masks, Cosplay props, model accessories
- Recycling classification：No.6
- Color：White
- Size：50 cm x 30 cm；A4
- Thickness：0.5 mm、1.0 mm
4. Special sheet series – TPU
Plastic sheet that can be decomposed in the natural environment – TPU
TPU (Thermoplastic polyurethanes) sheet is soft, non-toxic, and can be decomposed in the natural environment. It is suitable for use as a replacement material for molds that are difficult to demold, or other applications that require soft materials.
- Applications：Turn over mold (with undercuts), 3C product protective shell
- Recycling classification：General rubbish
- Color：transparent
- Size：A4
- Thiskness：1.0 mm
- Hardness：80A
Conclusion
There are many types of plastics and they are widely used. Before using a vacuum forming machine, in addition to considering the effect of shaping, you should also think about whether the plastic will have an impact on the environment when it is finally discarded. Emerson, the founder of MY YARD emphasized in an interview that if this machine can only be "introduced" but is not "environmentally friendly", he would not be willing to bring it to the market. For this demand of environmental responsibility, He and his team spent a lot of time learning the characteristics of plastics, and selected plastic, safe, non-toxic, environmentally friendly and harmless sheets. It can be said to be a model of social enterprise responsibility and deserves recognition.
（This article is reproduced with permission from MakerPRO，Original link）
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