The full English name of PVC is the abbreviation of polyvinylchloride (PVC molecular structure). Generally speaking, our common PVC is a kind of plastic decorative materials. Its chemical name is polyvinyl chloride. It is composed of amorphous thermoplastic resin made of vinyl chloride monomer through polymerization and certain additives (such as stabilizer, lubricant, filler, etc.). It has mechanical properties, strong acid and alkali resistance and low softening point. Stable chemical properties. It is often used to make thin plates, wires, cable insulation, seals and other items.
Classification of outdoor waterproof bags:
Material upper division
Pvc/tpu/eva, mainly these.
PVC waterproof bags are mostly PVC waterproof bags on the market, which are cheap and mainly adopt snap on type, anti splashing zipper and folding roll opening. Generally, it is difficult to integrate with watertight and air tight zippers. Even if they are integrated, the viscosity is insufficient.
TPU waterproof bags on the market are generally expensive. They are environment-friendly materials and can be easily exported to Europe and the United States. They have all kinds of openings. However, if waterproof zipper openings are used, they do not match and are of lower grade.
EVA waterproof bags made of EVA are rare in the market. They are mainly used in some swimming bags, and the price is medium.
Snap open waterproof bag
Division on opening
Folding roll opening, zipper opening, snap type, magnetic suction type
1. the waterproof bag with folded mouth is the most early choice. If you want to seal the roll mouth, you must ensure the long-term extrusion force. However, in fact, the waterproof bag has both extrusion force and rebound force. The fabric difference, including the hardness and elasticity of the fabric and the tension generated after folding with the roll mouth, will affect the durability. Generally, the ipx6/7 waterproof level can be maintained within 30 minutes. It will relax for a longer time, and the waterproof ability will be lost. It is mainly applied to waterproof bags with low price and low waterproof requirements.
Magnetic sealing waterproof bag
2. snap on waterproof bag is a small waterproof bag, such as mobile phone waterproof bag and transparent waterproof bag, which are often used. The male and female fastener combination of injection molding is adopted, and the fastener is welded on the opening of the waterproof bag to achieve the purpose of sealing through fastening. It is mainly used in small bags such as waterproof bags for mobile phones and digital products.
3. the waterproof bag with magnetic suction opening is a new opening method developed in recent years. Its practicality needs to be further verified. It needs to be evaluated in terms of the strength of the magnetic force, the hardness of the contact surface, and the impact of the magnetic force on the electronic products in the storage. It is mainly used in mobile phone waterproof bags, digital product waterproof bags and other small bags.
4. zipper openings are more and more widely used. The technology of waterproof zippers such as air tight zippers and water tight zippers is becoming more and more mature. Great progress has been made in process, sealing, stability, durability, smoothness and matching. Waterproof zipper openings have been adopted in many high-end bags, greatly improving the convenience and practicality of use. The zipper opening is consistent with people's use habits. It is easy to operate, reduces the user's learning cost, and saves the user's time for picking up items and sorting out. It can be applied to most bags.
Roll type waterproof bag for bicycle
Division on usage scene
Bicycle bag, swimming bag, urban leisure bag, outdoor mountaineering bag, diving bag, fishing bag, etc.
What are the names of PVC waterproof fabrics?
Waterproof oilcloth, knife scraping cloth, PVC laminating cloth, PVC mesh cloth
PVC sandwich fabric (waterproof fabric) has serious high-frequency welding overflow, some of which are even more than 2mm. The appearance was seriously affected, and there was no appearance.
In addition to the irregular overflow, it is more than 3mm, shilt. I really didn't see it.
Problems encountered in PVC waterproof fabric processing
1. the material is difficult to process, so we have to choose thick glue, which increases the weight, increases the overflow, and destroys the beauty
2. due to poor adhesion, the welding time and strength have to be increased or the voltage width has to be widened,
3. it is difficult to fuse with other materials. Even if it is fused, its adhesion is weak, and there is a great risk of peeling in use.
Compared with TPU, PVC waterproof fabric is relatively simple and rough, not so delicate and elegant.
The effect of welding with the anti water splashing zipper can only be summarized in one word: terrible.
The waterproof and water splashing zipper is not pressed well, too hasty!
PVC is the main waterproof package in the domestic market.
Therefore, it is necessary to talk about environmental protection and responsibility to the earth. Many inferior products are flooding the market. Although it is said that everyone is greedy for cheap, it is not cost-effective to compare the service life of the product with the price. In addition to the social requirements to reduce environmental pollution, the living space of low-quality waterproof bags is increasingly under pressure.
When the sun shines directly on PVC fabric, it may release unpleasant smell, which will bring obvious discomfort to sensitive people.
Problems in the use experience of PVC waterproof bag, private
Feeling: the weight increases the burden, the hand feels sticky, there is a plastic or irritating smell, and it is easy to get dirty and difficult to clean.
Service life: the service life is short. Some small bags have a one-time service life. For example, PVC mobile phone waterproof bags have small cracks after pulling at the seams, so there is a huge risk of reuse; Large bags, such as PVC rock climbing bags, mountaineering bags, double shoulder waterproof backpacks and bicycle backpacks, have been torn at the seams for about a year, more or less. The reverse tearing of PVC fabric is easy to occur, mainly due to its insufficient adhesion and elasticity. This physical property makes it much weaker than TPU waterproof fabric.
Damage to the earth caused by the scrapping of PVC waterproof package, Yu Gong
"PVC is a fighter among toxic plastics. From production, consumption and use to final disposal, it is endangering the environment and human health." Stabilizers (such as lead and cadmium) and plasticizers (phthalates, such as DEHP) that need to be added when PVC is made into various products after synthesis.
As well as the hydrochloric acid and the century's toxic dioxin produced by the combustion after waste, they are all harmful substances with a large origin.
Jia Mingxing, vice president and Secretary General of China Nonferrous Metals Industry Association, said, "the production of PVC with an annual output of tens of millions of tons in China is inseparable from mercury catalyst".
Due to the lack of oil resources in China, PVC is mostly produced by calcium carbide method. The mercury catalyst in the production process of vinyl chloride by calcium carbide method is the main source of mercury pollution and flows to the environment in various ways .
According to statistics, China consumes 20% of the world's Mercury, of which about 60% is used for PVC production by calcium carbide process. 
On the other hand, PVC production is a high energy consuming industry and involves a variety of toxic chemicals, including dichloroethane, vinyl chloride, mercury pollution, etc. once an explosion or leakage occurs, it will pose a great threat to the health of workers in the vinyl chloride plant and the nearby people.
PVC use - health hazard
In the process of PVC production and processing, some processing aids need to be added, such as fillers, stabilizers, lubricants, plasticizers, colorants and flame retardants. Among them, the use of stabilizer and plasticizer is very high. 
Before PVC is made into various finished products, plasticizers of different contents shall be added according to the softness required by the products. Generally speaking, 10-30% plasticizer shall be added to semi-rigid PVC and 30-70% plasticizer shall be added to soft PVC.
For example, the average plasticizer content of medical supplies is 20%-40%. If it is like fresh-keeping film, drip tube or drip bag, the plasticizer content can reach more than 70%, which is equivalent to PVC immersed in plasticizer.
There are many kinds of PVC plasticizers, but the most common one is a class of chemicals called phthalates.
"Phthalates and their metabolites and degradation products have negative effects on human health, such as endocrine disrupting effects, feminization of use in boys and precocious puberty in girls."
On the other hand, PVC is not resistant to light and heat. Under the influence of light and heat, it will release chlorine free radicals, resulting in material deterioration. In order to improve the thermal stability of PVC, an appropriate amount of stabilizer is often added to prevent or slow down the degradation of PVC during processing.
The pollution caused by stabilizers is mainly heavy metal pollution.
Commonly used stabilizers include metal salts such as lead, cadmium, zinc, barium and tin, which will seep out from PVC products and endanger human health.
"Lead, a commonly used stabilizer, can damage children's nervous system and hinder their IQ development; it can damage the female reproductive system and may cause cancer. Cadmium can affect renal function."
The third item is the physicochemical properties and common use of PVC
Waste disposal - Deadly relics
Non environmentally friendly materials
PVC wastes are difficult to handle. As they often contain plasticizers and heavy metals, if they are mixed with recycled plastics, they will pollute the recycled plastics and turn the circular economy into a toxic cycle.
At the same time, as PVC contains chlorine, if burned, it will not only release pungent and toxic hydrogen chloride gas, but also produce strong carcinogen - dioxin.
There are also environmental problems in the process of PVC waste landfilling. For example, a large number of untreated PVC piled up may cause combustion. In case of occasional fire in the landfill, the PVC waste in the landfill will burn to produce dioxins; Containers containing several plastic mixtures may leak lead containing stabilizers.
"The waste treatment of PVC seriously hinders the benign operation of waste classification and recycling system in China."