1.Brief Introduction of Hot-melt Adhesive Film
If you have never heard the name of hot-melt adhesive film, and you have no idea what it is used for, you’d better read this part of the text.
Different from our common sense, not all glues are liquid. Hot-melt adhesive film is a kind of industrial adhesive, which is solid, nonstick and film like at room temperature. It will melt when heated, and form bonding strength after cooling.
1.1 Advantages of Hot-melt Adhesive Film
As a kind of synthetic resin, hot-melt adhesive film is a very common branch. What are the advantages of hot-melt adhesive film? Why did you choose it?
First of all, hot-melt adhesive film is harmless. Lots of traditional adhesive contain organic solvent, which is very harmful to your body when volatilized into the air. The hot melt adhesive is melted by heating to soak the surface of the base materials. Therefore, it contains no solvent.
Second, hot-melt adhesive film is clean. As you know, Liquid glue will inevitably drop on the ground during gluing operation. But, hot-melt adhesive film is solid, nonstick, and film like at room temperature. It will never stick to the ground, so it can keep the workshop clean.
Third, the use of hot-melt adhesive film can improve efficiency. The curing time of traditional adhesives is relatively long. But, the curing of hot melt adhesive film only takes a few seconds, just the time it takes to cool down. So, it can save you a lot of time.
1.2. Application of Hot-melt Adhesive Film
Perhaps you are familiar with adhesives used in daily life. However, you may not know much about the application of hot melt adhesive film. Because the hot melt adhesive film is an industrial adhesive, which is used in production and is not widely used by ordinary people. In fact, hot melt adhesive film is very close to us in our daily life.
The clothes and shoes you wear were made by sewing, but now many of them have been produced with hot-melt adhesive film. For example, seamless underwear, sportswear, swimwear, socks, etc. And the upper, insole, heel, and sole of your shoe will all involve the use of hot-melt adhesive film. They are usually composed of several layers of materials.
In addition, the mobile phones, tablets, and other electronic products you use, as well as the wall coverings and blackout curtains used for home decoration, are all products that involve the use of hot melt adhesive film.
Therefore, the hot melt adhesive film is really around us. It silently contributes to many fields, even though you do not notice it. This is the hot melt adhesive film.
2.Classification of Hot-melt Adhesive Film
Hot melt adhesive film belongs to a kind of hot melt adhesive product. However, it itself can be divided into different categories according to different classification methods. The following mainly introduces the classification of the product from the perspective of product form and main ingredients.
2.1 Classification by Appearance
Hot melt adhesive film has different product forms due to different production processes. You can divide it into hot melt adhesive film with backing paper and hot melt adhesive film without backing paper by appearance.
Hot melt adhesive film with backing paper is usually produced by the coating method. You must tear off the release paper before using hot melt adhesive film for bonding. Normally, you need to pre-attach the adhesive film to one of the adherents before the formal lamination.
Hot melt adhesive film with backing paper is usually produced by the tape-casting method or the blowing method. Because the backing paper was abandoned, the product cost was greatly reduced. This makes the hot melt adhesive film popularized in the field of large-scale lamination.
2.2 Classification by Composition
Hot melt adhesive film is mainly composed of basic resin, tackifier, plasticizer, and some other additives, among which basic resin accounts for the largest proportion. Therefore, we can classify hot melt adhesive film according to the type of basic resin it contains.
According to the type of basic resin of hot melt adhesive film, it can be roughly divided into EVA hot melt adhesive film, TPU hot melt adhesive film, PES hot melt adhesive film, PA hot melt adhesive film, and PO hot melt adhesive film.
EVA hot melt adhesive film is made of ethylene vinyl acetate copolymer. It is currently the most widely used hot-melt adhesive film product due to its ability to bond a variety of materials. EVA hot-melt adhesive film is applied in shoe materials, the automobile industry, decorative building materials, packaging, and other fields.
TPU hot melt adhesive film is made of thermoplastic polyurethane. It is soft and has strong water-washing resistance. Therefore, TPU hot-melt adhesive film is mostly used in the clothing field. Today’s trackless clothing and waterproof clothing all depend on the development of TPU hot melt adhesive film.
PES hot melt adhesive film is made of polyester. It has a high bonding strength to metal materials. At present, it is mainly used for bonding some components in the electronic field and compounding materials in the new energy field.
PA hot melt adhesive film is made of polyamide. Its high-temperature resistance is good, but its low-temperature resistance is poor. Under the condition of below zero temperature, the material will become hard and lose toughness, so it needs to be modified.
The main component of PO hot-melt adhesive film is a polyolefin, which is the general name of a large category, mainly including polyethylene and polypropylene. PO hot-melt adhesive film has better comprehensive performance and also has better adhesion performance to metal materials. It is a kind of hot melt adhesive film product with a potential application field.
Although the hot-melt adhesive film is divided into the above categories according to the material, in fact, the composition of the hot-melt adhesive film of the same material is also very different. For example, the specific components of EVA hot-melt adhesive films of different models produced by different manufacturers vary greatly, because the formulas of different manufacturers are different.
3.How to Choose Hot-melt Adhesive Film
Adhesive is just like medicine, which can cure the disease when you choose the right medicine. Similarly, you also need to choose the hot melt adhesive film according to different adherents. The following factors shall be carefully considered in the selection of hot melt adhesive film.
If there are certain requirements for the color of the adherents, you should choose the hot melt adhesive film with the same color. If there is no special requirement for the color of the adherents, then the ordinary hot-melt adhesive film can be used.
3.2 Curing Time
High efficiency is an essential feature of hot-melt adhesive film. Generally, the operation time of hot melt adhesive film is about 15 seconds. With the popularization of modern assembly lines, machine speed is getting faster and faster. Therefore, you need to select the appropriate hot melt adhesive film products according to the specific situation of your machine.
3.3 Temperature resistance
Hot melt adhesive film is very sensitive to temperature. With the increase of temperature, the hot melt adhesive film begins to soften. When the temperature is lower than the glass transition temperature of the adhesive film, it will turn brittle. Therefore, the selection of the hot melt adhesive film should fully consider the temperature change of the production environment.
3.4 Characteristics of bonded material
You need to consider the characteristics of the adherend. Because you can’t find a kind of hot-melt adhesive film that can bond all materials. For example, the bonding strength of TPU hot-melt adhesive film to textiles is very high, while there is almost no bonding strength to PE.
You also need to consider the maximum heat resistance temperature of the adherents. For example, if the maximum temperature resistance of the material is 120 ℃, you must choose the hot melt adhesive film products with melting point below 120 ℃. Otherwise, in the process of melting the adhesive film, the adherend itself will melt at the same time.
3.5 Special performance requirements
The last thing you need to know is that the performance requirements of hot-melt adhesive film are different in different application fields. For example, the garment industry often needs hot-melt adhesive film with good softness and washability. Therefore, TPU hot melt adhesive film is a more appropriate choice. But in the shoe industry, softness and washability are not important. EVA hot melt adhesive film is just the right choice.
Last but not least, the hot melt adhesive film products you choose must be tested before being used in production, otherwise, you may suffer huge losses.
4.How to use Hot-melt Adhesive Film
When using hot melt adhesive film for lamination, you may encounter various problems of poor adhesion. Here are some suggestions for you when you use hot melt adhesive film bonding materials.
4.1 Proper Type
Different materials need to be laminated with different adhesives. There is no adhesive film that can bond all kinds of materials. When you have a new material to be bonded, you also need to find a new adhesive film for it. Because the adhesive film that can be used before may not be suitable now.
4.2 Three elements of hot pressing
Temperature, time, and pressure are the three most important factors for lamination. The melting of adhesive film requires a certain temperature and time, and proper pressure can help the adhesive quickly soak to the surface of the adherent. Otherwise, there will be a lack of glue or glue penetration, resulting in poor bonding.
4.3 Characteristics of bonded material
There are some cases where the bonding is not firm because you have not noticed some special properties of the adherents.
For example, wood is a material with high moisture content. A lot of water vapor will be produced by wood during hot pressing. Therefore, it is necessary to release the pressure at a specific time to ensure that water vapor is discharged.
5.Factors Affecting the Price of Hot Melt Adhesive Film
There are many factors affecting the price of hot-melt adhesive film, mainly including the following aspects.
5.1 raw materials
The components of hot melt adhesive film are various, and the prices of different materials are also different. Because the price of hot-melt adhesive film depends on the price of the raw materials it used.
5.2 Production process
Due to the characteristics of some raw materials, there will be additional losses in the production process, which will lead to higher costs.
Hot melt adhesive film is sold in rolls. It has three specifications: thickness, width, and length.
The width of the hot-melt adhesive film is usually between 1m and 2m, which depends on the width of the machine mold. The thickness of hot melt adhesive film is generally 0.015mm-0.2mm. Due to the limitation of the machine, it is difficult to manufacture adhesive film products beyond this thickness range.
The length of each roll of hot melt adhesive film is generally 100m-200m, which can also be customized according to customer needs. The thinner the product, the more meters can be made, and the thicker the product, the fewer meters can be made.
The price of adhesive film varies with different width and thickness. Sometimes the price is quoted in square meters, sometimes in meters, which is entirely up to you.
5.4 How to inquiry about the price？
If you are a purchaser, you may wonder how to inquire about the price of hot-melt adhesive film. Here are some key points.
First of all, you must know what materials you need to stick by using hot melt adhesive film, because this is related to the determination of the type.
Secondly, you need to tell us whether you want a hot melt adhesive film with backing paper or film without backing paper.
Then, the manufacturer can recommend some products suitable to you. When the sample is tested, the manufacturer will give you a ladder quotation based on your consumption.