EVA Hot Melts for Woodworking
EVA hot melt adhesive is a 100% solid, transparent, flexible Ethylene Vinyl Acetate Copolymer. It is normally categorized by percent VA content and melt flow rate (MFR) or melt index (MI). Most commonly used EVAs contain between 19% and 28% VA. The MI values are mostly ranging from 3 to 2500.In an EVA-based HMA formulation, a greater VA content can result in higher transparency, more polar, extended flexibility, and better wettability to substrates. The MI value is a simple indicator of molecular weight. A lower MI value reflects a higher molecular weight, cohesion, and internal strength.
Advantages of EVA Hot Melts for Woodworking
Short opening and setting times
In the fast-moving world of production, short curing times are crucial. EVA hot-melt adhesives offer exactly that – fast open and setting times that speed up the production process.
Durability
One major benefit of using Eva hot melt adhesive is its durability. It can form a strong bond that can withstand extreme conditions such as high temperatures, moisture, UV light exposure, and chemical exposure when cured properly. This makes it ideal for use in outdoor applications or environments where exposure to harsh chemicals or other hazardous materials may exist.
Versatility
Eva hot melt adhesive is also known for its versatility. It can bond various materials including plastics, metals, wood, rubber, and glass. This makes it perfect for use in situations where various materials need to be bonded together. Additionally, Eva hot melt adhesives come in different forms – including sheets and pellets – so they can be applied with ease regardless of the application or material type being bonded together.
Cost-Effective
Finally, another benefit of using Eva hot melt adhesive is that it is cost-effective compared to other types of glue. Since it does not require any special equipment or large quantities for application, this allows companies to save money on labor costs and materials costs when working with small projects or large-scale projects alike.
Short opening and setting times: In the fast-moving world of production, short curing times are crucial. EVA hot-melt adhesives offer exactly that – fast open and setting times that speed up the production process.
Why Choose Us
Our Factory
Zhejiang Good Adhesive Co., Ltd was established in 1996 in China, covers an area of more than 10000 square meters with annual output of 30000tons of environmental friendly hot melt adhesive series products base on EVA, polyolefin, elastomer, polyurethane, PA and animal protein.
Our Products
We specialize in researching, manufacturing, and selling hot melt adhesive with annual output of 30000tons of environmental friendly hot melt adhesive series products base on EVA,polyolefin,elastomer,polyurethane,PA and animal protein.
Applications fields
Applications fields cover bookbinding industry, packaging industry, tape and label coating, automobile assembly, interior decoration and damping sealing, air filter making, sanitary and medical products making, furniture industry, pest control, etc.
R&D Team
We have our own lab and R&D team, can provide you technical supports at any time. Raw materials are imported from American Dupon and Exxon, Canadian AT, Japanese TOSOH, etc., and our stric QC system will be the best safeguard for you.
Precautions When Using EVA Hot Melts
EVA hot melt adhesive is different from general cold glue. According to its characteristics, the following points must be mastered and paid attention to in use:
》To understand and master the various models and technical performance (including technical parameters) of each EVA hot melt adhesive type. Different types of hot melt adhesives have different opening time and curing time. In particular, it is necessary to strictly distinguish the usage of summer glue and winter glue. The opening and curing time will also change when the temperature is different.
》When using EVA hot melt adhesive, do not directly heat it with an open flame. Be sure to use spacer oil to heat (the boiling point of water should reach 100°C), or use a sealed electric heating plate.
》Before using the solid EVA hot melt adhesive, it must be preheated with a preheating device and then released into the working glue box of the glue liquid. The preheating time is generally about 2 hours.
When using glue, do not directly mix solid glue blocks (that is, glue that has not been preheated) into the glue box to prevent poor fluidity of the glue or apply the incompletely melted glue to the back of the book, resulting in uneven glue application.
》The amount of glue in the preheated glue pot should be controlled properly. If the amount is too much, the glue will melt in turn, which will cause deterioration and aging, lower viscosity, and affect adhesion.
》When repairing wireless glue binding equipment for a long time, the pre-gluing and working glue pot should be turned off to prevent the aging of the glue.
》The temperature of the molten colloid should be strictly controlled within the range of use.
》It is necessary to clean the pre-gluing pot and the working glue box regularly to keep the glue pot clean to prevent the accumulation of impurities in the glue and affect the accuracy of temperature control, and even cause the thermostat to malfunction and cause the colloid to burn. Generally, under normal production and operation, the preheated glue pot should be cleaned every 3 months. The working glue box (for glue application) should be cleaned every half a month. A system should be established for cleaning the glue pot to facilitate implementation.
While EVA hotmelts are an excellent solution for many industrial applications, the high temperature of the process needs to be carefully controlled to avoid smoke problems. When hot melt adhesives are heated, they inevitably release some fumes. That's the smell detected when working close to the hot melt nozzle. While some smoke is normal, too much smoke indicates a problem with your process that needs attention.
Check the production process
To stop hot melt adhesive smoke, check your various hot melt process parameters:
Temperature: The temperature of the melt gun or gluing equipment is critical. When too low, the adhesive cannot melt and flow properly. Too hot and the adhesive will become too runny and it will give off a nasty and irritating fumes. In some cases, charred adhesive discolors the final glue and may also cause charring. Adjust the temperature settings based on the manufacturer's settings for the fuser equipment and the manufacturer's recommendations for the temperature of the specific glue you're using.
Dispensing equipment and work area cleanliness: Adhesive residue near the dispensing equipment, applicator head and work area can cause melt problems and smoke. Adhesives that have burned and dried are more likely to smoke than fresh, unmelted hot melt adhesives. A common source of fumes is spent dry adhesive that builds up on application equipment.
How to preheat EVA Hot Melts
Add glue
Add the appropriate amount according to the amount of glue used and the size of the hot melt glue sol pool. During normal use, keep the liquid level range of 35%-80% in the sol pool. If you use a small amount of hot melt adhesive in a single use, you don't have to add too much. Generally, the liquid level can be controlled at about 50%, otherwise the hot melt adhesive will be repeatedly melted, resulting in waste of electric energy, and under the repeated high temperature of the heating tube, the hot melt adhesive will be partially deformed. Hot melt adhesive melts.
Warm up
Solid hot melt adhesives must be preheated before use, and must be preheated to a liquid state before use. The temperature adjustment should not be too high, because the initial melting state is relatively slow, especially for EVA hot melt adhesives. Partial decomposition will occur above 205°C. There are two heating methods for existing equipment, one is oil bath heating; the other is electric hot plate heating. In terms of performance, oil bath heating is better, and its advantage is that the temperature is stable. The market share of direct heating of electric hot plates is relatively high, basically reaching more than 80%. The reason is simple structure and low cost. The carbonization of the melt, especially when the temperature of the melt is too high, has a greater impact in this regard. The preheating time is generally 2 hours, and the central value of the temperature setting is 140~160℃. As the amount of hot melt adhesive increases, the upper and lower temperature limits are often 140℃ and 190℃.
Reasons and Solutions for Carbonization of EVA Hot Melt Adhesive
How Hot Melt Adhesive Causes Carbonization
Charring can be a common problem with hot melt adhesives used in packaging applications. These applications often require placing the adhesive in a large melt tank. This means that the adhesive is stuck in the can and “cooked”. Over time, some EVA hotmelts may char slower than others, but all types of hotmelts may be susceptible to this problem over time.
If not maintained properly, the reservoir can cause charring and damage to the entire unit. This can happen if the melt tank lid is left open for too long and contaminants fall into it.
Additionally, the reservoir may not be the right size for a given application and line throughput. This affects how much adhesive is used and how much adhesive is left in the tank. Also, if the sump temperature is too high, it increases the likelihood that the adhesive will “cook” faster and cause charring.
Solutions to reduce carbonization of hot melt adhesives
The EVA hotmelt used is the right one for your application. In some cases, low application temperature binders or metallocenes can do the job and are less prone to charring. However, some adhesives char more easily than others but are still suitable for specific applications. The sheet or process may require a binder that is easier to char to achieve the desired properties.
Influencing Factors of Curing Speed of EVA Hot Melt
The curing speed of EVA hot melt adhesive refers to the time from the beginning of sizing and pressing to 80% bond strength. The curing time required for general use ranges from 1 second to 10 seconds, and the curing speed required for automatic wire sealing is generally within 4 seconds. There are several factors that affect the curing speed of EVA hot melt adhesives.
First, the type of EVA has little effect on the curing speed, but the trend is that the curing speed corresponding to EVA with low melt index and low VA content will be faster.
The second is the effect of tackifiers. Choosing a tackifier with a high softening point and increasing the amount of tackifier will help to improve the curing speed. The use of tackifier has a great influence on the curing speed.
Finally, waxes have an effect on cure speed. Waxes generally play a role in viscosity adjustment and partial plasticization in hot melt adhesive systems. Waxes have the greatest effect on cure speed.
The general rule is that the higher the softening point of the wax, the faster the curing speed. The more wax you use, the faster the cure. However, the wax has a great adverse effect on the bonding strength, so the adjustment of the curing speed is limited to relying solely on the wax.
What Is EVA Hot Melts Made Of
EVA hot melt glue, also known as hot melt adhesive, is a thermoplastic adhesive that is solid at room temperature but melts when heated, allowing it to bond to surfaces upon cooling. Hot melt glue is commonly used in various applications, including packaging, woodworking, textiles, and electronics assembly. The composition of hot melt glue typically includes the following main components:
Polymers
Hot melt glue is primarily made up of synthetic polymers, which are long chains of repeating molecules. The specific polymer used can vary based on the desired adhesive properties, such as flexibility, strength, and temperature resistance. Common polymer types used in hot melt adhesives include ethylene vinyl acetate (EVA), polyolefins (such as polyethylene and polypropylene), and styrene block copolymers.
Resins
Resins are added to hot melt glue formulations to improve its tackiness, adhesion, and cohesion. These resins help the glue adhere to different surfaces and provide the necessary strength for bonding. They also contribute to the overall viscosity and flexibility of the adhesive.
Waxes
Waxes are included in hot melt glue formulations to control the melting point and viscosity of the adhesive. They help regulate the adhesive’s flow and contribute to its solid-state characteristics at room temperature.
Additives
Various additives may be incorporated to enhance specific properties of the hot melt glue. These additives can include antioxidants, UV stabilizers, colorants, and fillers. Additives help improve the adhesive’s stability, appearance, and performance in different environments.
Does EVA Hot Melt Have a Shelf Life
EVA hot melt adhesive is a plastic adhesive. Its physical state changes with temperature changes within a fixed temperature range, and its chemical properties remain unchanged. It is non-toxic and tasteless, and is an environmentally friendly chemical product. Hot melt adhesives are easy to pack, transport, and store. The product is solvent-free, pollution-free, non-toxic and environmentally friendly. Due to the advantages of simple production process, high added value, high bonding strength and fast speed, hot melt adhesives are favored by consumers.
So does EVA hot melt have a shelf life
The answer is of course yes. Hot melt adhesive also has a shelf life, and long-term contact with air will cause the hot melt adhesive to oxidize. Improper storage will cause the hot melt adhesive to turn yellow. Moreover, the EVA hot melt adhesive itself is not waterproof. If it is placed in a humid place for a long time, it will have a certain impact on the viscosity of the hot melt adhesive in an environment that is too high or too low. However, if it is kept properly, the storage time of the hot melt adhesive can be appropriately delayed.
How to store EVA hot melt
When the EVA hot-melt or hot-melt pellet is not in use, it is necessary to seal the hot-melt glue and store it in a cool and dry place, which can slow down the oxidation of the hot-melt glue. Avoid sunlight exposure, prevent contact with steam, water and alcohol solvents, generally can be stored for 1-3 years. Hot melt adhesives are chemical products and should be kept out of the reach of children.
FAQ
As one of the leading EVA hot melts for woodworking manufacturers and suppliers in China, we warmly welcome you to wholesale high quality EVA hot melts for woodworking from our factory. Also, custom service and cheap products are available.
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