Why do diapers use hot melt adhesive?

The production process of diapers is a relatively complex combination process, which is composed of surface non-woven fabrics, water-absorbent cores, PE composite bottom films, magic buckles and front waist stickers, anti-side leakage non-woven fabrics, elastic bands and many other materials. The combination of the above materials is bonded through hot melt adhesive, which is the current production process of all diapers. It can be seen that "hot melt adhesive" will be present in the normal production process of diapers.

What are the methods of gluing diapers?

There are two ways to apply glue. One is spraying glue, and the other is scraping glue. These two methods use a spray gun and a scraper gun. The spray gun uses several small holes in the spiral to blow out the gas at a set pressure. , the glue squeezed out from the glue holes surrounding the pores is sprayed in a spiral shape on the surface of the material to be composited, and then passes through a series of pressure rollers to firmly composite the materials together.

Is the smell of hot melt glue toxic?

Hot melt collagen material consists of main resin, tackifier resin, diluent or softening oil, additives and other ingredients. The inherent smell of raw materials is an important source of the smell of hot melt adhesive.

During the production process, hot melt adhesive may also have new odor sources, and the odor can be reduced through production process control. During the logistics and transportation of hot melt adhesive, it may also be contaminated with new odors. But generally speaking, the slight smell contained in the hot melt adhesive itself is non-toxic.

Is hot melt glue harmful to babies?

Hot melt adhesive is non-toxic and odorless, and is an environmentally friendly chemical product. Its physical state changes with changes in temperature. Therefore, when hot melt adhesive is used in the production of diapers, the resulting glue is a production defect and belongs to the after-sales scope of the product, but it will not cause any harm to the human body.

1. PUR hot melt adhesive for fabric bonding

It can greatly reduce the labor intensity of clothing through bonding and stitching, and the high-imitation clothing made is good, well-fitting and strong. Hot melt adhesives used for fabric bonding mainly include polyamides, polyphenols and polyurethanes.

2. PUR hot melt adhesive for lining processing

The adhesive lining is made by the surface of the fabric on the surface of the fabric. In use, the adhesive backing fabric is cut into the desired shape and size, and the side on which PUR hot melt glue is applied is thermally bonded to the back of the other fabric material. It is arranged on the high imitation clothing layer and serves as the skeleton of high imitation clothing, simplifying the handling and time of high imitation clothing, making high imitation clothing lightweight, beautiful, comfortable, retaining shape, washable, and durable. Interlining processing generally requires hot melt adhesives to be colorless, odorless, soft, fast, dry and moisture-resistant, and the adhesive does not affect the fabric and is light-resistant.

3. PUR hot melt adhesive for carpet bonding

Carpets used for PUR hot melt adhesives are mainly copolymers of ethylene and other olefinic monomers, such as ethylene-vinyl acetate copolymer, ethylene acrylate copolymer, etc. In most cases, ethylene-vinyl acetate copolymer (EVA) is used.

Integrated boards are being used more and more widely in decoration due to their unique material properties such as environmental protection, moisture-proof, mildew-proof, sound insulation, heat preservation, fire prevention, and convenient installation. In some areas, integrated boards have even become the first choice material for decoration. The main reason for this phenomenon is its environmental protection and convenient installation advantages.

Integrated boards are divided according to materials and can usually be divided into: bamboo and wood fiber integrated walls, aluminum integrated walls, and stone-plastic integrated walls. Since bamboo and wood fiber has a relatively wider market acceptance, this article uses bamboo and wood fiber integrated walls as the example. It is made of a base material produced by high-temperature composite production of bamboo powder, wood powder, polymer aldehyde-free polymeric components and other environmentally friendly materials, and is then coated with environmentally friendly decorative materials. Because the base material is made of environmentally friendly materials and compounded at high temperatures. The various raw materials that make up the base material have changed their material properties during the high temperature process. Almost all the volatile chemicals contained in the base material have been released after high temperatures, so choose qualified ones. The integrated board base material itself produced from raw materials rather than recycled materials can be very environmentally friendly. In the end, the key link in determining the environmental protection of integrated walls is surface coating.

PUR hot melt adhesive is much more environmentally friendly than cold glue. It is widely used in auto parts, textile industry, shoemaking industry, book binding, food packaging industry, household appliances, and electronic products. PUR hot melt adhesive is used in the building materials and home furnishing industries. Glue and PUR hot melt adhesive machines are already the first choice.

Compared with cold glue, PUR (polyurethane hot melt glue) is a reactive adhesive.

It has the following significant advantages:

A. It has the remarkable characteristic of irreversible moisture reaction - it does not rebound when encountering hot or cold environments;

B. 100% solid, no solvent - no harmful substances such as VOC, benzene, formaldehyde, etc. are emitted;

C. High initial bonding strength - short reaction time;

D. UV resistance - convert harmful UV light into harmless heat energy to protect materials;

E. High production efficiency - equivalent to 5 times the efficiency of cold glue equipment production;

F. High environmental performance - E0 level environmental protection.

Using hot melt glue to seal cartons  is already very mature in the industry, but sometimes the glued box will open as soon as you pinch it. What is going on?

First of all, it is necessary to determine whether the material used to make the box is the same as before, and whether the surface has been treated in any way, resulting in poor hot melt adhesive. In this case, the main reason is that the carton seal is not friendly to hot melt adhesive. For example: before some cartons are sealed with hot melt adhesive, their surfaces will be polished, laminated, etc. in order to be beautiful and high-end. Such carton materials will cause considerable difficulty in the bonding of hot melt adhesives. . Because the performance of hot melt adhesives for the same application on the market is not very different, it will be difficult to find a suitable hot melt adhesive, and passive selection may increase production costs. After comprehensive consideration, if the sealing effect is really poor, it is recommended to adjust the surface treatment process of the carton.

Secondly, whether the temperature has changed significantly from before, the external temperature will affect the curing speed of the hot melt adhesive. When the weather is cold, the curing speed will be shortened, and if the line speed does not keep up, it will not stick well. This problem can be solved in the following ways. First, increase the production line speed so that the glue can complete the box sealing operation with better pasting performance; second, increase the operating temperature of the hot melt glue machine by 5 to 10 degrees Celsius, and extend the cooling time. time; the third is to replace the hot melt adhesive and use one that does not dry as quickly in cold weather.

As a special spraying equipment for PUR hot melt adhesive, the PUR hot melt adhesive machine has its own requirements for the surrounding environment. It is charged during use, so flammable and explosive objects or gases should be avoided during installation. After installation, it is best to fix it in this position and not move it easily.

The PUR hot melt glue machine is a large-scale mechanical gluing equipment. The power cord must have a grounding wire during installation. The power of the 55-gallon PUR hot melt glue machine is 15KW, which is very powerful. The power cord requires a thicker copper wire to withstand the heating load, at least 10mm.

Since the curing of hot melt adhesive is relatively fast, if the PUR hot melt adhesive machine is operated in a place where air flows quickly, the cooling and solidification of the PUR hot melt adhesive will be accelerated, so that the glue coming out of the hot melt glue gun will be stringy, so the PUR hot melt adhesive machine cannot be installed at the vent. In addition, PUR hot melt adhesive machines also have requirements for humidity, which should be less than 85% RH, avoid direct sunlight, and have no corrosive gases or liquids around.

1. The PUR hot melt adhesive machine needs to be connected to the power supply by a professional electrician. The polarity of the power supply must not be reversed, and the wiring needs to be fixed with special terminals.

2. When installing the pressure plate PUR hot melt adhesive machine, a useful grounding wire must be correctly connected. Any equipment that uses high-voltage electricity needs to have a grounding wire. When a grounding wire is not used, any components protected by insulators on the PUR hot melt adhesive machine may still form voltage conductors, resulting in the risk of electric shock.

3. Based on the load required by the PUR hot melt adhesive machine and its peripheral equipment, check whether the power cord and insulation protection used comply with the regulations. The load of the wire must be 30% higher than the rated power of the PUR hot melt adhesive machine. above.

4. Ensure that the pur hot melt adhesive machine operates at the specified voltage. If the voltage used is different from the specified standard power supply, the hot melt adhesive machine may be burned.

5. Ensure that the operating voltage connected to the PUR hot melt adhesive machine complies with the regulations of the hot melt adhesive machine. Generally, the 5-gallon PUR hot melt adhesive machine uses a single-phase 220v AC voltage standard, and the 55-gallon PUR hot melt adhesive machine uses a single-phase 220v AC voltage standard. When using a 380V AC power supply, when the voltage used is too high or too low, the designed performance of the equipment cannot be achieved and the hot melt adhesive machine may be damaged. When wiring, ensure that the power cord is correctly connected to the correct voltage power supply.

Hot melt glue carton sealing machine is an automatic or semi-automatic packaging equipment that is upgraded and transformed on the basis of packaging machine. It can automatically complete glue spraying, ear folding, sealing, etc.

The hot melt glue box sealing machine uses an automatic glueing method to glue the folded sides of the carton. It is suitable for gluing a variety of carton sizes. It has a simple appearance, reduces power consumption, conforms to the concept of environmental protection and energy saving, and has low investment costs. The carton sealing machine is highly efficient, with a production capacity of 30-50 boxes/minute. The efficiency is 2-3 times that of manual carton sealing. It has a wide range of applications and can be adjusted according to the size of the carton anytime and anywhere.

Possible problems with hot melt glue carton sealing machine

1. Insufficient and uneven gluing:

The hot-melt glue machine has blocked glue during the pre-melting process or at the glue outlet, which may lead to uneven glue application. This is because the operating load capacity of the machine is insufficient to completely melt the adhesive, or the temperature setting of the hot melt glue machine is too low.

2. Excessive smoke or smell:

Similar problems can occur due to reasons such as the set temperature is too high, the mechanical current device is incorrect, the thermostat of the hot melt adhesive machine is faulty, the heater is faulty, the hot melt adhesive tank is not clean and other impurities or dust are mixed in, etc.

3. "Glue thread" is produced when applying glue:

The heating temperature set by the hot melt glue machine is low, the glue application procedures and methods are inappropriate (the amount of glue applied is too large), the temperature difference between the outdoor and indoor areas (the construction site is large, and the convection of the air can easily cause the ambient temperature to change (especially in winter)). Stringing phenomenon.

4. There is dirt or excessive adhesive on the edge of the box sealing machine.

Excessive glue application, mechanical failure during the trimming process, improper glue application position, and excessively high temperature of the hot melter may cause glue accumulation, thereby affecting the glue application effect.

5. Release after bonding:

The cause is that the hot melt glue carton sealing machine is cold (suddenly cooled) during the bonding process. Stable bonding conditions should be maintained (including temperature, pressure, and working speed, etc.), otherwise the bonding effect will be affected. In addition, incorrect selection of glue will also cause the carton bonding effect to be insignificant.

Cohesive strength of PUR hot melt adhesive machine

The law of influence between the cohesive strength of PUR hot melt adhesive colloid and wire drawing is: if the cohesive strength is large, the wire drawing phenomenon will be obvious; on the contrary, if the cohesive strength is small, the wire drawing phenomenon will not occur.

PUR hot melt adhesive curing time

The curing time of PUR hot melt adhesive is an important factor affecting the occurrence of stringing. Generally speaking, the PUR hot melt adhesive with a short curing time has a low probability of stringing, because the filaments formed when the hot melt adhesive is sprayed out of the muzzle, due to Rapid curing makes it impossible to stretch continuously and is prone to breakage, and sometimes no strands are visible.

Effect of machine temperature

If the PUR hot melt adhesive machine temperature is too low, the consistency of the PUR hot melt adhesive itself will increase and stringing will occur.

PUR reactive hot melt adhesive should be bonded within the opening time after application to ensure the best bonding effect. However, during the bonding process, bubbles may appear. What is the reason?

1. The temperature of the glue tank is too high. If the temperature is too high and the hot melt adhesive has poor heat resistance, this phenomenon may occur;

2. The hot melt adhesive itself. The hot melt adhesive is not completely melted and mixed during the production process. The air in the rubber will be released during the heating process by the user, or the hot melt adhesive is not vacuumed or cannot be vacuumed properly during the production process. thorough;

3. If there are bubbles in the glue coming out of the nozzle, you can consider whether the temperature of the hot melt glue machine is too high and whether there is residual glue that has not been drained out. You can try to drain the glue for a few minutes to see if the glue is smooth and without bubbles;

4. There are no bubbles when the glue comes out of the nozzle, but there are bubbles after the reaction. One possibility is that there is tension after bonding, and the external pressure is not strong enough, or the pressure is not good. Another possibility is that the adhesive was not positioned and pressed in time after pasting, causing it to bounce off when first bonded, resulting in bubbles on the edges or both ends.

Hot melt glue machines, hot melt glue guns, and hot melt hoses all have heating functions to prevent the hot melt glue from cooling during the circulation process, thereby affecting the product bonding effect. What to do if the hot melt glue tube or hot melt glue gun does not heat up? Today we will briefly introduce you to several troubleshooting methods.

1. The heating wire (rod) is damaged: first check the wiring and measure the resistance value, and then replace the heating wire after confirming the resistance.

2. Thermosensor failure: Check the wiring and measure the resistance value, and replace it after confirmation.

3. Poor line contact: Check whether the line contact is loose.

4. Corresponding temperature control meter failure: Check whether the solid-state relay has an input DC signal.

5. Solid state relay failure: Check and replace the solid state relay

6. Whether the fuse is burned out: Check and confirm. If damaged, please replace the fuse with a new one.

If the hot melt glue hose and hot melt glue gun are not heated during use, the stability of the glue will be affected. When the hot melt glue machine is used again, the solid glue in the hose or glue gun will not be able to melt and flow out, causing blockage and causing the entire set to heat up. The melting machine will not be able to be used. Therefore, when using the entire hot melt adhesive machine, it is necessary to maintain and repair it on time to avoid delaying production and causing unnecessary trouble.

The hot melt adhesive cools before bonding. The reasons and solutions are as follows:

(1) The use temperature of hot melt adhesive is low → increase the use temperature;

(2) The opening distance is too long → reduce the opening distance;

(3) The conveyor belt speed is too slow → increase the conveyor belt speed;

(4) The amount of glue applied is not enough → increase the amount of glue applied;

(5) The temperature of the adhered material and the environment is low → increase the temperature of the environment or the adhered material;

(6) The pressure is inappropriate → adjust the pressure.

It needs to be analyzed one by one for different reasons to obtain corresponding solutions.