Sponge foaming principle: the foam resin, foam additives and adhesive resin (so that the finished product has adhesion) mixed together; Foaming process is carried out. The foam sponge can be prepared by mixing 80 parts of vinyl acetate (EVA), 20 parts of APAO PT 3385, 20 parts of azodimethylamide, l9 parts of CaCO and 0.6 parts of diisopropylbenzene peroxide in the mold to foam, and then breaking the closed hole with mechanical force. Its density (d) is 0.028 g/cm and 25% compression hardness is 1.9 KPa
Common sponge foaming treatment method
1. Manual foaming method, which is the convenient method, will accurately weigh all sponge raw materials.
2. One-step foaming method. The polyether or polyester polyol and polyisocyanate, water, catalyst, surfactant, foaming agent, other additives and other raw materials are added in one step, mixed at high speed stirring after foaming.
3, prepolymer foaming method. Refers to the polyether polyol and diisocyanate prepolymer, and then add water, surfactants, catalysts and other additives in the prepolymer mixed under high-speed stirring for foaming, curing at a certain temperature can be matured.
4. Semi-prepolymer foaming method. Is to make part of the polyether polyol and diisocyanate prepolymer, and then the other part of the white and black materials, catalysts, water, surfactants and other additives are added, mixed under high speed stirring for foaming. This foaming method is similar to the prepolymer foaming method.
These are the four foam methods commonly used for sponges. After foaming, sponges can obtain better elasticity and water absorption, which can meet the needs of sponges in many industries.
1. Emulsification
Polyether, isocyanate, water, physical foaming agent, catalyst, color and other materials are not compatible with each other because of their different physical properties. Add the right amount of effective silicone oil, you can let them blend together, close contact. It’s like two people trying to fight, only when they can touch each other can the fight start.
2. Stable bubble effect
Under the action of catalyst, the carbon dioxide gas produced by the reaction of water and isocyanate is aggregated to form bubbles and escape under the action of gravity of the reaction system. When the physical foaming agent is added, the physical foaming agent also volatilizes and aggregates into bubbles under the action of reaction heat to escape. If the bubbles cannot maintain a certain stability at this time, it is bound to appear side-by-side and burst bubbles. Once the combined bubbles and broken bubbles are large enough to support the stability of the whole system, then collapse of bubbles will occur and foaming will certainly fail.
3. Homogenizing effect
Bubbles gathered in the foaming process have different sizes. At the end of the foaming reaction and the end of the gel reaction, the presence of silicone oil will make the bubbles of different sizes as normalized as possible, that is, the large bubble becomes smaller and the small bubble becomes larger.
When the gel reaction ends, the bubble is broken and a network structure of open holes is formed.
The molecular structure and amount of silicone oil and the amount of tin have obvious influence on the bubble rupture. If the silicone oil activity is high and the amount is large, then the bubble wall formed will be thick and the surface tension will be large. At the end of the gel, the bubble wine is difficult to break completely, and the liquid on the hole wall is difficult to flow to the sponge meridian immediately, forming a residual film.
When the amount of tin is large, the gel speed is fast, the liquid viscosity on the foam wall increases quickly, and the bubble hole is not easy to burst. Even if it bursts, the liquid on the foam wall cannot be completely transferred to the meridians, and some film will remain.
These films will be reduced in the sponge maturation process, but it is difficult to completely eliminate, so that after the sponge maturation is completely cut, you will see the reflective film distributed on the cutting surface. These films are particularly obvious on the colored cotton, which has a great impact on the product quality, especially the black industrial cotton. Customers are very picky about the highlights.
Iii. Solution
It can be eliminated in several ways.
1, choose relatively low activity of silicone oil and the appropriate amount, so that the foam wall of the late foaming foam is thin, easy to break.
2. Use acid-sealed delayed amine to replace part of T-9, give the gel in the foaming process to T-9, and give the delayed amine to complete the post-ripening. In this way, the viscosity before the bubble wall is broken can be greatly reduced, and the liquid can maximize the flow to the sponge meridian after the bubble wall is broken. Reduce film residue.
3. Add sponge to remove film brightening agent and remove residual film by chemical method.
Based on the principle of interface technology, the use of organosilicon surfactants can reduce the surface tension of some materials, the selection of reactive organosilicon materials, supplemented by advanced fatty alcohol, through reasonable manufacturing process, successfully developed the sponge film removal and lightening agent WM-655, the product has been applied to the production of black sponge, achieved satisfactory film removal effect. Under the condition that the amount of black paste is the same, the residual film is much less than that without removing film agent, and the blackness is obviously higher than that without removing film agent.
As we all know, when producing sponge, even if the opening rate of sponge is more than 95%, there is still a lot of residual membrane between the meridians of sponge. When the light hits the surface of the sponge, it can be seen as dotted with points of reflection. This phenomenon affects the perception of sponges. Especially for coloring sponge, the existence of film, resulting in color material itself color distortion, such as: black is not black, red is not red.
In order to solve this problem, many sponge factories have made a lot of attempts on the production process and formula, and achieved certain results, but this fundamentally can not completely solve the problem. Some experiments have pros and cons. For example, when hair black cotton, improve the amount of black paste, sponge blackness increases, the cost also increases; In addition, the increase of the amount of black color paste to the foaming process control has brought adverse effects. After all this effort, the product is still “shining”. In view of this, we will develop a film removal and brightening agent to remove the film remaining in the meridians after the maturation of the sponge, which will be helpful to improve the quality of the sponge.
Sponge is an industrial packaging product that can be seen everywhere. It is related to people’s clothing, food, housing and transportation. It can be said that many people cannot live without sponge. However, people sometimes do not know how to choose sponge products when faced with a wide variety of products. Today we’re going to talk about filter sponges.
The filter sponge is a high-tech material. It is designed for astronauts to help relieve stress during takeoff, landing and flight. Because of the pressure relieving characteristics of filter sponge, filter sponge is widely used in many places. Let’s take a look at the hidden side of filter sponges.
The difference between the filter sponge and the traditional sponge and the fat cotton: The filter sponge can absorb the weight of the body and feel like floating in the air. Filter sponges follow body shape instead of fighting body shape like sponges and polyester cotton, making people more attuned to it. Full body, neck, and waist support can be provided by allowing the spine and joints to rest in their natural physiological state. Release stress completely and enjoy a sense of weightlessness. The material of the filter sponge is anti-bacterial according to the European standard. Its high-density material can effectively resist the infiltration of sweat and odor, which can ensure that it is in line with personal hygiene and is harmless to human health.
The scientific name of nano sponge is melamine foam, melamine sponge, also known as high-tech foam, a clean, magic sponge, magic sponge, melamine sponge, is a new type of foam with high pore rate three-dimensional mesh structure. Its unique chemical structure and three-dimensional network crosslinking system make it have unique chemical and physical stability, in the weak acid and weak base environment will not aging, decomposition, no residual free formaldehyde, its hygiene can meet the requirements of food hygiene, with good secondary processing ability.
Sponge magic wipe using physical decontamination mechanism, relying on the nano-level capillary hole structure in the sponge, in the wipe process automatically adsorb stains on the surface of the object, like countless ultrafine vacuum cleaner in the work, only need water, completely does not rely on any chemical detergent to help degrade, so it is called magic. Explain capillarity: The surface of a liquid resembles a tensioning rubber film; if the surface is curved, it tends to flatten. So the concave exerts a pull on the liquid below, and the convex exerts a pressure on the liquid below. The surface of the infiltrated liquid in the capillary is concave, and it exerts a tension on the liquid below, making the liquid rise along the wall of the tube. When the upward tension is equal to the gravity force on the liquid column in the tube, the liquid in the tube stops rising and reaches equilibrium. The same analysis can also explain the phenomenon of non-infiltrating liquid descending in the capillary. Magic rub is the use of liquid surface to solid surface attraction effect, that is, to achieve physical decontamination.
Nano-sponge magic wipe is completely non-toxic and can be used to wash dishes and cups. Sponge dishwashing generally saves cleaning agent, and the ability to absorb hidden things is very strong, is a very good dishwashing appliance. Sponges are porous materials that absorb water well and can be used to clean things. In the selection of sponge, mainly to its touch and elasticity as the primary factor. It should be soft to the touch and malleable. Many people think that the magic magic rub (also known as nano sponge) toxic is it formaldehyde, but after a series of experiments said that nano sponge and formaldehyde did not exceed the standard, itself has good physical stability, is insoluble in water, the parameters are in line with environmental standards, all can be assured to use. But just because it’s not poisonous doesn’t mean it’s edible. Keep it out of reach of children to avoid ingestion.
Magic wipe formaldehyde is not toxic three reasons:
1. One of the characteristics of formaldehyde is very soluble in water, usually with nano sponge magic scrub bowl is soaked in water and then used, and the pore structure up to more than 95%, easy to absorb water. So even if there is some formaldehyde inside the nano sponge magic wipe, dissolved in water after the residue is very little. And formaldehyde is not used in a confined space, so much less enrichment, it has dissipated.
2. The use of magic wipe must be water, so that of the formaldehyde has been removed, as long as the entrance of the bowl dish with water rinse several times, more ventilation to dry, you do not have to worry about formaldehyde will remain in tableware, eating utensils.
3. Some people are worried about the use of nano sponge magic wipe is very close to us, it will not let the formaldehyde concentration of the surrounding air increase and affect our health? To answer this question, let’s do an experiment: the process of the experiment is very simple, that is, in a room with al one desk, test the formaldehyde concentration in the air of the room itself, and then put the nano-sponge magic wipe about 250px away from the test box to test whether the formaldehyde concentration in the air increases. Nano sponge formaldehyde test shows that the formaldehyde content is still in 0.03~0.05/m3, just opened nano sponge is when the concentration of formaldehyde content is high, but we are in use when nano sponge is used after soaking in water, formaldehyde dissolved in water is not so high content.
4. Nano sponge magic rub although contains formaldehyde, but formaldehyde is in the standard range of values, do not blindly say that there is formaldehyde release is not qualified. There are a lot of things containing formaldehyde, as for how much will be the consequences, or not exceed the standard.