JPS6045216B2 - Fire retardant for polyurethane foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides water-resistant coating by coating the outer surface of an inorganic granular material containing water of crystallization, such as one that releases crystallized water at high temperatures and forming an inorganic foam layer, with a silicone resin. sex,
The present invention relates to a fire retardant for polyurethane foam (hereinafter simply referred to as fire retardant) that has weather resistance and can be easily added without adversely affecting polyurethane foam raw materials.

Recently, polyurethane foam, which is lightweight and has excellent insulation properties, is often used as a core material for building materials.

In order to improve fire resistance, which is the biggest drawback of this foam, attempts have been made to add, for example, inorganic fillers. It is also known that it has a great effect on improving fire resistance. However, when adding this type of inorganic material such as borax that has crystallization water during foaming, some of the crystallization water is dissolved due to the exothermic reaction that occurs during foam formation and is added during foam formation. It turns out. Therefore, there was a disadvantage that the reaction rate of the foam raw material, the foaming rate, the foam structure, the adhesiveness, and others were greatly adversely affected. In particular, in the case of polyurethane foam, the mixing ratio of polyol and polyisocyanate is set to be constant, and the physical properties of the resulting foam are also determined. However, the crystallization water and the alkaline content of the borax acted catalytically on the foam raw material during the reaction, which had the disadvantage of significantly disrupting the reaction system. In other words, this means that an excess of alkaline catalyst has been added to the composition, which changes the foaming speed and changes the relative relationship (balance) between the viscosity and foaming pressure of the foam during the reaction with the foaming agent. ) collapses and the foaming agent evaporates to the outside by the difference in reaction speed, resulting in a disadvantage that the desired foaming ratio cannot be obtained. In addition, the density of the foam is determined by the fact that the crystallized water of borax etc. is dehydrated by the strong dehydrating action of polyisocyanate, which acts as a foaming agent.
It has the disadvantage that it disturbs the original balance between the vaporization timing of the blowing agent and the viscosity of the polymer, causing a large change in the expansion ratio, resulting in a higher expansion ratio than necessary or a lower expansion ratio.
In view of these drawbacks, the present invention has been developed as a foam raw material by coating the outer peripheral surface of a material with silicone resin, which has the excellent property of foaming at high temperatures and forming an inorganic foam layer, as a result of intensive research. The purpose of the present invention is to propose a fire retardant that can be added without adversely affecting the reaction and structure of the fire, and which can fully exhibit its original fire retardant properties in the event of a fire.

The object of the present invention is to be able to add these additives to foam raw materials during foam molding without adversely affecting the reaction of the foam raw materials, and to reduce the loss of crystallization water, weather resistance, and fire resistance of the additives themselves. The aim is to obtain a fire retardant that does not spoil.

In the present invention, the inorganic granules that have crystallization water and form an inorganic foam layer at high temperatures are composed of one or more of borax (pentahydrate salt, monomer salt) and sodium metaborate. Furthermore, silicone resin is used to cover almost the entire surface of the inorganic particles. The above-mentioned blending ratio of the inorganic granules and the silicone resin varies depending on the application, but the amount is such that the silicone resin sufficiently covers the surface of the inorganic granules. Next, examples of the fire retardant according to the present invention will be described.

Blend ratio Borax (150-200 mesh) 100g silicone resin (water repellent) 50g dibutyltin dioctate (catalyst) 0.2g toluene (solvent)
Prepare 50g of the above ingredients,
Therefore, silicone resin and toluene to which a catalyst has already been added are fed into an ultra-high speed stirrer (10,000 rpm).

Next, borax was added to this solution and stirred, and after about 2 minutes, it was taken out from the stirrer and the granules were dried (the solvent was evaporated) to produce a fire retardant. When the fire retardant thus produced was observed, a thin silicone resin film was formed on the outer peripheral surface of the borax.

Therefore, when we mixed this fire retardant into polyurethane foam raw materials (in a two-component mixed state, so-called cream time, gel time) and observed its effects, we found that as the amount of silicone resin used increased, As mentioned above, it was found that the adverse effects were reduced. Furthermore, it has become clear that there is no significant change in performance beyond a certain amount added. This is because even if the surface of the borax is coated with more than the necessary amount of silicone resin, it will not be effective. That is, it is sufficient that a portion of the borax components do not dissolve to the outside, and any larger amount will be wasted. In addition, fireproof particles coated with silicone resin (for example, coated with only 50g) are used at a temperature of 25℃ and a humidity of 5.
There was no change in the physical properties of the borax made of pentahydrate even if it was left for 10 days at 0% concentration, and the original inorganic foam was formed even at high temperatures. What has been described above is only one embodiment of the present invention, and not only the amount of silicone resin but also the rotation speed of the stirrer,
The amount of adhesion can also be controlled by using solvents and other additives.

As mentioned above, the fire retardant according to the present invention is a large compound that can be added to synthetic resin foams and other liquid materials that require fire resistance without changing the reaction, reaction rate, or physical properties of the material by dissolving additives or the like. It has characteristics.

Claims (1)

[Claims] 1. A fire retardant for polyurethane foam, characterized in that almost the entire outer surface of inorganic granules that release crystal water under high heat and form an inorganic foam layer is coated with silicone resin.