JPS582814B2 - Nannensei Hatsupouzaino Seizouhouhou - Google Patents

Description

Detailed Description of the Invention The present invention utilizes pearlite grains, which are highly fire and heat resistant, as a raw material for forming polyurethane foam with a closed cell structure, the reaction rate of which is greatly affected by temperature, like a catalyst. The present invention relates to a method for producing polyurethane foam with improved flame retardancy by adding the polyurethane foam without adding any additives.

Foamed materials made of polyurethane resin (hereinafter simply referred to as foam) are easily flammable and undergo rapid chemical reactions.
It is also known that the reaction system is a substance that is extremely sensitive to temperature.

In particular, raw materials for foams that form closed cell structures using Freon 11, Creon 12, etc. as blowing agents are more sensitive.

In addition, this type of resin is increasingly being used for building materials and the like because it exhibits super-insulating properties and is easy to inject and discharge regardless of the shape of the base material.

In order to make the foam flame retardant, fire-resistant and heat-resistant pearlite grains are added.

However, polyurethane resin is affected by temperature and generates heat.
Since it acts like a catalyst in the reaction system, if mere pearlite particles, so-called ambient temperature pearlite particles, are added during the reaction, various disadvantages will naturally occur.

In other words, if more than 30% (by weight) of pearlite particles at ambient temperature are added to the raw material in the middle of reaction, there is a problem that the reaction rate, viscosity, and foaming timing will change significantly from the intended settings. .

Especially in the bitterly cold winter, perlite grains are usually 5 to 1 even indoors.
Since the temperature of the raw material during the reaction is 30 to 40°C, the reaction only partially cools the area where the pearlite particles are added, making the reaction rate uneven, and also affecting the timing and viscosity of vaporization of the blowing agent before foaming. It also disturbs the foam structure and severely damages the foam structure.

Therefore, the foam has a varying density, the foaming ratio decreases due to the generation and communication of voids, and the foam structure is partially destroyed.

The mechanical strength of the foam is therefore severely reduced.

Of course, if the pearlite particles are in a small amount, they can be ignored, but when they are added in an amount sufficient to provide flame retardance, the above results cannot be avoided.

(2) Furthermore, since the reaction rate is partially disturbed, the reaction state of the resin becomes inconsistent, and the degree of adhesion becomes unsatisfactory, resulting in a deterioration of the overall adhesion.

■It takes a considerable amount of heat to raise the pearlite grains to the same level as the reaction temperature of the resin, and the surface heating of the pearlite grains cannot keep up with the rapid changes in the properties of the resin, causing the reaction to occur in the opposite direction. It will slow you down.

(2) Pearlite particles have oil absorption properties, and when pearlite particles are mixed with, for example, a two-component reaction type unfoamed polyurethane resin, the resin content is significantly reduced due to its oil absorption properties.

Therefore, the foaming ratio will be lower than the resin content supplied.

This is oily when mixed with the polyurethane resin A1B stock solution, and when pearlite grains with a large number of highly oil-absorbing pores on the surface are added and mixed, the pearlite grains create a large number of resins with low viscosity and high fluidity. This is because it is absorbed through the pores of the body.

Note that there is a disadvantage that the amount of material to be absorbed must be added beforehand to the discharged material.

Moreover, this kind of raw material is expensive, which directly affects the increase in the cost of the product.

Of course, if the discharge rate is reduced, various irregularities and shrinkage will occur in the foam, making it impossible to produce a product.

(2) Furthermore, if a catalyst is used in an attempt to eliminate such drawbacks, it is expensive in itself, and the reaction described above is only partial, so it is almost useless.

■There is no point in trying to make the foam flame retardant when the foam structure is impractical.

(2) In particular, when a large amount of pearlite particles of this kind are added to a foam, there are drawbacks such as a severe decrease in the insulation properties of the foam and an increase in the amount of resin used.

In order to eliminate such drawbacks, the present invention adds pearlite grains by heating them, for example, heating them to a temperature higher than the heating temperature of the raw material,
When these pearlite particles encounter resin during the reaction, the heat causes the resin adhering to the surface of the pearlite particles to react and expand rapidly, increasing the resin viscosity in a short period of time, blocking the oil absorption of the pearlite particles. The present invention proposes a method for producing foam that achieves the desired reaction rate and expansion ratio by preventing the adverse effects of temperature on other surroundings, and also improves flame retardancy.

EMBODIMENT OF THE INVENTION Below, the manufacturing method of the flame retardant foam based on this invention is demonstrated in detail using drawing.

FIG. 1 is a side view of the apparatus used for carrying out the above invention, in which 1 is a form, 2 and 3 are upper and lower mold members, and an endless metal plate or an endless band is made up of a large number of divided mold parts. are connected and sandwiched with the foam 1 facing each other to form a mold 4 having a constant thickness.

Note that the height of the mold is set to a gap smaller than the natural foaming height of the foam.

56 is a guide wheel, ? , 8 are drive wheels that wrap around the upper and lower mold members, and 9 and 10 are auxiliary wheels that support the mold members 2 and 3 facing each other vertically at the mold 40 portion.

Reference numerals 11 and 12 denote temperature control devices which are equipped with ducts for blowing heated air toward the respective mold members 2 and 3, thereby curing the resin raw material in a short time.

13 is a caterpillar type molding machine, for example, and the mold members 2,
3, guide wheels 5, 6, drive wheels 7, 8, auxiliary wheels 9, 10, and temperature control devices 11, 12.

As is clear from the figure, the lower die member 3 extends in a direction opposite to the direction in which the die 4 moves (to the left in the figure).

Reference numeral 14 denotes a foam raw material feeder, which is installed at a suitable location in front of the mold 40 entrance.

This feeder connects tanks 15 and 16 that separately contain polyisocyanate and polyol, which are the raw materials, to a mixer 17.
It becomes connected to.

Reference numeral 18 denotes a perlite grain dispersing machine such as a pipebrator or a mixer, and a heating device 19 is connected to the upper part thereof.

This heating device 19 creates a flame atmosphere in a heater or a cylindrical body and passes through it for a short period of time.
This heats the aggregate to ℃.

20 is made of pearlite grains, shirasu balloons, vermiculite, etc., and is added in an amount of 30 to 200 parts by weight per 100 parts by weight of the synthetic resin raw material.

Note that the upper and lower limits are set because if the amount added is small, it will not have much of an adverse effect and almost no flame retardancy can be expected.

Further, the upper limit is set because if the amount of resin is too small, it becomes difficult to evenly mix large pearlite particles.

21 is a base material for the lower side (surface material), such as a metal plate or a plaster board; 22 is a base material for the upper side (rear surface material), which is made of, for example, aluminum foil, waterproof paper, or synthetic resin film.

Next, to explain the manufacturing method of the present invention, the molding machine 1
3 is rotated in the direction of the arrow, and the base material 221 is fed from the left side and placed on the lower mold member 3.

When the base material 21 arrives under the mixer 17, the resin mixture 23 is spread (discharged) onto the plane thereof.

When this surface arrives under the aggregate spreader 18, for example, 25~
Pearlite grains heated to 80° C. by the heating device 19 are dropped and scattered (sometimes scattered).

Note that if the temperature exceeds 100°C, there may be an adverse effect such as scorch on the reaction of the resin itself.

Next, a base material 22 is placed on top of this and passed through a molding machine 13 into a mold 4.
from the outlet as flame retardant foam.

Then, when this foam was cut and observed, it was found that (1) the foam structure was not rough and a homogeneous cell structure of closed cells was formed.

■The pearlite grains hardly absorbed any resin, and there were signs that a thin skin layer had been formed on the surface of the pearlite particles due to rapid reaction foaming of the resin.

However, no effect on the surrounding foam structure was observed.

(2) The expansion ratio was slightly lower than that of the raw material alone, and was much higher than when it was added without heating.

In addition, flame retardancy was approximately 3rd class flame retardant.

■Mechanical strength has improved compared to before.

■No defective areas (voids) were observed in the foam.

Here, an example will be shown to make these more clear.

Example 1 Compounding ratio Polyurethane resin 100 parts by weight Pearlite grains (average particle size 3 mmφ) 30 parts by weight Then, polyurethane resin raw materials (polyol and polyisocyanate) were each heated to 20°C, mixed at a ratio of 1:1, and heated. Dispense onto warmed molds.

Then, this raw material reacts, for example, at cream time, 6
Perlite particles heated to 0° C. were added to allow free foaming.

In this case, the bulk specific gravity is 0.0480 g/cm3, and the graph of the bulk specific gravity when the pearlite temperature is changed to 10℃, 25℃, and 80℃ with this mixture is shown in Figure 2. become.

Example 2 Compounding ratio: Polyurethane resin: 100 parts by weight Perlite particles (average particle size: 3 mmφ): 50 parts by weight A foam was produced using this under the same conditions as in Example 1.

In this case, as in Example 1, the bulk specific gravity when the temperature of the pearlite grains is varied is shown in FIG. 2@.

Comparative Example 1 Compounding ratio Polyurethane resin 10 parts by weight Perlite grains (average particle size 3 mmφ) 10 parts by weight These components were added and mixed in the same manner as in Example 1 to produce a free foam.

In this case as well, the characteristics of the bulk specific gravity when the addition temperature of pearlite grains is varied are shown in FIG. 2 θ.

As is clear from FIG. 2, when the amount of pearlite grains added is small, the bulk specific gravity is not reduced so much, but as it increases, the effect becomes more pronounced.

What has been described above is only one embodiment of the present invention, and other inorganic powder and granules such as borax, boric acid compounds such as sodium metaborate, silicic acid compounds, carbonates, etc.
It is also possible to set it around 90.

As described above, according to the method for producing flame-retardant foam according to the present invention, the foam raw material that reacts sensitively to heat is immediately foamed by the heat on the surface of the additive, and the surface of the oil-absorbing pearlite grains is surrounded. A major feature of this method is that oil absorption, which adversely affects the expansion ratio, can be blocked to a minimum extent, and flame-retardant foam can be manufactured at low cost with the best expansion ratio.

Furthermore, since the heated pearlite particles are added without inhibiting the resin reaction foaming state, there is no need to use an expensive catalyst as in the past, and costs can be significantly reduced.

Further, according to the present invention, a homogeneous foamed structure can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an apparatus for carrying out the present invention;
The figure is a characteristic diagram showing the bulk specific gravity of a foam produced by the production method according to the present invention. 1... Foam, 2, 3... Mold member, 4
...Mold, 13...Molding machine, 17...
... Mixer, 18 ... Perlite spreader, 1
9... Heating device, 20... Aggregate, 21
, 22...Base material.

Claims (1)

[Claims] 1. When producing a flame-retardant polyurethane foam consisting of a closed cell structure of a predetermined shape by adding pearlite particles to a polyurethane resin raw material whose reaction rate and viscosity rapidly change depending on temperature, and causing the raw material to react and foam, the above-mentioned A method for producing flame-retardant polyurethane foam, characterized in that 30 parts by weight or more of perlite particles heated to about 25 to 80°C are added to 100 parts by weight of the raw material when the raw material is in a cream time state.