KR20050110058A - Polyurethane foam having fire retardancy and the manufacturing method thereof - Google Patents

Abstract

The present invention relates to a flame-retardant polyurethane foam and a method for producing the same, wherein the method of the present invention is a polyurethane by gelling silicate, dispersing the gelated silicate in a polyol and / or diisocyanate solution, and then mixing the two solutions. Consists of producing a foam, the present invention can be flame retardant to a flame retardant second level at a low cost of the polyurethane foam which is extremely vulnerable to fire.

Description

Polyurethane foam having fire retardancy and the manufacturing method

The present invention relates to a flame retardant polyurethane foam and a method for manufacturing the same, and more particularly, to a polyurethane foam that is harmless to a human body and has excellent flame retardant effect, and a method of manufacturing the same.

Polyurethane is widely used as a material for insulation construction of various buildings, including refrigerated warehouses, insulated houses, ships, vehicles, trains or subways. In order to construct polyurethane, di-isocyanate, usually a methylene diisocyanate (MDI) solution and a polyol solution are mixed at a constant ratio, and a foamed urethane molding is constructed using a foaming machine.

Polyurethane is produced separately from the MDI solution and the polyol solution, so that the polyurethane contractor mixes the two products to construct or manufacture the polyurethane foam, and the MDI solution and the polyol solution are mixed in one container. There is a one-part product that gives two solutions to react by giving. Two-component type is mainly used for building construction or sandwich panel manufacturing in consideration of convenience of work.

Polyurethane is an ideal insulation material because it is easy to install and has excellent insulation, and the material is relatively inexpensive, but the decisive disadvantage is that it is vulnerable to fire. Therefore, there have been many efforts to impart flame retardancy to the polyurethane, and a representative conventional technique for this is as follows.

The technology has been developed to improve the flame retardancy by introducing a halogen-based flame retardant to the polyol to the polyurethane, but it is expensive and lacks the flame retardant effect, it is not widely used due to the large amount of toxic gas in the fire.

As a technique for improving this problem, a technique using an organophosphorus flame retardant may be mentioned. The technique of improving the flame retardancy of the polyurethane foam by using an organophosphorus flame retardant has solved the above problem, but the organophosphorus flame retardant used has a disadvantage in that the flame retardancy decreases with time, and thus is not widely used.

As a technique for resolving this disadvantage, US Pat. No. 4,407,981 uses a reactive phosphorus polyol and phosphorus isocyanate that is chemically bonded to the flame retardant rather than physically mixed with the polyurethane. As described above, flame-retardant polyurethanes typified by reactive phosphorus polyols and phosphorus isocyanates are known to have a low flame retardant effect even after a relatively long period of time, and other physical properties are also retained. Flame retardant components used in this prior art are triphenyl phosphine, triphenylphosphate, triarylphosphate esters. Problems of this prior art include that the polyol used must be at least triol, the manufacturing process is too complicated and the cost of the product is too high.

As the technology of the other series and the above-mentioned technology may be a technique disclosed in Korean Patent Publication No. 1980-0000949. This technique aims to improve flame retardancy by applying inorganic polymers such as boric acid compound and perlite as flame retardant to polyurethane. However, this technique is not practical because it not only lacks the effect of improving the flame retardancy of polyurethane, but also has the disadvantage of inherent properties of polyurethane such as adhesion, reactivity, impact resistance, and wear resistance.

The present invention is to solve the problems of the prior art as described above, it is an object to provide a polyurethane foam excellent in flame retardant effect while maintaining the inherent properties of polyurethane.

Another object of the present invention is to provide a polyurethane foam having a simple manufacturing process and a low manufacturing cost. It is another object of the present invention to provide a polyurethane foam that is continuously flame retardant and free of toxic components in the event of fire.

The process of the present invention consists in preparing a polyurethane foam by gelling the silicate, then dispersing the gelled silicate in a polyol and / or diisocyanate solution and then mixing the two solutions.

The polyurethane foam of the present invention is composed of foamed by adding 10 to 100 parts by weight of gelled silicate based on 100 parts by weight of the total of polyol and diisocyanate resin.

Hereinafter, the present invention will be described in detail.

The silicate used in the present invention is a compound represented by M2O.nSiO2.xH2O, where M represents a metal belonging to group 1A of the periodic table, n is an integer of 2-6, and x is an integer of 20-40. Specific examples of metals belonging to Group 1A include lithium, sodium and potassium.

When such a silicate is applied to the resin as it is, it not only adversely affects the foaming of the resin, but also has a small effect of improving the flame retardancy of the obtained foam, and many attempts to achieve flame retardancy of the polyurethane using the silicate have failed. will be.

In the present invention, a modified silicate is used which is converted into a network structure by gelling the silicate. The gelation method is to add 3-20% by weight of one or two or more selected from sodium chloride, calcium chloride and potassium chloride as a gelling agent to the silicate, stir and leave for at least 3 hours. If the addition amount of the gelling agent is less than the above range, the gelation is insufficient, and if it exceeds the above range, the added gelling agent is present without being dissolved in the silicate. Considering the price, workability of the material, and physical properties of the final product, sodium chloride is most preferred among the three gelling agents.

In the present invention, sodium silicate or potassium silicate may be appropriately used in the silicate, but in view of economical efficiency, the use of low-cost sodium silicate is preferable.

The two-component polyurethane resin composition is composed of a polyol (Liquid A) and an isocyanate (Liquid B), and when the two liquids are mixed, foamed within 30 seconds to 1 minute to form a foam with pores and solidify. Solution A typically contains 2 g of silicon, 2 g of catalyst, 25 g of blowing agent, and 1 g of water based on 100 g of polyol (PPG). The mixing ratio is 130 g of liquid A and 195 g of liquid B.

The silicone contained in the polyol functions to form pores, and the blowing agent and water interact with each other to foam the urethane. The catalyst serves to activate the chemical reaction in the process of mixing the polyol isocyanate to form the polyurethane foam. Of course, the amount of blowing agent, silicone, catalyst, water and the like added to the liquid A may be adjusted according to the use of the final product.

In addition, in order to obtain a change in physical properties such as strength and flexibility in the manufacturing process of the polyurethane foam, it is also possible to change the mixing ratio of the liquid A and liquid B. Usually, the mixing ratio is adjusted to the liquid B, and the liquid B is increased and decreased within the range of 150 to 300 g in the liquid A 130g.

Commercially available solution A has a light blackish brown color, the crude liquid specific gravity is 1.14 (20 degrees), the stock solution viscosity is 60 20 cps (20 degrees), the liquid B is dark blackish brown and the crude liquid weight is 1.23-1.25 (20 degrees). The stock viscosity is 80-200 cps (20 degrees).

In the present invention, flame retardance can be imparted to the obtained polyurethane foam regardless of the composition ratio of the liquid A and liquid B, and 10-100% by weight of the modified silicate is added based on the mixed liquid of liquid A and liquid B. If the amount of modified silicate is less than the above range, the desired flame retardancy cannot be obtained. If the amount of the modified silicate is above the above range, flame retardancy can be obtained, but there is a possibility that the physical properties of the polyurethane are lowered.

Since the modified silicate is well dispersed in the liquid A or liquid B, it can be dispersed in any liquid. However, since the irritant odor may occur in the liquid B, it is preferable to disperse it in the liquid A in consideration of workability.

Embodiments of the present invention are as follows.

(Production Example 1)

* Preparation of modified sodium silicate (1)

1, 3, 10, 15, 20, 25% by weight of sodium chloride was added to sodium silicate, stirred slowly for 5 hours, and left for 5 hours to prepare a gelated modified silicate. The obtained modified silicate is called silicate 1, silicate 2, silicate 3, silicate 4, silicate 5, and silicate 6 in order.

Silicate 6 was not applicable because of the unreacted sodium chloride as it is. If unreacted sodium chloride is present in the silicate, it will be impossible to use because it will block the spray nozzle during operation.

(Examples 1-4 and Comparative Example 1)

To 130 g of A solution consisting of 100 g of polyol (PPG), 2 g of silicon, 2 g of catalyst, 1 g of water, and 25 g of blowing agent, 200 g of silicate 1-5 obtained in the preparation example was added and stirred to disperse the silicate in a solution, followed by B 195 g of isocyanate (MDI) as a liquid was mixed with A liquid to obtain a polyurethane foam.

The flame retardance of the obtained foam was as Table 1 below.

ingredient Comparative Example 1 Example 1 Example 2 Example 3 Example 4 A amount 130 g 130 g 130 g 130 g 130 g B amount 195 g 195 g 195 g 195 g 195 g Silicate 1 200 g - - - - Silicate 2 - 200 g - - - Silicate 3 - - 200 g - - Silicate 4 - - - 200 g - Silicate 5 - - - - 200 g Flame Retardant (ASTM D1692-59T) burning self extinguishing non burning non burning non burning

(Production Example 2)

* Preparation of modified potassium silicate

In the same manner as in Preparation Example 1, potassium silicate was used instead of sodium silicate, and the amount of sodium chloride added was 15% by weight. The obtained silicate is called silicate 7.

(Example 5)

The same procedure as in Example 1 was conducted except that silicate 7 obtained in Preparation Example 2 was used. The physical properties of the obtained polyurethane foam were as shown in Table 2 below.

ingredient Example 5 A amount 130 g B amount 195 g Silicates7 200 g Flame Retardant (ASTM D1692-59T) non burning

(Production Example 3)

* Preparation of modified sodium silicate (2)

15% by weight of potassium chloride was used as gelling agent in the same manner as in Preparation Example 1. The obtained sodium silicate is called silicate 8.

(Example 6)

The same procedure as in Example 1 was conducted except that silicate 8 obtained in Preparation Example 3 was used. The physical properties of the obtained polyurethane foam were as in Table 3 below.

ingredient Example 6 A amount 130 g B amount 195 g Silicate 8 200 g Flame Retardant (ASTM D1692-59T) non burning

(Comparative Example 1)

In the same manner as in Example 1, sodium silicate was used instead of modified silicate. As a result, foaming did not occur and the obtained polyurethane did not have the desired level of flame retardancy.

(Comparative Example 2)

In the same manner as in Example 1, potassium silicate was used instead of modified silicate. The result was a slight foaming reaction and the resulting polyurethane did not have the desired level of flame retardancy.

(Comparative Example 3)

In the same manner as in Example 1, 30 g of sodium chloride was used in place of the modified silicate. Foaming took place normally, but the polyurethane foam obtained had no flame retardancy at all.

According to the present invention, the polyurethane foam which is extremely vulnerable to fire can be flame retarded to a flame retardant level 2 at low cost.

Claims (4)

After gelling the silicate, the gelled silicate is dispersed in a polyol and / or diisocyanate solution and then foamed by mixing the two solutions, wherein the amount of gelated silicate is used based on 100 parts by weight of the mixture of the polyol and the diisocyanate resin. Method for producing a flame-retardant polyurethane foam, characterized in that 10 to 100 parts by weight. The method for producing a flame retardant polyurethane foam according to claim 1, wherein the gelled silicate is obtained by adding 3-20% by weight of a gelling agent selected from sodium chloride, potassium chloride, and calcium chloride to the silicate and slowly stirring. The method of claim 1 wherein the gelled silicate is dispersed in a polyol resin. A flame-retardant polyurethane foam, characterized in that 10 to 100 parts by weight of gelled silicate is added to 100 parts by weight of the total polyol and diisocyanate resin.