KR20060003170A - 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, the production method of the present invention is 125 parts by weight of a polyol containing 10 to 20 parts by weight of a conventional flame retardant, one selected from zinc powder or feldspar powder or mixtures thereof 6 to 40 parts by weight of the mixture is stirred at room temperature, and then mixed with MDI and foamed and cured. 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. have.

Polyurethane, Foam, Flame Retardant, Zinc, Feldspar, Phosphorus Flame Retardant

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 problems to some extent, but the organophosphorus flame retardant used has a disadvantage in that flame retardancy decreases with time, and thus is not widely used. In addition, it can be pointed out that the problem of improving the flame retardancy is also insufficient.

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. In addition, this technique is pointed out as a big problem that the flame retardant used is in the form of particles, which greatly reduces the workability by blocking the nozzle for spraying the resin.

In addition, Germany's BASF, one of the world's leading polyurethane manufacturers, wanted to obtain polyurethane flame retardant by adding calcium carbonate powder to polyol and reacting with MDI. The problem of clogged nozzles is frequent and has not been put to practical use.

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.

In the manufacturing method of the present invention, 125 parts by weight of a polyol containing 10-20 parts by weight of a common flame retardant is mixed with 6-40 parts by weight of one selected from zinc powder or feldspar powder, and stirred at room temperature, followed by MDI. It consists of mixing with.

Polyurethane foam of the present invention is foamed by mixing 3-18 parts by weight of one selected from zinc powder or feldspar powder or a mixture thereof with respect to 100 parts by weight of the polyol and MDI.

Hereinafter, the present invention will be described in detail.

The two-component polyurethane resin composition is composed of a polyol (Liquid A) and MDI (Liquid B), and the two liquids are mixed within 30 seconds to 1 minute to form a foam with pores and solidify. Solution A typically contains 10-20 g of conventional flame retardant, 2 g of silicone, 2 g of catalyst, 25 g of blowing agent, and 1 g of water based on 80 g of polyol (PPG). The mixing ratio is generally mixed with 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 plays a role in activating a chemical reaction in the process of forming a polyol and MDI to form a 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, one selected from zinc powder or feldspar powder or 100 parts by weight of the mixed liquid of liquid A and liquid B Adding 4-18 parts by weight of the mixture achieves the desired flame retardancy.

The polyol generally contains a common flame retardant, particularly a phosphorus flame retardant, and phosphorus flame retardants are generally used in polyurethane because of their low toxicity and environmental pollution compared to halogen flame retardants and antimony flame retardants. Specific examples thereof include TCPP (trichloropropyl phosphate). However, the use of the phosphorus-based flame retardant alone does not achieve the desired flame retardancy, and even if the phosphorus-based flame retardant is mixed with any other known flame retardant, a desired level of flame retardancy is also not obtained.

The present inventors concluded that the existing flame retardants could not impart desirable flame retardancy to polyurethane, and experimented with various kinds of inorganic flame retardants known to be flame retardant until now, and as a result, inorganic flame retardants that can be dissolved in polyols. It was found that the addition of phosphorus zinc powder and feldspar powder was very effective. Although a method of dissolving a flame retardant in MDI may be considered, it is preferable to dissolve the flame retardant in a polyol in consideration of workability since MDI generates an irritating odor upon stirring.

When zinc powder or feldspar powder is added to the polyol and slowly stirred at room temperature for 3 hours or more, it melts, which not only solves the problem that the particles block the nozzle, which is a problem of the prior art using inorganic flame retardant, but also uses a small amount. You can also give the desired level of flame retardancy.

When using zinc powder alone, 6-15 weight part is suitable with respect to 125 weight part of polyol, and 10-40 weight part is suitable with respect to 125 weight part of polyol when feldspar powder is used alone. If it is less than the above range, the effect of improving flame retardancy is insufficient, and if it exceeds the above range, it may adversely affect the physical properties of the polyurethane.

More preferably, a mixture of zinc powder and feldspar powder is used, and the ratio is 3 to 10 parts by weight of zinc powder and 6 to 30 parts by weight of feldspar powder relative to 125 parts by weight of polyol. When used in this ratio and when used with a common flame retardant, it exhibits excellent flame retardancy enough to pass the second level fire retardant test in Korea.

The flame retardant class 2 test was conducted for 6 minutes at 700 ℃ with iron plate removed from specimens of 4-5cm in thickness and 220cm in width and length, respectively. A mouse test that collects the generated gas and supplies it to surviving mice in a confined space to test survival rate is the most stringent flame retardancy test in the world. For reference, the flame retardant class 3 test is a test in which a space of a certain size is formed on a steel plate and the specimen is mounted behind the steel plate. The check items are the same as the flame retardant class 2 test.

The feldspar powder used is not limited, but kali feldspar powder or soda feldspar powder is preferred.

Embodiments of the present invention are as follows.

(Examples 1-10 and Comparative Examples 1,2)

70 parts by weight of polyether (MW 500), 10 parts by weight of polyether (MW 1000), 2 parts by weight of silicon as a foaming agent, 2 parts by weight of catalyst, 1 part by weight of water, 25 parts by weight of blowing agent (HCFC R-141b) and phosphorus-based flame retardant With respect to 125 parts by weight of polyol consisting of 15 parts by weight of TCPP (trichloropropyl phosphate), add zinc powder and califeldite powder as shown in Table 1 below, stir slowly for 5 hours, and then measure the amount of blowing agent lost. Supplemented.

To each of the polyols obtained as described above, 210 g of MDI was mixed with stirring to obtain a foam hardened flame retardant polyurethane foam after 60 seconds. The flame retardance of the obtained foam was shown in Table 1.

division Zinc powder Calistone Powder Flame retardant Example 1 0 10 Level 3 Example 2 6 0 Level 3 Example 3 4 12 2nd class Example 4 5 10 2nd class Example 5 6 10 2nd class Example 6 6 8 2nd class Example 7 6 6 2nd class Example 8 5 8 2nd class Example 9 3 12 2nd class Example 10 0 30 Level 3 Comparative Example 1 2 0 Below level 3 Comparative Example 2 0 8 Below level 3

As can be seen from the above examples, the present invention can make the polyurethane foam extremely vulnerable to fire to flame retardant level 2 at low cost.

Claims (4)

To 125 parts by weight of a polyol containing 10 to 20 parts by weight of a common flame retardant, 6-40 parts by weight of one selected from zinc powder or feldspar powder or a mixture thereof are mixed and stirred at room temperature, followed by mixing with MDI to foam-cure Method for producing a flame retardant polyurethane foam. The method for producing a flame retardant polyurethane foam according to claim 1, wherein 3 to 10 parts by weight of zinc powder and 6 to 30 parts by weight of feldspar powder are used. The method of producing a flame retardant polyurethane foam according to claim 1, wherein the flame retardant is a phosphorus flame retardant. A flame retardant polyurethane foam made by the process according to claim 1.