RU2048482C1 - Process for preparing rigid polyurethane foam or polyisocyanurate foam - Google Patents

Abstract

FIELD: heat insulation of gas pipelines, refrigerating plants and other industrial installations. SUBSTANCE: polyurethane or polyisocyanurate foam is prepared by reacting a mixture of polyetherdiols having a molecular weight of 400 to 2100 and polyetherpolyols having a functionality of 3 to 8, the amount of polyetherdiols being from 10 to 40 wt parts per 100 wt parts of hydroxyl-containing compounds, a foaming agent, an organosilicon foam stabilizer, desired additives of the catalyst and polyisocyanate. The product has high strength and low fragility and high spreadability of the foaming composition. EFFECT: more efficient preparation process. 1 tbl

Description

 The invention relates to a technology for the manufacture of thermal insulation from rigid polyurethane foam (PUF) or polyisocyanurate foam (PCU) and can be used to make sandwich panels used in industrial, administrative and residential buildings and structures for thermal insulation of heat and gas pipelines, refrigeration units and other objects in various industries.

There are various methods for producing PPU or PCU, in which the foam is obtained on the basis of a mixture of hydroxyl-containing compounds, namely a mixture of aromatic polyester and polyester. The required qualitative characteristics of the foam are achieved (within certain limits) by changing in the known methods the type and number of components included in the foamable composition [1, 2]
A common disadvantage of the known methods for producing polyurethane foam is the use as a blowing agent of ozone-depleting chlorofluoroalkanes.

The most promising is the method in which water is used as a blowing agent. A known method of obtaining a rigid polyurethane foam with a density of 6-150 kg / m ³ based on a mixture of hydroxyl-containing compounds, which contains at least 50 wt. simple hydroxyl-containing polyesters with a functionality of at least four. Water is used as a blowing agent [3]
The known method, although it allows you to get hard PUF without the use of ozone-depleting chlorofluoroalkanes, however, it does not make it possible to achieve low fragility of the PUF. Also, the spreadability of the foamable composition used is not high enough, which significantly limits the scope.

 The objective of the invention is to obtain a rigid polyurethane foam or PCB with high strength in combination with low brittleness of the product and high spreadability of the foamable composition.

 This problem is solved by the fact that the proposed method for producing rigid polyurethane foam or polyisocyanurate foam by reacting a hydroxyl-containing component, including hydroxyl-containing compounds, water, an organosilicon foam stabilizer and target additives with an isocyanate-containing component in the presence of a catalyst, in which, according to the invention, a mixture of simple hydroxyl-containing compounds is used polyetherdiols with a molecular weight of 400-2100 and polyester polyols with a functionality of 3-8, and if ETS polyetherdiols mol. m. 400-2100 is 10-40 wt. hours per 100 wt. including a mixture of hydroxyl-containing compounds.

 In accordance with the invention, the following components are used.

 As the isocyanate-containing component, mainly technical diphenylmethanediisocyanate (crude MDI polyisocyanate containing 24-32.5% of isocyanate groups) and / or prepolymer products of diphenylmethanediisocyanate or toluene diisocyanate with low molecular weight glycols containing 20-32% isocyanate are used predominantly.

 As polyetherdiols used compounds with a total mol. m. from 400 to 2100 polymerization products of alkylene oxides and low molecular weight diols.

 Polyester polyols are polymerization products of alkylene oxides with polyhydroxyl-containing compounds, for example, sucrose, xylitol, glycosides, glycerin, trimethylopropane, pentaerythritol, similar compounds, as well as ethylene diamine, diethylenetriamine, diphenylmethanediamine. These polyether polyols are used alone or in a mixture with each other. The mixture of hydroxyl-containing compounds included in the hydroxyl-containing component is made so that the number of polyetherdiols per mol. m. 400-2100 was 10-400 wt. hours per 100 wt. including a mixture of hydroxyl-containing compounds.

 The catalyst used is tertiary amines, for example triethylamine, dimethylcyclohexylamine, dimethylethanolamine, tin-containing compounds, for example tin dibutyl dilaurate, potassium or sodium salts of carboxylic acids, for example, formates, acetates, 2-ethylhexoates, dimethylaminopropionates, as well as salts of quaternary acids or ammonium these compounds.

 Water is used as a blowing agent. If necessary, you can use a mixture of water with traditional foaming compounds, such as methylene chloride, dichlorofluoropropane, trichlorofluoromethane.

 Stabilization of the cellular structure during foaming is carried out by organosilicon block copolymers such as KEP-2, KEP-3, KEP-6 and others.

 The hydroxyl-containing component may also include various target additives, such as flame retardants, fillers, colorants, chain extenders and other necessary additives.

 The processing of the foamable composition is carried out both on casting machines to obtain PPU or PCU, and in the manual mixing method on a mechanical mixer, as well as by spraying.

 To obtain PU foam samples, weighed portions of hydroxyl-containing compounds, a blowing agent, a foam stabilizer, and target additives are sequentially introduced into a 500 ml plastic vessel and all mixed on a mechanical stirrer for 30 s. Then add the required amount of catalyst and polyisocyanate, the whole composition is mixed and poured into the appropriate form.

 Both individual mixtures of hydroxyl-containing compounds and their mixtures with a blowing agent and other necessary additives can be preliminarily prepared.

 Examples of the invention with different ratios of hydroxyl-containing compounds, as well as the properties of the foam are shown in the table. As the polyether polyols, Laprol 1008 polyethers are used (product of the addition of propylene oxide to sucrose, M.M. 1000, functionality f 8); Laprol 564 (product of the addition of propylene oxide to a sucrose-glycerin mixture, M. M. 560, f 4.0); Laprol 373 (product of the addition of propylene oxide to glycerol, M.M. 3.70, f 3.0); Lapramol 294 (product of the addition of propylene oxide to ethylene diamine, M.M. 290, f 4.0).

 As the polyether diols, polyesters of the Laprol 402-2-100 grades are used (product of the addition of ethylene oxide to diethylene glycol, M.M. 400); Laprol 502 (product of addition of propylene oxide to diethylene glycol, M.M. 500), Laprol 1052 (product of addition of propylene oxide to ethylene glycol, M.M. 1050); Laprol 2102 (product of the addition of propylene oxide to ethylene glycol, M.M. 2100).

 According to the data in the table, it is obvious that the invention (examples 1-8) can significantly improve the spreadability of the composition (an indicator of the length of the flow) and reduce brittleness (an indicator of the specific impact strength), without reducing the compressive strength and heat resistance compared to the prototype (example eleven). Examples 9, 10 are outside the scope of the invention.

Claims (1)

 METHOD FOR PRODUCING RIGID FOAM POLYURURETHANE OR FOAM POLYISOCYANURATE by reacting a hydroxyl-containing component, including a hydroxyl-containing compound, water, an organosilicon foam stabilizer, and target additives, with an isocyanate component in the presence of a catalyst, characterized in that a polyhydroxyl-molar compound is used. 400 2100 and simple polyether polyols with a functionality of 3 to 8, and the number of polyether diols with a mol.m. 400 2100 is 10 40 parts by weight per 100 parts by weight hydroxyl-containing component.

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