CS201782B1 - Method for preparing polyurethanes - Google Patents

Abstract

Invention of a solution for the preparation of polyurethane, especially a flexible integral polyurethane foam based on polyether epoxy. For the preparation of poXyurethane, poXyesterpoXyoXy is used, prepared in the presence of such catalysts, which are also catalysts at the same time! in ohemia polyurethanes. This means that the catalyst no longer needs to be added to the subsequently prepared poXyol component and this type of polyetherpoXyoX, but only its concentration is adjusted. As catalysts for the transesterification and at the same time for the preparation of polyurethanes, suitable organic compounds of titanium, zirconium, lead and oin are used in combination with β tertiary amines, e.g.: triethylamine.

Description

201 782 i

It is an object of the invention to provide a modified process for the production of polyurethanes, especially elastic polyurethane foam.

In the production of polyurethane elastomers, in particular a two-step process is usually used for the production of flexible integrally polyurethane foam. In a first stage, the prepolymers with free -NGO groups are formed by reacting the polyester polyols, polyether polyols or other hydroxyl group containing compounds with excess diisocyanate. In the second stage, the prepolymer reacts with the polyol component containing the necessary admixture of polyurethane formation.

Procedures for describing the preparation of polyurethanes with integral scales are also disclosed in the patent literature (e.g., U.S. Pat. No. 1,486,246, Belgian Patent No. 706,7191, p. No. 3,251,788 and 3,468,991) Despite the considerable refinement of the polysurethane production technology, including integral polyurethane foam, the known processes have a number of drawbacks and difficulties, predominantly in the catalytic system. Some catalysts are solids and have some difficulties in homogeneous distribution to the polyol component. On the other hand, the activity of the catalysts is satisfactory, possibly resulting in problems with storability of the initial components for the final product.

In the preparation of polyurethanes or flexible integral polyurethane diapers, it is necessary to ensure that the components do not contain any impurities that have a catalytic effect. For example, it is known that some metals used in the preparation of polyether polyol, e.g., alkali metals, cause trimerization of the diisocyanates in the prepolymer preparation, as a result of the Soho, the prepolymer of the desired properties cannot be prepared. Also, in the preparation of lukewarm polyurethane, make sure that the course of the reaction is sufficient to ensure that it is sufficiently coarse, reproducible and reactive! unwanted secondary reactors. These are, for example, acidic substances which delay the difficulty of forming the urethane, which requires adjustment of the catalyst system. In order to reduce the impact of trace metal impurities, it is proposed to add compounds to the polyol, such as 2,4-penta-dione (aethylaethone), benzylaethone, alizarin, alpha-nitroso-beta-noftol, or other compounds, which make chelates with these trace impurities (e.g. U.S. Pat. No. 2,110,583), the use is not effective enough. Many impurities negatively affect the storage capacity of the polyol component, the course of polyurethane formation and its meohanic properties. The polyether polyols or polyester polyols are prepared so as to contain a minimum content of substances that influence the course of the polyurethane formation prior to preparing the prepolymer.

According to the invention, the process for the preparation of polyurethanes, in particular flexible integral polyurethane foam for use in footwear, from polyol starting material by reacting at least one polyisocyanate in the presence of auxiliaries such as activators, stabilizers and crosslinkers, respectively blowing agents, takes place by a polyol polyol component or a mixture thereof with a polyether polyol component by reaction with a polyisocyanate, prepares a prepolymer, introducing, prior to preparing the prepolymer, a tertiary amine and / or at least one substance in which the tertiary amine is present in the system 2 201 782 chemically bonded titanium, zirconium, lead or oin and the final polyurethane are prepared by a prepolymer reactant and a polyol component containing a wide range of residues and a residual amount of a catalytically active substance imparting 5 to 90% by weight. of the total amount of catalyst used.

The process of the present invention substantially removes the drawbacks of the prior art by applying the catalyst and, secondly, in the immediate follow-up of the process chosen, also making the catalyst system easy, manageable and reproducible with increased utilization of feedstocks when the carriage is reduced and further losses due to the failure of the technology.

By suitable choice of the catalyst system, it utilizes the metals present in the yields of the raw materials, in particular from the previous processes, and reduces their consumption and the cost of the final product.

In the process of the invention, polyisocyanates of aromatic, aliphatic or cycloaliphatic nature, having two or three -NCO groups, are used. Polyisocyanates commonly referred to as "MDI" - commonly known as methylone bis (phenyl-4-isocyanate), also referred to as ρ, ρ'-diphenylmethane diisocyanate, are used in either pure or crude form. Among the other possible diisocyanates, "TDI", toluene diisocyanate, which is usually present as a mixture of 2,4- and 2,6-isomers in a ratio of 80: 20% or 65: 35 5% in many cases, especially in the preparation of cold p polyurethane foam, a mixture of diphenyl diisocyanate and toluene diisocyanate is used. Other possible diisocyanates for this process described in U.S. Pat. file no. 3 251 787 ·

As a further major component, a compound is used which contains at least two hydroxyl groups, for example polyetherpolyol or polyesterpolyol by mol. a weight of 400 to 10,000, preferably 2,000 to 5,000, containing at least 10 5 primary hydroxyl groups. In addition to the compounds mentioned above, active hydrogenora compounds can be used, the hydrogen atom of which is bound to another atom other than oxygen, such as sulfur, nitrogen, and the like by reacting polyisocyanate and the active hydrogen compound to prepare component prepolymers, referring to lysis as component A. Component B (polyol component) contains as a base a linear polyether polyol or polyester polyol or a substance containing an active molar moiety. Other components of this component are catalysts, emulsifiers, stabilizers, flame retardants, blowing agents, low molecular weight compounds containing active hydrogen and other volatile substances. Example 1

Polyurethane integral foam is prepared by homogenizing these yard components:

a) Component A 136 wt. the diphenylmethane diisocyanate is melted and heated to 60 ° C. 100 wt. parts of polyester polyol with mol. a weight of 2,000 and an OH number of 56 mg KOH / g, which was heated to 80 ° C and contained 0.001 wt. ohemioky of lukewarm tartrate and 0.05% by weight. triethylamine. After homogenization, the material could not react for 24 hours. A prepolymer with 18 wt. free-NCO groups, viscosities of 750 mPa.s and density of 1,180 kg / m 3 at 40 ° C.

b) Component D

The polyol component is prepared by mixing the following substances: a linear polyester polyol prepared from adipic acid, butanediol and monoethylene glycol mol. weight 2,000 and OH numbers 56 mg KOI / g, containing 0.002 wt. of lead lead and 0.06 wt. triethylenediamine 36,544 wt. parts - branched polyester polyol prepared from adipic acid, diol and triol by mol. of 2 700, OH of 48 ing KOH / g at 5.00 hiuot. parts - butanediol-1.4 8.00 wt. parts of triethylenediamine 0.15 wt. part - water 0.20 wt. part - dibutyloindilaurate * 0.006 wt. part

Both components are not able to react in a 1: 1 ratio, so the polyurethane material, which at a specific weight of 600 kg / m 3, has the following physical-mechanical properties: tensile strength: 6.8 MPa modulus 100: 2.17 MPa ductility : 420 Tensile strength: 19.2 N / mm

hardness *: 68 ° ShA Example 2

A microbubble structure polyurethane integral foam is prepared from the following components: - diphenylmethane diisocyanate modified with polyetherpolyol and polyesterpolyol having the same OH disulfide of 56 mg KOH / g and an average weight of 2,000 so as to contain 18% of its -NCO groups in an amount of 50 wt. parts - linear polyester prepared from adipic acid, butanediol and monoethylene glycol mol. weight 2,000 (containing 0.03% zirconium bound, 0.002 lead bound and 0.001% triethylenediamine in the amount of 4l, O5 part by weight - butanediol-1.4 8.5 part by weight - triethylenediamine 0.15 part by weight - Vaseline oil 0.10 parts by weight - water 0.20 parts by weight

According to the present invention, a modified diphenylmethane diisocyanate is first prepared which cannot be reacted with the other components of the reoepture. A polyurethane material is thus obtained

Claims (1)

Process for preparing polyurethanes, in particular elastic integral polyurethane foam for use in shoemaking, from a polyol starting material by reacting with at least one polyisocyanate in the presence of auxiliaries such as activators, stabilizers and crosslinkers, respectively. and a blowing agent, characterized in that at least one of the polyester polyol component or a mixture thereof with the polyether polyol component is prepared with a polyisocyanate by means of a polyol isocyanate, and for the preparation of the prepolymer a amine and / or at least one amine and / or at least one substance is introduced into the system. and the final polyurethane is prepared by reacting a prepolymer with a polyol component, containing auxiliaries and a residual amount of catalytically active substance of from 5 to 90% by weight. from the amount of catalyst used in the field.