DD231214A3 - PROCESS FOR PREPARING POLYURETHANE CHROMIUM FUZZERS - Google Patents

Abstract

The inventively prepared Polyurethanoldformweichschaumstoffe are preferably used in the furniture industry and in transportation. The object and the object of the invention are to produce a special urethane-modified polymethyl polyphenyl isocyanate reacting with a special polyol mixture for the production of flexible polyurethane foams which have an increased elasticity and reduced closed-cell density when using a urethane-modified polymethylene polyphenyl isocyanate and the polyurethaneoldable foam system has a good Formfuellvermöegen. According to the invention, a mixture consisting of a polyol A, polyol B and polyol C is used as the specific polyol mixture, and as urethane-modified polymethylene polyphenyl isocyanate, the reaction product is reacted with 85 to 95% by weight of a phosgenated aniline-formaldehyde condensate containing 55 to 75% by weight. Contains% diphenylmethane diisocyanate and consists of at least 95% of the 4.4 isomers and 5 to 15 wt .-% polyol A or polyol B or mixtures thereof.

Description

Process for the preparation of flexible polyurethane foam

Field of application of the invention

The invention relates to a process for the production of polyurethane foam foams which are preferably used in the furniture industry and in the transport industry »

Characteristic of the known technical solutions

The production of flexible polyurethane foams is known. According to DE-OS 2,415,733, DE-OS 2,346,996 and DD-PS 130 040 is used as a urethane-modified isocyanate a mixture of Polymethylenpolyphenylisocyanat and tolylene diisocyanate, wherein the reaction of the isocyanates is carried out in excess with Polyoxyalkylenpolyolen. The salient part of the process is the toxicity due to the relatively high humidity of TDI. According to DE-OS 2,815,554 and DE-OS 2,815,579, the toxicity is reduced and the Pormstandzeit significantly shortened by using a urethane-modified aromatic isocyanate, which is prepared by reaction of a mixture of Polymethylenpolyphenylisocyanat and diphenylmethane diisocyanate with hydroxyl-containing compounds containing 2 to 4 active Zerewitinoff hydrogen atoms and have a molecular weight of 60 to 1500.

According to BP 0 004 879, a polyoxyalkylene diol having a molecular weight is used to prepare the urethane-modified isocyanate

used above 2000, containing more than 50 % primary OH groups and according to US Patent 4,237,240, the mixtures are used with polyester alcohols as Polyo! component.

According to DD-WP C 08 G / 233 933 2, it is possible by using a reaction product of a phosgenated aniline-formaldehyde condensate containing 60 % to 70 % Dlphenylmethandiisocyanat and from at least 95 % of the 4.4'-isomer and a polyoxyalkylenepolyol, having in the molecule 2 to 3 OH groups and a molecular weight greater than 2000 to use traditional Polyoxyalkylentriole for Polyurethanaltfwiemwieichschaumherstellung having a molecular weight of 4000 to 7000, an ethylene oxide content of 5 % to 25 % and a content of primary OH groups of more than 50 % have ·

The polyurethane foaming moldable foams produced in the manner described have the disadvantages that they have an increased closed-cell density and relatively low elasticity. Such polyurethane wax foam systems also exhibit reduced flowability.

Object of the invention .

The object of the invention is to produce polyurethane foam compositions having increased elasticity and reduced closed-cell content when using a urethane-modified polymethylene polyphenyl isocyanate, the polyurethaneoldable foam system having good pore filling capacity.

Explanation of the essence of the invention

To achieve the object, the invention is based on the object, in addition to additives, of reacting a special urethane-modified polymethylene polyphenyl isocyanate with a special polyol mixture in order to produce polyurethaneoldish flexible foams. ,

According to the invention, the object is achieved by using as the polyol mixture a mixture consisting of 75 to 98% by weight of polyol A which is a polyalkylenetriol having a molecular weight of 4000 to 7000 and 50% of primary OH groups

and an ethylene oxide content of TO % to 20 % has "from 1 to 10% by weight" of polyol B which is a polyoxyalkylene diol or polyoxyalkylene triol. having a molecular weight of 600 to 3500 and containing 50 % to 100 % ethylene oxide and predominantly primary OH groups, and from 0 to 15 % by weight polyol C, which is a polyoxyalkylene polyol having a molecular weight of 100 to 3500 and at most 15 $ Containing ethylene oxide and predominantly has secondary OH groups and that is used as the urethane-modified polyimethylene polyphenyl isocyanate, the reaction product of 85 to 95 wt .-% of a phosgenated aniline-formaldehyde condensate containing from 55% to 75% by weight of diphenylmethane diisocyanate and from at least 95% of the 4.4 isomer and * 5 weight -% to 15 wt -.% polyol or polyol Δ B or their mixtures exist. ,

The polyol A used according to the invention is generally prepared by propoxylation of glycerol, trimethylolpropane and other suitable starting compounds with reactive hydrogen atoms and subsequent ethoxylation. At a molecular weight of 400 to 7,000, the functionality of the polyol is 2.3 to 2.7.

The polyol B used according to the invention is prepared by alkoxylation of diols or triols or their mixtures. The alkoxylating agents used are ethylene oxide or ethylene oxide and propylene oxide, the products obtained being intended to be liquid at room temperature, for example polyethylene glycol 600, polyoxyethylene-polypropylene triols having a molecular weight of 1000 to 3500 based on glycerol or its mixtures with ethylene glycol.

The polyol G used according to the invention is prepared by alkoxylation, preferably propoxylation, of such starting compounds, such as glycerol, sucrose, xylitol, water or their mixtures. Examples of such polyols are propoxylated glycerol having a molecular weight of 1,000 to 3,500, polyoxyethylene polyoxypropylene polyols having a molecular weight of 1,000 to 4,000, an ethylene oxide content of at most 15 %, and an array of ethylene oxide groups at the beginning or in the middle of the polyol chain based on glycerol or its mixtures with water or ethylene glycol, propoxylated solutions of

Sucrose in glycerol and water, as well as propoxylated xylitol. The polyols A, B and C have the following functions in the production of polyurethane molding foams:

Polyol A is the basic polyol for foam production,

- Polyol B serves as a cell opener and improves the elasticity of the foams U ₀

Polyol C is a modifier for improving cure and tensile strength.

The proportions of said polyols in the polyurethaneoldisholdable foam system are of importance for the processing and the characteristic value level of theoldold polyurethane flexible foams and must be determined precisely depending on the polyurethaneoldable foam system.

An increase in the amount of polyol B beyond the above-mentioned concentration leads to the deterioration of the curing of the polyurethane low-temperature flexible foam and to the reduction of the tensile strength. If the amount of polyol B is too low, it does not fulfill its puncture and the desired effect is not achieved.

An increase in the concentration of polyol C over the mentioned limit causes a reduction in elasticity and a deterioration of the tonnage surface.

To a large extent, the amount of polyol used is G of the molecular weight of the polyol B, wherein the dependence carries an opposite character, that is, the higher / the molecular weight of the polyol B, the lower amounts of polyol C are to be used appropriately. For example, while at a molecular weight of polyol B of about 600 the same amount of polyol C is needed, in a polyoxyethylene polyoxypropylene polyol, ethylene oxide content about 70 wt. 5a, with a molecular weight of about 3500, only a small amount of polyol C is required or needed Polyol G can not be used at all.

As has been surprisingly found, in the preparation of flexible polyurethane foams based on urethane-modified polymethylene polyphenyl isocyanate, in particular of reaction products from 85 to 95 parts by wt. one

Phosgenated aniline-formaldehyde HKqndensats containing 55 bia 75% diphenylmethane diisocyanate and consisting of at least 95 % of 4.4 * isomers, and 5 to 15 wt .-% polyoxyalkylene A or B or mixtures of A and B necessarily the polyol invention to use a to obtain high elasticity and minimal closed-cell content of the flexible polyurethane molding foams. The polymethylene polyphenyl isocyanate used for urethane modification is a per se known product obtained by phosgenating a condensation product of aniline with formaldehyde. The composition of the isocyanate depends on the reaction conditions. The phosgenation product contains a certain amount of di- and polyvalent compounds and may have a different isomeric composition of the diphenylmethane diisocyanate. According to the invention, a polymethylene polyphenylisocyanate is preferably used which contains 55 to 75 % of diphenylmethane diisocyanate and consists of at least 95 % of the 4,4'-isomer.

The preparation of the urethane-modified isocyanate is generally known and is generally carried out by reaction of the isocyanate with a small amount of suitable hydroxyl-containing compounds.

According to the invention, hydroxyl-containing compounds which are already characterized as polyol A and B are polyoxyalkylene polyols which are particularly suitable. The stated polyols can be used both individually and in admixture. The amount of polyol used is 5 to 15 wt .-%. The urethane-modified polymethylene polyphenylisocyanates are liquid at room temperature with an ICO content of 24 to 30 SS.

Apart from the described polyol mixture and the urethane-modified polymethylene polyphenylisocyanate, the customary catalysts, blowing agents and other additives are used for the preparation of the polyurethaneoldish flexible foams. Preferred catalysts are the known compounds, for example tertiary amines, such as triethylenediamine, dimethylcyclohxylamine, dimethylethanolamine and the like, and metal salts Tin salts, suitable »

The propellants are water or water and low-boiling halogenated hydrocarbons such as Freon-11. There are übliciie propellant quantities, d. H. 1.5 to 5.0% by weight of water, preferably 2 to 3 to 5% by weight, and 0 to 20% by weight of freon-11, preferably 0 to 15% by weight.

Suitable surfactants which improve the homogeneity of the starting components and regulate the foam structure are organosilicon compounds. Further, conventional additives such as flame retardants, fuels, fillers, etc. can be used. To prepare the flexible polyurethane foam, all starting components are mixed or mixtures of polyol, catalysts, blowing agents, stabilizers and the various additives previously prepared and then added the urethane-modified polymethylene polyphenylisocyanate "The EGO / OH ratio is 0.8 to 1.3 to 1. The mixture of all starting components is foamed and the polyurethane cold molded flexible foam is added with a temperature of 20 to 50 ⁰ C in a mold and the same cure within 2 to 6 min of ·

The foaming process is characterized by low toxicity. There is no noticeable isocyanate odor. The moldings are easy to demold and walk and have a good appearance. The mold-filling capacity of the two-parted polyurethane mold-softening system according to the invention is markedly improved in comparison to similar compositions based on polymethylene-polyphenyl-isocyanates.

The invention is explained in more detail below with reference to the following examples:

Embodiments 1 to 1?

Table 1 contains the for the polyol mixture according to the invention

used polyol types, and their essential characteristics.

In Table 2, Examples 1 to 9>, the composition of

Polyol mixtures according to the invention indicated.

Table 3> Examples 10 to 15 »are the composition

and the characteristic values of the urethane-modified polymethylene polyphenyl isocyanates used for foaming.

The preparation of the urethane-modified isocyanates is carried out in a known manner by mixing and reaction of the polyol and the isocyanates at a temperature of 20 to 50 ^° C. The polyol dissolves readily in the isocyanate with low heat generation.

Exemplary embodiments 16 to 25

The preparation of the polyurethane polyolefin soft foams takes place in a known manner. For this, the constituents of the polyol components indicated in Tab. 4 »Examples 16 to 25» are weighed into a vessel and mixed with. Help of a stirrer at 3000 rev / min intensively mixed.

In Examples 16, 17, 19, 21 to 25 and 18 and 20 are then each 650 parts by weight of the polyol mixture prepared in this way, each with 325 or 354 parts by weight of the urethane Polymethylenpolyphenylisocyanates described corresponding to the total mixing ratio in an aluminum mold, with a capacity of 1β 1 foamed. The mold temperature is 30 to 35 ⁰ G and the mold residence time 4 min. The physico-mechanical properties of the produced flexible polyurethane flexible foams are given in Table 5. It is easily obtained walkable moldings with good elasticity and satisfactory characteristics.

Table 1: Characterization of the polyol types used

Polyol B Polyol C

Polyol A

B - 1

B - 2

B - 3

C C - 2

G - 3

C -

polyol

Polyoxyethylene polyoxypropylene triol

Polyoxy-polyoxy-polyoxy-polyoxy -

ethylene-ethylene-methylene propylene

diol polyoxy-polyalkylenediol

propylene propylene

lentriol triol

polyoxypropylene

pylenpo-

lyol

polyoxyethylene

propylene-

triol

polyoxyethyl "

polyoxypropylene

pylentriol

starter glycerol Ethylene glycol glycerol glycerol water Sucrose glycerol glycerol glycerol av. Mo molecular weight 5000 600 900 3500 135 540 2000 3500 OH number, mg KOH / g 34 185 170 48 870 475 56 48

Ethylene oxide content% by weight

13

100

60

70 10

-

_ 9 - Table 2: Composition of the polyblends

Polyol type / No. of example .1 2 3 4 5 6 7 8

Polyol A, Gevj .-% 83.0 92.0 94.0 94.0 93.5 96.5 96.5 95.5 90.0

Polyol B-1, Gevj .-% 6.0 4.5 4.0 3.5 2.0

¹¹ B ~ 2, Gevj. ~% -, - - 3,5 - -

»B-3, wt. ~% - - - - - 3,5 3,5 10,0

Polyol 0-1, wt.% - - - 2.5 - - - -

Polyol C-2, GevJ .-% - 3.5 2.0 - - - -1.0

Polyol C-3, wt.% "-.-.- 4,5 -. -

Polyol C ~ 4, wt. ~% '11,0 -' - - - - '-

Table 3ϊ Composition and characterization of urethane-modified polyraethylene polyphenyl isocyanates

Characteristic value / Wr. of the example

10

11

12

14

15

Content of diphenylmethane diisocyanate in polymethylene polyphenyl isocyanate,% by weight

59.2 63.8

67.2

63.0

63.2

63.2

Amount of polyraethylene poly phenyl isocyanate,% by weight 92.5 92.5 92.5 90 90 95 of polyol B-1 B-1 B-1 A A / B-1 B-2 Amount of polyol, wt.% 7.5 7.5 7.5 10 7.5 / 2.5 5 Viscosity, 20%, m Pas 630 490 240 380 440 280 NCO content, % 27.5 27.1 28.2 27.0 26.9 28.4

- 11 -

Part 4: Formulations of Polyurethane Cold Foaming System

Component / Wr. of the example 16 17 18 19 20 21 22 23 24 2 \

Polyol mixture with additional:;

substances . j

1 2 3 4 4 86.0 85.8 95.1 85.9 95.2 2.5 2.5 3.3 2.5 3.3 0.3 0.5 0.7 0.4 0.6 0.7 0.4 0.5 0.7 0.5 - 0.3 0.2 - 0.2 0.5 0.5 0.2 0.5 0.2

2, 5 2.6 2.5 2.5 2 ο, 4 0.3 0.4 0.4 0 ο, 7 0.5 0.7 0.7 0 - 0.3 , _ - ο, 5 0.5 0.5 0.5 0

Polyol Mixture, Example No. 1 2 3 4 4 5 6 7 8 S Polyol Mixture, Wt. '86.0 85.8 95.1 85.9 95.2 85.9 83.8 85.9 85.9 water parts by weight

 Triethylenediamine wt.-T

 (33% in dipropyne)

glycol)

Dimethylcyclohexylamine wt.-tf

 Dime thy! Ethanolamine wt.-T

 Silicone Stabilizer Wt. ~ T "(block copolymer

Siloxane u. Polyether) ·

Trichlorofluoromethane Gew.-G. ¹ . 10.0 10.0 - 10.0 - 10.0 12.0 10.0 10.0 10

urethane-modified 14 11 14 12 11 10 11 15 10 1

Polymethylene ' "

isocyanate, example Wr.

* ί

Table 5J Physico-mechanical properties of the prepared polyurethane cold-mix white foams

Characteristic value / Wr. Example 16 17 18 19 20 21 22 23 24.

Mixing ratio 100: 50 100: 50 100: 60 100: 48 100: 60 100: 50 100: 50 100: 50 100: 50 100: 5

Polyol mixture with additives: urethane-modified polymethylene polyphenyl isocyanate (in parts by weight)

Bulk density, mold-foamed, 41 45 49 44 50 43 42 44 45 in the core, kg / m compression set, % 50%, 23 ° 0, 72 '! Ι 50%, 70 ° 0, 22 h tensile strength, kPa rebound resilience, % indentation hardness, 1 40%, plate A

~

2.6 2.6 1.9 3.1 1.9 3.3 2.3 1.7 1.6 2.4 4.6 ^4.5V 4.6 4.2 4.6 , 4.9 6.4 4.7 3.9 3.5 82 76 87 80 87 78 70 98 87 73 61 59 58 57 58 59 58 60 60 61 560 510 690 460 690 580 530 600 620 620

Claims (1)

Process for the preparation of polyurethane cold foams, which have an increased elasticity and reduced closed cell content and are produced on flexible polyurethane foam systems having good mold filling properties by reacting a polyol mixture with additives and with a urethane-modified polymethylene polyphenylisocyanate, characterized in that a mixture is used as the polyol mixture, consisting of 75 to 98% by weight of polyol A which is a polyalkylenetriol having a molecular weight of 4,000 to 7,000 and having 50 % primary OH groups and an ethylene oxide content of 10 to 20 % , from 1 to 10% by weight of polyol B which is a polyoxyalkylene diol or polyoxyalkylene triol having a molecular weight of 600 to 3500 and containing 50 % to 100 % ethylene oxide and predominantly primary OH groups, and from 0 to 15% by weight polyol C which is a polyoxyalkylene polyol having a molecular weight of 100 to 3500 is and at most 15% Ethy contains lenoxid and predominantly secondary OH groups and that is used as a urethane-modified Polymethylenpolyphenylisocyanat the reaction product of 85 to 95 wt .-% of a phosgenated aniline-formaldehyde condensate containing 55 to 75 GeWo-% diphenylmethane diisocyanate and from at least 95 % of 4.4 'isomers and 5 to 15 wt .-% polyol A or polyol B or mixtures thereof.