CS229504B1 - Method for the producing hard polyurethan foams - Google Patents

Description

The invention relates to a process for the production of polyurethanes, in particular rigid polyurethane foams, based on technically readily available polyester polyols, mainly produced from dibasic by-products.

It is known that polyurethane foams are produced by reacting aromatic and / or aliphatic and / or cyicloaliphatic isocyanates having a number of functional groups per molecule greater than 1, with compounds containing more than 1 active hydrogen per molecule, in the presence of a catalyst, blowing agent, stabilizer, emulsifier, flame retardants and / or other additives. They can be prepared in a single-stage or prepolymer manner.

Many compounds containing —NCO groups can be used as isocyanates, but in particular, crude 4,4‘-diphenylmethane diisocyanate or toluylene diisocyanate are suitable. The second major component is a polyol component which contains a compound with active hydrogen - polyether polyols and / or polyester polyols and foam preparation aids (Viewe & R. Hochtlen A., Kuaststoff-Handbuch, Band VII Polyurethane, Caer Hanser Verlag, Munchen 1966 ).

. In practice, polyether polyols are mainly used, especially from an economic point of view. The lack of raw materials for the production of basic components for polyurethanes and the technical complexity of their production forces them to look for and use other available resources.

According to the present invention, the process for producing rigid polyurethane foams by reacting at least one aliphatic or aromatic di-polyisocyanate with a polyol in the presence of auxiliaries as catalysts and stabilizers is such that the polyol used consists partly or wholly of a polyester polyol obtainable by esterification, polyesterification or roesterification of the acid component partly or wholly by the distillation residue from the production of terephthalic acid and / or dimethyl terephthalate and the alcohol component based on aliphatic di-tetraols.

The main and quite surprising fact is that the polyester polyol, prepared from esterification and distillation residues from the production of dimethyl terephthalate as well as terephthalic acid, is without purification or, after a simple treatment, suitable for producing mainly hard polyurethane foam having excellent physico-mechanical properties, in particular dimensional stability at low temperatures. This technical advantage and the raw material availability are combined with the possibility of combining the above-mentioned polyester polyols with known types of polyester polyols and polyether polyols, depending on the required technical and other parameters of the final polyurethane foams.

The polyurethane foams produced have very good technical and utility properties, which they retain even at low and elevated temperatures, such as very good dimensional stability, mechanical strength and excellent thermal insulation properties.

Polyurethanes are usually made by mixing two components - polyol and isocyanate. In this case, the polyol component is considered to be organic compounds containing a hydroxy group in the molecule, but also mixtures thereof with excipients.

In the narrower sense, the polyol components are a single compound or a mixture of organic compounds containing at least one active hydrogen group in the molecule.

For the preparation of polyurethanes, e.g. Polyurethane foam, polyester polyol alone based on esterification residues, respectively. distillation residues from the production of dimethyl terephthalate as well as terephthalic acid or a mixture of β with other polyester polyols and / or polyether polyols. Possible polyesterpolyols are condensation products, respectively. also transesterification i. polyesterifications based on other polycarboxylic acids or their anhydrides with divalent or polyhydric alcohols or polyglycols. Adipic acid is suitable for their preparation, furthermore it can be oxalic, malonic, succinic, glutaric, pimelic, cork, azelaic acids. Then unsaturated dicarboxylic acids, such as e.g. maleic, fumaric, itaconic, phthalic anhydride and maleic anhydride (Trans. Plast. Inst. London 26, 187, 1958; Mod. Plast. 35, 9, 145, 1958; Eng. Chem. 2, 27, 1963; В. IOS Final Report N _o 1498; Dombrov EA, Polyurethane SNTL, Prague 1961, p. 32).

Suitable alcohols are ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol poles, propylene glycol, dipropylene glycol, and optionally other polypropylene glycols, butylene glycols or polybutylene glycols.

Among the polyhydric alcohols, e.g. glycerol, hexanetriol, butanetriol, trimethylolpropane, trimethylolethane, pemtaerythltol, mannitol, sorbitol and others (V. IOS Final Report N _o 1498, N _o 1166; Brit. Pat. 882 603, Brit. Pat. 927 175).

Suitable polyether polyol which can be used to produce a mixture with polyester polyol based on distillation residues from the production of both dimethyl terephthalate and terephthalic acid are mainly products of reaction of polyhydric alcohols, polycarboxylic acids or polyhydric phenols with one low molecular weight 1,2-epoxy compound containing one epoxy group or a mixture of low molecular weight 1,2-epoxy compounds. Suitable low molecular weight 1,2-epoxy compounds include ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide,

2,3-epoxyhexane, triethyl-2,3-epoxyoctane, epichlorohydrin, epibromohydrin, styrene oxide, glycidyl ether, methylglycidyl ether, phenylglycidyl229504 ether, butylglycidylsulfide, glycidylmethylsulfone, glycidyl methacrylate, glycidyl acrylate, glycidyl acrylate, glycidyl acrylate, glycidyl acrylate, glycidyl acrylate, glycidyl acrylate.

The epoxides used for the preparation of the polyether polyols are, in particular, compounds which are formed by substitution of hydrocarbons, ethers, sulfides, sulfones or esters by a monoepoxy group and which contain at most 18 carbon atoms per molecule. In particular, polyether polyols based on low molecular weight alkylene oxides are used to prepare the hard polyurethane pony. They may furthermore be polyesteramides or mixtures thereof with polyesters prepared by known processes from polyhydric acids, alcohols, optionally amines, other known polythioethers (NSC Pat. 1,105,156) or polyacetals (NSC Pat. 1,039,744 and 1,045,095).

Suitable di- to polyisocyanates according to the invention are organic polyisocyanates, e.g. arylpolyisocyanates of the benzene or naphthalene series, which are more reactive and less toxic than aliphatic diisocyanates and polyisocyanates.

The best are

2,4-toluylenediisocyanate, 2,6-toluylenediisocyanate and mixtures thereof, further phenylenediisocyanate, alpha-naphthylenediisocyanate, 4-toluylenediisocyanate, n-hexylenediisocyanate, methylene-bis- (4-phenylene) 4,4'-phenylene diisol, 4-phenylene diisole, 4,4'-phenylene diisocyanate. 1'-diisocyanate, 5'-dimethoxy-4'-diphenylindiisocyanate, 4,4'-methanediphenyl diisocyanate,

1,5-naphthylene diisocyanate, 2,4-chlorophenylene diisocyanate, hexamethylene diisocyanate,

1.3- cyclopentylene diisacyanate,

1,2-cyclohexylenediisocyanate,

1.4-cyclohexylene diisocyanate, cyklopentylidéndiizokyanáit, cyklohexylídéndiizofkyanát, p-phenylene diisocyanate, mHfenyléndiizokyanát, 4,4 difenylpropándiizokyanát, di-phenyl methane ^and 4,4'-diisocyanate, l-methyl-2,4-phenylene diisocyanate, 4,4 & apos difenyléndiizokyanát,

1.2- propylene diisocyanate,

1,2-butylene diisocyanate, ethylidene diisocyanate, propylidene diisocyanate, butylidene diisocyanate,

1.3.5- triisocyanatebenzene,

2.4.6- triisocyanate toluene,

2,4.6-triisocyanato-chlorobenzene, 4,4 ‘, 4'-triphenylmethane trisocyanate, polymethylene polyphenylisocyanate or mixtures thereof.

High molecular weight polyisocyanates are the liquid reaction products of diisocyanates and polyhydroxy compounds or polyamines. In addition, polyisothiocyanates or mixtures of polyisocyanates may be used. Technical uncleaned or crude e

polyisocyanates, e.g. crude mixture of methylene-bis [4-phenylisocyanate).

In addition, in some cases, it is appropriate to use as a di- to polyisocyanate component a prepolymer, a product after partially reacting the polyester polyol or a mixture thereof with diisocyanates. The choice of the type of diisocyanate used depends on the properties of the starting materials and the desired properties of the product.

The nature and amount of auxiliaries, such as catalysts and catalysts, have a considerable influence on the properties of rigid polyurethane foams. activators, stabilizers, emulsifiers, blowing agents, solvents, quenching agents, fillers and the like.

Many known compounds can be used as activators (J. H. Saunders and C. Frish in Polyurethanes, translation: Khimija polyurethanes, Izdatelstvo "Khimija", Moscow 1938).

Among the known compounds, in particular tertiary amines, e.g. N, N'-dimethylcyclohexylamine, dimethylethanolamine, triethylenediamine, dimethylaniline, pyridine, ethylmorpholine, quinoline and the like, or organometallic compounds such as dibutyltin laurate, n-butyltin trichloride, trimethyltin orthohydroxide, dimethyltututin hydrochloride, dimethyltutin tin. When using unpurified distillation, esterification residues for the preparation of polyester polyol, it is necessary to take into account in the preparation of the polyurethane foam with the catalytic influence of the metals present, in particular the salts Mn, Co _L Mo, Fe, Cr, Ni and other metals.

The effect of the catalysts is often increased by the correct choice of the amounts of the individual components, with a synergistic effect being obtained by using tin salts and tertiary amines. By suitable choice of concentration, type and ratio of catalysts it is possible to influence not only the reaction of the hydroxyl group with the isocyanate, but also the formation and properties of the foam.

Of the available blowing agents, those which generally release gaseous compounds upon heating or conversion with the isocyanate are generally used. Low molecular weight liquids and water are preferably used in foaming. The reaction heat and the reaction of water with diisocyanate causes foaming of the mixture to form a sufficiently stable foam which maintains its form until the mass gels. Suitable low molecular weight liquids are fluorochlorohydrocarbons having a boiling point of approximately 20 to 50 ° C or mixtures thereof, e.g. trichlorofluoromethane, trichlorofluoroethane, dichlormonofluoromethane, monochloroethane, mtonochlorofluoroethane, difluoromonochloroethane, or difluorodichloroethane. However, compounds having a boiling point of 5050 to ž 110 ° C and possibly higher boiling points may be used (U.S. Pat. No. 2,865,869).

The stabilizers ensure the formation, size and uniformity of the foam cells. They are generally organosilanes, e.g. mixed polysiloxane-polyoxyalkylene polymers (U.S. Pat. Nos. 2,834,748 and 2,917,480).

The importance of emulsifiers is to improve solubility, respectively. homogenization of the reaction components or auxiliary substances. Many of the commonly known ionic and especially nonionic emulsifiers are suitable, furthermore dioctyl phthalate, dibutyl lithium and the like.

The process according to the invention can be carried out by known processes by pouring or spraying on conventional equipment used for the production of polyurethane materials. Depending on the type of foaming device. the dosage mode of the individual components is selected. The process can thus be carried out batchwise, semi-continuously and continuously.

Further details of the method according to this. The invention as well as other advantages are evident from the examples.

Example. 1

For the preparation of the rigid polyurethane foam, polyesiterpolyol, prepared by re-esterification of the distillation residues, respectively, is used. esterified residues from the production of dimethyl terephthalate diethylene glycol and pentaerythritol in a molar ratio of 3: 7: 1. To 100 g as follows. prepared polyesterpolyol having a hydroxyl number of 460 mg KOH / g and an acid number of 0,6 mg KOH / gs, and · add 1 g of Tegostab B 1903 silicone stabilizer, 1 g of dimethylcyclohexylamine, 0,1 g of stannous octoate, 1 g of water, 30 g of trichlorofluoromethane ledon-11).

The mixture is thoroughly mixed with a turbine stirrer, and then 135 g of crude 4,4'-methanediphenyl diisocyanate, known under the commercial designation Desmodur 44 V, are added. The foam start time is 23 s and the foam growth time 45 s. The prepared foam having a density of 30 kg / m 3 has a fine uniform texture and excellent dimensional stability at temperatures of -30 to 90 ° C.

Example 1 a d 2

The polyester polyol described in Example 1 is used to prepare the rigid polyurethane foam. The polyol component is prepared by mixing ^: 100 g of polyester polyol, 1.5 g of LK-221 silicone stabilizer, 0.4 g of dimethyl terephthalate, 10 g of Phosgard XA 995 flame retardant, 2 g of the emulsifier Disperglermittel EM and 30 parts by weight of trichlorofluoromethane. After homogenization, 135 g of Tedimon 31 diisocyanate are added to the polyol component with stirring. The foam preparation times are as follows. start time 110 s, cross-link time 300 s, end of gluing 400 s. It gets -that hard. foam with a density of 38 kg / m3 and with destroyed flammability as well as excellent dimensional stability at a temperature of -30 ° C.

Example 3

Transesterification, respectively. reesterification of the distillation residues from dimethylterephthalate production with diethylene glycol and trimethylpropane at a mass ratio of 1.8:. 1.6: 1, a polyester polyol having a hydroxyl value of 435 mlligrams of KOH / g and an acid number of 1.1 mg KOH / g is obtained. The polyol component is prepared by mixing 60 g of prepared polyester polyol, 40 g of sucrose-based polyetherpolyol and propylene oxide (Slovaprop T-450) having a hydroxyl value of 440 mg KOH / g, 1 g of Tegostab B 1903 silicone stabilizer, 1 g triethylenediamine, 0.1 g dibutyltin dilaurate , 45 g of dichlorofluoronethane-Ledon 11, and 0.5 g of Slovasol SF emulsifier.

After homogenization, 115 g of 4,4'-methanediphenyl diisocyanate (Desmodur 44) are added. The characteristic foaming times have the following values: start time 20 s, crosslink time 50 s, gluing time 50 s. A foam having a uniformly pronounced fine structure and having a bulk density of 35 kg / m ³ a is obtained. excellent dimensional stability at -30 ° C.

Example 4

For the preparation of a rigid polyurethane foam, a mixture of polyesierpolyols consisting of 60 parts by weight of parts of polyester polyol prepared according to Example 3 and 40 parts by weight of parts of polyester polyol prepared from ethylene glycol, adipic acid and trimethylolpropane per mole is used. ratio 1: 0.8: 0.8. The polyol component is prepared by adding to the blend of polyester polyols 1.5 wt. Parts of stabilizer LK 221, 1.5 wt. Parts of dimethylethanolamine, 2 wt. parts of the emulsifier Di-spergiermittel EM, 10 parts by weight, parts of the Phosgard XA 995 flame retardant and 35 parts by weight, parts of trichlorofluoromethane. After homogenization, 100 parts by weight of polyol component with 135 parts by weight of parts of Tedimone diisocyanate 31 are reacted.

A hard foam having a very good dimensional stability at 70 ° C and —25 degrees Celsius is obtained.

Example 5

For the preparation of a rigid integral polyurethane foam is used. Polyester component is prepared by mixing 100 g of polyester polyol, 1.5 g of Tegostav B 1903 silicone stabilizer, 7 g. 1,4-butylene glycol, 1.5 g triethylamine, 0.15 g dibutyltin dilaurate, 1 g emulsifier Slovasol SF and 30 g trichlorofluoromethane.

After homogenization, 135 g of crude 4,4 ' -methanediphenyldiisocyanate was added with stirring, and the stirred mixture was poured into 22504 separated metal mold heated to 50 [deg.] C. A foam with an excellent compact integral surface with a density of 450 kg / m ^{3 is} formed.

Claims (1)

Process for producing rigid polyurethane foams by reacting at least one aliphatic or aromatic di- to polyisocyanate with a polyol, in the presence of auxiliaries as catalysts and stabilizers, characterized in that the polyol used consists partly or completely of polyester polyol by mixing 100 parts by weight of polyester polyol, produced according to Example 3, with 2 wt. parts of an emulsifier / Slovasol SF, 1 wt. parts of triethylenediamine. Mixing with 115 g of 4,4‘-diphenylmethane diisocyanate produces a high-strength, rigid polyurethane mass. of the invention obtainable by esterification, polyesterification or re-esterification of an acid component consisting of a total or total distillation residue from the production of terephthalic acid and / or dimethyl terephthalate and an alcoholic component based on aliphatic di-tetraols.