NO133577B - - Google Patents

Description

Process for the production of plastics containing urethane groups.

Urethane-group-containing plastics are produced, as is known, from hydroxyl-group-containing polyesters or polyethers, and a

polyisocyanate, possibly also using a network forming agent. Used

water as a network forming agent, then you get

a foam if one does not ensure that

the carbon dioxide formed is removed from

the reaction mass.

Up to now, mainly urethane group-containing plastics have been produced from

polyesters. When using polyethers

as starting material especially by such as

predominantly manages to field secondaries

hydroxyl groups available for the reaction with the isocyanate, and due to a

less polar build-up has a small initial viscosity, difficulties of many kinds arise, especially when it

concerns the production of foam materials

as it is difficult to bring the rack-building reaction into harmony with the carbon dioxide evolution. For this reason, one prefers to carry out a pre-reaction

while first reacting polyisocyanate i

excess in a separate reaction step with

the polyhydroxyl compound, and then

transfers the isocyanate group-containing "pre-adduct" under water and possibly additional polyisocyanate addition in foam material.

According to another embodiment, one has

in addition to or instead of water, other propellants or inert gases are also used

to produce the cell structure.

Efforts are being made to produce plastics

in particular foams on a polyether basis in a

one-step process where the reaction components polyether, polyisocyanates

and water at the same time are mixed together. In this way, all difficulties due to the fact that the pre-adduct is not completely stable, and that even when it is only slightly changed during longer storage of this foam-forming recipe must be adapted to the new chemical composition of the pre-adduct, are eliminated.

It is known to accelerate the turnover of polyhydroxyl compounds and polyisocyanates with catalysts.

The object of the invention is now a method for the production of urethane-group-containing plastics including foams of hydroxyl-group-containing polyethers, polyisocyanates and possibly network-forming agents in the presence of special catalysts which are generally applicable and can be used in the production of homogeneous as well as porous urethane-group-containing plastics, whether in two -step or in one-step procedures.

The special catalysts are particularly capable of coordinating the various side-by-side reaction series in the production of foams in a one-step process. The new method is characterized by the fact that stannous chloride, stannous salts and dialkyltin salts of carboxylic acids with 1-18 C atoms, trialkyltin oxides, dialkyltin oxides and dialkyltin chlorides are used as catalysts.

The hydroxyl group-containing polyethers suitable for the method practically always have a molecular weight of at least 500, and are obtained by condensation of alkylene oxides such as propylene oxide, ethylene oxide, butylene oxide, tetrahydrofuran or their mixtures.

Mention must also be made of the addition products of the aforementioned alkylene oxides with water or di- or polyhydric alcohols such as ethylene glycol, 1,2,6-hexanetriol or pentaerythritol. (Encyclopedia of Chemical Technology, Volume 7, Pages 257-262 1951, published by Interscience Publishers, Incorporated).

Polyethers also include such compounds which contain condensed aromatic residues, e.g. the reaction products of a polyalkylene glycol ether with an organic carbonic acid or anhydride and phenols, e.g. phthalic acid, phthalic anhydride, terephthalic acid, 2,2'-bis-(4-hydroxyphenyl)-propane. Polyethers with a hydroxyl number above 25 and an acid number not above 5 are preferred.

Polyisocyanates suitable for the reaction with hydroxyl group-containing polyethers are listed in U.S. Patent No. 2,764,565. Single mention may be made of 2,4-toluylene diisocyanate and 2,6-toluylene diisocyanate, hexamethylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate. For the production of foams, a technical mixture of 2,4- and 2,6-toluenediisocyanate is preferred. As catalysts, in addition to tin II chloride, tin II salts of carbonic acid with 1-18 C atoms are applicable. Those of carbonic acid with 1-8 C atoms are preferred.

Mention may be made of tin II octoate, tin II oleate, tin II stearate, tin II acetate, tin II-(2-ethylhexoate), suitable catalysts also include dialkyltin salts of carboxylic acids with 1-18 C atoms, again those with 1-8 C atoms are preferred. The two alkyl groups can be the same or different, and suitably contain both 1-18 C atoms. Examples may be mentioned of dibutyltin diacetate, dibutyltin diformate, dimethyltin adipate, dibutyltin maleate, dipropyltin diacetate, diethyltin diformate, dipropyltin dioleate, dipropyltin dipropionate, diamyltin dipropionate, dioxyltin diacetate. The trialkyltin oxides, dialkyltin oxides and dialkyl ditin chlorides must also have alkyl residues with 1-18 C atoms. Mention may be made of tributyl tin oxide, trioctyl tin oxide, dibutyl tin oxide, dipropyl tin oxide, dibutyl tin chloride, dipropyl tin chloride, dioctyl tin chloride.

As mentioned, the catalysts are suitable for the production of homogeneous as well as porous urethane group-containing plastics, using methods known per se.

Examples of network forming agents include ethylene glycol, water, diethylene glycol, trimeylolpropane, diethanolamine, ethylenediamine, 1,3-butylene glycol, 1,4-butylene glycol.

In the production of foams from polyethers containing hydroxyl groups, polyisocyanates and propellants, possibly water, the catalysts are suitable for the two-stage as well as the one-stage process. Here, the foam formation is advantageously carried out in the presence of a siloxane-oxy-alkylene block polymer with the general formula

in which R, R' and R" mean alkyl residues with 1-4 C atoms, p, q and r mean an integer from 4-8, and (CnH,nO)z means an oxyalkylene block with 15-19 oxyethylene units and 11—15 oxypropylene units with z = 26 — 34. Siloxanesoxyalkylene block polymers are described in U. S. patent No. 2,834, 748. Their use as additives in the production of polyurethane foams is in itself already the subject of the Norwegian patents no. 97 881. Tertiary amines can also be used as catalysts. Triethylenediamine, tetramethylbutyldiamine, N-ethylmorpholine or 1-alkyl-4-(dialkylaminoalkylene)-piperazines are preferred, above all those with alkyl residues with 1-4 C- atoms and alkyl residues with 2-4 C atoms. Examples include 1-methyl-4-dimethylaminoethyl-piperazine, 1-ethyl-4-diethylamino-ethylpiperazine, 1-butyl-4-dibutyl-aminoethylpiperazine. The catalysts are used in amounts of 0.01-5 parts by weight, advantageously 0.1-3 parts by weight per 100 parts by weight of polyether. When using them together with one of the known tertiary amines, the tin compounds are preferably used in amounts of 0.1-0.5 parts by weight, and the tertiary amine in an amount of 0.2 - approx. 3 parts by weight per 100 parts by weight polyether. In the case of foam production, siloxane-oxyalkylene block polymers are suitably used in amounts of 0.1-10 parts by weight per 100 parts by weight polyether. As a particularly suitable siloxane-oxyalkylene block polymer, mention must be made of the compound with the formula:

where (C^H.^O) means an oxyalkylene block with approx. 17 oxyethylene units, and approx. 13 oxypropylene units.

If foams are to be produced, the reaction of polypropylene glycol ethers and toluylene diisocyanate with the use of the above-mentioned siloxaneoxyalkylene block polymers has proven particularly suitable. The foams have good tear resistance and better elasticity compared to polyester-based foams.

The foam's hardness increases with the amount of a more than two-functional component in the reaction mixture. The volume weight of the foam can be varied by adding water. Usually 1.5-5 parts by weight of water are used per 100 parts by weight polyether. An excess of polyisocyanate over all hydrogen atoms present is necessary. This surplus will ideally amount to at least 10 per cent.

Instead of water, you can also work with other propellants that supply an inert gas or an inert steam that propels the reaction mixture. It can be mentioned e.g. air, carbon dioxide, methylene chloride, nitrogen or dichlorodifluoromethane. The tin catalysts are often used dissolved in solvents.

Such solvents are suitable, e.g. methylene chloride or dichlorodifluoromethane which can also serve as a propellant. Further suitable solvents are e.g. acetone or ethyl acetate. The foam formation can be carried out at a room temperature of 20° C as well as at elevated temperatures, e.g. at 100°C.

The resulting foams are particularly suitable as upholstery materials, e.g. arm supports or as carpet underlay. The homogeneous plastics are suitable as casings in the electrical industry, as adhesives for casting or forming elastic bodies such as rollers, rings, clubs and shock absorbers.

In order to further describe and clarify the invention, some examples must be given which show particular embodiments of the invention.

Example 1:

With an apparatus of the type indicated in US Patent No. 2,764,565, 100 parts by weight of polyethylene ether glycol having an average molecular weight of 2,000 and a hydroxyl number of 56, 38 parts of a mixture of 2,4- toluylene diisocyanate and 20% 2,6-toluylene diisocyanate, 5.5 parts by weight of an activator containing 1 part of dibutyltin-dl-(2-ethylhexoate), 3.0 parts of water and 1.5 parts of a compound of the formula

in which (CnH.,nO) represents 17 oxyethylene units and 13 oxypropylene units and the value of z is thus 30. The diisocyanate and the activator mixture are injected into a stream of the polyalkylene ether glycol in this

equipment and the mixing of the components takes place almost immediately. The resulting mixture is emptied from the apparatus and a chemical reaction occurs almost instantaneously, as the reaction mixture begins

ner to foam and expand. After the chemical reaction is finished, the expanded cellular mixture solidifies into a cellular polyurethane, which has a density of 32 kg/m:i.

Example 2.

100 parts by weight of a triol produced by condensation of propylene oxide and glycerol and which has a molecular weight of 3000, 5.5 parts of an activator mixture containing approx. 1 part dibutyl-tin-di-(2-ethyl-hexoate), 3 parts water and 1.5 parts of a compound of the formula

in which (Cn<H>2llO) represents 17 oxyethylene units and 13 oxypropylene units and the value of z is thus 30 and 38 parts of a mixture containing approx. 80 percent 2,4-toluylene diisocyanate and 20 percent 2,6-toluylene diisocyanate are mixed together almost instantaneously. The resulting mixture reacts to form a cellular polyurethane, which has a density of 32 kg/m3.

Example 3.

In an apparatus of the type indicated in US Patent No. 2,764,565, approx. 100 parts by weight of polypropylene ether glycol having an average molecular weight of 2000 and a hydroxyl number of 56, 35 parts of a mixture of 80% 2,4-toluylene diisocyanate and 20% 2,6-toluylene diisocyanate, 5 parts of an activator which contains 1 part dibutyl tin diacetate, 2.5 parts water and 1.5 parts of a compound of the formula

in which (CnH2nO) represents 17 oxyethylene units and 13 oxypropylene units. The diisocyanate and activator mixture is injected into a stream of the polyalkylene ether glycol in this apparatus and mixing of the components is achieved almost instantaneously. The resulting mixture is emptied out of the apparatus and a chemical reaction occurs almost instantly, as the reaction mixture begins to foam and expand. After the chemical reaction has ended, the expanded cellular mixture solidifies into a cellular polyurethane with a density of approx. 40 kg/m3.

Example 4.

In an apparatus of the type mentioned in US patent no. 2,764,565, 100 parts by weight of polypropylene ether glycol with an average molecular weight of 2,000 and a hydroxyl number of 56 are mixed substantially simultaneously, 35 parts of a mixture of 80 percent 2 ,4-toluylene diisocyanate and 20 per cent.

2,6-toluylene diisocyanate, 5 parts of an activator containing 0.5 parts of stannous chloride, 2.5 parts of water and 1.5 parts of a compound of the formula

in which (CmH.,mO) represents 15 oxyethylene units and 15 oxypropyl units. The diisocyanate and activator mixture is injected into a stream of the polyalkylene ether glycol in this apparatus and mixing of the components is achieved almost instantaneously. The resulting mixture is emptied out of the apparatus and a chemical reaction occurs almost instantly, as the reaction mixture begins to foam and expand. After the chemical reaction is finished, the expanded cellular mixture solidifies into a cellular polyurethane having a density of 40 kg/m<3>.

Example 5.

With an apparatus of the type shown in US Patent No. 2,764,565, 100 parts by weight of polypropylene glycol with an average molecular weight of 2,000 and a hydroxyl number of 56 are mixed at about the same time, 35 parts of a mixture of 80 percent 2,4-toluene -diisocyanate and 20 per cent 2,6-toluylene diisocyanate, 4.8 parts of an activator containing 0.2 parts triethylenediamine and 0.1 part dibutyl fcinn-di-(2-ethyl-hexoate), 2.5 parts water and 1.5 parts of a compound with the formula

in which (<C>M<H>2liO) represents 15 oxyethylene units and 15 oxypropylene units. The diisocyanate and activator mixture is injected into a stream of the polyalkylene ether glycol in this apparatus and mixing of the components is achieved almost instantaneously. The resulting mixture is emptied from the apparatus and a chemical reaction occurs almost immediately, as the reaction mixture begins to foam and expand. After completion of the chemical reaction, the expanded cellular mixture solidifies into a cellular polyurethane with a density of 40 kg/m<3>.

Example 6.

With an apparatus of the type indicated in US Patent No. 2,764,565, 100 parts by weight of polypropylene ether glycol with an average molecular weight of 2,000 and a hydroxyl number of 56, 38 parts of a mixture of 80 percent 2.4 are mixed substantially simultaneously -toluylene diisocyanate and 20 per cent.

2,6-toluylene diisocyanate, 5.5 parts of a mixture containing 1 part of dibutyltin diacetate, 3.0 parts of water and 1.5 parts of a compound of the formula

in which (CmH,,mO) represents 17 oxyethylene units and 13 oxypropylene units and the value of z is thus 30. The diisocyanate and activator mixture is injected into a stream of the polyalkylene ether glycol in this apparatus, and mixing of the components is achieved approximately at once . The resulting mixture is emptied out of the apparatus and a chemical reaction occurs almost instantly, as the reaction mixture begins to foam and expand. After completion of the chemical reaction, the expanded cellular mixture solidifies into a cellular polyurethane, which has a density of 32 kg/m:<1>.

Example 7.

With an apparatus of the type disclosed in US patent no.

2,764,565 are mixed at about the same time 100

parts by weight polypropylene ether glycol with an average molecular weight of 2000 and a hydroxyl number of 56, 38 parts of a mixture of 80 percent 2,4-toluene diisocyanate and 20 percent 2,6-toluene diisocyanate, 5 parts of

an activator containing 0.1 part dibutyltin di-(2-ethylhexoate); 0.4 parts of 1-methyl-4-dimethyl-aminoethyl-piperazine, 3.0 parts of water and 1.5 parts of a compound of the formula

in which (<C>M<H>211O) represents 17 oxyethylene units and 12 oxypropylene units and the value of z is thus 30. The diisocyanate and activator mixture is injected into a stream of the polyalkylene ether glycol in this apparatus and mixing of the components is achieved approximately immediately. The resulting mixture is discharged from the apparatus and chemical reaction occurs almost instantaneously as the reaction mixture begins to foam and expand. After completion of the chemical reaction, the expanded cellular mixture solidifies into a cellular polyurethane with a density of 32 kg/m<:i>.

Example 8.

With an apparatus of the type indicated in US patent no. 2,764,565, 100 parts by weight of polypropylene ether glycol with an average molecular weight of approx. 2000 and a hydroxyl number of 56, 38 parts of a mixture of 80% 2,4-toluylene diisocyanate and 20% 2,6-toluylene diisocyanate, 5 parts of an activator containing 0.1 part dibutyltin- di(2-ethylhexoate), 0.2 parts of tetramethyl-butylenediamine, 3.0 parts of water and 1.5 parts of a compound of the formula in which (CnH.,nO) represents 17 oxyethylene units and 13 oxypropylene units and the value of z is thus 30. The diisocyanate and activator mixture is injected into a stream of polyalkylene ether glycol in this apparatus and the mixing of the components is achieved almost instantaneously. The resulting mixture is emptied out of the apparatus and a chemical reaction occurs almost instantly, as the reaction mixture begins to foam and expand. After completion of the chemical reaction, the expanded cellular mixture solidifies into a cellular polyurethane with a density of 32 kg/n<r>'.

Example 9.

100 parts by weight of the condensation product of hexanetriol-1,2,6 and propylene oxide with a molecular weight of 700 are mixed with 36 parts of a mixture of 80% 2,4-

toluylene diisocyanate and 20 percent 2,6-toluylene diisocyanate. The condensation product of hexanetriol-1,2,6 and propylene oxide is produced by a commonly known method, such as e.g. by having hexanetriol-1,2,6 and potassium hydroxide in a suitable reaction vessel and heating the mixture to 150° C. Propylene oxide is then added at this temperature. As the reaction progresses, the pressure drops and more propylene oxide is added to the reaction vessel. When the desired molecular weight is reached, the reaction is stopped and the alkali is neutralized. 1 mol of hexanetriol is used per 10 moles of propylene oxide. 20 parts of methylene chloride are added as a liquid substantially simultaneously with the mixture of the diisocyanate and the condensation product of propylene oxide and hexanetriol. Together with the other ingredients, mix 2 parts of dibutyl tin di-(2-ethylhexoate) and 1.5 parts of a stabilizer with the formula at about the same time

in which (CnH:)]iO) represents 17 oxyethylene units and 13 oxypropylene units and z is equal to 30. In a preferred embodiment, the catalyst is mixed with a suitable organic thickening agent for it and the resulting solution is added to the stabilizer and the condensation product. The diisocyanate is then added to the resulting mixture. The various ingredients can be mixed in an apparatus of the type shown in US Patent No. 2,764,565 and the methylene chloride acts as a propellant and produces a cellular structure. The resulting foam will have a density of 32 kg/m<:!>.

Example 10.

100 parts by weight of a triol produced by condensation of propylene oxide and glycerol and which has a molecular weight of 3000, 1 part of dibutyl tin diacetate, and 9 parts of a mixture containing 80 percent 2,4-toluylene diisocyanate and 20 % 2,6-toluylene diisocyanate are mixed together at about the same time. The resulting mixture reacts and forms a solid non-porous elastic polyurethane. The mixture can be filled into a mold, spread out as a sheet, painted with a brush, spread as a paint or used in many other ways before the mixture

hardens into a firm elastic non-porous poly-

urethane.

Example 11.

100 parts by weight of a triol produced by condensation of propylene oxide and glyce-

role and which has a molecular weight of 3000, 1

part tributyl tin oxide and 9 parts of a mixture containing 80 percent 2,4-toluylene diisocyanate and 20 percent 2,6-toluylene-di-

isocyanate are all mixed together at about the same time. The resulting mixture reacts to form a solid non-

porous elastic polyurethane. The mixture can be filled into a mold, spread as a sheet, painted with a brush, spread as a paint or be-

used in many other ways before mixing

gen hardens into a firm elastic non-porous polyurethane.

Example 12.

100 parts by weight of a triol produced by condensation of propylene oxide and glyce-

role and which has a molecular weight of 3000, 1

part of dibutyltin chloride and 9 parts of a mixture containing 80 per cent 2,4-toluylene diisocyanate and 20 per cent 2,6-toluylene-di-

isocyanate are all mixed together at about the same time. The resulting mixture reacts to form a solid non-

porous elastic polyurethane. The mixture can be filled into a mold, spread as a sheet, painted with a brush, spread as a paint or be-

used in many other ways before mixing

gen hardens into a firm elastic non-porous polyurethane.

Example 13.

With an apparatus of the type shown

in US Patent No. 2,764,565 inter-

at about the same time 100 parts by weight of polypropylene ether glycol with an average

equal molecular weight of 2000 and a hydroxyl number of 56, 38 parts of a mixture of 80 percent 2,4-toluylene diisocyanate and 20 percent 2,6-toluylene diisocyanate, 5.5 parts of an activator containing 1 part tributyl -tin oxide, 3.0

parts water and 1.5 parts of a compound with the formula

in which (CnH:,nO) represents 17 oxyethyl-

lene units and 13 oxypropylene units,

and the value of z is thus 30. The diisocyanate and the activator mixture are injected into a stream of the polyalkylene ether glycol in this apparatus and the components' mixture up-

is reached almost instantly. The resulting mixture is poured out from the device and

misc reaction occurs almost immediately,

as the reaction mixture begins to foam

me and expand. After the end of the chemical reaction, the expanded cell solidifies

shaped mixture into a cellular poly-

urethane which has a density of 32 kg/m<3>.

Claims (4)

1. Process for the production of urethane group-containing plastics including containing foams of hydroxyl group-containing polyethers with a molecular weight of approximately 500 or more, polyisocyanates and possibly network-forming agents in the presence of catalysts, characterized in that what catalysts are used stannous chloride, tin II or dialkyl tin salts of carboxylic acids with 1-18 C atoms, trialkyl tin oxides, dialkyl tin oxides and/or dialkyl tin chlorides, possibly together with tertiary amines. 2. Method according to claim 1, characterized in that the catalysts are used in quantities of 0.01-5 parts by weight per 100 parts by weight polyether. 3. Method according to claim 1, in particular for the production of foams from polyethers containing hydroxyl groups, polyisocyanates and water, characterized in that the foam formation is carried out in the presence of the tin catalysts mentioned in claim 1 and in the presence of a siloxane-oxyalkylene block polymer with the general formula in which R, R' and R " means alkyl radicals with I—4 C atoms, p, q and r mean an integer from 4—8, and (CMH.;ilO)z means an oxyalkylene block with 15—19 oxyethylene units and II—15 oxypropylene -units with z = 26— 34. 4. Method according to claim 3, characterized by the use of 0.01-5 parts by weight tin catalyst and 0.1-10 parts by weight siloxane-oxyalkylene block polymers per 100 parts by weight polyether.