DE1299887B - Process for the production of fiber-forming polyurethanes - Google Patents

Description

These glycols can accordingly have both one and two secondary hydroxyl groups. You can used in a mixture with one another or with glycols with exclusively primary hydroxyl groups will. These are e.g. E.g .: ethylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 2,2-diethyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propane

Terephthalic acid, succinic acid, adipic acid, azelaic acid and sebacic acid. Also mixtures of several Alcohols and several acids have been used for the polyester.

Polyurethanes based on polyesters containing hydroxyl groups, polyisocyanates and Chain extenders containing amino and / or hydroxyl groups and having a molecular weight less than 500 are known. They can be processed into highly elastic moldings as well as to films in the casting process, to coatings of paper and fabrics and also for the production of elastic fibers. The working techniques customary for synthetic high polymers were used, such as the wet spinning process, the dry spinning process and the melt spinning process. The one for that Processes according to the invention which are used as starting material are known per se

Way by thermal condensation from dihydric 15 diol, 2,4-cyclohexanedimethylol and xylylene glycol. gen alcohols with dibasic carboxylic acids. Dicarboxylic acids are: succinic acid,

keep; for example from ethylene glycol, 1,2-propylene glycol, glutaric acid, adipic acid, methyladipic acid, pime-1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene-licic acid, suberic acid, azelaic acid, sebacic acid, maglycol, 1,4-butylene glycol, 1,6-hexamethylene glycol, linic acid, brassylic acid, malic acid, fumaric acid, l ^ -dimethylolcyclohexane, 1,5-pentamethylene glycol, 20 itaconic acid, dilonoleic acid, diphenic acid, isophthalic acid, Terephthalic acid, hexahydroterephthalic acid, ρ - phenylenediacetic acid, dihydromuconic acid and ß-methyl adipic acid.

At least 80% of the dicarboxylic acids should ali-

It has been shown that elastic fibers are phatic in nature and have at least 6 carbon-based polyesters made from glycols with seconds atoms. If necessary, acids with terminal hydroxyl groups, inadequate strengths, permanent carboxyl groups are preferred,
show in comparison with fibers based on the starting material for the invention

Polyesters from glycols with only primary moderate process serving polyester must be a small one Hydroxyl groups. On the other hand, elastic fibers tend to contain one or more trihydric alcohols contain polyesters made from glycols in the proportions given above, only primary hydroxyl groups are suitable trihydric alcohols are: glycerine, tristallize and have insufficient elasticity properties - methylolpropane, 1,2,6-hexanetriol, 1,2,4-butanetriol, stocks. The claimed process allows trimethylol butane, trimethylol pentane, 1,3,5-tri-polyurethane fibers produce which has a lower 35 (hydroxmethyl) benzene, 1,3,5-trihydroxyhexahydro remaining Deformation and greater elasticity benzene.

or m. a. W. a greater recovery rate Also to be mentioned are addition products of

after the deformation has taken place, as was previously the case with ethylene oxide or propylene oxide high-melting or highly crystalline polyesters, polyhydric alcohols. The necessary amounts of was known. The invention enables the use of trihydric alcohols are critical. It appears formation of polyesters which have a lower crystallization namely that less than 0.003 mol of a trivalent Alcohol in the polyester only has an insignificant effect on the tensile strength of the elastic polyurethane threads have while amounts above 0.075 moles

greater than that of poly-based fibers per equivalent of secondary hydroxyl groups esters from glycols with secondary hydroxyl polyurethane threads, which only have a low tear resistance to have. A preferred amount of trihydric alcohols is around 0.003 moles per equivalent on secondary hydroxyl groups. Is preferred

tion tendency and lower melting points than previously for the production of elastic fibers common polyester. Here is their strength

groups.

The new process for the production of fiber-forming polyurethanes from hydroxyl groups

pointing polyesters, polyisocyanates and amino 50 Use of polyesters with a molecular and / or hydroxyl group-containing chain weight of 500 to 5000, especially between 1000 lengthening agents with a molecular weight below
500 is characterized in that made of dicarbon

acids, glycols with at least one secondary

and 3000. The acid number should expediently be below 10, primarily between 0 and 2. To do this, one sets a small excess of GIy-

Hydroxyl group and trihydric alcohols come into play. The hydroxyl number of the polyester should be Recovered polyester can be used, with a triple-expedient under 224 and particularly advantageous

hydric alcohol in amounts of 0.003 to 0.075 mol, based on equivalent sec. Hydroxyl groups,

between 35 and 110.

Any ali-

The production of the polyester as a starting material- 60 phatic, cycloaliphatic and aromatic diisorials for the process according to the invention is carried out in to cyanate use, for. B. 2,4-toluene diiso-

cyanate, 2,6-tolylene diisocyanate and their technical Mixtures, hexamethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, thiodipropyl diisocyanate, Phenylene diisocyanate, chlorophenylene diisocyanate, dianisidine diisocyanate, 1,5-naphthylene diisocyanate

has been set.

known way by thermal condensation of the components at 100 to 200 ° C. Glycols with at least one secondary hydroxyl group are:

1,2-propylene glycol, 1,3-butanediol, 2,3-butanediol, 1,3-pentanediol, 1,4-pentanediol, 2,3-pentanediol, 2,4 - pentanediol, 1,5 - hexanediol, 1,4 - hexanediol,

isocyanate, 4,4'-diphenyl imethane diisocyanate, 4,4'-biphenyl diisocyanate, 3,3'-dimethyl-4,4'-biphenyldiiso-

cyanate, 4,4'-dicyclohexylmethane diisocyanate. Aromatic diisocyanates and especially 4,4'-diphenylmethane diisocyanate are preferred.

Chain extenders containing amino and / or hydroxyl groups and having a molecular weight below 500 are e.g. B. diamines, glycols, hydrazine, alkylhydrazines, arylhydrazines, carbodihydrazide, alkyl- and aryl-substituted carbohydrazides, hydroxylamine. Examples include: ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,4-tetramethylenediamine, 1,6-hexamethylenediamine, 1,10-decamethylenediamine, isopropylaminopropylamine, 3,3'-diaminodipropyl ether, benzidine, 4 , 4'-diaminodiphenylmethane, p-phenylenediamine, m - phenylenediamine, 2,4 - tolylenediamine, 2,6 - diaminopyridine, ethanolamine, ethylethanolamine, methylethanolamine, ethylpropanolamine, 3-aminopropanol, 4 - aminobutanol, 4 - aminobenzyl alcohol, 1,4 - Butanediol, hydroquinone - bis - (ß - hydroxyethyl ether), ethylene glycol, quinite, hexahydrocycatechol, 1,6-hexanediol, 1,3-propanediol, 2,3-butanediol, 1,3-butanediol, 1,5-pentanediol, glycerine α-alkyl ethers, xylylene glycol, 1,4-dimethylolcyclohexane, the Diels-Alder addition products of butenediol and anthracene, diols which are substituted in the chain or in the ring by foreign atoms such as oxygen, nitrogen or sulfur atoms, hydrazine and symmetrical ones or asymmetric derivatives such as methylhydrazine, phenylhydrazine, Ν, Ν'-dimethylhydrazine, N-methyl-N'-phenylhydrazine, N-ethylhydrazine, N, N'-diethylhydrazine, carbohydrazide, and alkyl substitution products such as N-methylcarbohydrazide, Ν, Ν'-dimethylcarbohydrazide, N-ethylcarbohydrazide and Ν, Ν'-dipropylcarbohydrazide.

The diisocyanate is used in such an amount that the ratio of NCO groups to the sum of the OH and / or NH ₂ groups in the polyester and chain extender is somewhat greater than 1, advantageously between 1.01 and 1.2. An optimum is 1.04. In general, 2 to 6 moles per polyester and 1 to 5 moles of chain extender per mole of polyester will be used. 2.3 to 3 moles of diisocyanate and 1.2 to 1.9 moles of chain extender per mole of polyester are preferred, with the aim of an NCO to OH or NH ₂ ratio of about 1.04. It is advisable to premix the polyester and chain extender for a short time at 50 to 110 ° C. and then add the diisocyanate. The reaction is exothermic and the temperature of the reaction mixture increases by about 30 to 50 ° C in 2 minutes. However, the order in which the components are combined is not critical and can also be changed as required.

The reaction is interrupted before the final hardening. Time and temperature are largely depending on the reaction components used in each case. The reaction melt is poured into Trays to be placed in a dry heat oven, e.g. B. exposed between 80 and 130 ° C for 10 to 30 minutes are. The polyurethanes are then removed from the oven, cooled to room temperature and granulated. Final hardening is usually not necessary; it takes place during melt spinning the fiber-forming polyurethanes or even after the fiber has been formed. From the process product elastic fiber is obtained in various ways. So you can melt spinning the mass or dissolve and dry or spin wet. For coarser elastic threads, the polyurethanes are drawn in on a rubber roller mill thick fur and cut it into threads. Solvents are suitable for the solution spinning process Dimethylformamide, tetrahydrofuran, dimethylacetamide, N-methylpyrolidine, dimethylpropionamide, Dimethyl sulfoxide and methoxydimethylacetamide. The wet spinning process is used to spin dip the solution in a nonsolvent such as water

ίο the dry spinning process one spins into one Hot air fireplace. The melt spinning process is preferred. The uncured one is extruded Polyurethane mass in fiber form, winds it up and hardens it in an oven for 8 to 20 hours at 90 to 120 ° C, preferably at 100 to 110 ° C. It can be elastic polyurethane threads from 30 to Manufacture 1000 den and more.

example 1

Production of the starting material

A mixture of 1 mole of 1,2-propylene glycol, 2.3 mol of ethylene glycol, 0.08 mol of trimethylolpropane and 2.51 mol of adipic acid is added with stirring 200 ° C heated, the condensation water first under reflux and then in a vacuum of 10 mm Hg Will get removed. The esterification is terminated when a hydroxyl number of 59 and an acid number of 1.9 are reached. The viscosity of the polyester in the Brookfield viscometer is 790 cP / 73 ° C.

Implementation according to the invention

100 parts by weight of the polyester are mixed with 9 parts by weight of 1,4-butanediol at 60 ° C. for 30 minutes and then added at this temperature 40.1 parts by weight of 4,4'-diphenylmethane diisocyanate. The NCO to OH ratio is 1.04. After an exothermic reaction with stirring for 2 minutes the reaction mass is poured into dishes treated with a silicone release agent. The thickness of the The mass in the bowl is 0.3 to 1.3 cm. The dishes are 15 minutes at 110 ° C in one Oven held with the product solidifying. It is then cooled to room temperature and the polyurethane cut into pieces and ground. The ground polyurethane is fed into a melt extruder brought and extruded a thread of about 400 den. Cure after 18 hours at 110 ° C the thread shows the following properties:

Tensile strength 470 kg / cm ²

Elongation 650%

Permanent stretch after
lOminute relaxation

at 3O ⁰ C 2%

The polyurethane is extruded through a rubber band mouthpiece and kept at 110 ° C for 18 hours cured, rubber band for measuring the tensile strength at an extruder temperature is obtained from 200 to 215 ° C is 14 kg / cm.

Example 2
Production of the starting material

A polyester is produced as in Example 1, but with 0.01 mol of 1,2,6-hexanetriol instead of with 0.08 moles of trimethylol propane and with 2.44 moles of adipic acid. The polyester has an OH number of 56,

10

20th

an acid number of 1.5 and a viscosity of 650 cP at 73 ° C.

Implementation according to the invention

The polyester is used according to Example 1 to produce a polyurethane, 39.4 parts by weight of 4,4'-diphenylmethane diisocyanate being used (NCO to OH ratio 1.04).

Tensile strength 356 kg / cm ²

Elongation 72O%

Permanent stretch after
lOminute relaxation
at 30 ⁰ C 6%

The polyurethane is extruded through a rubber band mouthpiece and kept at 110 ° C for 18 hours cured, a rubber band is obtained for measuring the tensile strength at an extruder temperature from 175 to 200 ° C is 45 kg / cm.

Example 3

Production of the starting material

A polyester is prepared according to Example 1, but using 0.03 mol of trimethylolpropane and 2.47 moles of adipic acid. The hydroxyl number is 58, the acid number 1.5 and the viscosity 700 cP / 73 ° C.

Implementation according to the invention

This polyester is made according to Example 1 using the components and specified there their proportions, but with 39.9 parts by weight of 4,4'-diphenylmethane diisocyanate (NCO- to OH ratio 1.04) a polyurethane mass is produced and extruded into threads.

Tensile strength 410 kg / cm ²

Elongation 700%

Permanent stretch after

lOminute relaxation

at 30 ⁰ C 4%

The polyurethane is extruded through a rubber band mouthpiece and kept at 110 ° C for 18 hours cured, a rubber band is obtained for measuring the tensile strength at an extruder temperature from 195 to 210 ° C is 36 kg / cm.

Example 4 - comparative example

The polyester is produced according to Example 1, but without using trimethylolpropane and using 2.44 mol of adipic acid. The OH number is 56, the acid number 1.5 and the viscosity 600 cP / 73 ^° C. This polyester is converted into 4,4'-diphenylmethane diisocyanate according to Example 1 with the components listed there and their proportions, but with 39.4 parts by weight (NCO to OH ratio 1.04) a polyurethane is produced that is extruded into threads.

Tensile strength 161 kg / cm ²

Elongation 820%

Permanent stretch after
lOminute relaxation
at 3O ⁰ C 23%

The polyurethane is extruded through a rubber band mouthpiece and kept at 110 ° C for 18 hours cured, a rubber band is obtained for measuring the tensile strength at an extruder temperature from 150 to 180 ° C is 36 kg / cm.

Example 5 - comparative example

A polyester is according to Example 1, but with 0.2 mol of glycerol instead of trimethylolpropane and made with 2.64MoI adipic acid (OH number 56, Acid number 1.5 and viscosity 1000 cP / 73 ° C). This polyester becomes according to Example 1, but with 39.4 parts by weight of 4,4'-diphenylmethane diisocyanate (NCO to OH ratio 1.04) made a polyurethane. It does not melt without decomposition and cannot be used to make thread. It shows the effect of a too high content of trivalent alcohol. The polyurethane cannot go under 220 ° C can be extruded.

Claims (1)

Claim: Process for the production of fiber-forming polyurethanes from hydroxyl groups Polyesters, polyisocyanates and chain extenders containing amino and / or hydroxyl groups with a molecular weight below 500, characterized in that dicarboxylic acids, glycols with at least a secondary hydroxyl group and trihydric alcohols are used are, with a trihydric alcohol in amounts of 0.003 to 0.075 mol, based on equivalents sec. Hydroxyl groups.