DE2035975B - - Google Patents

Description

40 (c) Adding and mixing water or any other non-solvent for the Polymer in the polymer solution, so that the mixture in a gel portion and a liquid portion is separated, and then the use

45 preparation of the gel portion for the coating.

The above-mentioned procedure (a) is described in detail in British Patent Specification 849,155. However, it is disadvantageous that a precisely regulated atmosphere is required and that a

The invention relates to an improved process for the long period of time required for the coagulation of a film material with high moisture permeability to produce a tough and soft polyurethane coating film of any thickness. In addition, not only the relative humidity and a uniform microporous structure, but also the temperature must be regulated with a backing pad or as an unsupported film, 55, and it is in industrial implementation where a base material or a film or not simply the To regulate atmosphere to obtain homo-plate with a gene and uniformly microporous films containing a urea compound. Solution of a film-forming, wholly or mainly In addition, with such a moisture-based polyurethane polymerizate in a controlled atmosphere, more than a few hours of water-miscible organic solvent ^{can be} deformed by a 0.6 mm thick layer of dimethyl, the coated base material with a formamide solution to be well watered with 20% polyurethane, an inorganic salt from the group to wet and coagulate. It is also difficult to determine the correct degree of coagulation sodium chloride, potassium chloride, aluminum chloride. Ammonium chloride, sodium sulfate, potassium sulfate, aluminum. The above procedure (b) is detailed

miniumsulfal or ammonium sulfate containing ⁶ 5 z. B. in the French patent 1 225 729 be-coagulation liquid for coagulating the poly- written. A remarkably good microscopic film is then treated according to this procedure, and the polymerizate is obtained. However, it washes and dries, and if the is used, the colloidal dispersion formed is

3 4

position of the so-called colloidal dispersion directly with regard to the daily changing meteorological

before the actual gelation of the polymer solution gischen conditions and in particular

to a large extent on the concentration and the temperature to keep the humidity sufficiently low. About it

temperature of the polymer solution to be used, which makes it almost impossible to

The amount of nonsolvents 5 to be added for this purpose can be seen in the coating stage and the subsequent one

and the method of adding the nonsolvent to eliminate the immersion step.

influenced, so that it is necessary to very carefully the aim of the invention is to provide an improved process

set and control optimal conditions. for the production of a moisture-permeable film

Therefore, it is difficult to provide this operation industrially or in sheet material which is uniform

perform. io has micropores, but no macropores. It

The mode of operation (c) is, for example, in the case of an economical, advantageous manner

gischen patent 624 250 described. However, sheet material is microporous, on top of one

the step of separating the gel is complicated, and fibrous or other porous base material

the control and adjustment of the appropriate concentration applied coating can be produced, which

Tration and viscosity of the gel are difficult. 15 natural leather in terms of durability,

In addition, in the case of the above, the appearance and toughness are not inferior.

Working methods (b) and (c) the tendency that the strength

ability of the obtained, microporous film reduced parts according to the invention can be overcome

will. nen and that it is possible to use a sheet material or

But there has also already been a method of working to obtain a film which, in terms of the

Production of a foil or a film with high moisture permeability is good and an equal-

Moisture permeability and having a microporous, microporous structure. Even if

sen structure described, according to which a solution of the layer of the coating solution of the atmosphere

consisting entirely or mainly of polyurethane under any temperature and humidity conditions

Polymer is exposed in water-miscible solutions, no macropores are in

means in which at least one inorganic needle formed, solidified film material is

irium or potassium salt is dispersed, forms on a base.

material is applied, the layered Ma- The inventive method for production material in an aqueous solution of a water-soluble, of film material with microporous structure with inorganic salt coagulated and then the material through a support base or as an unsupported film material is washed and dried (French coating of a fibrous or porous basic patent 1 565 893). It was also already a material or a sheet or plate with a a procedure for the production of a film or regulator of the coagulation rate contains Film with higher moisture permeability, a solution of a film-forming, synthetic poly- and a microporous structure, after 35 merisats, which wholly or mainly consists of polyester a urethane containing a polyurethane and urea, dissolved in a solution mixed with water applied to a base material, the paintable organic solvent, treating the coated Material coated in an aqueous solution for coagulation of the polymer at least a water-soluble, inorganic or or- sats with an aqueous coagulation liquid that Ganic salt of certain metals coagulates and 4 ° inorganic salt in the form of chlorides or sulfates then the product is washed and dried from sodium, potassium, aluminum or ammonium (French patent 1,547,876). contains, washing out the polymer film and drying

This way of working made it possible to use the NEN and in the case of using the film or

Implementation in comparison with the above-described plate as a base, peeling off the film from the

45 using conventional processes (a) to (c).

simple and at the same time a film with high draws that a coating solution is used

Moisture permeability and a microporous one that acts as a regulator of the coagulation speed

To produce structure. However, in the above 5 to 90 weight percent based on thiourea occurred

mentioned, improved working methods a problem of the polymer present in the coating solution

in the mass production of microporous film 5 ° sat, and that optionally also the aqueous,

or microporous film. the coagulating agents containing chlorides or sulphates

In the continuous bulk liquid there is also thiourea in an amount of up to

Production system contains a time span of a few mi- to 150 g / l.

utes (which, however, depend on the particular The advantages of the invention are as follows:
Device is different) between the application 55

the coating polymer solution to the base (1) Since the polymer coating solution is thio material and the immersion of the coated manure contains, it can be easily and evenly terials in the coagulation bath. Therefore, one is suspended on the base material without any suspicion The solution layer of the atmosphere is applied during the work, and that on this Period of time exposed, and therefore it absorbs 60 layered material can instantly and konlinu-moisture from the air. This moisture absorbs into a coagulating and regenerating tion has a detrimental effect on the coagulation bath, which is referred to below as a coagulation bath tion in the coagulating bath, and it causes what is called to be immersed, which out Formation of undesirable macropores in the above-mentioned aqueous solution, coagulated layer. This tendency is in particular 65 In addition, the coated material, noticeable when the atmospheric humidity even when the lapse of time between the raises than 45% relative humidity. layers and dipping into the coagulation

However, it is very difficult to keep the moisture in the bath for a long time and even if the moisture

The atmosphere is not regulated, a Vorpoiymerisat not produced by a urethane detrimental by water or moisture in the organic diisocyanate compound with a poly atmosphere influenced. The coagulation own alkylene ether glycol or polyester with terminal Shafts of the polyurethane are noticeably treated with hydroxyl groups. The prepolymer improves. 5 is then by means of a chain extender that reacts

(2) In the coagulation stage, as a result of the synergistic hydrogen atoms, the chain is lengthened, e.g. B. gistic effect of the thiourea «in the ^diamm > diol or polyol to form em polyurethane coating solution and the inorganic salt elastomer.

in the aqueous coagulating ^bath the coagulating, the organic dnsocyanate can em aromatic,

speed of Polymerisatlösungsschicht ¹⁰ overall ahphaüsch "or acyclic Dnsocyanat or

regulates so that the difference between the koa mix of these may be, e.g. B. toluene-2,4-diiso-

rate of regulation on the surface of the ^cva , ^nat 'toluene - 2,6 - dnsocyanate diphenylmethane

Polymer solution layer and the coagulant 4,4 - diisocyanate, 1,5 - naphthylene diisocyanate, hexa-

Approximate speed inside the layer methylene diisocyanate or p-xylene diisocyanate.

is reduced and, in addition, the coagulation ^{15 The} Polyalkylenatherglykol is example po y

through the full strength of the coating ethylene ether glycol, polypropylene ether glyco, poly-

solution layer quickly and evenly causes tetramethylene ether glycol or polyhexamethylene ether

will. In addition, a solidified or ^ ^{οΙ or a} Copolymensat or a mixture of

coagulated film with a uniform microfiber.

porous structure can be formed without its ^2O . The polyester that can be used is to cause shrinkage or deformation. The ^ ⁿ polycondensate of an organic acid and a remaining solvent can readily apparent from the glycol. Preferred glycols are polyalkyleneglycols, coagulated layer was washed and extracted ^{w, ie,} ethylene glycol, propylene glycol, tetramethylene becoming. The inorganic salt, the ^{thiourine glycol or} hexamethylene glycol, cyclic glycols, substance and the solvent can easily be removed in the ²⁵ ^ e cyclohexanediol, or aromatic glycols, as in the subsequent washing step. Xylylene glycol In addition, the

dend acid succinic acid, adipic acid, sebacic acid

(3) There may be a viscous and soft microporous film _s ä _acid or terephthalic acid.

or a synthetic leather plate with a higher _A i _s chain extender can be a diamine, as in both

Moisture permeability than they methylenedi game, in conventional ₃₀ hydrazine, ethylene diamine,

tional is available. o-chloroaniline, can be used.

(4) There is no special device in front of the Koagu necessary. The implementation is monamine, triethylenediamine, N-ethylmorpholine, dibutylfach. The inorganic salt to be used and tin dilaurate or cobalt naphthenate, at the Herder Thiourea to be used are both 35 position of the polyurethane elastomers are used, cheap and easily available. In the invention, the polyurethane is molded

a solution used. The solvent for the

The polymer to be converted in the process according to the invention must be obtained from such organic solutions The base material is a medium selected for synthetic leather, which is customary to mix with water Basic material in the form of a textile that can be foiled and which is similar to that with an aqueous solution Materials, e.g. B. a woven fabric, an organic salt (and thiourea) extracted knitted goods, a "nonwoven" goods, a felt or can be. Therefore they are miscible with water a flannel made of fibers such as natural fibers, solvent suitable. Examples of these solvents synthetic fibers or semi-synthetic fibers, are any of the following listed types. It is also possible to use a foam sheet 45 solvent or a mixture thereof: N, N'-Di- or to use a sheet of paper as the base material. methylformamide, dimethyl sulfoxide, tetrahydrofuran, If desired, the film base material can be tetramethylurea, N, N'-dimethylacetarnide, dioxane a solution or emulsion of a synthetic poly- or butylcarbinol. In addition, all Kemerisats impregnated or with a latex of a clay, which by itself is not a good solvent Natural rubber or a synthetic rubber 5 ° for the polyurethane are, however, with the solution be pretreated. are easily miscible, e.g. B. acetone and methyl ethyl ketone,

The polymer coating solution can also be used as a diluent to such an extent.

onto a solid film or plate, e.g. B. made of glass, metal, as it is not acidic polymer

or plastic. coagulate.

The coating polymer solution is a solution 55. Optionally, a small amount of one

one or more other film-forming polymers in a water-miscible organic solvent,

Polymer which is wholly or mainly composed of which are soluble in the solvent, such as vinyl homo-

Polyurethane is made. According to the invention it is essential polymer, z. B. vinyl chloride, polyvinyl alcohol, poly

Lich that this coating solution thiourea entacrylonitrile, polyacrylic ester or polyacrylic acid or co-

holds. The coloring solution can also contain a coloring polymer of these, of the abovementioned poly-

exercise means, e.g. B. a dye or pigment, urethane solution can be added. The amount of such

a stabilizing agent or another reinforcing polymer can be 2 to 40 percent by weight,

Fabric, e.g. B. fibers, asbestos, potassium carbonate or fine - based on the polyurethane, be,

powdered silica. The concentration of the polymer in the poly

In practicing the invention, all of the 65 merisate solution can be in a range of 10 to

conventional, film-forming polyurethanes, which contain 40 percent by weight, preferably 15 to 35 percent by weight

are known to sicu. In all percent lying

common for the production of such a poly- The most important additive to the coating

Thiourea is to be added to the solution and must be contained therein. The amount of thiourea used is in a range of 5 to 90 percent by weight, preferably 20 to 70 percent by weight, whole particularly preferably 30 to 60 percent by weight, based on the weight of the polyurethane in the coating solution. If the amount of thiourea is more than 90 percent by weight, the polymer gels with the thiourea, while with an amount less than 5 weight percent the difference in the coagulation speed between the surface and the inside of the coating solution layer becomes large, so that the production of a film with a uniform, microporous structure becomes difficult.

When thiourea is added to and contained in the polymer solution, the coagulating properties become noticeably improved. So causes even if the lapse of time between applications the coating solution and immersing the coated material in the coagulating bath is the humidity in the atmosphere regardless of the humidity conditions in the atmosphere no detrimental effect on the coated polymer solution layer, and even if the humidity is not controlled, a film with high moisture permeability can and a uniform, microporous structure can be formed. Due to the synergistic effect of thiourea in the coating solution and inorganic salt (and thiourea) in the aqueous coagulating solution becomes the Coagulation speed of the coated layer of the polymer solution controlled, the Difference between the coagulation speed on the surface of the coated layer and the coagulation speed inside the coated layer becomes slow, so that the coating solution layer is coagulated uniformly both in the inner part and in the part lying on the surface and a film with a uniform, microporous structure is formed quickly. In addition, even if one is comparatively large amount of thiourea to the coating polymer solution is added and contained therein, this coating solution is stable, and continues to be are due to the dissolution and removal of thiourea remaining in the coagulated film In the subsequent washing stage, additional micropores are formed in the coagulated film, whereby the porosity is increased. In comparison with a coating solution containing urea is added, forms a coating solution, which according to the invention is mixed with thiourea became a film with smaller micropores and a higher moisture permeability during coagulation.

The polymer solution is adjusted to a viscosity such that it easily hits the surface a base material can be applied. Generally a viscosity is from about 20,000 to 200,000 cps preferred.

The polymer solution (coating solution) is applied to one or both surfaces of the base material, especially one for a synthetic leather, layered or applied.

The coating can be carried out in any known manner, e.g. B. by knife application, Roller application or spraying. Since the polymer solution is homogeneous or uniform, it can easily are applied to the base material, and there are no such drawbacks as that in FIG Belgian patent 624 250 described operation.

With regard to the coagulating bath, it is desirable to use water at an appropriate rate to be added to the polymer solution layer and the coagulation afterwards as uniformly as possible

ίο to effect the inside of the outer surface of the layer, so that a microporous structure can be formed. For this purpose it is necessary that, although the penetration and diffusion of water into the polymer solution layer from the coagulating bath and the solvent removal in the coagulating bath from the polymerizing solution layer occur simultaneously, the corresponding speeds are kept in a suitable ratio. This means, that no uniform, microporous structure is formed, but that super macropores are partially formed and numerous macropores are formed immediately under the surface layer, if the rate of coagulation is not higher than the rate of solvent removal. It it was found that when the substances listed below (additives) are present to adjust the Penetration rate (or coagulation rate) of water from the coagulating bath and the rate of solvent removal from the polymer solution layer into the coagulating bath satisfactory coagulation can be achieved. You can do this by using a aqueous solution for the coagulating bath, soft the aforementioned inorganic salt or the inorganic Contains salt and thiourea. This increases the coagulation speed of the coating solution regulated. So the difference between the coagulation speed in the surface part of the Coating solution layer and the coagulation speed inside the coating solution layer small, the coating solution layer becomes uniform in both the inner part and the surface part coagulates, and a film with high moisture permeability and a uniform, microporous structure rapidly formed.

The inorganic salt to be added to the coagulating bath is sodium chloride, potassium chloride, aluminum chloride, Ammonium chloride, sodium sulfate, potassium sulfate, aluminum sulfate, or ammonium sulfate. the suitable concentration of the salt in the coagulating bath is somewhat dependent on the particular polyurethane solution, the amount of the thiourea additive and the type of the other additive, they however, it is generally 50 to 450 g / l. Preferred concentrations are as follows:

6α Sodium sulfate More general Preferred salt Potassium sulfate Concentration Concentration Sodium chloride range (g / l) range (g / l) Potassium chloride 50 to 330 200 to 300 65 aluminum chloride .. 50 to 300 200 to 300 Ammonium chloride .. 50 to 300 150 to 300 Aluminum sulfate ... 100 to 300 150 to 300 Ammonium sulfate .. 150 to 450 150 to 300 100 to 250 150 to 200 100 to 200 150 to 200 100 to 350 150 to 300

209530/566

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If the content of the inorganic salt in the coagulating bath is lower than the lower limit of the above Area, becomes the difference in coagulating speed between the surface part and the inner part of the coating solution layer large, so that the formation of a film with a uniform, microporous structure becomes difficult. When the amount of salt is higher than the above is the specified upper limit, the formation of a film with uniform micropores becomes difficult, and at the same time there is a likelihood that salts will be precipitated.

The range of the amount of organic salt in the coagulating bath of the invention is comparatively wide. Even in a comparatively low concentration range, an excellent coagulating effect, as described above.

Sometimes the coagulating bath can also contain thiourea. The right concentration of thiourea to be contained in the coagulating bath is somewhat dependent on the kind and the The concentration of the inorganic salt present in the coagulating bath varies, but it is in generally in a range from 0 to 150 g / l, preferably from 0 to 100 g / l and very particularly preferably 2 to 70 g / l. If it is higher than 150 g / l, the concentration of the water-miscible solvent, z. B. Ν, Ν'-dimethylformamide, near the surface of the coating solution layer high, and the solubility of the inorganic salt is noticeably reduced, so that the salt crystallizes out on the surface and likely to irregularly damage the surface of the porous film.

The temperature of the coagulating bath is in the range of 30 to 60 ⁰ C, preferably 40 to 55 ° C. If it is lower than 30 ° C, it is likely that the crystals of the inorganic salt precipitate and damage the microporous film surface of the crystals will. If it is higher than 60 ^° C., it becomes difficult to carry out and the moisture permeability of the resulting film is lowered.

The films obtained by the process of the invention are always uniform, microporous Structure and no macropores, even if the composition, the temperature of the coagulating bath are set to a constant value and there is a change in meteorological conditions.

After coagulation, the film is washed with water to make the water-miscible, organic Solvent to remove the inorganic salt and thiourea remaining in the film, and it is then dried under normal conditions. Because the film is coagulated evenly and Has a uniform, microporous structure, it is easy to use such an organic solvent, inorganic Wash and remove salt and thiourea. Therefore, there is no risk that the Film adversely affected by any solvent lag in the drying stage

If the polymer solution is applied to one or both surfaces of a sheet or plate made of glass, metal or plastic is applied, the resulting microporous film can be from the base film or plate can be pulled off. When the polymer solution is applied to one or both surfaces of a base material is applied which is suitable for a synthetic leather, e.g. B. a woven or non-woven goods, foil, foam or paper 5 or the like, the resulting microporous film becomes solid bound on this base material. The material thus obtained can be used as synthetic leather.

The microporous film can be finished with an ordinary paint or varnish for leather without adversely affecting the desired properties and performance of the product. The invention will be further illustrated by the following examples explained in detail, where parts are always parts by weight. In these examples were the breaking strength, elongation, moisture permeability, flexural strength and presence determined by macropores in the resulting films as follows:

(1) Breaking strength and elongation:

These were on a sample with a width of 2 cm and a clamping length of 5 cm in a Pull speed of 3 cm / min as measured with an Instron tester.

(2) Moisture Permeability:

The weight increase of calcium chloride by ₃ "a predetermined area of the film sample in an atmosphere with a relative humidity of 80% at 30 ⁰ C was determined, and the moisture permeability was determined by the weight increase (mg) per unit time (h) per unit area (cm ² ) , ie mg / h / cm ² , reproduced. The larger this value, the higher the moisture permeability.

(3) Flexural Strength:

This was determined with a flexometer.

(4) Presence of macropores:

The cut surface of the film was examined microscopically. A double folded surface of the film was scratched with a razor blade, and the area exposed to the cut was observed with a microscope to determine whether there were macropores (10 microns or larger in average diameter).

example 1

105 parts of polyethylene adipate with an average molecular weight of 1100 and with endstän Digen OH groups were dissolved in 200 parts of anhydrous dioxane, and this was 400 parts Given methylene bis (4-phenyl isocyanate). The solution was in a nitrogen gas stream at 80 ° ( held for 2 hours and then cooled to 30 ° C. To the solution of prepolymer obtained sates, which has terminal —NCO residues

3.7 parts of ethylene glycol and 0.02 parts of tr äthylenediamine were together with 100 parts of anhydrous Dioxane given to carry out a chain extension reaction for 3 hours. The Polymerisa solution was then cooled and poured into water to remove most of the dioxane. D;

2449

Polymer was separated off and then ^{dried at 80 °} C. under reduced pressure. The polymer was dissolved in Ν, Ν'-dimethylformamide until it had a concentration of 30 percent by weight. The viscosity of this polymer solution was 45 10OcP at 30 ° C.

This polyurethane solution with the addition of 3.5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90 and 100% thiourea, based on the weight of the polyurethane, was used as the coating solution. The coating solution was applied to a glass plate to a thickness of about 1.0 mm. The coated glass plate was then left to stand for 5 minutes in an atmosphere with a relative humidity of 80% at 25 ^° C., and then it was immersed in an aqueous solution containing 200 g / l sodium sulfate at 40 ^° C. for 10 minutes.

Then the glass plate with the coagulated film thereon was ^{immersed in a bath of warm water at 50 °} C. for washing. The film was peeled from the glass plate with hot water for 30 minutes to remove the solvent well

washed and then ^{dried in the air at 100 °} C. for 30 minutes. The properties of the films thus obtained are shown in Table I. For comparison, the same procedure was also repeated except that no thiourea was added to the coating solution and further the same procedure was repeated except that 40% urea, based on the polyurethane, was added in place of thiourea. This He is also shown in Table I results. As can be seen from Table I, in the process according to the invention, the suitable amount of thiourea, which is mixed with the polyurethane solution and is to be contained therein, is in a range from 5 to 90 percent by weight, preferably 20 to 70 percent by weight and particularly preferably 30 to 60 Weight percent. It was found that when using a polyurethane solution mixed with thiourea in such a range as loading

For the layering solution, a tough and soft, uniformly microporous film with high moisture permeability was obtained.

Table 1

Amount of thiourea Moisture
permeability Macropores in the film present Breaking strength
(kg / mm ^! ) Elongation at break
(° / o) will 565 (%),
related to
Polyurethane 3.2 present 0.96 540 0 (control) 4.8 present 0.94 545 3 (control) 8.7 unavailable 0.96 517 5 10.0 unavailable 0.94 541 10 11.5 unavailable 0.92 520 20th 12.9 unavailable 0.91 525 30th 13.0 unavailable 0.93 540 40 13.1 unavailable 0.94 541 50 12.9 unavailable 0.93 528 60 11.5 unavailable 0.85 534 70 10.0 unavailable 0.81 480 80 10.2 unavailable 0.80 490 90 951
HOj 50% urea (Control) The coating solution gelled and failed not upset 6.8 0.92

Example 2

A microporous film was obtained in the same manner as in Example 1, with the exception that each coating solution prepared in Example 1 was applied to a glass plate in a thickness of 1 mm and then in an aqueous solution at 40 ^° C. for 10 minutes which contained 200 g / l sodium sulfate and 10 g / l thiourea. The results are given in Table II. For comparison, the same procedure was repeated, with the exception that the coagulating bath contained 10 g / l urea instead of thiourea and, on the other hand, the coating solution contained no thiourea (control a) g / l urea instead of thiourea and the coating solution contained 50 percent by weight (based on the polyurethane) urea instead of thiourea (control b) The results are also given in Table E.

As can be seen from table Π, even if! an aqueous solution containing both sodium sulfate and thiourea for a coagulating solution is used, the appropriate amount of the thiourea to be added to the coating solution! in a range from 5 to 90 percent by weight, preferably 20 to 70 percent by weight and very particularly more preferably 30 to 60 percent by weight in one such area becomes a tough, uniformly micro Obtained porous film with high moisture permeability. The effects are on thiourea more noticeable than with urea.

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Table II

Amount of thiourea " Moisture
permeability Macropores in the film Breaking strength
(kg / mm ² ) unavailable 0.94 Elongation at break
(%) will 550 (7o),
related to unavailable 0.92 560 Polyurethane 3.4 present 0.94 545 0 (control) 4.6 present 0.95 530 3 (control) 8.9 unavailable 0.98 529 5 10.9 unavailable 0.90 531 10 12.0 unavailable 0.95 535 20th 13.5 unavailable 0.96 532 30th 13.9 unavailable 0.98 530 40 13.9 unavailable 0.98 548 50 13.8 unavailable 0.97 545 60 11.9 unavailable 0.90 520 70 11.0 unavailable 0.85 485 80 10.6 unavailable 0.83 498 90 The coating solution gelled and could not be applied 951
100 / 4.5 Control a 6.0 Control b

Example 3

To the N, N'-dimethylformamide solution of the polyurethane prepared in Example 1, 40 percent by weight of thiourea, based on the weight of the polyurethane contained in the solution, was added with stirring and dissolved to prepare a coating solution. The coating solution was applied to a glass plate to a thickness of 1 mm in the same manner as in Example 1. The coated glass plate was then allowed to stand in an atmosphere having a relative humidity of 75% at 25 ° C for 5 minutes, and then it was immersed in an aqueous solution of sodium sulfate at a predetermined concentration for 10 minutes at 40 ⁰ C. Then, the glass plate with the film coagulated thereon was immersed in a warm water bath of 50 ° C. for washing. The film was pulled off the glass plate, washed with hot water for 30 minutes and ^{dried in the air at 100 °} C. for 30 minutes. The properties of the films thus obtained are shown in Table III.

Table III

concentration Moisture rWnlcronorpn in the movie Breaking strength Elongation at break of sodium sulfate permeability JVl ti IvI XJ JJ KJl CIl 1111 L 11111 (kg / mm ⁵ ) (%) in the coagulating bath (g / l) 4.8 present 0.95 510 0 10.5 unavailable 0.96 525 50 10.8 unavailable 0.96 530 100 10.7 unavailable 0.97 525 150 12.5 unavailable 0.98 520 200 12.9 unavailable 0.98 530 250 13.0 unavailable 0.97 546 300 10.5 unavailable 0.97 540 330 The salt crystallized out and the coagulating bath could not be used 350

As can also be seen from the results in Table III, the appropriate concentration of sodium sulfate is in the coagulating solution in a range from 50 to 330 g / l, preferably 200 to 300 g / l. It it was found that when the coating solution layer coagulated In a coagulating bath with a salt concentration in this area, a tough, soft film with high moisture permeability and a uniform, microporous structure was obtained.

6o

Example 4

A microporous film was prepared in the same manner as in Example 3 except that an aqueous solution containing 240 g / l sodium sulfate and thiourea was used as a coagulating bath in a concentration given in Table IV. The results are given in Table IV listed.

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Table IV

Thiourea Moisture Hfl Π V ^ AHAt ¹ AA Ii I ä * a ΒΤί Breaking strength Elongation at break concentration permeability iVLaJCrOpOrCn 1ΓΠ X ⁴ UITl (kg / mm ⁸ ) (%> in the coagulating bath
(g / l) 12.5 unavailable 0.98 53.5 0 12.6 unavailable 0.97 52.5 1 13.8 unavailable 0.96 53.6 2 13.8 unavailable 0.97 53.5 5 13.5 unavailable 0.98 54.0 10 13.8 unavailable 0.96 54.5 30th 13.9 unavailable 0.97 53.6 50 13.9 unavailable 0.95 54.0 70 12.5 unavailable 0.97 54.5 100 12.0 unavailable 0.96 53.0 130 12.0 unavailable 0.95 52.8 150 9.5 present 0.82 51.0 160

As can be seen from the results in Table IV, the appropriate concentration of thiourea is in the coagulating solution in a range from 0 to 150 g / l, preferably 0 to 100 g / l and particularly preferred 2 to 70 g / l to obtain a tough, soft, uniform and microporous film.

Example 5

In each case an N, N'-dimethylformamide solution which contained 35 percent by weight of a polyurethane of the ester type and a solution which was obtained by adding and mixing 40 percent by weight of thiourea, based on the weight of the polyurethane, in this polyurethane solution, were in a strength of 1 mm applied to a glass plate. The coated glass plate was then allowed to stand in an atmosphere having a relative humidity of 85% at a temperature of 2O ⁰ C for 3 minutes, and it was then that an inorganic into an aqueous solution (coagulating bath),

Containing salt in predetermined concentrations, ^{immersed at 40 0} C for 10 minutes. The glass plate with the film coagulated thereon was then immersed in a warm water bath at 50 ° C. for washing. The film was pulled off the glass plate, washed with hot water for 30 minutes and ^{air-dried at 100 °} C. for 3 minutes. The properties of the films obtained are shown in Table V.
As can be seen from the results in Table V, the properties of the films produced vary depending on the nature of the inorganic salt present together with the thiourea in the coagulating bath, furthermore that only with the particular inorganic salts used in the invention a uniform, microporous film with high moisture permeability can be produced. In the case of using other inorganic salts, a film with macropores is formed, the moisture permeability of which is low.

concentration
of the salt
(g / l) table 4- = present. V fracture
strain
Where) Moisture
permeability Macropores
in the slide *) Inorganic salt
in the coagulating bath 250 Thiourea
in the
Coating
solution*) fracture
strength
(kg / mm ² ) 536 4.8 + Sodium chloride 250 _ 0.84 535 13.8 - Sodium chloride 250 + 0.88 543 4.3 + Sodium sulfate 250 - 0.97 541 13.9 - Sodium sulfate 300 - | - 0.98 479 4.5 Aluminum chloride 300 - 0.81 480 11.5 - Aluminum chloride 200 0.87 375 4.3 + Aluminum sulfate 200 - 0.76 378 12.0 - Aluminum sulfate 300 0.76 517 4.5 + Ammonium chloride 300 - 0.99 518 11.0 - Ammonium chloride 350 0.99 528 4.5 4- Ammonium sulfate 350 - 1.03 528 13.4 - Ammonium sulfate 250 1.02 533 2.4 + Magnesium chloride 250 - 0.93 531 2.4 4- Magnesium chloride 200 -f 0.95 521 2.4 + Magnesium sulfate 200 - 0.92 520 2.5 + Magnesium sulfate 250 + 0.92 563 2.2 + Calcium chloride 250 - 1.06 560 2.2 + Calcium chloride 250 1.01 535 2.4 + Potassium nitrate 250 0.92 530 2.3 Calcium nitrate 250 0.93 531 4.2 -f Potassium sulfate 250 - 0.83 536 13.0 - Potassium sulfate 4- 0.89 209 530/566 *> - = not available.

Example 6

In each case a Ν, Ν'-dimethylformamide solution, which Containing 30% by weight of an ester type polyurethane, and a solution which by addition and Mixing 50 percent by weight of thiourea, based on polyurethane, in the above-mentioned polyurethane solution was produced, were applied in a thickness of 0.8 mm to the surface of a basic product with a thickness of 0.8 mm and a density of 0.51 and high gas permeability, which by joining of 28 parts of a nonwoven product (consisting of nylon 6 fibers of 1.2 denier and polyester fibers with 1.5 den) with 1.2 parts of a butadiene acrylonitrile copolymer was made, applied. The coated material was in an atmosphere with given temperature and humidity conditions for 5 minutes, and then it was immersed in an aqueous solution (at 45 ° C.) containing 250 g / l sodium sulfate for 10 minutes. Then the material with the coagulated film became

then washed thoroughly in a warm water bath at 50 ° C, and it was then in air at HO ⁰ C for 10 minutes dried.

Then, an acrylate paint for leather was used for coating the surface of this microporous polyurethane film layer sprayed on and dried. A clear nitrocellulose lacquer for leather was also applied to the Surface sprayed on for final treatment. Each of the products thus obtained was soft and glossy and gave exactly the same feel as natural leather. With regard to moisture permeability and It is excellent in strength as synthetic leather as shown in Table VI, and it has one Structure in which an evenly microporous film without macropores is firmly bonded to the basic product and is laminated.

For comparison, the same procedure was repeated with the exception that the coating solution Contained 50 percent by weight urea instead of thiourea. The result is on Listed at the end of Table VI.

Table VI Thiourea the atmosphere Relative
humidity Flexural strength Moisture
permeability Macropores
in the movie*) in the
Coating
solution*) temperature
CQ 52 no break at 200,000 bends 3.9 22nd 52 no break at 200,000 bends 8.1 - + 22nd 77 no break at 200,000 bends 4.1 - 27 77 no break at 200,000 bends 8.1 - 27 85 no break at 200,000 bends 3.8 + - 28 85 no break at 200,000 bends 8.0 - 28 93 no break at 200,000 bends 4.1 + - 25th 93 no break at 200,000 bends 8.0 - + 25th 83 no break at 200,000 bends 3.9 -f- - 35 83 no break at 200,000 bends 8.1 - + 35 85 no break at 200,000 bends 3.9 urea 28 - = present. ♦) - = not present. H

Example 7

Synthetic leather was produced in the same manner as in Example 6 except that an aqueous solution containing 250 g / l sodium sulfate and 10 g / l thiourea as a coagulating solution Instead of the aqueous solution of sodium sulfate was used. The results are in Table VII reproduced.

The synthetic leather obtained under these conditions was soft and shiny, and it had the feel made of natural leather, had high moisture permeability and high flexural strength.

Table VII

Thiourea the atmosphere Relative
humidity
(%) Flexural strength Moisture
permeability Macropores
in the movie*) in the
Coating
solution*) temperature
CQ 53 no break at 200,000 bends 3.8 25th 53 no break at 200,000 bends 9.9 - H- 25th 75 no break at 200,000 bends 3.2 + - 27 75 no break at 200,000 bends 9.8 - + 27 86 no break at 200,000 bends 4.0 -I- - 28 86 no break at 200,000 bends 9.8 - + 28 93 no break at 200,000 bends 3.8 -i- - 26th 93 no break in 200,000 beds 9.6 - T 26th 83 no break at 200,000 bends 3.9 + - 35 83 no break at 200,000 bends 9.9 - + 35 86 no break at 200,000 bends 4.5 -I- Control c-w 28

Control C-W = 50 "/" Urea (instead of thiourea) was added to the coating solution, and the thiourea

was replaced by urea in the coagulating bath. *) - = not available. + = present.

f /

Example 8

A solution which contained 25 by adding and mixing 45 percent by weight of thiourea in a N, N'-dimethylformamide ° / ₀ of a polyurethane from Estertyp, and solutions, which, based by adding and mixing 15 percent by weight of polyvinyl chloride or polyacrylic acid to the weight of the polyurethane, and 35 percent by weight of thiourea had been prepared in the above-mentioned polyurethane solution, were applied in a thickness of 0.8 mm to a mixed-spun broad fabric (# 120) made of polyester fibers and cotton. The coated material was allowed to stand in an atmosphere having a relative humidity of 85% at 25 ° C for 5 minutes, and then it was immersed in an aqueous solution at 40 ⁰ C, containing 250 g / l of sodium sulfate, immersed for 10 minutes. Then it was washed well with water and air-dried at 110 ° C for 10 minutes. The synthetic leather obtained in this way had a structure

door in which a uniform, microporous film was laminated and bound on this base material, the feel of natural leather and a high level of moisture permeability. Its properties are listed in Table VIII.

In Table VIII are also listed for comparison: Control A, in which the above Polyurethane solution was used as a coating solution and water was used as a coagulating bath; Control B, at

ίο which, in contrast to control A, is an aqueous one Solution containing 250 g / l sodium sulfate was used as a coagulating bath; and control C, at which a solution made by adding and mixing 25 percent by weight urea in the above Polyurethane solution had been prepared as a coating solution and an aqueous solution that 250 g / l sodium sulfate were used as a coagulating bath. These control samples were taken under under the same conditions as listed above.

Table VIII

Polymer in the
Coating solution Flexural strength Moisture
permeability Macropores
in the educated
Movie*) Polyurethane
Polyvinyl chloride and polyurethane
Polyacrylic acid and polyurethane
Control A
Control B
Control C no break at 200,000 bends
no break at 200,000 bends
no break at 200,000 bends
no break at 200,000 bends
no break at 200,000 bends
no break at 200,000 bends 8.5
8.5
8.4
2.0
3.5
4.5 +
+
+

·) - = not available.
- | - = present.

As can be seen from the results in Table VIII, the influence of the invention is remarkable when thiourea is contained in the coating solution and an aqueous solution of sodium sulfate as a coagulating solution is used.

Example 9

The same procedure as in Example 8 was repeated except that an aqueous solution was used was used as a coagulating bath, which contained 250 g / l sodium sulfate and 40 g / l thiourea.

The results are given in Table IX. It should be noted that controls A, B and C listed in Table IX are the same as in Example 8.

Table IX

Polymer in the
Coating solution Flexural strength Moisture
permeability Macropores
in the educated
Movie*) Polyurethane (according to the invention)
Polyurethane and polyvinyl chloride
(according to the invention)
Polyurethane and polyacrylic acid
(according to the invention)
Control A
Control B
Control C no break at 200,000 bends
no break at 200,000 bends
no break at 200,000 bends
no break at 200,000 bends
no break at 200,000 bends
no break at 200,000 bends 9.8
9.6
9.7
2.0
3.5
4.5 +
+
+

*) - = not available.
- | - = present.

As is also apparent from the results of Table IX, the effect of the invention is remarkable, when thiourea is contained in the coating solution and an aqueous solution as Coagulating bath is used, which contains sodium sulfate and thiourea.

As can also be seen from the results of the various examples listed above, after the method according to the invention does not produce a macropore in the coagulated film, even if one The solution layer coated as a film is exposed to any temperature and humidity conditions becomes, and it becomes a tough, soft, porous film with high moisture permeability and uniformity Preserve micropores.

At s ρ ι e 1 IU

A. According to the invention

30% by weight of thiourea and 3% by weight of carbon black (based on the polyurethane contained in the solution) were added with stirring to a 30% strength N.N′-dimethylformamide solution of an ester-like polyurethane to prepare a coating solution. The coating solution was applied so that it would have a thickness of about 0.6 mm on a nonwoven fabric 0.7 mm thick. The coated goods were left in an atmosphere with a relative humidity of 88% at 28 ^° C. for 5 minutes and then immersed in an aqueous solution (40 ^° C.) of sodium sulfate (220 g / l) for 20 minutes. Then the coated goods were washed with water and dried. The coagulated polymer layer had a microporous structure with micropores an average diameter of less than 5 microns, and the tensile strength was 1.1 kg / mm ² and the moisture permeability was 8.1 mg / cm ² / hr.

^B · According to the invention

The procedure of the first experiment was repeated with the exception that thiourea was also added to the coagulating bath in an amount of 12 g / l. The resulting microporous polymer layer had an average pore diameter of less than 3 microns. The tensile strength was 1.1 kg / mm ² and the moisture permeability was 8.9 mg / cm ² / h.

^C Comparative test according to the method of
French patent specification 1 565 «93

The same polyurethane solution as used in Experiment A above was 30 percent by weight (based on the polyurethane) Sodium sulfate powder with a particle size of 0.074 mm (200 mesh) added. Then the same procedure as in

Experiment A repeated. The porous polymer layer obtained consisted of a top macroporous layer (average pore diameter 100 to 350 microns), a central porous layer with conical pores (perpendicular to the surface or

as carrier material and an average of 50 to 100 microns in diameter) and a bottom layer with a pore diameter of an average of 5 to 50 microns. The tensile strength was 1.0 kg / mm ² , the moisture permeability was 3.6 mg / cm ² / h.

Claims (3)

Foil or plate as a base, the film is peeled off from it as a patent-pending film. raieniansprucne. If ^ a layer of a solution in organic solvent of film-forming polymer, 1. A method for producing film material 5 which is wholly or mainly made of polyurethane Microporous structure with a support underneath, is immersed in water, the surface becomes layer or as an unsupported film by coating the layer in contact with water quickly a fibrous or porous base material or to form a compact or dense structure a film or plate with a regulator coagulated. However, it will coagulate the inside the coagulation rate containing lion of the polyurethane layer is delayed. Hence will be Solution of a film-forming, synthetic polymer - mostly large cavities formed in the interior, sats, which is made entirely or mainly of polyurethane while the surface becomes so compact or dense, consists, dissolved in a water-miscible that it becomes difficult to obtain a uniform, microporous organic solvent, treating the loading structure to obtain the layer. The resulting layered base for coagulation of the poly 15 foil or film material as a whole has a merisats with an aqueous coagulation liquid - poor gas permeability, and it is the inorganic salt in the form of the chloride surface layer for synthetic leather is not satisfied- or making sulphates of sodium, potassium, aluminum. or contains ammonium, washing out the poly. It is already described in British Patent 981 642 or merisate film and drying and, in the case of using the film or plate as a base, in the case of the corresponding Belgian Patent 626 816 Moisture-permeable, pulling the film from the base as a carrierless, uniform, microporous film, which is used as the top film, characterized in that surface layer for synthetic leather is desired, a coating solution that is used as a regulator of coagulation speed 5 to in the mere coagulation of a polyurethane solution 25 is not obtained in water if any 90 percent by weight of thiourea, based on the following additional measures, is taken in the polymer present in the coating solution:
sat, and that if applicable also the aqueous, the chlorides or sulfates containing (a) exposure of the polymer solution layer to a Coagulating liquid additionally thiourea in a 3 ° humid atmosphere with controlled relative an amount up to 150 g / l. Humidity for a certain period of time 2. The method according to claim 1, characterized in that the layer is dipped into water; draws attention to the fact that the inorganic salt in the coagu _{(b), for example, of water or some other curing} liquid, is used in an amount of 50 to 450 g / l of solvent for the polymer in one go. 35 _fälti set amount to the polymer 3. The method of claim 1, marked _{by) dissolution to} p _o ly _me ri _S atlösung in a colloidal £! I ^M i ^ ^{e tem perature of the} coagulated »** to convert dispersion, but no gelation 30 to 60 ° C. _2U ^ _TUTsachen;