DE2035975C - - Google Patents

Description

The invention relates to an improved method for producing a tough and soft polyurethane film material with high moisture permeability and a uniform microporous structure with a backing pad or as a backing-free film, using a base material or a foil or Plate with a urea compound containing solution of a film-forming, wholly or mainly polymer consisting of polyurethane in a water-miscible organic solvent coated, the coated base material with an aqueous, an inorganic salt from the group Sodium chloride, potassium chloride, aluminum chloride. Ammonium chloride, sodium sulfate, potassium sulfate, aluminum sulfate or coagulating liquid containing ammonium sulfate for coagulating the polymer treated, then the F'olymerisatfilm washes out and dries and in lalle the use of the Foil or plate as a base, peel off the film from it as a linerless foil.

If a layer of a solution in organic Solvent from film-forming polymer which consists entirely or mainly of polyurethane, is immersed in water, the surface of the layer in contact with water is shaved coagulated to form a compact or dense structure. However, the coagulation of the inside becomes

ίο the polyurethane layer delayed. Hence will be mostly large cavities formed in the interior, while the surface becomes so compact or dense, that it becomes difficult to obtain a uniform, microporous structure through the layer. The resulting Foil or film material as a whole ... has one poor gas permeability and it is unsatisfactory as a surface layer for synthetic leather.

It is in British Patent 981,642 respectively

so the corresponding Belgian patent specification 626 81f already described that a moisture-permeable, uniform, microporous film, which as a top surface layer for synthetic leather is desirable for the mere coagulation of a polyurethane solution

not obtained in water unless any of the following additional measures are taken will:

(a) Exposing the polymer solution layer to a humid atmosphere with controlled relative:

Moisture for a period of time before immersing the layer in water

(b) addition of water or other non solvent for the polymer in ^e: ner sorg

amount adjusted to the polymer solution to convert the polymer solution into a colloidal dispersion, but no gelation to cause;

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

The above-mentioned procedure (a) is described in detail in British Patent 849,155 ben. However, it is disadvantageous that a precisely regulated atmosphere is required and that a long period of time required for the coagulation of a coating film of any thickness is. In addition, not only the relative humidity but also the temperature must be adjusted and it is not easy in industrial implementation to regulate the atmosphere to homo Generous and evenly microporous films can be obtained. In addition, such films are moist controlled atmosphere more than a few hours necessary to apply a 0.6 mm thick layer of a dimethyl formamide solution with 20% polyurethane to moisten and coagulate well. It is also difficult to determine the correct degree of coagulation. The above procedure (b) is detailed

z. B. · η of French patent specification 1 225 729 be wrote. A remarkably good microscopic film is obtained after this procedure. Jedocl the resulting colloidal dispersion is used in the Her

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

to regulate gischen conditions and in particular before the actual increase of the polymer solution

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

Amount of nonsolvents to be added for this purpose, see the coating stage and the subsequent ones

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 method

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. ₁₀ 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 coating, 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

Keü Jer obtained., microporous film reduced parts according to the invention can be overcome

we; 'i. nen and that it is possible to use a sheet material or

i. but also a method of working to obtain a film, which obviously the

Hf-ielling of a foil or a film with high moisture permeability gui. is and an equal

Fe ;. permeability and with a microporous, nrkroporous structure. Even if

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

even or mainly made of polyurethane under any temperature and humidity conditions

Is exposed to polishes in water-miscible solutions, no micropores are in

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

triui-s or potassium salt is dispersed, forms on a base.

material is applied, the layered material is The method of the invention for production

ter.u in an aqueous solution of a water-soluble film material with a microporous structure

an *, organic salt coagulated and then the Ma- 30 a carrier pad or as a linerless film through

tericil washed and dried ν '.td (French coating of a fibrous or porous base

Pjüntschrift 1565 893). It was also already a material or a sheet or plate with a

a procedure for the production of a foil or regulator of the coagulation speed

a film with a higher moisture permeability solution of a film-forming, synthetic poly-

and a microporous structure described, after 35 merisats, the wholly or mainly of poly-

which consists of a urethane containing a polyurethane and urea, dissolved in a water-mixed

Solution applied to a base material, the dissolvable organic solvent, treatment of the

layered material in an aqueous solution layered base for coagulation of the polymer

At least one water-soluble, inorganic or or- sate with an aqueous coagulant liquid that

Ganic salt of certain metals coagulates and inorganic salt in the form of chlorides or sulphates

then the product is washed and dried from sodium, potassium, aluminum or ammonium

(French patent 1 547 876 ', contains, washing out the Polymensatfilmes 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 (cj), the underlay as a linerless film is characterized by this.

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 work a problem that present in the coating solution polymer

in the mass production of microporous film 50 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) Di the polymer coating solution contains thio material and the immersion of the coated ma urea, it can easily and evenly terials into the coagulation bath. Hence, a layered material on the base material without any suspended solution layer will be applied to the atmosphere for a while, and exposed to the above period of time, and therefore it absorbs ^6o layered material can instantly and continuously absorb moisture from the air. This moisture absorption in a coagulating and regenerating ion has a detrimental influence on the coagulating bath, which is referred to in the following as coagulating bath in the coagulating bath, and it causes the bath to be immersed. Formation of undesirable macropores in which the above-mentioned aqueous solution consists, coagulate layer. This tendency is in particular 65 In addition, the coated Materml. remarkable when the atmospheric moisture even if the time between Aufhöher ''■; 45 ⁿ _'o relative humidity is layers and immersion coagulated in the ....><it sjhwieng very moisture in rungsbaci long.!. and even if the damp

the atmosphere is not regulated, not detrimental to water or moisture in the Affects atmosphere. The coagulation properties of the polyurethane are markedly improved.

2) In the coagulation stage, due to the synergistic Effect of the thiourea in the coating solution and of the inorganic salt in the aqueous coagulating bath, the coagulating speed the polymer solution layer regulated so that the difference between the coagulation rate on the surface of the polymer solution layer and the coagulation rate inside the layer is reduced and, moreover, the coagulation through the whole thickness of the coating solution density is effected quickly and evenly. In addition, a solidified or coagulating film can be formed with a uniform microporous structure without losing its To cause shrinkage or deformation. The remaining solvent can easily be removed from the coagulate layer washed out and extracted. The inorganic salt, the thiourea and the solvent can easily be removed in the subsequent washing step.

(3) It can be a tough and soft microporous film or a synthetic leather sheet with higher Moisture permeability, as is the case with conventional ones, can be produced.

(4) No special device is required in front of the coagulating bath. It's easy to do. The inorganic salt to be used and the thiourea to be used are both cheap and easily available.

The base material to be used in the method of the present invention is one for synthetic leather Usual base material in the form of a textile, foil-like Materials, e.g. B. a woven product, a knitted product, a "nonwoven" product, a felt or a flannel, which is made of fibers such as natural fibers, synthetic fibers or semi-synthetic fibers, consists. It is also possible to use a foam board or a sheet of paper as the base material. If desired, the film base material can be mixed with a solution or emulsion of a synthetic polymer impregnated or with a latex of a natural rubber or a synthetic rubber pre-treated to ground.

The polymer coating solution can also be applied to a solid film or plate, e.g. B. made of glass, metal or plastic.

The coating polymer solution is a solution in a water-miscible organic solvent Polymer, which consists entirely or mainly of polyurethane. According to the invention it is essential that this coating solution contains thiourea. The coating solution can also be a coloring agent, z. B. a dye or a pigment, a stabilizing agent or a reinforcing agent Material, /. 15. Fibers, asbestos, potassium carbonate or finely powdered c Kieselen.lt, included.

In practicing the invention, any of the conventional, film-forming polyurethanes, which are known per se. Generally used for the production of such a polyurethane a prepolymer prepared by adding an organic diisocyanate compound with a polyalkylene ether glycol or hydroxyl-terminated polyester is treated. The prepolymer is then by means of a chain extender, the reactive Has hydrogen atoms, chain-extended, e.g. B. diamine, diol or polyol to a polyurethane elastomer to build.

The organic diisocyanate can be an aromatic, ίο aliphatic or alicyclic diisocyanate or a Be a mixture of these, e.g. B. toluene-2,4-diisocyanate, Toluylene-2,6-diisocyanate, diphenylmethane-4,4'-diisocyanate, 1,5-naphthylene diisocyanate, hexamethylene diisocyanate or p-xylene diisocyanate. The polyalkylene ether glycol is, for example, polyethylene ether glycol, Polypropylene ether glycol, polytetramethylene ether glycol or polyhexamethylene ether glycol or a copolymer or a mixture of this.

The polyester which can be used is a polycondensate of an organic acid and a polycondensate Glycol. Preferred glycols are polyalkylene glycols such as ethylene glycol, propylene glycol and tetramethylene glycol or hexamethylene glycol, cyclic glycols such as cyclohexanediol, or aromatic glycols such as Xylylene glycol. In addition, the acid to be used can be succinic acid, adipic acid, sebacic acid or terephthalic acid.

A diamine such as hydrazine, ethylenediamine, methylenedio-chloroaniline, be used.

Optionally, a catalyst such as triethylamine, Triethylenediamine, N-ethylmorpholine, dibutyltin dilaurate or cobalt naphthenate, can be used in the manufacture of the polyurethane elastomer. In the invention, the polyurethane is used in the form of a solution. The solvent for the Polymer must be selected from organic solvents which are miscible with water and which are extracted with an aqueous solution of the inorganic salt (and thiourea) can be. Therefore, water-miscible solvents are suitable. Examples of these solvents are any of the solvents listed below or a mixture thereof: N, N'-dimethylformamide, Dimethyl sulfoxide, tetrahydrofuran, tetramethylurea, N, N'-dimethylacetamide, dioxane or butyl carbinol. In addition, all ketones, which by themselves are not good solvents are for the polyurethane, which are, however, easily miscible with the solution, e.g. B. acetone and methyl ethyl ketone, as a diluent to such an extent *: applied how they do not coagulate acidic polymer.

Optionally, a small amount of one or more of their film-forming polymers, which are soluble in the solvent, such as Vinylhomopolymcrisat.z. B. vinyl chloride, polyvinyl alcohol, polyacrylonitrile, polyacrylic ester or polyacrylic acid or copolymers of these, the above-mentioned polyurethane solution can be added. The amount of such other Polymeris.i'.c can be 2 to 40 percent by weight, based on the polyurethane.

The concentration of the polymer in the polymer solution can be in a range from 10 to 40 percent by weight, preferably 15 to 35 percent by weight.
The main 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 interior 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 of the coating solution and immersing the coated material in the coagulation bath proß 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 regulated, a film with high moisture permeability and a uniform, microporous structure can be formed. As a result of the synergistic effect of thiourea in the solution 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 small so that the coating solution layer uniform both in the inner part and in the surface lying part is coagulated and a film with a uniform, microporous structure is rapidly formed will. In addition, even if a comparatively large amount of thiourea is added 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 homogeneous or uniform, it can be easily applied to the base material, and it there are no such disadvantages as in the procedure described in Belgian patent 624 250.

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 intrusion and diffusion of water into the polymer solution layer from the coagulant bath and the solvent removal in the coagulating bath from the polymer solution layer occur at the same time, the corresponding speeds are kept in a suitable ratio. This means, that no uniform, microporous structure

ao is formed, but that super macropores are partially generated and numerous macropores directly may be formed under the surface layer if the coagulation speed is not higher than that The rate of solvent removal. It

It has been found that if the substances (additives) given below are present to adjust the rate of penetration (or rate of coagulation) of water from the coagulation bath and the rate of solvent evacuation from the polymer solution layer into the coagulation bath, satisfactory coagulation can be achieved. This is achieved by using an aqueous solution for the coagulating bath which contains the aforementioned inorganic salt. or the inorganic salt and thiourea contains. This regulates the coagulation speed of the coating solution. Thus, the difference between the Koagulierungsgeschwindigkcit in Obcrflächcnleil the Bcschichtungslösungsschicht and Koagulicrungsgeschwindigkeit inside the Bcschichtungslösungsschicht becomes small, the Beschichtungslösungsschichl is and coagulated uniformly both in the inner part in the surface portion, and it is a film r ί high moisture permeability and a uniform microporous structure rapidly educated.

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

fin Sodium sulfate I. More general Preferred salt Potassium sulfate Concen- tration 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

If the content of the inorganic salt in the coagulating bath is lower than the lower limit of the above range. will be the difference in the Coagulation speed between the surface part and the inner part of the coating solution layer large, so that it is difficult to produce a film having a uniform microporous structure will. If the amount of the salt is higher than the above upper limit, the formation of a Film with uniform micropores difficult, and at the same time there is a likelihood that Salts are 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 -'er coating solution layer high, and the solubility of the inorganic salt is noticeably reduced, 50 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 from 30 to 6O ⁰ C, preferably 40 to 55 ¹³ 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 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 will.

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, with information in parts always meaning 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 increase in weight of calcium chloride du ^ri; h j _O a predetermined area of the film sample in an atmosphere having a relative humidity of 80% at 30 ° C was determined, and the moisture permeability was determined by the weight increase (mg) per unit time (h) per unit area (cm ^J ), ie mg / h / cm ¹ . 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 upper

The surface of the film was scratched with a razor blade, and which exposed to the cut? Flat was observed with a microscope to determine the presence of macropores (10 microns or larger in average diameter).

example 1

105 parts of polyethylene adipate with an average molecular weight of 1100 and terminated with OH groups was dissolved in 200 parts of anhydrous dioxane, and this became 400 parts Given methylene bis (4-phenyl isocyanate). The solution was in a nitrogen gas stream at 80 ° C held for 2 hours and then cooled to 30 ° C. To the solution of prepolymer obtained sates, which has terminal - NCO residues were 3.7 parts of ethylene glycol and 0.02 parts of tri Ethylenediamine together with 100 parts of anhydrous dioxane added to a chain lengthening reactor to be carried out for 3 hours. The polymer solution was then cooled and poured into water to remove most of the dioxane. There

Polymer was separated off and then ^{dried at 80 °} C. under reduced pressure. The polymer was dissolved in N.N'-dimethylformamide until it had a concentration of 30 percent by weight. The viscosity of this polymer solution was 45 100 cP at 30 ° C.

This polyurethane solution with the addition of 3.5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90 and 100 ⁿ / ₀ 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 having a relative humidity of 80% at 25 ^° C., and then it was immersed in an aqueous solution containing 200 g / l of 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 off the glass plate, washed with hot water for 30 minutes to remove the solvent thoroughly and then dried in the air at 100 ° C. for 30 minutes.

For comparison, the same procedure was also repeated, with the exception that no thiourea was added was added to the coating solution and furthermore the same procedure was repeated, with the exception that that 40% urea, based on the polyurethane, was added instead of thiourea. Dic> e results are also shown in Table I.

As can be seen from Table 1, the inventive Process the appropriate amount of thiourea mixed with the polyurethane solution and is intended to be included therein, in a range of 5 to 90 percent by weight, preferably 20 to 70 percent by weight and particularly preferably 30 to 60 percent by weight. It was found that when using a polyurethane solution mixed with thiourea in such a range as a coating solution a tough and soft, evenly microporous film with high moisture permeability was obtained.

Table I.

Amount of thiourea Moisture
permeability Macropores in the film present Breaking strength
(kg / mm ¹ ) Elongation at break
(%) will 565 C /,),
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 5.1 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
110 / 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 coagulated contained 10 g / l urea instead of thiourea and, on the other hand, the coating solution contained no thiourea (control a). The same procedure was repeated with the exception that the coagulating bath contained 10 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 II.

As can be seen from Table II, even if: an aqueous solution containing both sodium sulfate and: also contains thiourea, is used for a coagulation solution, the appropriate amount of the zui Coating solution to be added thioureas; i 1 in a range from 5 to 90 percent by weight preferably 20 to 70 percent by weight and very particularly preferably 30 to 60 percent by weight. In a Such an area becomes a tough, uniformly micro-porous film with high moisture permeability receive. The effects are more noticeable with thiourea than with urea.

Table II

Amount of thiourea Moisture
permeability Macropores in the film Breaking strength
(kg / mm ² ) unavailable 0.94 Elongation at break
(7c) will 550 ( ⁰ U),
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 broken 95)
1001 4.5 Control a 6.0 Control b

H e i s ρ i c 1 3

To the example 1 he. provided N, N'-dimethylformamide solution of the polyurethane was 40 weight percent thiourea based on weight of the polyurethane contained in the solution, below Stir added and dissolved to make coating solution. The coating solution was applied in a thickness of 1 mm on a glass plate in the same way as in Example 1. The coated Glass plate was then placed in an atmosphere with a relative humidity of 75 ° / "at 25 '( allowed to stand for 5 minutes and then sit in an aqueous solution of sodium sulfate in a front given concentration for 10 minutes at 40 (immersed. Then the glass plate with the one here on coagulated 1-ilm in a warm water bath v.i 50 (J immersed for washing. The fiim wuu'u: · ■ i peeled off the glass plate, with hot water 30 mi grooves washed and in the air at KX) C wälm-ii Dried for 30 minutes. The properties of the Mi ■ ' Retaining foils are shown in Table HI *

Humidity Table III Breaking strength Bri. Hdclituini concentration permeable kit (kg / mm ² ) <7n> of sodium sulfate rVliik t'iinorcn im Γι Im in the coagulating bath 4.8 JVl d Γι I If I / V / l V> l I III! t JIIII 0.95 510 (g / l) 10.5 0.96 525 0 10.8 present 0.96 530 50 10.7 unavailable 0.97 525 100 12.5 unavailable 0.98 520 150 12.9 unavailable 0.98 530 2 (X) 13.0 unavailable 0.97 546 250 10.5 unavailable 0.97 540 300 unavailable erbad could not a become luewandt 330 unavailable 350 The salt crystallized out, and so did the coagulum

As can also be seen from the results in Table III results, the appropriate concentration of sodium sulfate in the coagulating solution is in a range from 50 to 330 g / l, preferably 200 to 300 g / l. 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 would.

Example 4

A microporous film was made in the same manner as in Example 3 except that the film was cut an aqueous solution was used as a coagulating bath, containing 240 g / l sodium sulfate and thiohaline substance in a conci specified in Table IV tration contained. The results are shown in the table.

Table IV

Thiourea Moisture
permeability Macropores in the film Breaking strength
(kg / mm =) Elongation at break
(%,) concentration
in the coagulating bath
(g / D 12.5 unavailable 0.98 53.5 0 12.6 unavailable 0.97 52.5 1 13.8 unavailable 0.96 53.6 * \
Z. 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 / i in order to obtain a tough, soft, uniform and microporous film.

Example 5

In each case a Ν, Ν'-dimethylformamide solution, which 35% by weight of an ester type polyurethane and a solution which by adding and Mixing 40 weight percent thiourea based on the weight of the polyurethane in this Polyurethane solution was applied to a glass plate in a thickness of 1 mm. the coated glass plate was then placed in an atmosphere with a relative humidity of 85% a temperature of 20 ° C for 3 minutes, and then it was poured into an aqueous Solution (coagulating bath), which is an inorganic

Containing salt in predetermined concentrations, ^{immersed at 40 °} 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 peeled from the glass plate, washed with hot water for 30 Miiu'en and dried at 100 ⁰ C for 3 minutes in air. 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 V fracture
strain
('/.) Moisture
permeability Macropores
in the slide) Inorganic salt
in d. ioagulating bath 250 Thiourea
in the
Coating
solution·) fracture
strength
(kg / mm =) 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 H- 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 + Ammonium sulfate 350 1.03 528 13.4 - Ammonium sulfate 250 + 1.02 533 2.4 H- Magnesium chloride 250 0.93 531 2.4 + Magnesium chloride 200 + 0.95 521 2.4 + Magnesium sulfate 200 - 0.92 520 2.5 H- Magnesium sulfate 250 + 0.92 563 2.2 -r- Calcium chloride 250 - 1.06 560 2.2 + Calcium chloride 250 + 1.01 535 2.4 + Calcium nitrate 250 0.92 530 2.3 H- Calcium nitrate 250 + 0.93 531 4.2 H Potassium sulfate 250 0.83 536 13.0 - Potassium sulfate + 0.89

- = not available.

+ = present.

309 607/417

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 iu a thickness of 0.8 mm on 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, ao Then the material with the coagulate film

1 °

then washed well in a warm water bath at 50 ^° C., and it was then dried in the air at 110 ° C. for 10 minutes.

Then an acrylic paint for leather was used for covering sprayed onto the surface of this microporous polyurethane film layer and dried. Further became a clear nitrocellulose lacquer for leather on the surface sprayed on for final treatment. Each of the products thus obtained was soft and shiny in appearance; gave exactly the same feel as natural leather. With regard to the moisture permeability and the 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 Ba5i? Ware 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
("/ ο) Flexural strength Moisture Macropores in the
Coating
solution*) temperature
( ⁰ C) 52 no break at 200,000 bends permeability in the movie*) + 22nd 52 no break at 200,000 bends 3.9 - - + 22nd 77 no break at 200,000 bends 8.1 4- 27 77 no break at 200,000 bends 4.1 + 4- 27 85 no break at 200,000 bends 8.1 + 28 85 no break at 200,000 bends 3.8 + 4- 28 93 no break at 200,000 bends 8.0 25th 93 no break at 200,000 bends 4.1 4- 25th 83 no break at 200,000 bends 8.0 35 83 no break at 200,000 bends 3.9 + 35 85 no break at 200,000 bends 8.1 urea 28 - = present. 3.9 ·) - = 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 In place of the aqueous reading of sodium sulfate was used. The results are in Table VII reproduced.

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

Table VII

Thiourea

in the

Coating solution *)

the atmosphere

temperature
CQ

Relative

humidity

Flexural strength

Moisture permeability

Macropores in the film *)

4-

Control-W
Control-W- ^

25th
25th
27
27
28
28
26th
26th
35
35

53 53 75 75 86 86 93 93 83 83

86 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
no break at 200,000 bends
no break in 200,000 beds
no break at 200,000 bends
no break at 200,000 bends

no break at 200,000 bends

3.8 9.9 3.2 9.8 4.0 9.8 3.8 9.6 3.9 9.9

4.5

50% urea (instead of thiourea) was added to the coating solution and the thiourea was replaced by urea in the coagulating bath.
') - = not available. 4- = present.

Example 8

A solution obtained by adding and mixing 45% by weight of thiourea in a N.N'-dimethylformamide solution containing 25% of an ester-type polyurethane, and solutions obtained by adding and mixing 15% by weight of polyvinyl chloride or polyacrylic acid, based on 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 ° C. containing 250 g / l of sodium sulfate 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 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 +
+
4-

·) - = not available.
f- = 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.

Also, as can be seen from the results of the various examples given above, according to the method of the present invention, no macropore is generated in the coagulated film even if a solution layer coated as a film is exposed to any temperature and humidity conditions, and it becomes tougher, softer, more porous Obtained film with high moisture permeability and uniform micropores.

Example 10
A. According to the invention

A 30 ° / _o by weight N, N'-Dimethylformamidiösung a esterartigen polyurethane were 30 percent by weight of thiourea, and 3 percent by weight of carbon black (based on the polyurethane contained in the solution) was added with stirring 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 fabric was left in an atmosphere of 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 1,565,893

To the same polyurethane solution as used in Experiment A above, 30 percent by weight (based on the polyurethane) sodium sulfate powder having a particle size of 0 "74 mm (200 mesh) was added. The same procedure as in Experiment A was then repeated. The resulting porous The polymer layer consisted of a top macroporous layer (average pore diameter 100 to 350 microns), a middle porous layer with conical pores (perpendicular to the surface or support and an average of 50 to 100 microns in diameter) and a bottom layer with a pore diameter of 5 to 50 on average The tensile strength was 1.0 kg / mm ² , the moisture permeability was 3.6 mg / cm ² / h.

Claims (3)

Patent claims: 1. Process for the production of film material with a microporous structure with a carrier substrate or as an unsupported film by coating a fibrous or porous base material or a film or plate with a solution containing a coagulation speed regulator a film-forming, synthetic polymer, which consists wholly or mainly of polyurethane dissolved in a water-miscible organic solvents, treating the coated substrate to coagulate the polymer with an aqueous coagulation liquid, the inorganic salt in the form of chlorides or contains sulfates of sodium, potassium, aluminum or ammonium, washing out the polymer film and drying and, if the film or plate is used as a base, peeling off of the film from the base as a carrierless sheet, characterized in that a coating solution is used as a regulator of the coagulation speed 5 to 90 percent by weight thiourea, based on the polymer present in the coating solution, contains, and that optionally also the aqueous one containing the chlorides or sulfates Coagulation fluid additionally contains thiourea in an amount up to 150 g / l. 2. The method according to claim 1, characterized in that the inorganic salt in the Koagu-Iierlösung is used in an amount of 50 to 450 g / l. 3. The method according to claim 1, characterized in that the temperature of the coagulating bath is 30 to 60 ⁰ C.