DE860044C - Printing blanket for textile rotary printing machines and process for its manufacture - Google Patents

Description

l. P. 175)

ISSUED DECEMBER 18, 1952

D10230 VII / 8c

for its manufacture

When using the known rubber printing blankets as a base for tissue to be printed, it shows It is clear that the rubber printing blankets were the usual followers, whose job it was to take over the To pick up paints running out of the fabric edge or through the fabric in order to prevent soiling of the tissue can only be replaced with good effect if it is the Printing in light shades is involved and the amount of color applied to the fabric is low. However, they are getting bigger When the amount of ink is applied to the fabric, the blanket cannot do its job because the smooth rubber surface is not able to absorb the then correspondingly larger excess of paint.

There has probably been no lack of attempts to assess the ink absorption capacity of the surface of the rubber printing blankets to increase. Nevertheless, it cannot be avoided that for certain patterns and for certain Types of fabric still have to find follower cloths use, with the costliness of their Procurement and maintenance must be accepted.

The present invention is intended to eliminate this deficiency and to create a printing blanket which offers an extremely large and extensive range of uses. Practical trials with the new printing blanket have shown that the use of followers is unnecessary will.

In tests, the aim of which was to test the strength and lifespan of rubber printing blankets To increase change in the internal structure of the printing blanket, it has been shown "that if a

Fabrics for the manufacture of which are made from linear, polymeric synthetic threads of high tensile strength and high elasticity have found use, is embedded in a vulcanized rubber layer in such a way that the Fabric forms the effective top layer, this fabric layer absorbs paint and paint when dry holds on. It was also surprisingly found that when this product was treated with water and Subsequent squeezing between the press rollers ίο the fabric also the color from between the The threads released the gaps so that it was completely clean and color-free. So the water displaced the color from the surface of the threads. In the one exposed to the crushing pressure Tissue displaced the threads due to the high elasticity and their embedding in the elastic, shape-changeable rubber compound removes the color-laden water from even the finest capillaries Gaps inside the yarn. This phenomenon, which is in sharpest contrast stands for the behavior of the natural fibers, which under the same conditions the color particles in their capillary spaces taking up and holding on was so striking that it made it necessary to have this phenomenon to follow up carefully. It was shown that the ability of yarns to produce colors from their to expel a large number of yarns made of synthetic threads is own. Fabrics made from such yarns are therefore suitable as the fabric surface of printing blankets under the prerequisite that 1. the filaments which are used to form the yarn find, have the following characteristic features: a) The yarns are made up of artificial threads Base of linear high polymers; b) the polymers form crystals; c) the polymers can be cold Ways to pull out to the final delicacy; d) the crystals are essentially lying as a result of the cold expansion oriented in the longitudinal direction of the threads; e) the polymers have low to negligible Water absorption capacity; f) the softening point of the polymers is above that for vulcanization the temperature required for the rubber and above the boiling point of water; g) the filaments are elastic and show high perfect elastic recovery; h) yarns made from such Filaments are also elastic. (Here it is not excluded that the elasticity of this Yarn is in a similar relationship to the elasticity of the filaments as it is Yarns, which are spun from natural textile fibers), and 2. the filaments within the yarn under the action of rolling pressure due to the embedding of the yarns. into an elastic, shape-changeable mass, e.g. B. a rubber layer, movement is possible.

If the effective area of a fabric with a printing blanket for textile printing machines the properties given above and this embedded in a vulcanized rubber layer is, it occurs when the printing blanket has passed through the printing press and then in a Washing device, as it is usual for printing blankets, is treated as follows: 1 ·. The ones from the pattern rollers Excess ink released is absorbed by the surface of the blanket; 2. after the passage of the blanket under the pressure point and the cessation of the pressure immediately become significant Amount of color in the spaces between the threads of the yarn on the blanket surface. sucks; 3. as soon as the first step of the washing process that now follows is the part of the loaded with the color If the printing blanket is treated with water in the washing device, this penetrates into the gaps between the threads of the yarns of the printing blanket; 4. in the subsequent pass through the ejection rollers the washing device narrows the spaces between the threads, and the water is squeezed out, taking with it the paint that had seeped into those spaces. This from the Ink expelled from the printing blanket forms a foam on the surface of the water in the roller mouth in front of the nip point of the pressure rollers.

The elastic rubber layer in which the fabric is embedded contributes significantly to the specified effect. On the one hand, this layer allows a mutual change in position of the threads as soon as the rolling pressure begins, and furthermore it supports the expelling effect of the yarn, whereby the liquid is removed from the innermost interstices g ₀ between the threads of the yarn.

It is not clear why parts of the color do not embed themselves in the fabric. The yarns of this fabric consist of many threads and it would therefore be expected under the action of the high During the printing process, small amounts of color in the innermost spaces between the Threads are pressed in and held there. Both cotton printing blankets and woolen ones If they go through the printing press several times, followers become hard and brittle, obviously because they have a filtering effect and hold back the color. For some unknown reason However, the new blanket does not act as a filter, so that the color in the spaces between the threads is not held back and therefore cannot have a destructive effect.

The use of such fabrics as the effective surface of printing blankets also results in an other respects to a surprising result. Such surfaces do not become brittle and show not the effort to be under the action of the high mechanical pressure during the printing process wear out. A cotton fabric in the effective surface of the blanket becomes under the influence gradually grind the rolling pressure. The surface of a woolen fabric becomes matted quickly and disintegrates into individual layers as the felt hardens. Although the yarn consists essentially of * oriented lying artificial filaments and has an elongation at break, which in their In the order of magnitude almost the same as that of cotton and wool, those made from them are artificial Fabrics made from yarn are not destroyed, they do not break or tear under the action of the stresses acting on them, but rather counter-

are the effects of rolling pressure almost indefinitely, as tests have shown which printing blankets according to the invention are subjected to several million rolling pressure loads without cracks or damage being found.

Even though the printing blanket usually runs through between nip rollers after washing, so It is generally advisable to dry the blanket further. This is done in that the blanket is guided around heated drying cylinders. The printing blanket then arrives at this point return to the printing press in a dry condition on all sides.

It has been found that yarns made from the above-mentioned filaments when vulcanized into one Rubber layer are embedded so that they form the effective surface of the printing blanket, the following have physical properties:

i. If the surface of the thread and the thread are dry, they will absorb paint and absorb some of it into the capillary spaces between the threads; 2. It takes water to the core capillary spaces on; 3. It ejects the color from the capillary spaces again as soon as the volume of these spaces is reduced; 4. It returns to its original properties on as soon as the surface of the threads is dry; 5. the fibers return to their initial state with sufficient speed so that every time it comes back into the area of the print zone, the named process can be repeated any number of times.

The working speed of one with such a

Blanket-equipped printing press is only limited by the speed with which the finishing work on the printed fabric can be carried out. The individual patterns require more or less time to develop the Paint, drying and other manufacturing work. Usually the fastest printing speed is 175 m / min with a blanket length of 25 m, at this speed with the printing blanket according to the invention in every respect achieve perfect printing. A limitation of the printing speed of the printing machine as The consequence of using the new blanket could not be determined. Even if the new blanket was washed and dried just as quickly as any other known printing blanket, so even if these had been made as waterproof as possible, it stood out from the The reasons given above are highly advantageous over these. Even if the well-known printing blankets provided on their surface with depressions and channels for increased absorption of paint are, this does not yet penetrate into the effective surface of the printing blanket, so that the color at strong pressure from ■ the depressions is pushed out. The printer must therefore work With such printing blankets, great care is taken to adjust the contact pressure of the individual printing rollers use when he's squeezing the paint over the edge or into the bottom of the pattern

want to avoid. This setting is therefore very sensitive and depends on the respective print pattern.

The new printing blanket, on the other hand, absorbs the color into its effective surface. Its color receptivity depends only to a small extent on the tissue structure; it is essentially due to the Capillary action of the active top layer. Because the color is safely held back by this top layer the new blanket is effective in traversing ink on both the fabric edge and even through the fabric to be printed, even with major differences in the press pressure while printing. As a result, the printer can achieve a higher quality clear print pattern without to require a greater amount of time for the adjustment work of the pressure rollers than before.

According to the invention, the new printing blanket consists of a color-absorbing, effective textile top layer of synthetic high polymers of the type described later, which with an elastic Interlayer is connected. This in turn is made up of a base layer made up of several layers of canvas worn, which are glued together by a rubber solution. The individual layers of the blanket are connected to form an endless fabric in the manner known from endless drive belts, whereby the connection points of the individual layers are offset from one another. · All layers are under Pressure and heat united in an endless belt-shaped band.

In the execution examples at the end of the Description will be the penetration of the rubber of the intermediate layer through the ink-receptive top layer thereby prevents a rubber compound of such toughness for the intermediate layer It is applied that it is exposed to the greatest pressure to which the effective layer in the company is exposed is not malleable. This is achieved in particular in that on the one hand in the mass of A heat-drying resin was introduced into the rubber layer, and the underside of the Fabric made of linear synthetic polymers is coated with such a resin. That with the The printing blanket with the fabric treated in this way is only exposed to the highest pressure when the The heat-drying resin has dried so far that the rubber compound can no longer pass through the pores of the Tissue can pass through. The use of a heat-drying resin has the advantage that once the adhesiveness of the rubber interlayer to the linear polymer fabric is increased and on the other hand, the drying of this resin takes place so quickly that the duration of use is shorter Prints is only short. It is possible, as is known to the rubber expert, the rubber compound too to add other substances in order to maintain the adhesive effect of the rubber layer on the fabric made of linear polymers to increase. These funds can also be used. When using one in the heat drying resin, however, as mentioned above, two effects occur at the same time, so that the Use of such is to be given preference.

On the other hand, it is also possible to do without the additional resin. In this case there must be: Vulcanize the rubber interlayer and its bond with the fabric in two steps go yourself. Of these, the first step is to have the fabric heated and the gum mass underneath such a low pressure is applied that it does not penetrate through the pores of the tissue. If the If the rubber layer is vulcanized to the required extent ίο, the second step is to increase the pressure and the vulcanization was completed. The adherence of the fabric to the rubber layer is in this case not as high as when a drying resin has been used, but is sufficient for many uses the end.

The blanket has two effects. On the one hand it should absorb excess paint, on the other hand But it also serves as a power transmission means, because it drives the washing device and often also one Number of auxiliary devices in the printing press itself. The construction of the blanket as such is not the subject of the invention. Rather, it can depend on the particular operating conditions and depending on the one to be transferred through the blanket Power for driving the printing press accessories may be different. The one given below Construction has been found useful for a wide variety of uses. The invention however, it is not limited to this embodiment of the printing blanket because, as I said, this is only available as Embodiment is to be assessed. "What is considered an invention is characterized in the claims.

The rubber intermediate layer mentioned in the following examples forms a tough, solvent-resistant, elastic layer with excellent adhesion to the fabric of the effective top layer of the printing blanket. The individual fabric layers of the underlying supporting fabric are united by binding agents. It goes without saying for the rubber specialist that the constituents given in the description for these binders can be replaced by other, equivalent ones, without differing results being obtained. The specified vulcanization temperatures can also be changed within wide limits, depending on the composition of the rubber compound. The inventor has found a temperature range of 157 to 163 ⁰ C and a pressing pressure of about 35 kg / cm ² as particularly favorable, since this has resulted in a printing blanket of high skill and long durability, which is against the relatively high temperatures in the drying devices for the printed fabric is sufficiently resistant. However, rubber compounds can also be used which vulcanize at different temperatures and different pressures and also give good results.

For the fabrics in the effective top layer of the printing blankets, polyvinyl chloride and vinylidene chloride have become popular or copolymers, as they are on the market today, have not proven to be useful. Endless filament yarns formed therefrom solidify at such low temperatures that their use is unsuitable or unsuitable for a large number of printing blankets. Printing blankets, which are not for the heavy loads in high-performance printing machines, e.g. B. for film printing, are intended, also do not need to be guided over drying cylinders at high speed. In this case would already be made of rubber layers that vulcanize at low temperatures in connection with one. Tissue, e.g. B. made of polyvinylidene vinyl chloride, which at high temperatures, such as those in high-performance printing machines occur, brittle and damaged, will give satisfactory results as the effective area of the blanket.

Fabrics with the most varied of structures in terms of setting, yarn types and thickness were produced subjected to a test, as well as napped and non-napped fabrics as well as those made from yarns endless threads or staple fibers. Taking into account the intended use, have with regard to of the tissue structure do not reveal any significant characteristic differences. Only in terms of The fabrics made from yarns made from endless threads were superior to those made from staple fiber yarns, so that preference was given to the latter. Twill fabrics and plain weave fabrics both give the color decreases in a satisfactory manner. go Limits are drawn solely with regard to the thickness of the tissue. Namely, if the thickness of the fabric is less than 0.125 mm, then when it is used as effective area of a printing blanket, the ink absorption capacity is too low to allow the ink to be used without danger of the spreading, unless the engraving of the pressure rollers is flatter than usual will. In general, it can also be said that fabrics with a lower thread density pores that are too large than twelve threads per centimeter in warp and weft in a 210/2 thread made of polyamide threads have, so that the specific color absorbency for the square centimeter of the tissue below the required level drops.

There is also a lower limit to the thickness of the rubber-elastic intermediate layer. This may only be so small that the movement of the filaments in the yarn is still possible. So if the Thickness of the rubber layer is less than 0.125 mm, 'so it is not sufficiently able to absorb the pressing pressure from the pressure rollers. A Printing blanket with a thinner rubber layer cannot be cleaned as easily and its lifespan is too low, so that an economical operation is not possible.

The focus of the invention and its use is therefore in the presence of certain, definable physical properties and not the chemical properties of the yarn. So are . B. the condensation products of hexamethylenediamine and adipic acid chemically different from the Products made from polymerized acrylonitrile, and these in turn are chemically different from the Condensation products of polycarboxylic acids and ethylene or other glycols. But all of these substances could find use, as many of the

other known man-made resins if they are available in the form of yarn or woven fabric. It goes without saying that the fabric in the effective layer of the printing blanket is not in the May dissolve solvents for the printing ink. Most of these inks are soluble in water and most blanket washing processes also use water as a detergent. So what As far as solvability is concerned, it is a condition for

ίο normal technical uses of the blanket, that the tissue embedded in its effective surface is insoluble in water. Just one A small number of printing inks use solvents for synthetic resins in the form of aqueous emulsions.

In this case, it is necessary to use such printing blankets, which both in water as even in such solvents, are insoluble. Because of their swellability, yarns are made from cellulose esters or made of regenerated cellulose not suitable.

ao, however, provided such yarns are effective Fabric layer find use, which are so water-resistant that they are hydrophobic Can count on yarns, and which also have the physical properties mentioned earlier, fabrics made from them can be used as effective surfaces for printing blankets.

Details of the new blanket and the installation of a printing press equipped with it illustrate the drawings. In it shows

Fig. Ι the schematic cross section through the printing blanket,

Fig. 2 shows the cross section through the effective layer of the printing blanket, as it is in exemplary embodiment III is described,

3 shows the cross section through the effective layer of the printing blanket in a modified embodiment according to Examples VI and VII,

FIG. 4 is an enlarged plan view of the printing blanket according to FIG. 3;

5 shows an enlarged section through the effective tissue layer along line 5-5 of FIGS. 4 and

6 shows a schematic representation of the printing press, consisting of the actual printing unit, the blanket laundry and the dryer section with the dryer drums.

The cylindrical, heat-resistant yarns made of endless threads, e.g. B. made of polyamides are denoted by 11, while Γ2 illustrates the weft threads. The rubber-elastic intermediate layer which receives the fabric is denoted by 13, of which only a small part, denoted by 14, penetrates into the lowermost layer of the individual yarns. The base layer 10 of the printing blanket B consists in the present case of canvas (example I), but a different fabric can also be used.

A printing blanket that is particularly valuable in terms of its properties results if the one that is effective for it Layer-forming fabrics such endless threads are used, whose cross-section is about that of a Ribbons with thickened edges, which therefore have a cross-section similar to a dog's bone. Such a cross-section often results when endless threads are spun from a liquid solution and the volume of the threads decreases as the solvent dries out. In the case the thread cross-section shrinks after fixing and takes a dog-bone-like cross-section at. A typical example of this is the cross-section of the threads made of polymerized acrylonitrile. If now fabric consisting of such threads with rectangular thread crossings for the effective surface a blanket can be used and this surface against a flat plate during vulcanization is pressed from chrome or stainless steel, it is found that the threads forming the thread of a thread bundle have shifted into a lenticular cross-section so that they, even if they were previously irregular in the yarn, at least in the outer layer of the yarn, in the shape of a roof tile have superimposed. This shows. 2 shown in one after a photomicrograph schematic cross section. The warp threads 15 are shown as overlapping thread cross-sections, while the weft threads 16 can be seen in a longitudinal section. The lines 17 in cross section 15 illustrate the position of the threads in the yarn after vulcanization is complete. At 18 she is elastic Rubber interlayer. If such a fabric is removed from the vulcanizing press, go so its surface is essentially flat and smooth and has the appearance of a fabric with it perpendicular crossing threads almost lost. It looks more like a fine atlas fabric. Nonetheless the individual threads are not glued together and not embedded in a solid mass. Have the threads rather, retain their receptivity due to the spaces between them, so that the printing blanket is solely under the action of water and the pressure between rollers cleans itself. Since this printing blanket is almost flat, it is particularly suitable for printing on Silk fabrics and other fine, thin fabrics suitable without having to! this a moiré effect or an imprint of the weave of the fabric in the topsheet of the blanket.

The wear resistance of the effective printing blanket surface can be increased by incorporating small amounts of rubber into the threads of this fabric, insofar as it is not embedded in the rubber-elastic layer. This can be achieved by the fact that, after a sufficient warm-up period in which the rubber mass passes through its softening stage and changes to the elastic state, the mass is ^{exposed to a pressure of 35 kg / cm 2} as long as it is still sufficiently plastic to cope with a higher pressure to be driven through the pores of the tissue. At this point in time, the rubber compound is not yet so fluid that it completely envelops the yarn threads, but hardens everywhere where it comes into contact with hot, polished metal surfaces. The threads therefore remain rubber-free at these contact points wherever they come into contact with such metallic pressing surfaces. The result is illustrated in FIGS. 3, 4 and 5. In FIG. 3, the embeddings of

Rubber, which have penetrated to the effective surface, denoted by 19, while 21 den not suggesting embedded part of the thread. The actual rubber-elastic layer bears the reference number 22. A top view, as can be seen in a photomicrograph, is illustrated in FIG White areas 21 represent the parts of the fabric that are capable of absorbing paint, while 19 represents the rubber embedding are designated. Fig. 5 shows a section along line 5-5 of Fig. 4 after a microphotographic Recording. The yarns 21 with the characteristic dog bone cross section of the Polyacrylonitrile have rearranged themselves to the lens-shaped yarn cross-section as soon as' the blanket had been exposed to pressure and heat during vulcanization.

This makes it possible to also use polyacrylonitrile yarns to be used for printing blankets, which have high wear resistance, comparable to that is like that of polyamide yarns. The rubber pillars in the crosshairs wear out Resistance. The ink receptivity is probably a bit lower, but such a one is suitable Printing blanket for many uses. Another way to get the full penetration To prevent the fabric of the effective layer through the moldable rubber compound, consists in that the effective surface area of the fabric for which threads made of artificial linear polymers are used have found, coated with a barrier compound, the viscosity of which is so high that it is on the surface of the fabric remains and does not penetrate to the other side of the fabric. After applying a Pre-vulcanization can be essential to such a barrier compound be abbreviated, and in some cases even omitted, since the barrier masses each penetrate the rubber-elastic mass effectively prevented by the fabric. As such a barrier mass can a water-soluble, forming mass, e.g. B. Polyvinyl alcohol or a 10% solution of oxyethyl cellulose, are used. Others too Film-forming masses can be used, provided that they are used after vulcanization of the printing blanket are still water-soluble and do not become brittle during vulcanization or when used reached vulcanizing temperature and vulcanizing pressure are not destroyed or melt. The blocking compound is removed when you insert the blanket into the printing press and several Paint, without using printing ink, i.e. empty, through the washing device, in which the barrier compound is completely removed from the effective surface of the printing blanket, so that this is able to take up the textile printing inks again.

If organic colors are used, such as B. pigment colors, the color emulsions disintegrate, and a sticky resin is deposited on the blanket, which is difficult to remove from the blanket surface can be removed by washing and also from the capillary spaces between the filaments of the yarns cannot be completely removed. But even when working with them The new printing blanket can be used with organic colors and enables perfect Self-cleaning when using water to wash off the paint under rolling squeezing pressure, if a film-forming detergent is in the effective area of the printing blanket before the ink is absorbed is pressed in, which after drying leaves a film covering the surface of the thread, before the effective blanket layer comes into contact with the emulsion ink.

Fig. 6 illustrates the setup and operation of the cleaning device as used in printing with organic inks. The printing blanket 23 runs around the impression cylinder 24 and serves as a carrier for the fabric to be printed, which it passes under the actual (pattern) printing rollers 26. After leaving the printing points, the printing blanket smeared with ink runs around the washing cylinder 27, washing brushes 28 washing the ink off its surface. These washing brushes are rinsed with water through spray nozzles 29. A squeegee roller 31 cooperating with the washing cylinder 27 squeezes the water out of the printing blanket. Subsequently, the solution of a detergent is dripped onto the surface of the printing blanket by means of a drip device 32, which is fed from a storage container 33. After being squeezed out again between the washing cylinder 27 and a squeezing roller 34, the printing blanket is guided over the drying cylinder 35 and then returns to the printing press. The squeegee roller 34 can be dispensed with if the detergent is supplied directly above the rollers 27 and 31. The detergent coating that remains after squeezing out dries while the printing blanket is passed over the drying cylinders 35. Is jajJDrückiux; h_ ^ uf ^^ irj £ r__effective n surface • with such a Ühgra ^ jj-ng ^ jmhiJriRnrlf in washing means, _so_ is squeezed out of the capillary spaces between the threads as soon as the printing blanket, between rollers 27 and 31 - ^ ios passes through. Effective film-forming detergents are soap (1 ° / ₀ sodium oleate in water), Kienölemulsion, various combinations of the main constituents of soap detergents, a well-known under the name Terposol Kienölersatz as well as suspensions of bentonite and sodium pyrophosphate. When working with emulsion inks, it is particularly important to ensure that the hydrophilic detergents completely envelop the individual fibers of the yarn before a varnish-like resin deposit comes into contact with the effective surface of the printing blanket. If you observe this caution, the emulsion inks can also be removed from the blanket to your complete satisfaction.

In the following examples, two rubber compounds are described, because of their high Resistance to solvents is preferred to ordinary rubber. As already mentioned, it is recommended that the printing blanket is resistant to solvents. It is this but not always essential. For the

If solvent resistance is not absolutely necessary, a large number of rubber-like copolymers instead of the neoprene rubber preferred by the inventor and butadiene-acrylonitrile rubbers are used. These other copolymers still result in printing blankets, which can withstand the mechanical stresses in stuff printing machines have grown fully.

Example of a multi-layer carrier fabric for the printing blanket

The multi-layer base layer consists of a layer of fine cotton canvas with a thread count of 26 X 23 threads per square centimeter and several layers of fine cotton fabric made from 12-thread warp yarns, which rests against the printing cylinder. The layer resting against the printing cylinder is on one side and the other layers are coated on both sides with a binding agent based on neoprene latex, which ^{when dried} gives a thickness of 0.013 to 0.025 mm. This vulcanizable latex binder is characterized by its exceptionally high surface adhesive strength and its high resistance to solvents. After the water has been removed from the binding agent, the fabric sub-layers and the fabric layer resting against the printing cylinder are pressed together under pressure and heat to form a uniform base layer. Since the multi-layer supporting fabric is always the same in the following examples, its structure is only described once.

Example I.

A smooth fabric with a thread count of 25 X 17.7 threads per centimeter in warp and weft made of 210/2 polyamide yarn has a weight of 238 g / m2 with a thickness of 0.42 mm, is washed and at a temperature of 149 stabilized up to 177 ^{0 C.} A coating layer A is then coated on one of the two fabric surfaces.

Composition of Coating Layer A.

Weight

Phenol-formaldehyde resin 9

Ethyl alcohol 12

The phenol-formaldehyde resin is used in the

Dissolved ethyl alcohol and this solution with

Rubber adhesive 1 200

mixed.

The rubber adhesive 1 consists of

Butadiene Acrylic Nitrile Rubber 295

Zinc oxide 15

Anti-aging agent 6

Sulfur 6

Coumarone-indene resin 6p

Soot 146

Paraffin wax 9

Stearic acid 3

Accelerator 37

Propylene dichloride 2500

The dry ingredients are mixed in a mixer until they form a homogeneous gum mass, which is then dissolved in the propylene dichloride.

This adhesive is applied in several successive operations until it precipitates of dry adhesive of 0.23 kg / m² is achieved, whereupon the solvent for the adhesive Will get removed.

The top layer consists of fine cotton canvas with a thread setting of 26 χ 22.8 Threads per square centimeter and is provided with a coating layer B.

Composition of the coating layer B

Weight

Phenol-formaldehyde resin 6.4

Ethyl alcohol 20.0

The phenol-formaldehyde resin is used in the
Ethyl alcohol dissolved, and this solution
mixed with

Rubber adhesive 1 according to the above composition 354.0

So many passages are made until there is a precipitate of 0.40 kg of dry matter per square meter whereupon the solvent is removed.

The underside of the canvas is coated with an adhesive based on neoprene latex and has a dry thickness of about 0.013 mm. While this coating layer is desirable, it can be omitted. Example IV gives the construction of a printing blanket without the coating layer.

The cover layer denoted by 10 in FIG. 1 is located on the outermost layer of the multi-layer base layer B. Your with the rubber binder The surface provided here faces the top layer of the multi-layer base layer B. The those Layer 11 containing polyamide threads is then coated with the binder on the side Top layer applied. The individual layers of the printing blanket are then offset against one another The joints are connected to one another, so that an endless belt is created.

The combined layers of blanket are then brought under a belt press and each individual sections are gradually subjected to successive treatment measures.

i. The press plates are heated to 157 to 163 ° C; 2. the press is set to an initial compression pressure of below 7kg / qcm; 3. 2 minutes after the onset of the low pressing pressure, the pressing pressure is increased to 35 kg / cm²; 4. the blanket is exposed to this increased pressure at a temperature of 157 to 163 ° C for a period of 8 minutes. iao

It proves to be particularly expedient to cool the input press edges of the press plates with water keep at a lower temperature. This creates press marks on the blanket surface Avoided, provided that the parts of the printing press located in the cooler zone of the press plates

then the blanket when the pressure is applied to the subsequent unprocessed section of the printing blanket exposed to higher temperatures.

Example II

One area of the tissue according to Example I lying in the active layer is treated with the following Provide coating:

Rubber adhesive ι (composition see example I)

From this is applied several times so visl applied so that a layer with 0.28 kg of dry matter per square meter has formed on the fabric. The cotton fabric forming the top layer has a setting of 26 × 22.8 threads per centimeter in warp or weft. It receives a one-sided coating of rubber adhesive 1 up to a layer weight of dry coating mass of 0.40 kg / sqm. The other fabric surface is covered with a neoprene

ao binder coated.

The surface of this cover layer provided with the neoprene paint is applied to the supporting body of the Printing blanket and the fabric side provided with the cover is placed on the top layer. the Layer ends are joined together with mutual displacement of the joints and the so formed Printing blanket inserted in the belt press.

The pressing plates obtain a temperature from 157 to 163 ⁰ C, and the pressing pressure is initially adjusted to 3.5 kg / cm ^2. After a pressure period of 6 minutes, the pressure is increased to 35 kg / cm ^a . At this pressure and the specified temperatures, the printing blanket is vulcanized for 4 minutes. This vulcanization process is continued step by step until the entire length of the blanket is vulcanized.

Example III

The one surface of the active layer containing the synthetic threads is coated with a solution coated with the following composition:

Parts by weight of high viscosity polyvinyl alcohol 10

Water 90

'

The viscosity of this solution should be so great that it does not strike through to the other side of the tissue. It covers the outside of the threads and closes the openings between them. The other The area of the effective layer is then painted over with the rubber adhesive 1. The number of orders is to be dimensioned in such a way that a layered ceiling of 0.28 kg / m² dry matter results.

The top layer of fine canvas with a thread count of 26 X 23 per centimeter is placed on a Area covered with rubber adhesive 1 until the coating weighs 0.40 kg dry matter received per square meter.

The opposite surface of the top layer is coated with a neoprene adhesive. The composition of the layers is the same as in Example II. Vulcanization takes place at a temperature between 157 and 163 ^° C. and a pressure of 35 at Layer of the printing blanket prevented.

Example IV

The effective layer consists of a fabric made of polyacrylonitrile threads. The thread density is 26.8 warp yarns 200/2 denier and 18.1 weft yarns 200/1 denier per centimeter. The weight of the fabric is 178 g / qm, with a thickness of 0.38 mm. The yarn consists of 1.5 denier polyacrylonitrile threads, one of which 80 threads make 200 denier yarn.

This fabric is coated on one side with a solution of the following composition:

Parts by weight

Butadiene Acrylonitrile Latex 15

Chemically inactive phenol-formaldehyde resin 10

Hexamethylenetetramine 0.8

Water 43

This results in a precipitation of 0.544 kg / m² of the fabric. After the coating has dried it is obtained the coated fabric surface one more coat with a latex paint 1 up to the amount of 0.16 to 0.22 kg dry matter per square meter.

Composition of latex paint 1

Parts by weight

Neoprene latex 415

Dampening agent 2.1

Sodium silicate 3.3

Ball mill charge ¹ ) 112

Methyl cellulose 8.3

Anti-foaming agents 0.1

Water 777 "o

The dried, coated fabric is placed on the layered support layer, and in doing so the individual layers butted against one another in such a way that the joints are offset. The "5 Vulcanization takes place as in Example I.

The top layer of fine canvas which was used in Example I is not absolutely necessary. However, if it is used, it is not necessary to paint it. In its place, the top layer of the multi-layer base layer is then given a particularly strong one Binder paint, which is chemically ineffective against painting the surface layer and about 0.27 kg dry matter per square

^x ) The ball mill feed mass is composed of

Parts by weight

Zinc oxide 90

Anti-aging agents 36

Response retarder, 18

Calcium carbonate 90

Iron oxide, in pigment form as a color to facilitate testing:. . 4.5

Dispersant 4.5

Bentonite 2.5

Water I95j5

meter results. In the present example, the paint of the surface layer consists of the latex paint i.

Example V
5

The same polyacrylonitrile fabric as in Example IV is used. It is given a one-sided Paint with a paint from

Parts by weight

ίο Liquid neoprene vulcanizing compound ^x ) .. ioo

Iron catalyst (6 ° / ₀ in heavy oil) ι

Methylene bis (p-phenyl isocyanate) in orthodichlorobenzene (50% solids) ... .24

The number of coats is calculated so that the dry substance of the paint is 0.28 kg / m².

On top of the dried paint is another coat of latex paint 1 after the composition in Example IV. The layer thickness of this paint is to be dimensioned so that it is 0.28 kg Contains dry matter per square meter.

Fine canvas with a thread setting of 26x22.8 per centimeter is also used with the above Apply latex paint until the paint contains approximately 0.22 kg of dry matter per square meter. The other side is given a neoprene binder paint. The union and further treatment of the printing blanket is carried out according to Example I.

When vulcanizing fabrics with polyacrylonitrile threads, it has proven to be useful on the top of the fabric to lay a polished plate of chrome or stainless steel. Yarns, their filaments have a dog-bone-like cross-section, displace during vulcanization in the manner indicated in the introduction. The smoother the heated metallic pressing surface, which is with the When the yarn comes into contact, the smoother the surface of the printing blanket will be.

Example VI

A fabric made of 200/3 denier polyacrylonitrile yarns in warp and weft and a thread setting of 14.3 χ 12.6 strands per centimeter with a weight of 196 g / qm with a thickness of 0.37 mm is provided with a coating and with the multilayer Supporting fabric according to Example V combined. As a pressure plate for the fabric side made of polyacrylonitrile yarns a polished stainless steel plate is used. The temperature of the press plates is

¹ J The composition of the neoprene vulcanizing compound is

Parts by weight

Neoprene rubber 100

Tone 100

Dibutyl sebacate 20

Zinc oxide 5

Magnesia 4

Sodium acetate 1.5

These components become a dense rubber compound grind and this is dissolved in

Parts by weight

Toluene 225

Naphtha 75

157 to 163 ° C and the pressing pressure initially about 3.5 kg / cm ² . It is increased to 35 kg / cm ² after 1 to I ¹ Z ₄ minutes. The pressing time at this temperature is 8 ¹ Z ₂ to 9 minutes. Here, the rubber layer and the adhesive layer for the cover layer pass through the fabric. However, since the protective agent layer is sufficiently hardened during the duration of the first, low pressure effect, the rubber compound cannot completely enclose the threads, but only comes into contact with the metallic surfaces. The thread, as far as it was in contact with these metal surfaces, therefore remains free of rubber. 3, 4 and 5 illustrate the printing blanket according to this procedure. A printing blanket with characteristic features similar to those shown in Example VI can also be obtained by the following procedure:

. Example VII

The polyacryhiitrile fabric according to Example VI is obtained a one-sided coating with coating material A up to a dry weight of the layer of 0.28 kg / m2. The top layer of fine sailcloth is covered on one side with a coating of paint B to provided to a dry weight of the layer of 0.41 kg / m². The composition of these two paints corresponds to the information in Example I. The other side of the top layer is in the already described manner coated with a neoprene binder. After the paints have dried, the individual layers combined with the layers of the multi-layer base layer in the manner indicated above and vulcanized together as described in Example VI.

Example VIII

A fabric made of a polyester, formed by the reaction of benzene-p-dicarboxylic acid and ethylene glycol, with a thread setting of 12.6x11.8 threads per centimeter of a 2ro / 4-denier yarn in warp and weft is coated with a paint A to provided to a dry weight of the coating mass of 0.28 kg / m². The so treated, painted Material is then further treated according to Example I.

Claims (10)

Patent claims: i. Printing blanket for textile rotary printing machines, characterized in that it consists of a flexible, compressible multilayer carrier layer (10) and a textile top layer (11,12) is formed from such yarns, which are made of elastic, cold-drawn threads of a synthetic, linear, crystalline high polymer, which is insoluble in and impermeable to the colors used in fabric printing, and that this top layer with the carrier layer via an elastically shape-changeable intermediate layer (13) through an adhesive layer, which is also insoluble in and impermeable to water and printing inks, connected in this way is that the intermediate layer is the yarn in of the effective top layer from the side facing the carrier layer, partially encloses, so that the surface of the textile top layer as an absorbent and storage layer for the Printing ink is used. 2. Printing blanket according to claim i, characterized in that that the mass of the intermediate layer is only the smaller part of the cross-section of the yarn fills in, so that the after the effective surface ίο of the printing blanket to located yarn surfaces are available for absorbing and storing the printing ink. 3. Printing blanket according to claim 1 and 2, characterized in that the yarn of the textile top layer consists of polyamide threads. 4. Printing blanket according to claim 1 and 2, characterized in that the filaments of the yarns in the textile top layer a dog bone-like, roughly the cross-section of a ribbon with thickened edges have a corresponding cross-section. 5. Printing blanket according to claim 4, characterized in that that the threads in the textile top layer consist of polymerized acrylonitrile. 6. Printing blanket according to claim 1, 3, 4, 5, characterized characterized in that the yarns of the textile top layer face from that of the carrier layer Page encompassing mass of the elastic, shape-changeable rubber intermediate layer (22) the gaps between the threads (fabric mesh) through to the effective surface of the printing blanket is sufficient, in which the not enclosed by the rubber compound of the intermediate layer Parts of the textile thread take on the absorption and storage of the color in such a way that ink-absorbing surfaces (21) and rubber surfaces (19) evenly over the entire effective surface of the blanket are distributed and each ink-absorbing surface is surrounded by rubber compound. 7. Process for the manufacture of printing blankets according to claim 1 to 6, characterized in that the textile upper layer with one side flexible, compressible, multi-layer carrier layer over a hot-vulcanizable, in Interlayer which is insoluble in water and printing ink and impervious to water and printing ink is connected, the fluidity of the intermediate layer during hot vulcanization is so limited that this is only to a small extent into the yarn cross-section, as far as it faces the carrier layer, penetrates and the pressure and Heat treatment is continued until a uniform, hot-vulcanized printing blanket originated. ■ 8. The method according to claim 7, characterized in that the union of the textile upper layer with the carrier layer is carried out with the interposition of the intermediate layer at heat and a pressure which is below 7 kg / cm ² and is dimensioned so that the mass of the intermediate layer is not through Pores of the textile layer penetrates, which pressure is applied until the mass of the intermediate layer has become so solid under the action of pressure and heat that it no longer flows ^{when the pressure is increased to 35.16 kg / cm 2 and that} the vulcanization of the blanket is completed at the same temperature under the high pressure. 9. The method for the production of printing blankets according to claim 1 to 6, characterized in that that the textile top layer is first coated with a water-soluble detergent is provided, which covers the threads of the top layer with a film (barrier layer) and the pores (meshes of the fabric) between the textile threads are closed, this coating is then dried, with * the back of the textile top layer is a hot-vulcanizable, elastic, malleable Intermediate layer connected, the surface of the textlien provided with this intermediate layer The top layer is placed on the unvulcanized surface of the carrier layer of the printing blanket and that The whole is vulcanized together with the application of pressure and heat, whereby the barrier layer only partial penetration of the mass of the rubber intermediate layer into the interstices between the threads The side of the textile upper layer facing the carrier layer allows, whereupon after the shark vulcanization has taken place the barrier layer is removed by washing, so that the fibers in the area of the effective top layer are enabled to absorb and store color. 10. Method for the continuous cleaning of endless rucksacks according to claims n 1 to 6, __ characterized in that on the textile surface in one uninterrupted operation an aqueous solution of a film-forming detergent (blocking agent) is applied to the printing blanket squeezed out and dried and in this state the pressure point is fed to after Absorption of excess paint in a washing device by washing brushes moistened with water treated with water and freed from water and paint by roller pressure. 1 sheet of drawings © 5578 12.52