DE1594057C3 - Adhesive strips or release films with release layers based on acrylate polymers - Google Patents

Description

The invention relates to thin, flexible sheets and strips of non-porous material such as Acetate cellulose, regenerated cellulose, polyethylene terephthalate or the like, with separating layers, in particular strips, in which one side with one Layer of pressure sensitive adhesive is provided.

Self-adhesive tapes are commonly manufactured and marketed wound in rolls brought. When using the strip, it should therefore be possible to use a piece of the strip without excessive force without gluing the backing, removing the adhesive or the like from the roll, regardless of the time and conditions under which the roll of tape was stored prior to use.

For these reasons it is generally necessary to use the back of the strip as a release liner designated layer, which has the purpose of applying the forces necessary for unwinding the roll Reduce. Various types of release agents have been used in such layers. After US Pat. No. 20 32 845 wax is used in such layers. Various soaps and others Surfactants are recommended for this in US Pat. No. 2,358,831. There are also materials that - like Werner's chromium complex of Stearic acid, which is described in US Pat. No. 2,8 03,557 - polymerized after application become known. Many polymers with adhesive repellent properties have also been recommended, for example copolymers of octadecyl acrylate and acrylic acid according to US Pat. No. 2,6 07,711. According to US Pat. No. 2,985,554, silicon-containing polymers can also be used for this purpose can be used.

The greatest disadvantage of the prior art release liners was the loss of their adhesive-repellent properties with aging. In the case of a strip roll, for those at an unwind speed of about 45.7 per minute, an initial force of perhaps 567 g / cm width was necessary for unwinding, after a long period of storage an unwinding force of 1417 had to be achieved up to 2835 g / cm width or more can be used. This disadvantage occurs especially when the Strip rolls are stored at higher temperatures, such as those in the vicinity of Department store roofs during the summer months, particularly in the southern areas of the United States and other areas with hot and humid climates are expected.

The second major disadvantage of the previously known release liners is that they have a loss of adhesiveness or cause stickiness. These losses can occur in the contact between the separating layer and the Adhesive immediately or only after longer storage enter. Here, too, this state is represented by a

ίο Alterang at elevated temperatures in general A known adhesive that has an initial bond strength of 992 g / cm wide, showed an adhesive strength of only 709 g / cm after contact with the release layer. In In some cases the adhesive strength can drop to zero.

A third disadvantage of the previously known separating layers becomes apparent when a piece of adhesive tape on the rear surface of another piece of strip is attached. This type of application results in the packaging or when multiple strips of strip are used to cover a surface. The failure of one end of the strip to adhere to another section of the strip is called "flutter", while the

Upper flaps of several strip sections when covering

the appearance of a surface is called "shingles".

For a successful application of this type the Adhesive adheres tenaciously to the separating layer. This is

of course the requirement of easy unwinding of the

ίο the opposite direction of the adhesive tape from the roll. Therefore it is a general view that release liners with good unwinding properties have the property of "fluttering" and are only suitable for "clapboarding" to a limited extent or vice versa. This view is however

Fortunately, π is not generally correct. In the "Schindclung" loosens the adhesive tape, ζ. Β. by sliding relatively slowly under a low one Peeling angle, while the unwinding from a roll is very fast and at a 90 ° angle Bond strength is very much dependent on both the peeling angle and the peeling speed. For different adhesives and for different release layers are the effects of the peeling angle and speed vary widely. It turns out that with a large number

4> of adhesives with those used according to the invention Separating layer surprisingly the most favorable conditions for an unexpectedly advantageous Combination of »non-flutter« and good »shingling properties« with easy unwinding are.

Another disadvantage of most of the previously known separating layers is the fact that they are in their Effect are too specific. While one gives good results against certain adhesives, it can

ϊ5 largely against an adhesive of a different type be worthless. The release agent used according to the invention can be used against any of the many Proven adhesives with which it has been tested. According to the invention, all of these disadvantages are

bo overcame previously known strips of this type. According to the invention, a separating layer is closed that has the following unexpected combination of properties:

bi 1. With regard to the power requirement, controlled rolling the strip roll, e.g. B. neither too heavy nor too easy with improved evenness of the rolling.

2. Preservation of these properties over a long storage period under various temperatures and Humidity conditions.

3. Little tendency to decrease the tackiness of the pressure-sensitive adhesive layer of the Strip.

4. Good "anti-flutter" and "shingling" properties.

5. Many choices in the choice of pressure sensitive adhesive that can be used and yet meet all of the aforesaid properties of the adhesive tape of the invention

The difficulty in attaining these goals, at least some of which appear fundamental, cannot be emphasized enough. Pressure sensitive adhesives are necessarily semi-liquid in nature in order to achieve adhesion with little or no pressure. They are mixtures of different substances and heterogeneous in their phase structure, especially on the surface that is in contact with the release layer. The production of the release agent film, which ^{weighs perhaps only 0.034 g / m 2} and is a few molecules thick alone, is obviously the most difficult one there it must maintain its cinematic integrity as well as high face orientation while exposed to the heterogeneous semi-liquid adhesive. It follows that the discovery of release backing sheets of the type of the present invention could not have been promoted by scientific prediction. The implication that a low energy surface is required for easy separation was roughly the level of knowledge available. An adhesive tape with the desired release properties under a variety of conditions, such as economy and all the other features of a technically valuable product, cannot be derived from technical knowledge alone.

The invention relates to adhesive strips or release films according to claim 1. From FR-PS 12 31 912 a release agent is known which consists of a tetrapolymer. This tetrapolymer has a very specific composition, the main component of which is 51% octadecyl methacrylate and 9% acrylic acid, 29% acrylonitrile and 11% methyl acrylate. The differ from this known release agent separating layers according to the invention are used considerably in that they are a copolymer of octadecylmetliiacrylate and acrylonitrile, in very specific proportions.

The pressure-sensitive adhesive strips according to the invention consist of a thin, flexible, practically non-porous support in the form of a film or sheet, a layer of a normal, tacky and pressure-sensitive adhesive on one side of the support and a release layer on the other side of the support. The release layer contains copolymers of stearyl methacrylate and acrylonitrile as release agents in proportions which are 50% by weight of stearyl methacrylate and 50% by weight of acrylonitrile to 80% by weight of stearyl methacrylate and 20% by weight of acrylonitrile. Preferably 50 wt ° / o by weight of stearyl methacrylate and 50 ^o / o by weight of acrylonitrile to 60 ° / o stearyl methacrylate and 40 wt .-% acrylonitrile are used. If the copolymer contains less than 20% by weight of acrylonitrile, the advantages sought by the invention cannot be realized. The term stearyl methacrylate used here means octadecyl methacrylate or mixtures of higher alkyl methacrylates which have at least 12 carbon atoms in the molecule and which mainly consist of octadecyl methacrylate.
The separating layer can be applied to the carrier in the form of a solution, for example by pressure roller technology or by spatula technique in the case of heavy application or by any other technique that enables the separating material to be applied in the desired thickness. After application, the solvents are evaporated from the layer by air drying or in an air circulation oven or on steam-heated rollers or the like. The choice of the solid to solvent ratio depends largely on the method of application and the drying equipment available.

Aromatic hydrocarbons, ketones, esters and the like should be mentioned here as solvents which can be used. The solvents can also contain a proportion of aliphatic or naphthenic hydrocarbon solvents. In general, the solvent used, the solids content and the method of application and drying do not have any significant influence on the basic properties of the adhesive tape produced, provided, however, that uniform coverage and drying are achieved for the release agent layer. According to the invention, separating layers which weigh from 0.0339 g / m ² to 0.678 g / m ² in the dry state give excellent results. Other advantages of the invention over the prior art will become apparent from the following description, examples and claims together with the drawings.

F i g. 1 is a partial schematic view of a pressure sensitive adhesive tape according to an embodiment of the invention;

Fig.2 is a likewise schematic view of a Release film according to another embodiment of the invention;

F i g. Figure 3 is a schematic view of a fiber reinforced pressure sensitive adhesive tape in accordance with this a slightly different embodiment of the invention. The cut is made across the tape to make the to show associated layers of threads.

In Fig. Figure 1 of the drawings is a pressure sensitive adhesive tape of one embodiment of the invention shown, which contains a thin, flexible and practically non-porous carrier film 11, as well as a pressure-sensitive Adhesive layer 12 on one side and a separating layer 13 on the other side of the carrier 11. This strip is intended to be wound into a roll in the form that the pressure sensitive Adhesive layer 12 faces downwards or inwards and in each turn the underside of the adhesive layer 12 remains in intimate contact with the outer surface of the separating layer 13. As above described, when the strip is unrolled, the adhesive layer separates without any extraordinary use Forces easily from the release liner, whereby the adhesive does not stick to the release liner. A conventional one first intermediate layer, which is not shown in the drawing, can be between the carrier 11 and the Klebsiiiffschicht 12 are arranged to clean a tv, better adhesion of the adhesive layer to the carrier to back up.

Another embodiment of this invention, as shown in Figure 2, is a release liner made from

a flexible and practically non-porous carrier film 21, which according to the invention has on both sides the separating layers 22 is provided. This type of release liner is and is often referred to as a cover sheet provided, together with a self-adhesive, preferably a double-sided adhesive strip, the adhesive layers on both surfaces has to be used in such a way that the release liner the opposite layers of the adhesive strip will separate when the strip is together with the release liner is wound into a roll, not shown. In another embodiment, also not shown, the separating film has a separating layer only on the one side. This is on the adhesive layer of an adhesive strip provided with adhesive on one side or an adhesive film applied for protective purposes. Therefore, this type of products according to the invention in generally as a separating film made of a thin, flexible and practically non-porous carrier film and a release layer on one side of the support. With such a release film should For protective purposes, the release layer makes intimate contact with a normal, sticky layer of a pressure-sensitive adhesive and still have an even and easy separation of the release film from allow the adhesive layer, regardless of whether this release layer on the carrier strip itself or is applied to one or both sides of a separate release film, which is then applied to the adhesive layer an adhesive tape can be applied.

The embodiment according to FIG. 3 contains a non-porous carrier film 31 and a separating layer 32 on one side Side of support 31. The following layers are recorded on the opposite side of support 31 in FIG Arranged sequence, for example, a thin intermediate layer 33, a first, directly on the carrier Adhesive layer 34, a layer of glass threads 35 impregnated with adhesive and a final one Layer of pressure sensitive adhesive 37 disposed over the adhesive impregnated layer 36 is. The separating layer 32 has a light and relatively uniform effect without tearing off the adhesive Unwinding parts of the adhesive tape wound into a roll. The threads 35 ensure a high tensile strength and tear resistance of the adhesive tape, which is used as an insulating tape can. Specific examples of possible embodiments of the invention are given below.

example 1

49.8 g of stearyl methacrylate, 60.9 g of acrylonitrile and 1 g of benzoyl peroxide are mixed. In one provided with three necks flask of 500 cc capacity, equipped with a stirrer, a reflux condenser and a Heizmantei, 200 g of toluene to the refluxing heated from the monomer mixture are then at intervals of 15 minutes for each about 10 cc during a Time of 3 hours entered in the round-bottom flask , while the temperature drops from 112 ° C to 92 ⁰ C therein. After the reaction mixture has been kept at a temperature of 92-94 ° C for a further 2 hours, a solution of 0, 33 g of benzoyl peroxide in 33 g of toluene are supplied. The reaction mixture is then held at a temperature of 94.degree. C. to 98.degree. C. for a further 3 hours. The total reaction time is 8 hours. The product obtained has a solids content of 25.6% by weight. Its proportion of substances. which did not volatilize during heating to 204 ° C for 15 minutes at a pressure of 10 mm Hg; are, is 24.8 wt .-% and the amount de: precipitate that results from the product with the same

· -, weight of methanol can be precipitated, amount 25% by weight. The intrinsic viscosity of the precipitated polymer is determined in ethyl methyl ketone - toluo 1: 4, is 0.04 and the acrylonitrile content of the precipitated polymer determined by nitrogen determination

ίο ren is 47.1%. The result is the stearyl methacrylate content from the difference to 52.9%. The softening point is lying at 99 ° C.

This release agent solution is diluted with a toluene / methyl ethyl ketone mixture (volume ratio 3: 1) to a solids content of 2 ° / c and applied to a 2 mm glass acetate film, so that a film with a dry weight of 0.17 g / m ² is formed. The solvent is removed by heating the film to a temperature of 65 ° C. for 5 minutes. On the opposite side of the film is a coated intermediate layer, whose dry weight 0.68 g / ^m: is. After drying, an adhesive layer is applied over this, which has the following composition in terms of weight parts of solid:

Crepe rubber
Polyterpene resin FP 115 ° C
Polyterpene resin FP 40 ° C
Butylated urea formaldehyde resin

2,5-di-tert-amylhydroquinone
Zinc dibutyldithiocarbamate
p-toluenesulfonic acid

loo weight parts

lOOGew.-Part

LOG weight parts

15 parts by weight
2 parts by weight
2 parts by weight
2.95 parts by weight

After the glue has dried, the

3) Tape cut and rolled up into rolls.

The unwind adhesion is initially 189.2 g / cir Width, after storage for 6 days at 49 ° C also 189.2 g / cm width and after a 6 day period Storage at a temperature of 66 ° C 446.4 g / cn width. Whenever the expression »Abwickelhaftbaren When used in this specification in relation to an adhesive tape or a release liner, so is This means the force in grams / centimeter width that is necessary to enclose the strip or the film with a Speed of 47.7 m / min by peeling off her; End in the radial direction from a roll of the strip! or film that is wound on a freely rotatable core. The quick adhesion is initially 1.1 * and after 6 days of storage at 49 ° C. 0.86 or after (days of storage at 66 ° C. 0.83 a very sensitive measure of the drop in stickiness is determined as follows:

A piece of the adhesive tape is placed with the adhesive layer facing upwards on a horizontal surface and a tall plastic ball is rolled onto the adhesive tape at a certain angle of attack.The vertical height before which the ball is launched is determined and the distance measured by the ball Rolls along the adhesive strip until it comes to rest The value that results when the square root of the third power of the starting height in cm multiplied by 2J5 * by the distance in cm multiplied by 2 ^ that the ball rolled is referred to as quick adhesion This ratio is a constant for a given adhesive tape. The ball used is made of nitrocellulose and has a diameter of 231 cn and weighs 1.916 grams. Before use, it is cleaned with petroleum ether and

then dried. The adhesive tape is for normal acetate film adhesive tape applications, such as, for example, for mending paper, as a packaging closure and the like, excellently suited.

Example 2

100 g of toluene are ^{brought to the boil in a 500 cm 3} three-necked flask equipped with a stirrer, a reflux condenser and a heating mantle. In the boiling toluene, a mixture of 69.2 g ι o stearyl methacrylate, 41.5 g acrylonitrile and 1.0 g benzoyl peroxide in amounts of 10 ml at intervals of 15 minutes in a total of 3 hours is entered, the The temperature of the reaction mixture drops ^{from lire to 91 G C.} After the reaction mixture a further 2 hours was held at a temperature of 91-97 ⁰ C, further 0.33 g of benzoyl peroxide are added dissolved in 3.3 g toluene, v / orauf the reaction mixture for another 3 hours at a temperature of 97 - 98 ° C is held 2ii. The total reaction time is 8 hours. The product has a solids content of 45.6% by weight. The non-volatile residue remaining after heating at 204 ° C. for 15 minutes at a pressure of 10 mm Hg is 41.3% by weight.

From 76.9 g of the product, a precipitate can be obtained with 300 g of methanol, the amount of which is 44.8 % By weight of the product. The content of the product determined by nitrogen analysis Acrylonitrile is 37.5% by weight and that by difference law The determined content of stearyl methacrylate is 62.5% by weight. The at 30 ° C in a solvent that consists of toluene and methyl ethyl ketone in a volume ratio of 4: 1, certain intrinsic viscosity of the with Methanol obtained precipitate is 0.11. The softening point is 74 ° C.

The adhesive tape is produced as in example 1, only the release agent used in example being replaced by the release agent obtained according to this example 2. The adhesiveness of the strip during rolling is initially 200.9 g / cm width, g 6tägiger after storage at 49 ⁰ C 457.6. The rapid adhesion is initially 3.8, after 6 days of storage at 49 ° C it is 4.2, and 3.6 after 6 days of storage at 66 ° C. The adhesive tape is very suitable for mending and sealing.

Example 3

A release agent is prepared as follows: In a 751 stainless steel vessel, which is provided with such a cooler and a stirrer, 18.0 kg of toluene are introduced and brought to boiling a mixture of 1 1 kg of stearyl methacrylate, 8.9 kg of acrylonitrile and 0.18 kg of azo-bis-isobutyronitrile is introduced into the reaction vessel over a period of about 3 hours at a rate of 0.11 kg / minute, while the temperature gradually ^{falls from 110 °} C. to 90 ^° C. The temperature is then again increased and maintained during the further reaction time 96- 100 ⁰ C. Two hours after the end of the addition eo of the monomer-catalyst mixture, a further 0.06 kg of azobisisobutyronitrile dissolved in 03 kg of toluene are added. The heating of the reaction mixture is then continued for a further 3 hours. After a total reaction time of 8 hours , 363 kg of toluene are introduced into the reaction vessel in order to cool the product and adjust it to a suitable viscosity.

The solids content of the product is 25.2% by weight, the non-volatile residue remaining after 15 minutes of heating at 204 ° C. at a pressure of 10 mm Hg is 24.2% by weight g of methanol precipitate a precipitate which, when dried, makes up 24.5% by weight of the product. The viscosity at 26 ° C. is 98 centipoise (determined according to Brookfield, with spindle No. 1 and 60 RPM). The softening point of precipitated with methanol, the precipitate is 85 ° C, its intrinsic viscosity measured in methyl ethyl ketone - toluene mixture in the volume ratio 1: 3 at a temperature of 3O ⁰ C, is 0.131, and its average molecular weight is 5840. Its detected by determination of nitrogen content of acrylonitrile is 45.5% by weight and the stearyl methacrylate content calculated as the difference is 54.5% by weight. The release agent is diluted with a toluene / methyl ethyl ketone mixture in a volume ratio of 3: 1 to form a 2% solution and applied to a 1.5 mm cellulose acetate film using a paint roller in such quantities that, after drying, a layer with a dry weight of 0 , 12 g / m ² results. At the same time, an intermediate layer with a dry weight of 0.47 g / m ^{2 is applied to the opposite side of the film.} After steam drying, an adhesive layer is applied to the intermediate layer, which has the following composition:

Crepe rubber

Styrene-butadiene copolymer

Aluminum hydrate

2,6-m-toluylene diisocyanate

Modified with rosin

Phenol-formaldehyde resin,

M.p. 150 ° C

2,5-di-tert-amyl-hydroquinone

Di-tert-butyl-p-cresol

Zinc dibutyl dithiocarbamate

Polyterpene resin m.p. 115 ° C

87.5 parts by weight

12.5 parts by weight

50.0 parts by weight

2.2 parts by weight

10.0 parts by weight
2.0 parts by weight
2.0 parts by weight
2.5 parts by weight

80.0 parts by weight

This adhesive is applied from a solution containing 28% by weight of solids in toluene with a dry weight of 25.4 g / m ² . 25 parallel threads of 150-1 / 0 glass yarn are then arranged per cm width on this adhesive layer, which are covered with a further layer of 37.7 g / m ² dry weight of the above-mentioned adhesive, which is in the form of a 22% by weight solid containing solution is applied.

A layer of the adhesive mentioned below , dissolved in toluene, is then applied to a release paper protected with silicone at a dry weight of 50.85 g / m2 :

Light creped natural rubber 100 parts by weight Phenol modified Polyterpene resin M.P. 115 ° C 40 parts by weight Glycol ester of a hydrogenated Resin m.p. 80 ° C 30 parts by weight Polyterpene resin F. P. 40 ° C 2 parts by weight

oil-soluble, thermosetting

Phenolic resin 5 parts by weight Zinc resin 5 parts by weight Zinc dibutyl dithiocarbamate 1 part by weight W-Di-n-amyl-hydroquinone 2 parts by weight Di-pentamethylene thiuram

tetrasulfide 1 part by weight

This layer is dried with removal of the solvent and at a temperature of 176 ° C 45 Cured seconds. The layer is then applied to the previously prepared carrier in order to Removal of the backing paper provided with a silicone coating to form the last adhesive layer. Of the resulting adhesive tape, as shown in FIG. 3 is shown schematically, coincides, is cut and wound into rolls that can be easily unwound. This adhesive tape has following properties: 368.3 g / cm wide adhesive strength on steel (PSTC-I method). Rapid adhesion 53, Unwind adhesion at 45.72 m / minute of 479.88 g / cm width and a 0 ° adhesion on one Crate board of 3 hours. After aging the roll for a period of 6 days at a temperature at 66 ° C the corresponding properties are 945.96 g / cm wide steel adhesion, rapid adhesion 47.814.7 g / cm wide unwinding adhesion and 4 hours 0 ° adhesion to a box board. The 0 ° adhesion on a box board is determined by applying a 3.8 cm long and 1.27 cm wide Section of the adhesive tape on a box board, attach a 200 g weight to the end of the adhesive tape for generating a 0 ° shear force and measuring the time to tear off at 21 ° C.

The adhesive tape produced according to the above information has excellent properties for use in the packaging and can be used to close heavy cardboard boxes to keep them closed of refrigerator doors during transport, for bundling heavy objects such as wood, pipes or Automotive parts and the like. The adhesive tape adheres excellently to its own support, so that the problem of strip end detachment when more than one layer is made around a bundle does not given is. Nevertheless, the role can be unrolled with ease that it can without difficulty handle is. Example 4

A solution of the release agent is prepared by first dissolving an emulsion polymer of ethyl acrylate, styrene and methacrylic acid in methyl ethyl ketone and after its complete dissolution a solution of the release agent according to Example 3 in toluene containing 25% solids is added. The weight ratios are such that the solids ratio of the copolymer to the release agent is 1: 4 and the total solids content of the solution is 2% A coating forms with a dry weight of approximately 0.17 g / m ² . At the same time, an intermediate layer, also using a paint roller, is applied to the opposite side, which has a dry weight of about 0.68 g / m ^2. These layers are then dried on steam-heated drying rollers. An adhesive layer of toluene solution is applied over the intermediate layer and dried , which has the following composition in parts by weight:

Synthetic polyisoprene with a high cis content Polyterpene resin FP 115 ° C Polyterpene resin F. P. 125 ° C
Di-tert-butyl-p-cresol

The dry weight of this adhesive layer is 23.7 g / m ² . The tape is then cut into smaller widths and wound onto cores. The properties of this adhesive tape are as follows:

30th

50

55

Adhesive Fast Unwinding on liability adhesive Steel in speed in g / cm width g / cm width Without storage 457.56 8.0 245.52 After 6 days storage at 49 ° C 546.84 5.6 334.8 at 66 ° C 468.72 4.5 357.12 Example 5

The release agent according to Example 3 is diluted to a 2% solids solution with a toluene-methyl ethyl ketone mixture (volume ratio 3: 1) and applied to a 2 mm thick cellulose acetate film using a paint roller so that a layer with a dry weight of about 0 , 17 g / m ² is produced, which is dried over steam-heated rollers. The composition of the adhesive in parts by weight of solids is:

2 ethylhexyl acrylate-vinyl acetate copolymer
Polyvinyl ethyl ether
2,5-di-tert-amyl hydroquinone

43.3 parts by weight

25.4 parts by weight 1.3 parts by weight

The adhesive tape produced in this way is cut and wound on cores. The properties are the following:

Adhesion unwinding steel in capacity in g / cm width g / cm width

30132

290.16

Without storage

After 7 days of storage

at 49 ° C

After 14 days of storage

at 49 ° C 279.0

After 6 months of storage

at room temperature 357.12

78.12
78.12
89.28
89.28

The adhesive tape is ideal for repairing, sealing and other applications in the Packaging.

Example 6

The carrier of Example 5 provided with the release layer is provided with an intermediate layer over which a layer of the adhesive according to the following composition is drawn, which has a dry weight of ^{about 333 g / m 2}

60

parts η Heller creped 95.0 parts by weight Natural rubber Polyisoprene rubber with high 112 ^ parts by weight cis content 100.8 parts by weight 100 65 styrene-butadiene copolymer 111.0 parts by weight 30th Aluminum hydrate 3.2 parts by weight 40 lanolin 7.2 parts by weight 1 Di-tert-butyl-p-cresol

2,5-di-tert-amylhydroquinone
Polyterpene resin FP 115 ° C
Zinc resin

oil-soluble, thermosetting
Phenolic resin

Phenol modified polyterpene resin F.P. 115 "C

4.0 parts by weight

138.2 parts by weight

24.0 parts by weight

5ü, 4 weight parts 30, O weight parts

This adhesive is made from a toluene solution applied and dried. The resulting adhesive strip is cut and wound onto cores. Of the Adhesive tape has the following properties:

Adhesive- Fast- Unwind-

ability to adhere to steel in

g / cm width g / cm width

Without storage 491.04

After 7 days

Storage at 49 ° C 553.68

After 14 days

Storage at 49 ° C 446.04

0.14 111.60 0.50 178.56 0.33 178.56

The adhesive tape works very well as an electrical one Insulating and holding tape.

Example 7

The adhesive strip is produced according to Example 6, but with an adhesive layer of 37.29 g / m ² dry weight on a 1 mm polyester resin film, instead of the \ 2

Acetate cellulose film. The adhesive tape has the following Characteristics:

Adhesive fast unwinding

ability to adhere to steel in

g / cm width g / cm width

Without storage 542.52

After 7 days

Storage at 49 ° C 502.20

After 14 days

Storage at 49 ° C 513.36

0.20 145.08
0.25 312.48
0.33 323.64

This adhesive tape is also ideally suited as an electrical insulating and retaining tape in areas where the greater strength of the polyester foil serving as a carrier is useful.
There is a great variety of materials which can be used in accordance with the invention in place of the thin, flexible, non-porous carrier films. In particular, materials such as cellulose acetate, regenerated cellulose, polyethylene, polypropylene, vinyl resin films, polyesters such as polyethylene therphthalate and the like are suitable. The invention is described in detail herein, and it is further indicated how it can be put into practice. In contrast to the known prior art, it will be easy to find innumerable variations, applications, modifications and expansions of the principle on which the invention is based without departing from the scope of the invention.

1 sheet of drawings

Claims (1)

Patent claims: 1. Adhesive strips or separating foils with thin, flexible and practically non-porous carrier sheets and separating layers made of copolymers of higher Alkyl methacrylates, characterized in that the separating layers consist of a copolymer 50 to 80% by weight of octadecyl methacrylate or a mixture of alkyl methacrylates consisting predominantly of octadecyl methacrylate Contains at least 12 carbon atoms in the molecule and 50-20% by weight of acrylonitrile as a release agent. Z adhesive strips or separating foils according to spoke 1, characterized in that the separating layer has a dry weight of 0.0339 to 0.678 g / m ²