DE1569940B2 - Use of an impregnated, compressed paper as a carrier film in adhesive strips - Google Patents

Description

reinforced paper whose properties are unexpectedly improved can be obtained. It it was found that by compacting the web horizontally to its surfaces at the same time Exertion of a force acting perpendicular to the surfaces that causes a substantial ripple of the Prevents web, and impregnation or incorporation of a fiber binding agent into the web a reinforced Paper is obtained. This process and the impregnated, densified, stretchable paper made with it with high splitting resistance, the fibers of which inside are parallel to the flat surfaces of the paper compressed, distorted and anchored in themselves and made of an evenly distributed stretchable polymer Fiber means are kept in their changed position, are the subject of the German patent 11 60 293. This paper is characterized by the following properties:

1. Unexpectedly high splitting resistance at low costs or unexpectedly high cost savings at the previously usual splitting resistance.

2. Exceptional adaptability and suppleness, d. H. the paper can be smooth and Slightly curved surfaces and other three-dimensional structures nestled and smooth in different ways Shapes are applied to flat surfaces.

3. High elasticity.

4. The paper is flat and level.

5. Versatility in the properties that are directly attributable to the material used.

The subject of the invention is the use of an impregnated, compressed, stretchable paper with high splitting resistance, the fibers of which are pressed together parallel to the flat surfaces of the paper and distorted and connected by a stretchable polymeric fiber binder, as a carrier film in adhesive strips, in particular those used, for example, as masking strips in the spray painting of automobiles be used. These adhesive tapes are not only due to the unexpectedly high splitting resistance and the low cost is important, but the extraordinary adaptability and flexibility of the wearer, combined with its flat, even structure and tear resistance, enable light weight Application to curved and irregular surfaces and results in sharply defined paint lines without smudging on the edges of the adhesive tape. Thanks to its flat, level support and the The ease with which the strip can be applied is the abrasive effect on the fingers during the Application minimal.

To produce the adhesive strips, the paper backing is provided with an adhesive. As adhesives non-tacky, solvent-activatable or tacky, pressure-sensitive adhesives can be used will. Pressure-sensitive adhesives based on relatively non-polar ones are preferred Elastomers used, such as natural rubber, polyisoprene and vulcanizable elastomeric copolymers, which contain at least 40% butadiene and 10% styrene.

The adhesives can either by themselves provide the desired level of tack in the absence have additional tackifier, or known tackifiers such as rosin, hydrogenated or dehydrated resins, glycols and glycerides of such resins, polyterpenes, coumarone-indene resins, Polyalkylstyrenes, oil-soluble aldehyde resins or other adhesives can be used. The adhesive can contain inert fillers such as zinc oxide, magnesium

S carbonate, calcium carbonate, lead oxide, clay, titanium dioxide; Aluminum oxide, hydrous aluminum oxide, powdered glass, silica or any other, for normal sticky and pressure sensitive Adhesives contain common fillers. Depending on

ίο intended use for the adhesive tape Other additives such as antioxidants or pigments can also be used. Typical pressure sensitive Adhesives are described in British patent 6 11211, the USA patents 24 15 901, 24 05 926, 23 97 774 and in many other patents. Suitable, usually Non-tacky adhesives are the usual, water-activated, organic, solvent-based adhesives activated resinous adhesives, for example from

ao vinyl chloride polymers.

Optionally, a primer layer known per se, e.g. B. according to the USA patent specification 24 24 996, be attached between the paper backing and adhesive to improve adhesion. To that To facilitate the unwinding of the adhesive tape, it may be advantageous to place on the surface of the underlay, to which the adhesive is not applied, a release agent, e.g. B. that in the U.S. Patent 26 46 371 described type, to apply a Hal'lcn of the adhesive on the top of the pressure-sensitive Adhesive tape prevented.

The normally tacky and pressure-sensitive adhesive is applied to at least one side in the usual way of the reinforced paper applied.

A typical test that is used to determine that when the The strip is not split open as follows: The thumb of one hand is inserted into a cylindrical one Core on which the adhesive tape is wound. The free end of the adhesive tape goes with the other Hand gripped and quickly pulled away from the roll. During this movement, the roller is left on the free rotation of the thumb inserted in the core. It doesn't matter how fast the strip goes this way

+5 is unwound: The carrier used according to the invention is not split.

The following examples have been submitted retrospectively.

J ₀ example 1

A common absorbent crepe paper made from relatively lightly ground, bleached softwood kraft pulp fibers, is impregnated with a conventional latex of a low modulus rubber by passing the web through a bath of the impregnating agent and is passed through conventional squeegee rollers and then dried in the usual way. The impregnation is controlled so that the amount of impregnating agent adhering to the web after drying is about 25% Weight of the dry web is. The composition of the latex totaling about 27% solids is given below.

Components parts by weight

Butadiene-acrylonitrile copolymer

(72: 28) 762

Butadiene-styrene copolymer

(50:50) 182

Thermosetting phenol-formaldehyde resin 13

Butadiene-styrene copolymer

(10:90) 83

Tetrasodium salt of ethylenediamine

tetraacetic acid 7

Antioxidant 0.5

Water 551

The impregnated web is then compacted according to the method of German Auslegeschrift 11 60 293 under the conditions detailed below. Before compaction, the web is given a moisture content of about 15 to 20% of the weight of the dry impregnated web by treatment with steam, and it is then compacted to about 75% of the original length ^{at a roller temperature of about 120 ° C. in one pass.} After drying, the web represents the compressed paper to be used according to the invention. After the compression, the impregnating agent in the web is cured by exposing the web to a temperature of 193 ^° C. for about one minute in a forced-air oven. The resulting consolidated paper has unexpectedly high resistance to splitting for the small amount of impregnant it contains. It is exceptionally cuddly, very elastic and supple, flat, very tear-resistant and tensile-strength and has various other properties that make it particularly suitable as a carrier for pressure-sensitive masking tape.

The same paper web, but not creped in this case, is made in the same way as that Treated creped paper. The result is an impregnated, compressed paper that is unexpectedly high Splitting resistance and high conformability, elasticity and elongation in the same order of magnitude like the creped material, but with higher tensile strength, lower tear strength and lower Has air permeability or porosity.

Both the flat and the creped impregnated, compacted paper come in sheet form with Using a doctor blade coated with a backing material or a release agent that is in a solution of Toluene and methyl ethyl ketone (50:50) to total solids is diluted by about 31% and has the following composition:

Parts by weight

Epoxy resin 6

Polyvinyl chloride acetate copolymer

sat (87: 13) 600

High molecular weight polyester (plasticizer) 210

TiO ₂ 150

Solvent 516 240

Composition of solution 516:

27.216 kg of sorbitan monostearate
6.804 kg of toluene diisocyanate
0.142 kg of triethylamine
119.2 liters of toluene

55

60

The coated paper is ^{exposed to a temperature of 150 °} C. for about one minute in order to cure the backing layer. The backing layer obtained has a weight of about 8.5 g / m ² . The opposite sides of the sheets provided with the backing layer are then coated with a self-adhesive, which is dissolved in toluene to a solids content of about 35% and has the composition given below, using a roller applicator running in the same direction. The adhesive layer is dried and then cured by exposing it to a temperature of 193 ° C for about one minute. The self-adhesive layer obtained weighs about 68 g / m ² .

Composition of the adhesive in parts by weight

Polyisoprene 50.0

Butadiene-styrene copolymer

(77:23) 50.0

Diethylene glycol esters of dehydro-

abietic acid 109.0

p-octylphenol formaldehyde resin 19.9

Zinc oxide 55.3

2,5-di-tert-amylhydroquinone 2.2

Tetrasodium salt of ethylenediamine

tetraacetic acid 1.6

2,6-di-tert-butyl-p-cresol 2.2

Each of the on one side with the release agent and on the other side with the pressure sensitive Adhesive-coated webs are then cut to narrow widths in the usual manner, and the The self-adhesive strips obtained are wound up into rolls with the adhesive side inward.

The rolls of adhesive tape obtained from the flat and creped original webs can be inserted without Quickly unwind signs of splitting of the paper backing and apply to smooth and rough surfaces and withdraw from these again without splitting. After unwinding, both adhesive strips have one relatively high elongation, namely of more than 25%. They are also very elastic and supple. Perhaps more importantly, these adhesive tapes have the extraordinary ability to to nestle smoothly and slightly curved surfaces and other three-dimensional objects and be smoothly applied in various shapes to flat surfaces. For example, can them in relatively sharp curves with no puckering on one edge of the tape on flat surfaces be glued, and when used as a cover strip, they result in sharply delimited painted surfaces without smudging at the edges of the adhesive tape. This is mainly due to the fact that the The adhesive tape lies flat and smooth on the surface to be painted and does not curl at its edges is. Due to the smooth and flat texture, the fingers with which the strip is applied also rub only minimally. In addition, these adhesive tapes are very cheap, mainly conditional due to the small amount of impregnating agent contained in the carrier and the large variety of cheap paper types, which can be used.

Example 2

Inexpensive (13 cents / pound) absorbent paper was made with an aqueous latex in an amount impregnated so that the impregnant content after drying 15 percent by weight of the original Paper weight. This paper was then produced using the German Auslegeschrift procedure 11 60 293 compressed by 24.5% and obtained an impregnated and compressed paper, which despite the relatively small amount of binder and the cheap starting material a considerably improved

Has splitting resistance. It is extremely elastic and supple as well as supple and is particularly suitable as a carrier for cover strips. It is coated on one side with the backing layer or release agent compound according to the preceding example and heated in the manner described there in order to dry and cure the release agent layer. The backing layer obtained weighs about 10 g / m ² . As in the previous example, the other side of the paper is coated with a self-curing, pressure-sensitive adhesive, which is dissolved in toluene at a solids content of the solution of about 33%, in an amount of about 82 g / m ^2.
Composition of the self-curing adhesive in parts by weight

Polyisoprene 87.5

Butadiene-styrene mixed polymer

(77:23) 12.5

Thermoplastic terpene as a tackifying agent (melting point

315'C) 80.0

Maleic acid ester 10.0 modified with rosin

Aluminum hydrate 50.0

2,5-di-tert-amylhydroquinone 2.0

2,6-di-tert-butyl-p-cresol 2.0

Toluene diisocyanate 2.5

The self-adhesive sheet obtained is cut into strips as in the previous example, which be wound up into rolls with the adhesive side inwards. The adhesive tape will not split if it ίο is unwound quickly from the roll, and has in the ability to snuggle up to surfaces of the most varied of shapes is exceptional. He lets himself Apply even in sharp curves on flat surfaces without forming creases at the edges. If used to cover patterns with tight curvatures, leave the spray paint on achieve sharp boundaries. The cover strip described above is the in this regard Superior to commercially available adhesive tape and still considerably cheaper because it is made from much cheaper raw paper is made and a much smaller amount of binder, namely only about 15 percent by weight, the carrier is added.

509 542/379

Claims (1)

1 2 to a small extent, through the use of soft and Claim: more stretchable polymers in the impregnating agent improved will. By using soft Use of an impregnated, compacted, polymer in smooth papers will also be minor stretchable paper with high splitting resistance, 5 measures of the achievable stretchability of the finished adhesive Improved fibers parallel to the flat surfaces of the strip. However, the Andes is enough overall Paper squeezed together and distorted and the fit and conformability of a soldier a stretchable polymeric fiber binder rather, smooth paper for many purposes does not work, so are connected, as a carrier film in adhesive strips. that the carrier tears. One example is usage 10 of self-adhesive strips with paper backing to cover a painted surface on which a pattern with Curvatures and curves should be painted. So far it has been used to produce adhesive tapes with the required properties in relation to pressure-sensitive substances or self-adhesive tape 15, crack resistance, tear resistance, elasticity and with paper backing are known. In the case of stretchability, the paper is usually used as a carrier before impregnation or backing paper, it is important to crepe that. The creping can be done as a gradual the fibers are held together so tightly that the original web is pulled apart, with in Paper with sufficient splitting resistance and resistance spacings exert a force on the freely moving web has stood against plucking and does not form any cavities 20 is exercised at right angles to the plane of the web, or tears if it is kinked. For example, will be designated. This results in a downside Self-adhesive strips with paper backing usually loosen or "open" the web and the formation manufactured by having one side of the beam with one of relatively large corrugations or ridges in Glue coated and then the tape at after the web. The path is loosened or »opened«, inwardly directed adhesive side wound up into rolls 25 by inserting the superimposed fibers of the web into will. If no intermediate layer or no follower is defined, areas separated by a distance used or any other special precaution to be separated from each other in order to reduce the size and measure is gripped, the backing easily splits the number of spaces between the fabeim fast unwinding because the adhesion of the cores in these areas increase. Through this on the back the pad on the inside of the loosened or opening will have sufficient impregnability wound tape is greater than the cohesion of the created or the incorporation of such Im fibers in the document. The amount of impregnating agent enables the necessary splitting resistance to be achieved. Here is one too or to increase its Aufspaitwiderstands the high amount of the relatively expensive impregnation incorporation an impregnant which the fibers 35 means required, so this method also connects with each other. To this end, which is disadvantageous in terms of cost. various stretchable polymers, e.g. B. rubber also came; Although the mechanical method-like polymers and their mixtures are used. This of creping improves the stretchability and norma impregnation agents allow the paper for the most part a sufficient increase in absorbency, its characteristic elasticity, but bind the 4 ° to the necessary splitting-resisting fibers so tightly that the base does not stand Achieve, but has, for example, split up when, for example, a self-adhesive, creped carrier for adhesive masking strips is unwound from the roll. Usually talked about disadvantages, e.g. B. great overall thickness, sufficient reinforcement to prevent splitting of the lacquer can be achieved at the points between the webs, if it is possible to run under the belt and at the edge of the, sufficient amounts of the impregnating agent in piling up the bands, limited ability to get used to train. Usually the paper is allowed to lay curvatures and curves and become saturated with the waterproofing agent to conform to the necessary curved surfaces etc.
To achieve reinforcement. Since the costs of the impregnating agent were previously of the opinion that the base paper to the gniermittel are relatively high, this 5 ° achievement of the greatest possible splitting resistance in the method is disadvantageous. With certain adhesive tapes, it is usually not possible or even must not be relatively open with conventional absorbent papers and you want gaps between the fibers, so much impregnating agent must be present in the paper web so that the paper works properly that splitting is prevented. For these reasons and for other reasons, this method does not allow the use of large quantities of the impregnating agent. Until recently, all the relevant bodies on this Ge-solution to the problem of creating the necessary area were in agreement that splitting resistance left much to be desired. The raw paper for the production of reinforced carrier In addition to the splitting resistance or the inner or backing highly porous, very absorbent or strength, which is self-absorbent for the paper backing, have a low density and is required in its adhesive strip, the backing must also the ^6o structure must come close to the blotting paper and must have the necessary strength, elasticity and elongation, in the production of such base papers or their curves around the tape with the formation of a desired pattern on a surface before or during the impregnation The aforementioned properties can be used without tearing. In addition, the carrier must significantly change the impregnation to be so flat or even that it would completely impair the results achieved ^{on the 6 5.}
Surface to which it is applied. It has now been found that by taking the tear resistance of self-adhesive strips with paper backing in the opposite direction, that is, by compressing this type of paper in a certain way and impregnation,