Adhesive tape, preferably self-adhesive tape, comprising of at least two layers A and B laminated directly on one another, with at least one or both layers A or B being an adhesive

Abstract

Adhesive tape having at least two layers A and B laminated directly on one another, with at least one or both layers A or B being an adhesive, and the interfaces of the layers A and B laminated on one another being subjected to a physical method, the physical method being selected from the group consisting of corona discharge, dielectric barrier discharge, flame pretreatment and plasma treatment, before the layers are laminated to one another, with the two methods differing from one another.

Claims

1. An adhesive tape, comprising at least two layers A and B laminated directly to one another, at least one or both layers A or B being an adhesive, layer B being in the form of a foam, and the interfaces of the layers A and B that are laminated to one another being subjected to a physical method, the physical method being selected from the group consisting of corona discharge, dielectric barrier discharge, flame pretreatment and plasma treatment, before the layers are laminated to one another, and the treatment applied to one of said at least two layers differing from the treatment applied to the other.

2. The adhesive tape as claimed in claim 1, wherein the interfaces laminated to one another possess an acid-base interaction or donor-acceptor interaction having been intensified or generated by the different types of physical treatments of the interfaces, one of which has been treated with an acidically modifying gas and the other having been treated with a basically modifying gas.

3. The adhesive tape as claimed in claim 1, wherein the first physical treatment is a corona treatment in air and the second physical treatment is a corona treatment in N.sub.2, the O.sub.2 content of the N.sub.2 atmosphere being <1000 ppm.

4. The adhesive tape as claimed in claim 1, wherein at least one of the layers A or B is viscoelastic.

5. The adhesive tape as claimed in claim 1, wherein the adhesive is a pressure-sensitive adhesive.

6. The adhesive tape as claimed in claim 1, wherein the layer B is an adhesive bonding component.

7. The adhesive tape as claimed in claim 1, wherein the physical methods differed with respect to the dose which was applied to each of the interfaces.

8. The adhesive tape as claimed in claim 1, wherein the treatment time for the interfaces of the layers A and B is different.

9. The adhesive tape as claimed in claim 1, wherein the physical methods differed with respect to the process selected.

10. The adhesive tape as claimed in claim 1, wherein in the case of the physical methods the following pure, or mixtures of, process gases form a treatment atmosphere: N.sub.2, O.sub.2, H.sub.2, CO.sub.2, Ar, He, ammonia, ethylene, optionally with steam or other volatile constituents being added.

11. The adhesive tape of claim 1 consisting of said two layers A and B laminated directly to one another.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates the improved long term activation on double-sided treatment of layers A&B after storage

(2) FIG. 2 illustrates the higher anchoring forces on different double-sided treatment versus single-sided treatment

(3) FIG. 3 illustrates the higher anchoring forces for different double-sided treatment versus identical double sided treatment

(4) The tables below and FIG. 1 give an overview of selected results.

(5) The denotation beneath the groups of bars shows the dose and the process gas.

(6) For the diagram and the table, the notation for the treatment should be read as follows:

(7) TABLE-US-00002 Laminate of Treatment of layer A Treatment of layer B treated layer A Dose Process Dose Process and treated layer B [Wmin/m.sup.2] gas [Wmin/m.sup.2] gas / untreated untreated 33N.sub.2/ 33 nitrogen untreated 33L/33L 33 air 33 air 100L/100L 100 air 100 air 33N.sub.2/33L 33 nitrogen 33 air 33N.sub.2/100L 33 nitrogen 100 air 100N.sub.2/33L 100 nitrogen 33 air 100N.sub.2/100L 100 nitrogen 100 air

(8) TABLE-US-00003 Laminate of treated Average value layer A and treated of anchoring layer B Measurement 1 Measurement 2 Measurement 3 force [N/cm] Lamination: immediate / 3.6 3.7 3.7 3.7 Storage: 7 days 40 C. 33 L/33 L 15.2 15.3 15.1 15.2 33 L/100 L 15.5 15.6 15.4 15.5 33 N2/ 16.3 16.3 16.0 16.2 33 N2/33 L 14.8 14.9 15.1 14.9 33 N2/33 N2 15.2 15.3 15.3 15.2 33 N2/100L 15.2 15.3 15.3 15.2 100 L/33 L 17.4 17.4 17.5 17.4 100 L/100 L 14.0 14.0 13.6 13.9 100 N2/ 17.7 17.7 17.4 17.6 100 N2/33 L 17.1 17.0 17.2 17.1 100 N2/100L 17.7 17.6 17.1 17.5

(9) TABLE-US-00004 Average 1 2 3 value Lamination: after 3 days / Storage: 7 days 40 C. 33 L/33 L 9.9 9.8 10.5 10.1 33 L/100 L 7.4 7.3 7.4 7.4 33 N2/ 13.2 12.9 12.5 12.8 33 N2/33 L 15.4 15.4 15.2 15.4 33 N2/33 N2 33 N2/100L 15.5 15.5 15.4 15.5 100 L/33 L 7.4 7.4 7.4 7.4 100 L/100 L 6.3 6.3 6.3 6.3 100 N2/ 17.8 17.7 17.6 17.7 100 N2/33 L 16.7 17.3 17.0 17.0 100 N2/100L 17.1 17.0 16.6 16.9

(10) TABLE-US-00005 Average 1 2 3 value Lamination: after 15 days / Storage: 7 days 40 C. 33 L/33 L 6.3 6.4 6.4 6.4 33 L/100 L 5.0 5.1 5.0 5.0 33 N2/ 8.6 8.5 8.4 8.5 33 N2/33 L 15.1 15.0 15.2 15.1 33 N2/33 N2 33 N2/100L 15.6 15.2 15.5 15.4 100 L/33 L 5.6 5.6 5.5 5.6 100 L/100 L 5.2 5.1 5.1 5.1 100 N2/ 15.5 14.5 15.2 15.1 100 N2/33 L 16.8 16.7 16.7 16.7 100 N2/100L 16.3 16.4 16.3 16.3

(11) TABLE-US-00006 Average 1 2 3 value Lamination: after 30 days / Storage: 7 days 40 C. 33 L/33 L 5.3 5.1 5.2 5.2 33 L/100 L 4.4 4.4 4.4 4.4 33 N2/ 7.0 7.1 7.0 7.0 33 N2/33 L 15.0 14.9 14.9 14.9 33 N2/33 N2 33 N2/100L 12.8 12.5 12.4 12.6 100 L/33 L 4.8 4.9 4.8 4.8 100 L/100 L 4.5 4.5 4.5 4.5 100 N2/ 11.4 11.1 11.4 11.3 100 N2/33 L 16.2 16.1 16.1 16.1 100 N2/100L 16.2 16.3 15.9 16.2

Comparative Example 1

Specimens 3 and 4

(12) It is found that the equal treatment of interfaces exhibits a significant drop in the anchoring forces after just three days of off-line storage.

Comparative Example 2

Specimens 5 and 8

(13) Surprisingly, however, it was possible to find in particular that with an equal dose at different kinds of treatment atmosphere, the anchoring force exhibited is virtually the same even after 30 days.

Comparative Example 3

Specimen 5 with 8

(14) Treatments with a dose the same on both sides but three times lower than in example 2 and with different process gas show a stable effect over the entire storage time period, and significantly high anchoring force values, where the skilled person would actually have expected significantly lower values.

(15) With combinations selected in a skilful way, there is a large operating window, as may be seen from the results for specimens 5, 6, 7, and 8.

Example 2

Increased Bond Strengths

(16) Surprisingly for the skilled person it was also possible to find that the anchoring force between two differently treated carriers (layer VP and layer PA) show an anchoring force which is higher overall than the carriers treated single-sidedly and treated in the same way double-sidedly.

(17) In this example the layers were treated with an indirect PlasmaLine plasma process from VITO, Belgium (PlasmaLine) in nitrogen as process gas. Via a slot nozzle, a linear atmospheric plasma is blown out via the process gas onto the carrier to be treated.

(18) Test method analogous to example 1, but layers A and B laminated immediately

Example 2a

Verification of a Higher Anchoring Force on Suitably Set Double-Sided Treatment Relative to Single-Sided Treatment

(19) In this experiment, fractions of carbon dioxide were added to the principal nitrogen process gas. As an example, a list will be given here of how the treatment parameters in the table below and FIG. 2 are to be read:

(20) TABLE-US-00007 Layer A Layer B CO.sub.2 fraction in CO.sub.2 fraction in Electrical N.sub.2 process gas Electrical N.sub.2 process gas Treatment power [W] [%] power [W] [%] 2500 W 2500 0 2500 2 0%/2500 W 2% 1000 W 0%/ 1000 0 0 0

(21) The electrical power reported is based on the treatment breadth of the discharge unit, of 400 mm.

Experimental Parameters 1

(22) TABLE-US-00008 Treatment parameters [Electrical power/CO.sub.2 content] Specimen Average values [N/cm] Layer A Layer B 1 15.0 2500 W/0% 2500 W/1% 2 15.1 2500 W/0% 2500 W/2% 3 14.4 2500 W/1% 2500 W/0% 4 14.6 2500 W/0% 1000 W/0% 5 14.7 2500 W/0% 1000 W/1% 6 15.3 2500 W/0% 1000 W/2% 7 3.5 1000 W/0% 8 6.2 1000 W/1% 9 7.6 2500 W/0% 10 10.5 2500 W/1%

(23) FIG. 2 shows significantly higher anchoring forces (left-hand axis, in N/cm) on different double-sided treatment versus single-sided treatment.

(24) The results of a different double-sided treatment versus a single-sided treatment show an increase in the anchoring force of more than 200%.

Example 2b

Verification of a Higher Anchoring Force for Suitably Set Double-Sided and Different Treatment Versus Double-Sided Identical Treatment

Experimental Parameters 2

(25) TABLE-US-00009 Treatment parameters [Electrical power/CO.sub.2 content] Specimen Average values [N/cm] Layer A Layer B 1 14.4 2500 W/0% 2500 W/0% 2 15.3 2500 W/0% 1000 W/2% 3 10.5 2500 W/1%

(26) FIG. 3 shows the higher anchoring forces for different double-sided treatment versus identical double-sided treatment.

Example 3

Equal or Higher Anchoring Force for Double-Sidedly Different Treatment with Higher Dose (or Electrical Power) Versus Double-Sidedly Different Treatment with Low-Set Dose (or Electrical Power)

(27) TABLE-US-00010 Treatment parameters [Electrical power/CO.sub.2 content] Specimen Average values [N/cm] Layer A Layer B 2 15.1 2500 W/0% 2500 W/2% 6 15.3 2500 W/0% 1000 W/2%

(28) From the table above it is apparent that the anchoring force in the case of treatments of the layers with a low electrical power or dose achieves the same or higher level as a treatment combination with high settings.

(29) Within the treatment process this allows a saving of energy, but with an equivalent anchoring force.

Example 4

Higher Anchoring Force by Combination of Air Corona and N2 Corona on Opposite Interfaces

(30) In the case of lamination of two layers using a corona treatment on both surfaces in particular it is also possible to achieve an increased integral strength if a corona with air as process gas is used on one surface, and a corona with N2 as process gas is used on the other surface.

(31) The treatment in examples 4a and 4b took place in web form with a DBD electrode configuration (Vetaphone). The differentiated treatment of the layers A and B increases the maximum force achieved.

Example 4a

Increase in the Anchoring Force Between VP and AP

(32) A particular increase in the anchoring force between layers VP and AP was generated by means of the process taught. Measurement took place by the T-peel test method, after three days of storage at 23 C. The maximum force in the T-peel test was increased by more than 180% if the treatment atmosphere for the treatment of the respective layers was differentiated.

(33) TABLE-US-00011 Treatment parameters Release VP PA force [N/cm] Dose Process gas Dose Process gas 3 d RT 33 N2 10.7 33 N2 33 N2 8.1 33 N2 33 Air 14.8

Example 4b

Increasing the Anchoring Force Between a PE Foam and AP

(34) In this example it can be seen that the specific combination of air corona and N2 corona on the interfaces to be laminated to one another can bring an advantage in the case of lamination to a PE-based foam (from Sekisui Alveo, 400 m, closed-cell). The advantage is clearly manifested especially after accelerated aging at 40 C.

(35) TABLE-US-00012 Anchoring Treatment parameters force in [N/cm], Carrier foam Adhesive PA after storage mode Dose Process gas Dose Process gas 7 d RT 7 d 40 100 Air 2.5 2.9 100 Air 50 Air 4.7 5.7 100 Air 50 N2 4.8 7.0

(36) The results demonstrated by way of example here can be understood on the basis of the comprehensively described acid-base interactions.

(37) Integrated Material System Examples

(38) Below, the invention is to be described in more detail, with reference to a number of examples, for integrated material systems, without wishing thereby to restrict the invention unnecessarily.

(39) TABLE-US-00013 Layer A Layer B open-cell and closed-cell foam acrylate adhesive carriers, especially of polyethylene and polypropylene heat-activatable tackifying resin viscoelastic carrier layer low-melting polyolefin carrier heat-activatable tackifying resin layer viscoelastic carrier viscoelastic carrier viscoelastic carrier pressure-sensitive adhesive viscoelastic carrier pressure-sensitive adhesive with a viscoelastic carrier fabric carrier synthetic rubber adhesive.sup.1 nonwoven carrier hotmelt acrylate adhesive.sup.1 polypropylene film carrier dispersion acrylate adhesive.sup.1 satinized or creped paper carrier dispersion acrylate adhesive.sup.1 injection molded parts of PE and straight acrylate adhesive.sup.1 PP, especially of PA steel pressure-sensitive acrylate adhesive .sup.1PSAs joined with a further carrier material or on a release liner

(40) It is also possible to employ materials which have themselves already obtained a physical surface modification by a process.