METHOD FOR INCREASING THE ADHESIVE PROPERTIES OF PRESSURE-SENSITIVE ADHESIVE COMPOUNDS ON SUBSTRATES BY WAY OF PLASMA TREATMENT
A process increases adhesion between a layer of pressure-sensitive adhesive and a substrate, wherein the layer of pressure-sensitive adhesive has a first surface facing away from the substrate and a second surface facing toward the substrate and a third surface of the substrate. The process treats (i) the second surface of the layer of pressure-sensitive adhesive that faces toward the substrate and (ii) the third surface of the substrate with atmospheric-pressure plasma, and adhesive bonds the layer of pressure-sensitive adhesive to the third surface of the substrate.
1 . A process for increasing the-adhesion between a layer of pressure-sensitive adhesive and a substrate, wherein the layer of pressure-sensitive adhesive has a first surface facing away from the substrate and a second surface facing toward the substrate and a third surface of the substrate, the process comprising:
treating (i) the second surface of the layer of pressure-sensitive adhesive that faces toward the substrate and (ii) the third surface of the substrate with atmospheric-pressure plasma; and
adhesive bonding the layer of pressure-sensitive adhesive to the third surface of the substrate.
2 . The process according to claim 1 , further comprising a treatment atmosphere for treating the second and third surfaces, wherein the treatment atmosphere comprises
the following pure process gases, or mixtures of: N 2 , compressed air, O 2 , H 2 , CO 2 , Ar, He, ammonia, and ethylene, and, optionally, N 2 and compressed air.
3 . The process according to claim 1 , wherein
treatments of the second and third surfaces with the atmospheric-pressure plasma take place at or in the vicinity of atmospheric pressure.
4 . The process according to claim 2 , wherein
reactive aerosols are present in the treatment atmosphere or are added to the treatment atmosphere.
5 . The process according to claim 1 , wherein
the plasma is applied by of one or more nozzles.
6 . The process according to claim 1 , wherein
the plasma is applied by of a rotary nozzle, using compressed air.
7 . The process according to claim 1 , wherein
the second and third surfaces are treated immediately prior to the adhesive bonding of the layer of pressure-sensitive adhesive to the substrate.
8 . The process according to claim 3 , wherein
(i) for a treatment directly prior to the adhesive bonding, a chronological separation between the treatment and the adhesive bonding is <1 s,
(ii) for an in line treatment prior to the adhesive bonding, the chronological separation is in a first range from seconds to minutes,
(iii) for an off-line treatment, the chronological separation is in a second range from hours to days, and
(iv) for a treatment in a production process of an adhesive tape, the chronological separation is in a third range from days to months.
9 . The process according to claim 3 , wherein
wherein the treatments of the second and third surfaces comprise a first treatment and a second treatment, wherein the first treatment initially takes place, and then the second treatment takes place with chronological separation from the first treatment immediately prior to the adhesive bonding of the layer of pressure-sensitive adhesive to the substrate.
10 . The process according to claim 9 , wherein
at least one of the first and second treatments comprises a plurality of individual treatment steps.
11 . The process according to claim 1 , wherein
chronological separation between multiple treatments varies from about 0.1 s up to 1 year.
12 . The process according to claim 9 , wherein a
pretreatment of one of the second and third surfaces uses a first plasma generator, and at a subsequent juncture a different second plasma generator is used to supplement or refresh the first or second treatment.
13 . The process according to claim 3 , wherein
the treatments of the second and third surfaces are identical.
14 . The process according to claim 1 , wherein
the layer of pressure-sensitive adhesive is based on natural rubber, synthetic rubber, or polyurethanes, and the layer of pressure-sensitive adhesive is composed mostly of acrylate.
15 . The process according to claim 1 , wherein
the layer of pressure-sensitive adhesive forms a carrierless, single-layer, double-sided adhesive tape.
16 . The process according to claim 1 , wherein
the layer of pressure-sensitive adhesive has been applied on a carrier comprising a foil, a foam, a nonwoven, and/or a textile, or a viscoelastic carrier.
17 . The process according to claim 1 , wherein a
the thickness of the layer of pressure-sensitive adhesive or of the adhesive tape formed thereby is ≧20 μm and/or at most ≦1500 μm.
18 . The process according to claim 1 , wherein
the substrate is selected from steel, aluminum, polyester, PVC, PC, PE, PP, EPDM, ABS, rubber, glass, ceramic, coating materials and coatings, CEC, composite materials, wood-composite products, coated paperboard packaging materials, foils, bottles, plastics containers, packaging, and housing parts.
19 - 20 . (canceled)