Pressure-sensitive adhesive mass for low energy or rough surfaces

Patent metadata

Field	Value
Publication number	US-9683144-B2
Application number	US-201415023760-A
Country	US
Kind code	B2
Filing date	Sep 15, 2014
Priority date	Sep 27, 2013
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

Pressure-sensitive adhesive mass comprising an at least partially cross-linked polyacrylate, based on a monomer mixture comprising a) an acrylic acid ester of the formula CR 3 2 ═C(R 2 )(COOR 1 ), b) an acrylic acid of the formula CR 5 2 ═C(R 4 )(COOH), c) olefinically unsaturated monomers having at least one functional group, and d) 0 to 95 wt. % of acrylic acid ester of the formula CR 8 2 ═C(R 7 )(COOR 6 ), and 20 to 60 parts by weight of at least one tackifying resin.

First claim

The invention claimed is:

1. A pressure sensitive adhesive comprising:
an at least partly crosslinked polyacrylate based on a monomer mixture, the monomer mixture comprising
a) 5 to 100 wt. % of acrylic esters of the formula CR 3 2 ═C(R 2 )(COOR 1 ) as monomers A, where R 1 is a branched alkyl group having 16 to 22 C atoms which has at least two branching sites, R 2 is selected from the group consisting of H, methyl and halogen, and R 3 independently at each occurrence is H or halogen,
b) 0 to 20 wt. % of acrylic acid of the formula CR 5 2 ═C(R 4 )(COOH) as monomers B, where R 4 is selected from the group consisting of H, methyl and halogen, and R 5 independently at each occurrence is H or halogen,
c) 0 to 30 wt. % of olefinically unsaturated monomers having at least one functional group as monomers C, where the monomers C do not fall within the monomers A, B, and D, and
d) 0 to 95 wt. % of acrylic esters of the formula CR 8 2 ═C(R 7 )(COOR 6 ) as monomers D, where
R 6 is a linear, singly branched, cyclic or polycyclic alkyl group having 1 to 14 C atoms, R 7 is selected from the group consisting of H, methyl and halogen, and R 8 independently at each occurrence is H or halogen;
at least one tackifying resin, which is present in a proportion of 20 to 60 parts by weight per 100 parts by weight of polyacrylate.

2. The pressure sensitive adhesive as claimed in claim 1 , at least half of the monomers A including an alkyl group R 1 having three or more branching sites.

3. The pressure sensitive adhesive as claimed in claim 1 , wherein R 2 is H or methyl and R 3 is H in the monomers A.

4. The pressure sensitive adhesive as claimed in claim 1 , wherein the alkyl groups R 1 of the monomers A have a main chain on which side chains are attached at the branching sites, and at least 75% of the side chains have 2 to 4 C atoms.

5. The pressure sensitive adhesive of claim 1 , wherein the tackifying resin has an average molecular weight of less than 4000 g/mol.

6. The pressure sensitive adhesive as claimed in claim 1 , wherein the tackifying resin is selected from the group consisting of pinene resins, indene resins, and rosins, and also their disproportionate, hydrogenated, polymerized or esterified derivatives and salts; aliphatic hydrocarbon resins; alkylaromatic hydrocarbon resins; aromatic hydrocarbon resins; terpene resins; terpene-phenolic resins; C5 and C9 hydrocarbon resins, which may be at least partly hydrogenated; natural resins; and combinations thereof.

7. The pressure sensitive adhesive as claimed in claim 1 , wherein the tackifying resin has a DACP of greater than 0° C.

8. The pressure sensitive adhesive as claimed in claim 1 , wherein the tackifying resin has a DACP of less than −20° C.

9. The pressure sensitive adhesive as claimed in claim 1 , wherein R 6 in the monomers D is selected from the group consisting of methyl, ethyl, propyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, lauryl, and the branched isomers thereof; cycloalkyl groups and polycyclic alkyl groups, the cycloalkyl groups and polycyclic alkyl groups optionally being substituted by alkyl groups, halogen atoms or cyano groups; and combinations thereof.

10. The pressure sensitive adhesive as claimed in claim 1 , wherein the monomer mixture comprises a proportion of at least 80 wt. % of monomers A or of at least 80 wt. % of the monomers A and D together.

11. The pressure sensitive adhesive as claimed in claim 10 , wherein the tackifying resin is present in a proportion of at least 40 parts by weight per 100 parts by weight of polyacrylate.

12. The pressure sensitive adhesive as claimed in claim 1 , wherein the monomer mixture comprises a proportion of monomers A of up to 40 wt. %.

13. The pressure sensitive adhesive as claimed in claim 1 , wherein the monomer mixture comprises a proportion of 0.01 to 10 wt. % of monomers B and/or of 0.01 to 20 wt. % of monomers C.

14. A method for producing a pressure sensitive adhesive, comprising the steps of:
(A) generating a monomer mixture, the monomer mixture comprising
a) 5 to 100 wt. % of acrylic esters of the formula CR 3 2 ═C(R 2 )(COOR 1 ) as monomers A, where R 1 is a branched alkyl group having 16 to 22 C atoms which has at least two branching sites, R 2 is selected from the group consisting of H, methyl and halogen, and R 3 independently at each occurrence is H or halogen,
b) 0 to 20 wt. % of acrylic acid of the formula CR 5 2 ═C(R 4 )(COOH) as monomers B, where R 4 is selected from the group consisting of H, methyl and halogen, and R 5 independently at each occurrence is H or halogen,
c) 0 to 30 wt. % of olefinically unsaturated monomers having at least one functional group as monomers C, where the monomers C do not fall within the monomers A, B, and D, and
d) 0 to 95 wt. % of acrylic esters of the formula CR 8 2 ═C(R 7 )(COOR 6 ) as monomers D, where
R 6 is a linear, singly branched, cyclic or polycyclic alkyl group having 1 to 14 C atoms, R 7 is selected from H, methyl and halogen, and R 8 independently at each occurrence is H or halogen;
(B) polymerizing the monomer mixture to form polyacrylate;
(C) mixing the polyacrylate with at least one tackifying resin, which is used in a proportion of 20 to 60 parts by weight per 100 parts by weight of polyacrylate; and
(D) at least partly crosslinking a mixture obtained according to step (C), to form the pressure sensitive adhesive.

15. The method as claimed in claim 14 , step (B) being carried out in a solvent.

16. The method as claimed in claim 15 , the solvent in a further step (E) being removed by heating.

17. The method as claimed in claim 14 , the polyacrylate for step (C) being liquefied by heating.

18. The method as claimed in claim 14 , the crosslinking in step (D) taking place by irradiation with UV radiation, by irradiation with an ionizing radiation, thermally, or through a combination thereof.

19. A pressure sensitive adhesive produced by the method of claim 14 .

20. An adhesive tape comprising a pressure sensitive adhesive of claim 19 and a carrier, and the carrier being provided with the pressure sensitive adhesive.

21. The adhesive tape as claimed in claim 20 , the carrier being provided with the pressure sensitive adhesive by the mixture obtained according to step (C) being applied to the carrier and subsequently crosslinked in step (D).

22. A method for bonding substrates having a surface energy of less than 40 dyn/cm 2 , which comprises bonding said substrates with the pressure-sensitive adhesive of claim 19 .

Assignees

• Tesa Se

Inventors

• Ellringmann Kai
• Husemann Marc

Classifications

• C08F220/1818

  C13or longer chain (meth)acrylate, e.g. stearyl (meth)acrylate · CPC title

• C09J7/385

  Acrylic polymers · CPC title

• C09J133/06 Primary

  of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical · CPC title

• C08F220/08

  Anhydrides · CPC title

• C09J4/06 Primary

  {Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond} in combination with a macromolecular compound other than an unsaturated polymer of groups C09J159/00 - C09J187/00 · CPC title