METHOD FOR DETACHING ADHESIVELY BONDED SUBSTRATES

Abstract

The present invention is directed to a method for detaching two substrates bonded by an adhesive, in particular by treating with a debonding agent. In addition, the present invention relates to the use of the method in recycling parts of the electronic devices. The method comprises the steps of: (1) treating two substrates bonded by an adhesive with a debonding agent comprising acetone and/or oleic acid at a temperature from 20° C. to 90° C., and (2) removing the substrates from the adhesive.

Claims

1. A method for detaching substrates bonded by an adhesive, comprising the steps of: (1) treating two substrates bonded by an adhesive with a debonding agent comprising acetone and/or oleic acid at a temperature from 20° C. to 90° C., and (2) removing the substrates from the adhesive.

2. The method according to claim 1, wherein the debonding agent further comprises at least one additive selected from water, an alkanolamine, a non-ionic surfactant, and combination thereof.

3. The method according to claim 1, wherein the debonding agent comprises at least 95% of acetone based on the weight of the debonding agent.

4. The method according to claim 1, wherein the debonding agent comprises oleic acid, water, an alkanolamine, and a non-ionic surfactant.

5. The method according to claim 1, wherein the method further comprises a step of cleaning the substrates before step (1) and/or after step (2).

6. The method according to claim 1, wherein the treating temperature in step (1) is from 20° C. to 70° C.

7. The method according to claim 1, wherein the adhesive is selected from the group consisting of epoxy resins, acrylates, and polyurethanes.

8. The method according to claim 1, wherein the substrates are each independently selected from the group consisting of metals, glass, polymers, ceramics, cork, and rubbers.

Description

EXAMPLES

Example 1 (According to the Invention)

[0059] Samples were prepared by bonding two substrates, 100 mm×25 mm at room temperature, with commercial adhesives according to Table 1. The thickness of each substrate was 1.6 mm, the bondline was 0.25 mm, and the bonding area was 25×12.5 mm overlap. Then each sample was immersed in a 5% aqueous solution of oleic acid used as the debonding agent at 60° C. for 30 minutes. After washing the debonding agent by water, substrates and adhesives were separated by an Instron tester and the tensile shear strength (TSS) was tested according to ASTM-D1002 at 23° C. and 50% humidity. The reduction ratio of the TSS compared to the values in the reference example was calculated. The test results are shown in Table 1.

Example 2 (According to the Invention)

[0060] Samples were prepared by bonding two substrates with commercial adhesives according to Table 1. The thickness of each substrate was 1.6 mm, the bondline was 0.25 mm, and the bonding area was 25×12.5 mm overlap. Then each sample was immersed in acetone (99.7% purity) used as the debonding agent at 30° C. for 30 minutes. After washing the debonding agent by water, substrates and adhesives were separated by an Instron tester and the tensile shear strength was tested according to ASTM-D1002 at 23° C. and 50% humidity. The reduction ratio of the TSS compared to the values in the reference example was calculated. The test results are shown in Table 1.

Example 3 (According to the Invention)

[0061] Samples were prepared by bonding two substrates with commercial adhesives according to Table 1. The thickness of each substrate was 1.6 mm, the bondline was 0.25 mm, and the bonding area was 25×12.5 mm overlap. Then each sample was immersed in an aqueous solution containing 1.24% triethanolamine, 0.6% oleic acid, 1.5% ethoxylated isodecanol and 0.4% ethoxylated isotridecanol used as the debonding agent at 60° C. for 30 minutes. After washing the debonding agent by water, the substrates and adhesives were separated by an Instron tester and the tensile shear strength was tested according to ASTM-D1002 at 23° C. and 50% humidity. The reduction ratio of the TSS compared to the values in the reference example was calculated. The test results are shown in Table 1.

Example 4 (Comparative Example)

[0062] Samples were prepared by bonding two substrates with commercial adhesives according to Table 1. The thickness of each substrate was 1.6 mm, the bondline was 0.25 mm, and the bonding area was 25×12.5 mm overlap. Then each sample was immersed in diethylene glycol (99.5% purity) used as the debonding agent at 60° C. for 30 minutes. After washing the debonding agent by water, the substrates and adhesives were separated by an Instron tester and the tensile shear strength was tested according to ASTM-D1002 at 23° C. and 50% humidity. The test results are shown in Table 1.

Reference Example

[0063] Samples were prepared by bonding two substrates with commercial adhesives according to Table 1. The thickness of each substrate was 1.6 mm, the bondline was 0.25 mm, and the bonding area was 25×12.5 mm overlap. The samples were not treated by debonding agent, but the substrates and adhesives were separated by an Instron tester and the tensile shear strength was tested according to ASTM-D1002 at 23° C. and 50% humidity. The test results are shown in Table 1.

TABLE-US-00001 TABLE 1 HHDD 3542.sup.1 HHDD 6010.sup.2 HHD 8540.sup.3 TSS Reduction TSS Reduction TSS Reduction Substrate/Adhesive (in MPa) (%) (in MPa) (%) (in MPa) (%) Reference Polycarbonate 20 — 12 — 9.5 — Stainless steel 5 — 6 — 22 — Ink coated glass 4 — 4 — 4 — Example 1 Stainless steel 0.5 90 1.1 82 1.3 94 Example 2 Polycarbonate 1.9 91 1.3 89 1.1 88 Stainless steel 0.25 95 0.6 90 2.2 90 Ink coated glass 0.4 90 0.7 81 0.24 94 Example 3 Polycarbonate 1.9 90.5 1.8 85 2.7 72 Stainless steel <0.02 99 0.8 86.7 4 82 Ink coated glass 0.4 90 0.6 85 0.8 79.0 Example 4 Polycarbonate 18 10 11.1 8 9.2 3 Stainless steel 4.75 5 6 0 22.4 2 Ink coated glass 3.16 21 3.9 2 3.7 8 .sup.1HHDD 3542 is a polyurethane hot melt adhesive obtained from Henkel. .sup.2HHDD 6010 is a two-part polyurethane adhesive obtained from Henkel. .sup.3HHDD 8540 is an acrylate adhesive obtained from Henkel.

[0064] As can be seen from Table 1, after treating by the debonding agent according to the present invention, the banded substrates made of various materials could be easily removed from various types of adhesives as the bonding strength was significantly reduced. However, diethylene glycol used in the comparative example could not efficiently separate the banded substrates in similar conditions.