Polymer Compositions Suitable For Producing Plated Products

Abstract

A method for the production of metal-plated articles, including the step of depositing an electrically-conductive metallic layer on a surface of an article comprising a polymer composition comprising by weight: a) 40-60% of a propylene homopolymer, or propylene copolymer containing up to 5% by weight of ethylene and/or another C.sub.4-C.sub.10 α-olefin, and having a melting temperature of 155° C. or higher and/or a fraction soluble in xylene at 25° C. of 10% by weight or less; b) 10-20% of an ethylene-based elastoplastic copolymer, optionally, a copolymer of ethylene with C.sub.4-C.sub.10 α-olefin; c) 2-6% of a styrene block copolymer; d) optionally, up to 3% of a propylene homopolymer having a Melt Flow Rate (230° C./2.16 kg) of 500 g/10 min. or more; e) 15-50% of a filler; and f) optionally, up to 6% of a color pigment.

Claims

1. A method for the production of metal-plated articles, comprising the step of depositing an electrically-conductive metallic layer on a surface of an article comprising a polymer composition comprising by weight: a) 40-60% of a propylene homopolymer, or propylene copolymer containing up to 5% by weight of ethylene and/or another C.sub.4-C.sub.10 α-olefin, and having a melting temperature of 155° C. or higher and/or a fraction soluble in xylene at 25° C. of 10% by weight or less; b) 10-20% of an ethylene-based elastoplastic copolymer, optionally, a copolymer of ethylene with C.sub.4-C.sub.10 α-olefin; c) 2-6% of a styrene block copolymer; d) optionally, up to 3% of a propylene homopolymer having a Melt Flow Rate (230° C./2.16 kg) of 500 g/10 min. or more; e) 15-50% of a filler; and f) optionally, up to 6% of a color pigment.

2. The method according to claim 1, wherein the component (a) is present at concentrations of 45-50% by weight.

3. The method according to claim 1, wherein the component (b) is present at concentrations of 12-18% by weight.

4. The method according to claim 1, wherein the component (c) is present at concentrations of 34% by weight.

5. The method according to claim 1, wherein the component (d) is present at concentrations of 1-2% by weight.

6. The method according to claim 1, wherein the component (e) is present at concentrations of 25-40% by weight.

7. The method according to claim 1, wherein the component (f) is present at concentrations of 14% by weight.

8. The method according to claim 1, wherein the metal used for plating is selected from the group consisting of copper, chromium, gold, silver, aluminum, nickel and metal alloys.

9. The method according to claim 1, wherein the color pigment is black.

10. A metal-plated article prepared by the method according to claim 1.

11. The metal-plated article according to claim 10, wherein the article is selected from the group consisting of interior automotive parts, exterior automotive parts, and surface automotive parts.

12. The metal-plated article according to claim 10, wherein the article is a furniture part.

13. The metal-plated article according to claim 10, wherein in the article is selected from the group consisting of tooling parts and household items.

Description

DESCRIPTION OF THE FIGURE

[0058] The FIGURE shows a ranking given to the chroming quality by assigning a score (0=no chroming, 1=acceptable; 2=good) on the basis of visual evaluation. The plaque on the left was assigned score of 0, the plaque in the middle was assigned a score of 1, and the plaque on the right was assigned a score of 2.

EXAMPLES

[0059] The following examples are included to demonstrate embodiments. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered to function well, and thus can be considered to constitute exemplary modes of practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of this disclosure.

[0060] For the comparative examples and the examples of an embodiment, various compounds were formulated to prepare test specimen.

Example 1—Preparation of Polymer Composition 1

[0061] Polymer Composition 1 was prepared by melting and mixing the following components: 35.8% by weight of AdstifHA600U as component (a), 14.8% by weight of Engage™ 7467 as component (b), 3.3% by weight of Kraton™ D 1101 as component (c), 1.6% by weight of Metocene™ MF650Y as component (d), 40% by weight of talc (the commercial product sold under the trademark JETFINE® 3CA) as component (e), 1% by weight of black pigment (the commercial product sold under the name BK MB LD-32232) as component (f) and 3.5% by weight of master additives. The mixing was effected in a twin-screw extruder at a temperature of 280° C. Components (a) and (d) and modifier components (b) and (c) were initially molten, and subsequently component (e) was mixed with the melt.

Example 2—Preparation of Polymer Composition 2

[0062] Polymer Composition 2 was prepared as described in Example 1, with the difference that CaCO.sub.3 was used as component (e) instead of talc.

Example 3—Preparation of Polymer Composition 3

[0063] Polymer Composition 3 was prepared as described in Example 1, with the difference that no black pigment was used and the polymer components were re-balanced to maintain the same relative proportions in weight as defined in Example 1.

Example 4—Preparation of Polymer Composition 4

[0064] Polymer Composition 4 was prepared as described in Example 1, with the difference that a mixture of 40% by weight of CaCO.sub.3 and 15% by weight of mica was used as component (e) instead of 40% by weight of talc and the polymer components were re-balanced to maintain the same relative proportions in weight as defined in Example 1.

Example 5—Preparation of Polymer Composition 5

[0065] Polymer Composition 5 was prepared as described in Example 1, with the difference that 50% by weight of talc was used as component (e) instead of 40% by weight and the polymer components were re-balanced to maintain the same relative proportions in weight as defined in Example 1.

Example 6—Preparation of Polymer Composition 6

[0066] Polymer Composition 6 was prepared as described in Example 1, with the difference that 50% by weight of CaCO.sub.3 was used as component (e) instead of 40% by weight of talc and the polymer components were re-balanced to maintain the same relative proportions in weight as defined in Example 1

Example 7—Preparation of Polymer Composition 7

[0067] Polymer Composition 7 was prepared as described in Example 1, with the difference that talc HAR 3G 84L (supplied by IMYERS Specialties) was used as component (e).

Comparative Example 1

[0068] For comparative purposes, the following Polymer Composition A was prepared. Polymer Composition A was prepared by melting and mixing the following components: 47% by weight of Hifax CA 60 A (supplied by LyondellBasell), 50% by weight of talc Ultra C, 1% by weight of black pigment and 2% of master additives.

Comparative Example 2

[0069] For comparative purposes, the commercial polymer Metocene™ MF650Y was used in the chromium-plating tests.

Example 8—Chromium-Plating Process for Preparing Chromium-Plated Plaques Cleaning the Articles

[0070] Rectangular plaques made of the polymer compositions prepared according to the previous Examples 1-7 and Comparative Examples 1 and 2 were cleaned with an alkaline soak cleaner, commercially available from Enthone Inc. under trade name Enplate® PZ-454. The plaques were cleaned by immersing the plaques for about 5 minutes in a bath of this cleaning solution at an operating temperature of 50° C. After cleaning, the articles were rinsed in fresh water, by immersion, to remove the cleaning solution.

Removal of Filler from the Resin Surface

[0071] The mineral filler was removed from the plaques surfaces by immersing the plaques in a bath of ammonium bifluoride, commercially available from Atotech Italia S.r.l. under trade name Adhemax® PA Conditioner at an operating temperature of 30° C.

Cleaning the Treated Resin Surface

[0072] The plaques were then further cleaned by washing the plaques in tap water several times and then, in deionized water for about 40 seconds at an operating temperature of about 37° C.

Drying the Treated Resin Surface

[0073] The plaques surfaces were then dried in a forced air oven with filtered air heated to a temperature of about 70° C. for about 20 minutes.

Electroless Plating of the Resin Surface

[0074] The plaques surfaces were electroless plated by tin-palladium transfer techniques, that is, contacted with CrCl.sub.3 aqueous solution to deposit elemental chromium by chemical reduction.

Electroplating

[0075] The electroless plated plaques surfaces were electroplated to provide a metallic finish. The surfaces were electroplated with copper followed by nickel followed by chromium. The thickness of the electroplated coating was about 0.66 mm. At the end of the plating cycles, the chromium plated articles were dried in a forced air oven with filtered air heated to a temperature of about 70° C. for about 20 minutes.

Example 9—Quality Evaluation of the Chromium-Plated Articles

[0076] The results of the chromium-plating process carried out as described in previous Example 8 on rectangular plaques made of the polymer compositions prepared according to the previous Examples 1-7 and Comparative Examples 1 and 2 are reported in the following Table 1. Plaques have been evaluated considering the adhesion of the chromed coating, scratch resistance, and delamination. An overall ranking has been quantified, assigning a score (0=no chroming, 1=acceptable; 2=good) on the basis of visual evaluation. An example of the assignment of such “chroming scores” is provided in the FIGURE.

TABLE-US-00001 TABLE 1 Polymer Composition (Examples) 1 2 3 4 5 6 Comp. 1 7 Comp. 2 Chroming Score * 2 2 1 2 2 2 0 1 0 * 0 = No chroming, 1 = Acceptable, 2 = Good

[0077] The results reported in Table 1 show that some specific polymer compositions achieve chroming score of 2.

Example 10—Mechanical Properties Evaluation of the Chromium-Plated Articles

[0078] Elastic flexural modulus (ISO 178) and tensile stress at break (ISO 527) were measured for the rectangular plaques made of the polymer compositions prepared according to the previous Examples 1, 2, 4, 5 and 6 before and after chroming process according to Example 8.

The results of such tests are reported in Table 2 and are expressed in terms of percent improvement of the mechanical property after chroming.

TABLE-US-00002 TABLE 2 Polymer Composition (Examples) 1 2 4 5 6 Elastic Flexural Before (MPa) 3700 1530 1670 3610 1600 Modulus - ISO 178 After (MPa) 9940 8670 8950 13540 7940 Improvement (%) 168 466 436 275 396 Tensile Stress at Before (MPa) 20.0 12.6 10.0 18.3 10.0 break - ISO 527 After (MPa) 22.6 18.8 14.1 18.3 12.4 Improvement (%) 13 49 41 0 24