GB2428605A

GB2428605A - Two part fluororubber and amionsilane coating for sealing corner

Info

Publication number: GB2428605A
Application number: GB0523549A
Authority: GB
Inventors: Gopalan Krishnamachari
Original assignee: GDX North America Inc
Current assignee: GDX North America Inc
Priority date: 2005-07-13
Filing date: 2005-11-18
Publication date: 2007-02-07
Also published as: GB0523549D0; GB0514406D0

Abstract

The coating is made from an organic solution of a fluoroelastomer and a silane including a primary amine group. The rubber can be cured at room temperature and preferably includes acid groups. The substrate is preferably a moulded elastomer which may be coated on a modified polymer containing a silane crosslinking agent. The two part coating can be applied on the other surface of the substrate from the first coating or on top of the first coating. The coating is applied to a seal, trim or guide, preferably a sealing corner 3 connecting extended vehicle window seals 6, 7.

Description

MOULDED MEMBER AND COATING

The invention relates to a moulded sealing, trimming or guiding member, a sealing system having such a member, a method of making such a member and a method of coating such a member.

It is well known in the vehicle industry to employ around the periphery of a window opening a seal having a glass run channel. Such a seal normally has means, such as arms or channels, to enable the seal to be securely located on flanges or other members forming part of the window frame. The glass run channel is normally defined by a base and two opposing side walls. In a typical window frame, such as the window frame in the driver's door of a vehicle, the seal normally extends up the so- called A-pillar, around into the so-called header and around into and down the so-called B-pillar. Where there is a sharp angle involved such as between the header and the A-pillar or B-pillar, a sealing corner is usually provided between the header and A-pillar and between the header and B-pillar. The sealing corner is typically provided in the region of the glass run channel with three sealing lips, one of which abuts the outer face of a pane of glass, another of which abuts the inner face of the pane of glass, and a third of which abuts the edge region of the pane of glass. Such a sealing corner is disclosed in GB2326435.

Such seals are subject to wear due to repeated movement of the pane of glass in the run channels and to other environmental attrition. It is known to add a coating to a seal and, in particular, to a corner seal to improve, for example, its abrasion resistance. A known coating is an Acheson water based coating which is applied on a Chemlok 459X primer. The primer improved the surface energy to bond to the water borne urethane coating. This is applied following application of a primer. In order to obtain the most desirable abrasion resistance properties, the corner seal should be at a raised temperature when the coating and primer are applied. It is however inconvenient to apply a primer and to bake the sealing corner and primer/coating. A coating with more desirable properties is therefore sought.

According to the present invention, there is provided a moulded sealing, trimming or guiding member having a Lord HPC-5B coating thereon. The moulded sealing, trimming or guiding member is in the embodiment described below a sealing corner and is included in a sealing system having a first extruded sealing member at a header, a second extruded sealing member at a pillar and the sealing corner, wherein the sealing corner is located between and joined to the first and second extruded sealing members. The moulded sealing, trimming or guiding member may be made by a method of injection moulding in a mould. The moulded sealing, trimming or guiding member may be coated by a method wherein the coating is brush applied.

The composition of the Lord HPC-5B coating is the subject of US patent application serial number 11/037,678, which is herein incorporated in its entirety by reference.

An embodiment of the invention is described in the following, by way of example only, reference being made to Figures 1 and 2 in which: Figure 1 shows a schematic of a sealing system including a corner seal, and Figure 2 shows a cross-section of the sealing system of Figure 1 through line II. Figure 1 shows a sealing corner 3 of generally known configuration (from GB2326435), which is typically but not necessarily injection moulded, having a first end 4 and a second end 5, to which are respectively secured a first extruded sealing member 6 serving as a header component and a second extruded member 7 serving as a pillar component. The sealing corner 3 may be formed by injecting liquid EPDM material into an appropriately shaped and heated mould. The sealing corner 3 and the header component 6 are joined at a first join 8 and the corner seal 3 and the pillar component 7 are joined at a second join 9, possibly during the moulding process that forms the sealing corner 3 itself.

Figure 2 shows the sealing corner of Figure 1 through line I-I with a glass run channel in which are located an outer glass sealing lip 10, a glass edge sealing lip 11, and an inner glass sealing lip 12. Other regions 14 and 15 of the corner seal 3 are provided for the purpose of securing the seal 3 to flanges and the like, which form part of a window frame.

A pane of glass 13 has an edge extending into the glass run channel and is moveable in the channel. The outer glass sealing lip 10 abuts an outer side of the pane, the inner glass sealing lip 12 abuts the inner face of the pane of glass, and the glass edge sealing lip 11 abuts the edge region of the pane of glass.

In use, the pane of glass is moved longitudinally with respect to the pillar component 7 in accordance with a window being opened or closed. The pane of glass abuts when closed onto the header component.

In accordance with the embodiment of the invention, the sealing corner 3 has a coating of Lord HPC-5B applied to its surface in the following way, as described below.

The sealing corner 3 is at a raised temperature for a time following being produced by injection moulding in a mould. The sealing corner 3 is removed from the mould during this time and a coating is brush applied to the sealing corner 3 while the sealing corner remains at the raised temperature, which is preferably 38 to 48 c at the time of application, and more preferably still about 43 c.

The coating is preferably applied without primer, cures in normal ambient conditions and adheres to the sealing corner 3 without surface treatment of the sealing corner. The coating also meets solvent resistance requirements and has improved abrasion resistance over known coatings.

Tests have been conducted as described in the following.

Lord HPC-5B Coating and Chemglaze Z306 coating were tested for abrasion resistance on a sealing corner with and without a primer, Autoseal 3690 Primer. The sealing corners tested were Dodge Ram EPDM sealing corners produced by GDX.

In practice, some residual heat remains from the injection moulding process by which the sealing corner is manufactured (that is the sealing corner has a raised temperature when it is removed from the mould). Accordingly, to simulate the actual coating process as closely as possible the corners were heated to 54 C prior to application of the primer (when used) and 43 C prior to application of the coating.

Approximately twenty sealing corners were treated. The sealing corners were wiped with Xylene solvent to remove surface contaminates. The sealing corners were then heated to 54 centigrade. Autoseal 3690 Primer was then brush applied to half of the sealing corners. The primer was allowed to dry at room temperature for 15 minutes. A dry primer thickness was targeted of 0.1mm. All the sealing corners were then heated to 43 centigrade. The Lord HPC-5B Coating was then applied to half of the sealing corners with primer and half of the sealing corners without primer. The Chemglaze Z306 was then applied to the remaining sealing corners with and without primer. The coatings were brush applied to the sealing corners and it was attempted to apply each coating in a single brushstroke to minimise brush streaks. A dry coating thickness of 1.0 mm for the Lord HPC-5B and the Chemglaze Z306 was targeted. The sealing corners were allowed to cure at room temperature for at least 16 hours before testing.

A dime scrape test (up to 50 rubs), a cross-cut test (tape adhesion test) and a cross-hatch test (tape adhesion test) were conducted on at least one sealing corner which had been treated with a Chemglaze Z306 coating with a primer, a Chemglaze Z306 coating without a primer, a Lord HPC-5B coating with a primer and a Lord HPC-5B coating without a primer. The results are summarised in the following table.

Coating Chemglaze Z306 Lord HPC-5B Primer Autoseal 3690 None Autoseal 3690 None Test Dime Scrape Pass - 50 rubs Fail - less than 28 Pass rubs Pass - 50 rubs rubs before coating break through Cross-Cut Pass Pass Fail - Coating Pass delamination Cross-Hatch Pass Fail - Coating Fail Coating Pass delamination delamination The Chemglaze Z306 with the Autoseal 3690 Primer and the Lord HPC-5B without primer provided the best adhesion. The Lord HPC-5B and the Chemglaze Z306 provided a more aesthetically pleasing appearance without the use of primer.

It will be appreciated that there were various modifications that can be made to the embodiment described above. Many of the illustrated features of the sealing corner, such as the different components for locating the sealing corner relative to the window frame, may be varied considerably. Although the embodiment described above is a sealing corner, a Lord HPC5B coating can be applied to any moulded sealing, trimming or guiding member and the advantages of the invention maintained.

Claims

1. A sealing, trimming or guiding member having thereon a coating comprising an ambient temperature curable coating composition in a mixture of two parts providing a non-volatiles content of from 4% to 25% by weight, and comprising a part A which comprises an organic solvent and fluoroelastomer dissolved therein, said fluoroelastomer containing crosslinkable sites in quantitative amount according to an acid number of from

2 to 6 mg base per gram, and a part B which comprises an organosilane comprising hydrolysable groups and a mono primary amine, wherein the ratio of amine equivalents in part B to acid equivalents in said part A ranges from 3:1 to 12:1 and wherein a cured I...

* * *. unsupported film from said coating exhibits at least 200% elongation.

* 2. A sealing, trimming or guiding member according to claim 1 wherein said fluoroelastomer has an acid number of from 3 to 5 mg base per gram. * p

S

3. A sealing, trimming or guiding member according to claim 1 wherein said film forming polymer is a hydrogenated random or block diene copolymer having a molecular weight of about 20,000 to 200,000.

4. A sealing, trimming or guiding member according to claim 1 wherein said acid equivalents are from functional groups selected from a sulfonic acid, a sulfenate, a sulfinite, chlorosulfonic acid, a carboxylic acid, a dicarboxylic acid, a partial ester of a carboxylic anhydride, and cyclic imides of dicarboxylic acids.

5. A sealing, trimming or guiding member according to claim 1 wherein said acid equivalents are provided from an a,J3-unsaturated carboxylic acid.

6. A sealing, trimming or guiding member according to any one of the preceding claims wherein said curing is selected from the group consisting of aminopropyltriethoxy, aminopropyl trimethoxy silane, aminoethylaminopropytriethoxy aminoethylaminopropyltrimethoxy silane, 3aminopropyl triethoxy silane, 3-aminopropyl trimethoxy silane, 3 -aminopropyl methyly dimethoxysilane or 3 -aminopropyl methyl diethoxy silane, N-(2-aminoethyl)-3 -aminopropyl trimethoxy silane, N- methyl-3 -aminopropyl trimethoxy si lane, N-phenyl-3-am inopropyl trimethoxy silane, bis(3 -aminopropyl) tetramethoxy and bis(3 - aminopropyl) tetraethoxy disiloxane. I.

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7. A sealing, trimming or guiding member according to claim 1 having thereon a multi-layer coating, comprising a primer layer and a top S coating, wherein the primer layer comprises a film former having a Tg of less than 0.degree. C. which is cured with from 25 to 150 phr of an organosilane, and wherein said top coating is made of the ambient temperature curable coating composition.

8. A sealing, trimming or guiding member according to claim 1 having thereon a multi-layer according to claim 7 wherein the primer coating comprises a polymer selected from the group consisting of carboxylated polyisoprene, carboxylated NBR, and carboxylated polyolefin.

9. A sealing, trimming or guiding member having first and second surfaces, adhered to said first surface is a cured coating comprising a film of carboxylated NBR, carboxylated isoprene, or carboxylated ethylene copolymer, cured with from 25 to 150 phr of an organosilane, and on said second side is adhered a cured coating made of the ambient temperature curable coating composition.

10.A sealing, trimming or guiding member according to claim 1 wherein said substrate is a moulded article from an elastomer selected from I- INBR, natural rubber, polyisoprene, polybutadiene, styrene butadiene and ethylene propylene rubber.

11. A sealing, trimming or guiding member according to any one of claims 1 to 10 wherein the coating has a thickness of about 1mm.

12.A sealing, trimming or guiding member according to one of claims 1 and 11, wherein the surface of the sealing corner is substantially or wholly coated with the coating. * ..

13.A sealing, trimming or guiding member according to any one of claims a. .

1 to 12 wherein said member is a sealing corner intended to serve as part of a sealing system when located between a first extruded sealing member at a header and a second extruded sealing member at a pillar, the sealing corner being capable of being joined to the two extruded members.

14.A sealing system having a first extruded sealing member at a header, a second extruded sealing member at a pillar, and the sealing corner of claim 13, wherein said sealing corner is located between and joined to the first and second extruded sealing members.

15. A method of making the moulded sealing, trimming or guiding member of any one of claims ito 13 including the step of producing the member by injection moulding in a mould.

16. A method of making the moulded sealing, trimming or guiding member according to claim 15 and further including the steps of removing the member from the mould at a time following injection moulding and at which the member is at a raised temperature resulting from the injection moulding, and applying the Lord HPC-5B coating before the member has cooled.

17. A method of making a moulded sealing, trimming or guiding member according to claim 16 wherein the coating is applied when the member is at between 38 and 48 c, and is preferably at approximately 43 c.

18. A method of coating the moulded sealing, trimming or guiding member of any one of claims 1 to 13 wherein the coating is brush applied.

19. A method of coating a moulded sealing, trimming or guiding member according to claim 18 wherein the coating is applied by a single brush stroke.

S

20. A moulded sealing, trimming or guiding member substantially as :55.: hereinbefore described with reference to the accompanying drawings.

21. A sealing system substantially as hereinbefore described with reference to the accompanying drawings.

22. A method of making a moulded sealing, trimming or guiding member substantially as hereinbefore described with reference to the accompanying drawings.

23.A method of coating a moulded sealing, trimming or guiding member substantially as hereinbefore described with reference to the accompanying drawings.