WO2023031327A1

WO2023031327A1 - Voc treatment of moulded interior trim parts for a vehicle

Info

Publication number: WO2023031327A1
Application number: PCT/EP2022/074311
Authority: WO
Inventors: Xiaoning YAN; Jinjing CHEN
Original assignee: Autoneum Management AG
Current assignee: Autoneum Management AG
Priority date: 2021-09-03
Filing date: 2022-09-01
Publication date: 2023-03-09
Anticipated expiration: 2024-03-03
Also published as: CN115746387A

Abstract

Moulded automotive interior trim part comprising at least one layer, whereby at least part of the outer surface of the moulded trim part is covered with a network of aminosilane and/or aminosiloxane molecules partly hydrogen bonded to the adjacent surface.

Description

VOC treatment of moulded interior trim parts for a vehicle

Technical Field

[0001] The application is directed to thermoformed automotive trim parts comprising at least a polyurethane foam or felt layer, and a method for producing such a trim part.

Background Art

[0002] Vehicle passengers are aware of the volatile components released from the interior parts of a new car in the period directly after production, in particular if they produce the so called "new car smell". The release may continue over a longer stretch of time and may be accelerated by the car standing in an environment with a raised temperature, like parking in the sun or used in an overall warmer climate.

[0003] The release of the volatile components might be a health risk at low quantities but it also creates an unwanted odour in the car. The release will decrease over time to a level not noticeable for the user of the car. However, the noticeable phase might be prolonged by the use of a closed air-conditioning system.

[0004] Of the volatile components the group of aldehydes, particularly formaldehyde and acetaldehyde are among the most problematic, they may be released by interior trim parts comprising at least a foam layer or a felt layer. Trim parts with a foam layer that are obtained with an in mould foaming process, are prone to high levels of free formaldehyde and acetaldehyde. In addition, the use of certain mould release agents might increase the emission levels. Felt material in particular felt materials containing reclaimed or recycled fibrous material might have raised levels of acetaldehyde. While virgin polyester might emit volatile components in particular in the first phase after production of the polyester.

[0005] Moreover, trim parts may be exposed to external sources of VOCs during production, transport and storage, which might be absorbed by the parts. These absorbed VOCs may be released again during the use in the car increasing the level of VOCs emitted.

[0006] There is a need for automotive trim part with at least a polyurethane foam layer and/or thermoplastic- or natural fiber felt layer, which is reduced in its levels of emitting compounds, in particularly reduced in the emitted levels of formaldehyde and acetaldehyde.

[0007] State of the art solutions are either unpredictable, may release the compounds in a later phase, or are difficult to apply or maintain on the part. In addition, many proposed solutions are either catching formaldehyde or acetaldehyde but not both.

[0008] It is therefore the object of the current invention to supply a method of treating interior automotive trim parts with at least a polyurethane foam layer and/or thermoplastic- or natural fiber felt layer, to reduce the level of released formaldehyde and acetaldehyde, without the problems of the current solutions.

Summary of invention

[0009] This problem is solved by the moulded interior trim part comprising at least one layer according to main claim 1 , as well as with the method of treating such a moulded part according to claim 7.

[0010] In particular by covering at least part of the outer surface of the moulded trim part with a network of aminosilane and/or aminosiloxane molecules partly hydrogen bonded to the adjacent surface, it is possible to obtain a considerable reduction of the emission of both formaldehyde and acetaldehyde in almost equal levels. While by state of the art systems, the reduction efficacy of the one, for instance formaldehyde is reducing the reduction efficacy of the other molecule, for instance acetaldehyde, this could not be observed by the treatment according to the invention. Even more surprisingly also the amount of acrolein emission was reduced.

[0011] The reduction could be established with in particular treated foam, but also full carpet construction showed a decrease in emission after the covering of at least part of the surface with a network of aminosilane and or aminosiloxane molecules partly hydrogen bonded to the adjacent surface.

[0012] The reduction of the emission is defined as the emission of the measured and relevant molecules in the surrounding air. Either a Tedlar bag according to ISO 12219-2 for the VOC testing, or a cubic meter chamber was used to sample the emission over a predefined period and temperature. Afterwards the air was measured with a suitable method for instance according to DIN ISO 16000-3:2013-01.

[0013] Surprisingly only a small amount of aminosilane is needed to cover the surface and to achieve a reduction of at least formaldehyde, acetaldehyde and acrolein to legally acceptable levels. The aminosilane might be available in the network after drying as aminosiloxane. Hence, the final network might be a combination of aminosilane and/or aminosiloxane.

[0014] Independent of the moulded shape of the part, an aminosilane is used in a concentration of at least 0.02% by weight of the part weight and not more than 0.1 % by weight of the part weight is needed to achieve the result. It seems that further increasing the aminosilane will not increase the effect expected, it would even reduce the expected effect as the molecules might bind to each other and are no longer available to catch the VOCs.

[0015] The moulded automotive interior trim part according to the invention may comprise preferably at least one layer selected from the group of a polyurethane foam layer and a thermoplastic and/or natural fiber felt layer and pile carpet layer, for instance a tufted carpet or needlepunch carpet.

[0016] The moulded automotive interior trim part may comprise further layers selected from the group of a polyurethane foam layer and a thermoplastic and/or natural fiber felt layer and/or pile carpet layer, eventually perforated film or foil layer and nonwoven scrim layer. These further layers may form the outer layer of the moulded trim part with the surface treated according to the invention.

[0017] All surfaces of the moulded automotive interior trim part may be covered with the network of aminosilane and or aminosiloxane molecules partly hydrogen bonded to the adjacent surface. The surfaces that cannot be reached by passengers during normal use are to be preferred, in particular the backside of a floor system may be covered.

[0018]

[0019] Preferably the aminosilane or aminosiloxane is one of the group of silane compounds with an amino or diamino group and at least one alkoxy group.

[0020] Preferably the aminosilane is at least one of one member selected from the group consisting of - N-(2-aminoethyl)-3-aminopropyl trimethoxysilane,

- N-(aminoethylaminomethyl)phenyltrimethoxysilane,

- N-(2-aminoethyl)-3-aminopropyltris(2-ethylhexoxy)-silane,

- Aminoethyl-aminopropyl-trimethoxysilane,

- 3-(Dimethoxymethylsilyl)propylamine,

- N-(2-Aminoethyl)-3-aminopropylmethyldimethoxysilane,

- 3-aminopropyltrimethyxysilane, trimethoxysilyl-propyldiethylenetriamine,

- bis (2-hydroxyethyl)-3-aminopropyltrimethoxysilane, and the like.

[0021]

[0022] A preferred method of treating a moulded automotive interior trim part to obtain a coverage with a network of aminosilane molecules partly hydrogen bonded to the adjacent surface according to the invention is having the steps of :

(1) spraying on at least one of the surfaces of the moulded automotive trim part a water based solution comprising at least an aminosilane, and

(2) thermally drying the thus treated trim part such that water evaporates and the aminosilane forms a molecule network covering at least part of the surface and binding to the adjacent material.

[0023] Surprisingly, a thin coverage with a network of aminosilane and or aminosiloxane molecules is already enough to reduce the formaldehyde and acetaldehyde emissions with more than 50% for the full part.

[0024] Any moulded automotive trim parts containing at least a first layer of polyurethane foam and/or fibrous felt moulded in its final shape may be treated with the solution according to the invention to reduce the release of aldehydes particularly formaldehyde and acetaldehyde.

[0025] Surprisingly, using an aminosilane or amino-siloxane as scavenger coated on the surface is already enough to reduce the aldehyde release of the part.

[0026] The aminosilane is preferably applied to at least the back outer surface of the part, the one facing the body of the car.

[0027] Preferably, the aminosilane containing solution is sprayed in a spray booth mainly on the back surface of the part, such that overspray and aerosols in the booth can also reach the other surface of the part - for instance a carpet surface like a tufted or needle punch type surface. Hence the part is fully covered with the solution, preferably more on the back surface than the front surface.

[0028] Alternatively, the pile surface may be covered or placed in a carrier surface to prevent any overspray and only the backside of the moulded part is treated.

[0029] The part may be sprayed at least partially on the back surface, the full back surface or even partially or fully the front surface. Preferably, the main concentration is placed on areas that cannot be reached by the passengers during normal use of the car, for instance the back of the part including side faces, as well as areas underneath seats or the upper areas directly under the dashboard to reduce or prevent passengers from touching treated surfaces.

[0030] Preferably, the trim part comprises at least 0.3% of scavenger based on the weight of the part, sprayed on at least one side of the part. Preferably, the scavenger is sprayed as a water based solution.

[0031] All sorts of interior parts may be treated this way to reduce emission of VOCs, in particular flooring parts, floor mats, innerdash parts, behind dashboards, door panels and overhead panels or ceiling panels as well as small trim parts used to close small gaps in the overall coverage.

[0032] The treatment might also be used on moulded foamed seat parts to reduce the emission of these parts, preferably before the seat parts are covered with fabric.

Example 1

[0033] At least two 20 gram portions (with equal weight and size) of polyurethane foam blocks cut from a standard commercial available foam, were used to test each component. Each foam block was sprayed with a water-based solution containing the component on a surface of the block and the blocks were dried immediate after the treatment in a hot air oven.

[0034] The thus treated blocks and untreated blocks from the same foam source were packed in bags for VOC emission testing according to according to DIN ISO 16000-3:2013-01. [0035] The blocks were treated such that there was 0.02 gr of the mentioned component per 20 gr foam block using following components:

- SC1 N-(2-Aminoethyl)-3-aminopropylmethyldimethoxysilane

- SC2 3-Aminopropyltrimethoxysilane

- SC3 Aminoethyl-aminopropyl-trimethoxysilane

- SC4 3-(Dimethoxymethylsilyl)propylamine.

[0036] Figure 1 shows the % reduction of emission of formaldehyde, acetaldehyde and acrolein measured on the samples as described. Surprisingly, the emission of all three components could be reduced, for all 3 components at least a reduction of 80% could be achieved depending on the aminosilane taken. In particularly SC1 and SC2 showed a high reduction in emission for both aldehyde components in parallel.

[0037] It was found in these and other experiments that the treatment is functional independent of any residual mould release agents on the final part surface to be treated.

Example 2

[0038] Three different kinds of carpet flooring system coming directly from the production line were treated with SC1 on the carpet surface and dried. Each sample was put in a bag and measured with the same method as example 1.

[0039] Untreated and treated carpet flooring system were prepared and compared.

[0040] Also here, it could be shown that the levels of emission of formaldehyde, acetaldehyde and acrolein, could be substantially reduced.

[0041] For a first polyamide tufted carpet with mainly nonwoven backing layers and LDPE and EVA latex layers, a reduction of over 90% of formaldehyde emission could be achieved and in addition a 70% reduction of the acetaldehyde, while acrolein was reduced under the detectable level.

[0042] The second one was also a polyamide-tufted carpet with a similar layout as the first carpet tested. In addition, here the formaldehyde emission was reduced over 90% while the reduction of acetaldehyde emission was almost 60%. [0043] The last carpet treated was a needle punch nonwoven carpet with EVA latex and LDPE layers as well as nonwoven backing layers. In this case, the reduction was similar to the tufted carpet samples. With a reduction of respectively 11% of formaldehyde, 67% of acetaldehyde and acrolein under the detectable level.

[0044] Although carpets were different in the layout, they all showed comparable reduction levels showing that the system is less dependent on the surface treated and the materials used for the flooring part.

[0045] Although it is shown that flooring systems may be treated on the pile surface to achieve good results, it is more preferable that surfaces are treated that may not be touched by passengers during normal use. Hence, preferably the backside of the flooring parts facing the body of the car.

Claims

8 Claims

Claim 1. Moulded automotive interior trim part comprising at least one layer, characterised in that at least part of the outer surface of the moulded trim part is covered with a network of aminosilane and/or aminosiloxane molecules partly hydrogen bonded to the adjacent surface.

Claim 2. Moulded automotive interior trim part according to claim 1 , whereby the aminosilane is at least 0.02% of the part weight and not more than 0.1 % of the part weight.

Claim 3. Moulded automotive interior trim part according to claim 1 , whereby the at least one layer and/or at least one additional layer is selected from the group of a polyurethane foam layer and a thermoplastic and/or natural fiber felt layer and/or pile carpet layer, foil, film and nonwoven scrim layer.

Claim 4. Moulded automotive interior trim part according to one of the preceding claims whereby all surfaces of the moulded automotive interior trim part are covered with the network of aminosilane or aminosiloxane molecules partly hydrogen bonded to the adjacent surface.

Claim 5. Automotive interior trim part according to one of the preceding claims whereby the aminosilane or aminosiloxane is one of the group of silane compounds with an amino or di-amino group and at least one alkoxy group.

Claim 6. Automotive interior trim part according to one of the preceding claims whereby the aminosilane or aminosiloxane is preferably at least one of one member selected from the group consisting of N-(2-aminoethyl)-3-aminopropyl trimethoxysilane, N-(aminoethylaminomethyl)phenyltrimethoxysilane, N-(2- aminoethyl)-3-aminopropyltris(2-ethylhexoxy)-silane, Aminoethyl-aminopropyl- trimethoxysilane, 3-(Dimethoxymethylsilyl)propylamine, N-(2-Aminoethyl)-3- aminopropylmethyldimethoxysilane, 3-aminopropyltrimethyxysilane, trimethoxysilyl-propyldiethylenetriamine, bis (2-hydroxyethyl)-3- aminopropyltrimethoxysilane and the like.

Claim 7. Method of treating an automotive interior trim part according to one of the preceding claims with the steps of

(2) thermally drying the thus treated trim part such the water evaporates and 9 the aminosilane forms a molecule network of aminosilanes and or aminosiloxanes covering at least part of the surface and binding to the adjacent material.