EP3030708B1

EP3030708B1 - Spacer fabric treated with c6 based perfluoroalkyl polymer and method of preparing thereof

Info

Publication number: EP3030708B1
Application number: EP13747397.1A
Authority: EP
Inventors: Frank Jost
Original assignee: Baldus Ausruestungsgesellschaft Mbh
Current assignee: Baldus Ausruestungsgesellschaft Mbh
Priority date: 2013-08-08
Filing date: 2013-08-08
Publication date: 2019-10-23
Anticipated expiration: 2033-08-08
Also published as: US20160194821A1; MX2016001611A; ES2774260T3; WO2015018449A1; EP3030708A1; MX369708B; PL3030708T3

Description

The present invention relates in general to treated spacer fabrics and a method of preparing such spacer fabrics and more particularly to a spacer fabric being treated for imparting the spacer fabric with at least one or all of the properties selected from good flame retardancy, good oil repellency, high spray rating and low volatile emissions. Furthermore, the invention relates to the use of a specific liquid treating composition for preparing a treated spacer fabric having at least one or all of the properties selected from good flame retardancy, good oil repellency, high spray rating and low volatile emissions.
Spacer fabrics are three-dimensional fabrics, which are available in different executions and material thicknesses. They provide excellent properties such as a low weight, durable elasticity, springiness and their climate effect. This material is used, for example, as automotive textile in climatic and ventilated seats, seat covers, head liners, instrument and door panels as well as in composite constructions or as consumer textile in mattresses and furniture or in technical clothing and shoes.
If used in the automotive industry spacer fabrics are required to further provide specific properties like good oil repellency, high spray rating, good flame retardancy and low volatile emissions. Especially, good flame behavior and low volatile emissions are mandatory requirements for spacer fabrics when used in the automotive industry today. Furthermore, good oil repellency and high spray rating are desired requirements for such spacer fabrics because of their better processability in the automotive industry. Recently, so-called C8 fluorocarbon polymers have been used as state-of-the-art treating material for imparting spacer fabrics used in the automotive industry with the required oil repellency and spray rating. To achieve the also required flame retardancy the spacer fabrics were and still are additionally treated with flame retardants.
Prior to the breakthrough of fluorocarbon polymers, water repellent coatings were only achievable by wax emulsions or silicone applications, both of which were available in water borne emulsions or in solvent solutions. The early developments of fluorocarbons were only available in solvent based solutions, generally hazardous solvents, and of course environmental implications have led to the development of water based fluoropolymer emulsions, which are much safer and easier to handle. The fluoropolymers have outclassed the performance characteristics of silicones and waxes as they are exceptional at performing their functions at much lower levels, thereby reducing volume and cost factors. Recent concerns over the past few years have highlighted specific products associated with fluoropolymers, namely PFOA and PFOS (Perfluorooctanoic acid and Perfluorooctane Sulphonate, respectively); (source: www.texchem.co.uk/fluoroinfo.html).
PFOA is an abbreviation for Perfluorooctanoic Acid. C8 telomer is a chemical compound that contains 8 carbon atoms and 17 fluorine atoms. Many water and oil repellent products used for long term protection of textiles are based on C8 telomers. In manufacturing a trace amount of PFOA can be generated as an unintended by-product in C8-based repellent materials. In 2000, the U.S. Environmental Protection Agency (EPA) became concerned about data that indicated that PFOA is found in human blood in the general population. During the 90's it had become apparent that these materials had spread throughout the global environment and that they were accumulating in biological systems. Since then, the EPA and the industry have conducted studies, and collected and shared information regarding PFOA. In January 2006, the U.S. Environmental Protection Agency (EPA) approached the eight largest fluorocarbon producers and requested their participation in the 2010/15 PFOA Stewardship Program, and their commitment to reduce PFOA and related chemicals globally in both facility emissions and product content 95 percent by 2010, and 100 percent by 2015. As a result of the EPA recommendation, all fluorochemical companies chose to stop manufacturing, using and selling Perfluorooctanoic Acid (PFOA) and C8 telomer-based water and oil repellent products by the end of 2012. In fact they are transitioning even earlier than the original target, so that getting C8-based materials is currently impossible. The C6/C8 discussion is complex. Reducing PFOA makes sense. At the same time, moving from C8 to C6 may require using 50% more fluorochemical in similar formulations to get the same performance; (source: www.greenshieldfinish.com/pdf/ C8toC6ConversionSummary.pdf).
According to "http://marketplace.yet2" chemicals containing perfluoroalkyl (CF₂)_n-sections or tails have been used in industry to provide to substrate a) resistance to and prevention of staining by substances that contain one or more of: oil, grease, organic solvent, and water, b) surfactant properties to help aqueous-based solutions spread over low surface area surfaces such as oil, c) non-stick properties. In the last few years, chemicals containing perfluoroalkyl tails where n = 8 or greater have come under regulatory and market pressures because of their potential to form PFOA (Perfluoro Octanoic Acid/salts) or the fact that these products contain low levels of PFOA impurities. Environment Canada and the EPA have stopped approving any new products that contain C8 or longer perfluorocarbon tails in their structure, and California has proposed legislation in place to do the same. Chemicals containing perfluoroalkyl sections where n < 8 are generally less efficient, in that most of the chemicals of this type in the marketplace do not contain reactive functionality capable of forming covalent bonds. As a result, they are not locked in place on a substrate surface, and can reorient or be removed, causing them to lose efficiency; (source: "http://marketplace.yet2.com/app/list/techpak?id=45112").
Chemicals containing perfluoroalkyl sections are more expensive than e.g. wax emulsions or silicone applications.
US 7 552 604 B1 discloses the production of double needle bar spacer fabric suitable for applications such as transportation vehicles. The spacers are made of polyester yarns and can be treated with a fluorochemical finish composition to impart stain water and/or oil resistance to the spacer.
WO 2012/147582 A2 discloses a method to treat a twill weave with a C6-perfluoroalkyl based polymer. US 2011/257327 discloses the application to textiles of a water and oil repellent comprising C4-C6 perfluorinated polymer being low in bioaccumulation potential.
Against this background, it was an object of the present invention to provide a method of preparing a spacer fabric which is substantially free of PFOA and PFOS, or in general free of any C8 telomer-based water and oil repellent products, and which nonetheless exhibit the properties with respect to oil repellency, spray rating, flame retardancy and low volatile emissions required by the automotive industry. Furthermore, in the light of the relative expensiveness of chemicals containing perfluoroalkyl sections it is a further object of the invention to provide a cost-efficient method of preparing such a spacer fabric.
The above described object has surprisingly been solved by the present invention.
This invention is a method of preparing a treated spacer fabric according to claim 1, comprising the steps:

a) providing a spacer fabric of a thermoplastic polymer;
b) providing a liquid treating composition comprising one or more C6-perfluoralkyl based fluoropolymer(s) and a solvent;
c) treating the spacer fabric by immerging the spacer fabric into a bath of the liquid treating composition;
d) removing excessive treating composition from the treated spacer fabric;
e) drying the treated spacer fabric; and
f) fixing the treated spacer fabric.

A "spacer fabric" as herein referred to comprises at least a first and second fabric layers that are arranged in an opposing back-to-back, spaced apart relationship with each other. The first and second fabric layers are interconnected to each other with one or more spacer fibers that interconnect the first and second fabric layers and define a space between these layers. The spacer fibers comprise a resilient material that is able to maintain the space between the fabric layers, while still permitting the layers to be reversibly compressed together. As a result, the spacer fabric provides a relatively light weight and flexible fabric.
In context of the present invention it is preferred that the spacer fabric has a thickness in the range of 1.0 to 7 mm, more preferably in the range of 1.4 to 6 mm, and most preferably in the range of 1.6 to 5 mm. The weight per unit area of the provided spacer fabric used for the preparation of the treated spacer fabric of the present invention is preferably in the range of 100 to 500 g/m², more preferably in the range of 150 to 400 g/m², and most preferably in the range of 200 to 350 g/m². Furthermore, the spacer fibers that interconnect the first and second fabric layers are preferably monofil fibers.
The spacer fabric of a thermoplastic polymer provided in step a) of the inventive method and used to prepare the treated spacer fabric is based on a thermoplastic polymer or at least mainly consists a thermoplastic polymer. The thermoplastic polymer is preferably selected from the group consisting of polyester, polyamid and a combination thereof. Spacer fabrics made of polyester are particularly preferred. "Based on" means that the spacer fabric comprises the thermoplastic polymer, for example, as material for the first fabric layer, for the second fabric layer or for both. Alternatively, the spacer fabric comprises the thermoplastic polymer as material for the spacer fibers that interconnect the first and second fabric layers. Also, the spacer fabric can comprise the thermoplastic polymer as material for the spacer fibers and only one of the first fabric layer and the second fabric layer. "At least mainly consist of" means that the material the spacer fabric is made of consists of at least 50 % by weight of the thermoplastic polymer. Preferably, at least 90 % by weight, more preferably at least 95 % by weight or even 100 % by weight, of the spacer fabric is made of a thermoplastic polymer as defined above.
The treated spacer fabric prepared according to the present invention is particularly suitable for use in an automobile because of its good flame retardancy and low volatile emissions properties. Furthermore, the treated spacer fabric prepared according to the present invention is also particularly suitable for use in an automobile because of its high spray rating and/or good oil repellency properties.
The treated spacer fabric prepared according to the present invention has an acceptable flame retardancy measured according to FMVSS 302 (corresponds to DIN 75200). According to FMVSS 302 the first side of the fabric is applied to a flame. It is measured the distance of burning, the time of burning and the velocity of burning in the machine direction as well as the cross direction. The same is measured on the second side of the fabric. Each of the measurements is repeated 3 times. "Acceptable" here means that at least five of the six measurements on the first and the second side in cross direction yield a velocity of burning of less than 100 mm/minute, preferably less than 85 mm/minute, most preferably less than 70 mm/minute.
The treated spacer fabric prepared according to the present invention has a total emission according to VDA 277 (5 hours, 120 °C) of less than 100 µgC/g, preferably less than 90 µgC/g.
The treated spacer fabric prepared according to the present invention typically has a fogging according to DIN 75201-B (16 hours, 100 °C) of less than 100 mg, preferably less than 90 mg, most preferably less than 80 mg.
The treated spacer fabric prepared according to the present invention typically has a smell according to VDA 270-2 (40 °C) of not worse than grade 3, preferably of grade 2, most preferably of grade 1.
The treated spacer fabric prepared according to the present invention typically has a emission of formaldehyde according to VDA 275 of less than 3.0 mg/kg, preferably less than 2.5 mg/kg, most preferably less than 2.0 mg/kg.
The treated spacer fabric prepared according to the present invention typically has a spraytest rating according to AATCC 22 of at least 70, preferably at least 75, most preferably at least 80.
The treated spacer fabric prepared according to the present invention typically has an oil repellency rating according to AATCC 118 of at least 4, preferably at least 5, most preferably at least 6.
"For use in an automobile" as herein referred to means that the treated spacer fabric prepared according to the invention is used as material for the manufacture of car seats, car ceilings, dashboards, car interior, rear panel shelfs, airbag housings, airbag openings, protection cushions and the like.
"C6-perfluoralkyl based fluoropolymer(s)" as herein referred to is one or more fluorocarbon derivatives, each derivative comprising idependently from each other, one or more perfluorohexyl tails and/or one or more perfluoroalkyl (CF₂)_n-sections with n = 6. The C6-perfluoralkyl based fluoropolymer(s) may additionally comprise a polymeric backbone bearing more than one groups selected from the perfluorohexyl tails and the perfluoroalkyl (CF₂)_n-sections. The polymeric backbone may additionally comprise one or more spacer groups between the polymeric backbone and one or more of the the perfluorohexyl tails and/or the perfluoroalkyl (CF₂)_n-sections. The polymeric backbone may additionally comprise one or more side groups which can bond via any kind of chemical or physical bond to the surface of a spacer fabric. Preferred C6-perfluoralkyl based fluoropolymers used according to the invention are fluorocarbon derivatives comprising more than one perfluorohexyl tails and a polymeric backbone bearing the perfluorohexyl tails.
A "C8-perfluoralkyl based fluoropolymer" as herein referred to is a fluorocarbon derivative comprising one or more perfluorooctyl tails and/or one or more perfluoroalkyl (CF₂)_n-sections with n = 8.
A "treated spacer fabric" as herein referred to means a spacer fabric which has been treated with any kind of substance, compositions or solutions. The treating substances or compositions can be in the solid, pulverulent, liquid, viscous or gaseous state. Further, any kind of treatment is encompassed, e.g. dipping, immerging, spraying or the like. The only proviso is that an amount of such a substance or composition remains on or is adhered to the spacer fabric. The substance can be adhered to the spacer fabric by any kind of chemical and/or physical bonding.
A "liquid treating composition" as herein referred to means an emulsion, a solution or any other kind of liquid composition which can be used to treat a spacer fabric.
The provided liquid treating composition used in the method of the invention has a concentration of the C6-perfluoralkyl based fluoropolymer(s) in the in the range of from 0.3 to 10 g/l, preferably in the range of from 0.4 to 8 g/l, and most preferably in the range of from 0.5 to 6 g/l. It is preferred that the liquid treating composition is an aqueous liquid treating composition.
The provided spacer fabric is preferably free of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS) and perfluorooctane sulfonate (PFOS). "Free of" perfluorooctanoic acid, perfluorooctanesulfonic acid and perfluorooctane sulfonate means here that the spacer fabric comprises not more than 1 ppm, preferably not more than 100 ppb, most preferably not more than 10 ppb, of the sum of perfluorooctanoic acid, perfluorooctanesulfonic acid and perfluorooctane sulfonate, based on of the total weight of the spacer fabric. If questionable, it should be ensured that the spacer fabric provided is free of perfluorooctanesulfonic acid, perfluorooctane sulfonate and perfluorooctanoic acid. "Being ensured to be free of" perfluorooctanesulfonic acid, perfluorooctane sulfonate and perfluorooctanoic acid means here that it has been actively ensured by appropriate measures that the provided spacer fabric indeed comprises not more than 1 ppm, preferably not more than 100 ppb, most preferably not more than 10 ppb, of the sum of perfluorooctanoic acid, perfluorooctanesulfonic acid and perfluorooctane sulfonate, based on of the total weight of the spacer fabric. An appropriate measure in this context can be a pre-washing step where the provided spacer fabric is washed prior to step c). Alternatively, the provided spacer fabric can be prefixed prior to step c). "Prefixing" means here that the provided spacer fabric is heated and, optionally, brought into uniform shape by, for example, stretching the spacer fabric. The heating may also lead to a reduction of any PFOA, PFOS and PFOS eventually present on the provided spacer fabric.
The liquid treating composition is preferably free of perfluorooctanesulfonic acid, perfluorooctane sulfonate and perfluorooctanoic acid. This means that the liquid treating composition comprises not more than 1 ppm, preferably not more than 100 ppb, most preferably not more than 10 ppb, of the sum of perfluorooctanoic acid, perfluorooctanesulfonic acid and perfluorooctane sulfonate, based on of the total weight of the liquid treating composition.
Beside the preferred absence of any PFOA and PFOS, of course, it is also preferred that both the provided spacer fabric and the liquid treating composition are free of any C8-perfluoralkyl based fluoropolymers - due to the environmental problems discussed above.
In the inventive method there is a step d) to remove excessive treating composition from the treated spacer fabric. Excessive treating composition can be removed, for example, by squeezing out the excessive treating composition from the spacer fabric. Squeezing out can be performed, for example, by nip-rolling the spacer fabric between two rubber rolls. Other methods of removing excessive treating composition can also be used. When removing excessive treating composition it is particularly preferred that all of the removed treating composition - or at least a major part thereof - is separated from the bath containing the liquid treating composition which is used in step c) for treating the spacer fabric. This can be achieved, for example, by preventing at least a major part or all of the removed treating composition from flowing back to the bath containing the liquid treating composition. A "major part" here means more than 40 % by weight, preferably more than 50 % by weight, even more preferably more than 60 % by weight, and most preferably more than 70 % by weight, of the removed treating composition.
As a result after removing excessive treating composition the so-called "pick-up" is preferably in the range of 50 to 150 %, more preferably in the range of 60 to 100 %.
The "pick-up" as herein referred to is defined as the increase of weight of the wet treated spacer fabric after treatment with the treating composition and after removing excessive treating composition compared to the spacer fabric prior to the treatment. This means, if e.g. 100 gram provided spacer fabric have a weight of 150 gram after being treated with the treating composition and after removing of excessive treating composition the pick-up is 50%.
In a preferred method the excessive treating composition is removed from the spacer fabric by squeezing out between two rubber rolls. The pressure between the two rubber rolls is preferably in the range of 1 to 8 bar, more preferably in the range of 3 to 6 bar.
The advantage of separating the removed treating composition from the bath containing the liquid treating composition is that fiber preparations washed out from the spacer fabric by excessive treating composition does not accumulate in the bath containing the liquid treating composition. This in turn prevents the spacer fabric immerged into the bath for treatment from being contaminated with the accumulated fiber preparations present in the bath. Contamination of the spacer fabric with accumulated fiber preparations present in the bath can be a problem because the properties selected from flame retardancy, oil repellency, spray rating and low volatile emissions can be negatively affected by the fiber preparations contamination, especially since such fiber preparations contamination is typically inhomogeneous or non-uniform.
"Fiber preparations" herein referred to are chemical substances not having an intended function at the final spacer fabric but which adhere to the provided spacer fabric as a result of the manufacture of the spacer fabric. Typical fiber preparations are lubricants and static inhibitors. The chemical substances behind these lubricants and static inhibitors are, for example, fats, waxes, oils and esters of phosphoric acid.
"Excessive treating composition" here means that amount or portion of treating composition which is absorbed from or adhere to the spacer fabric after the treated spacer fabric has left the immerging bath but which is not needed, e.g. for achieving the desired properties, such as good flame retardancy, good oil repellency, high spray rating and/or low volatile emissions, or which is just too much since it makes the treated spacer fabric too wet for adequate or sound further processing.
In the inventive method there is a step e) of drying the treated spacer fabric. To "dry" a spacer fabric in context of the present invention means that the spacer fabric is dried by means of, for example, warming or heating the spacer fabric, by blowing warm or cold air over or through the spacer fabric or by irradiating the spacer fabric with e.g. IR-radiation or the like. The degree of "drying" or dryness is not critical and depends on the desired properties of or the demands on the final spacer fabric.
In the inventive method there is a step f) of fixing the treated spacer fabric. To "fix" a spacer fabric in context of the present invention means that the treating composition adhered to the spacer fabric is fixed. This fixing is a process where as a result of temperature and/or time and/or other causes the treating composition adhered to the spacer is hardened and/or aged and/or solidified and/or tempered and/or the like. Fixing may also include a crosslinking process of the C6-perfluoralkyl based fluoropolymer(s) of the treating composition and/or a covalent binding process of the C6-perfluoralkyl based fluoropolymer(s) to the thermoplastic material of the spacer fabric.
In the inventive method there is prior to step c) an optional step of pre-fixing the spacer fabric. To "pre-fix" a spacer fabric in context of the present invention means that the spacer fabric is brought into uniform shape by, for example, stretching and subsequently or at the same time heating the spacer fabric. Pre-fixing by means of heating can also be an alternative method to the optional pre-washing step of the provided spacer fabric mentioned above in context with removing of any PFOA, PFOS and PFOS eventually present on the provided spacer fabric.
The liquid treating composition used according to the present invention preferably comprises water as solvent and additionally one or more emulsifier(s) or surfactant(s).
As emulsifier(s) or surfactant(s) non-ionic emulsifier/surfactants is/are preferred. Polyoxyethylene glycol alkyl ethers and polyoxypropylene glycol alkyl ethers are particularly preferred.
Additionally, further ingredients can be present in the liquid treating composition, for example, alcohols like isopropanol as an auxiliary agent.
In a preferred embodiment of the invention the liquid treating composition comprises the C6-perfluoralkyl based fluoropolymer(s), the emulsifier(s), isopropanol and the water.
In a particularly preferred embodiment of the present invention the concentration of fiber preparations in the liquid treating composition in the bath is kept low as long as the treating step c) is performed. This means that it should be ensured - by appropriate measures - that the concentration of fiber preparations in the liquid treating composition in the bath is low, preferably as low as possible, when the spacer fabric is immerged into the bath of the liquid treating composition.
An "appropriate measure" for keeping the concentration of fiber preparations in the bath of liquid treating composition low can be, for example, ensuring that all or at least a major part of the removed treating composition is separated from the bath containing the liquid treating composition. The separation avoids accumulation of fiber preparations which can be washed out from the spacer fabric by excessive treating composition. Another measure for keeping the concentration of fiber preparations low could be the dilution of "used" liquid treating composition with fresh and uncontaminated liquid treating composition or even - if a predetermined amount of fiber preparations contamination is reached - the substitution of "used" liquid treating composition with fresh and uncontaminated liquid treating composition.
It is also preferred according to the present invention that the spacer fabric provided in step a) comprises fiber preparations in an amount as low as possible. Ideally, the provided spacer fabric is free of fiber preparations. Therefore, and in order to achieve best results with the present invention, it should be ensured - by appropriate measures - that the provided spacer fabric comprises fiber preparations in an amount as low as possible or is essentially free of fiber preparations, at least when entering the treating step c), i.e. when the spacer fabric is immerging into the bath of the liquid treating composition.
An appropriate measure in this context can be a pre-washing step where the provided spacer fabric is washed prior to step c). Alternatively, the provided spacer fabric can be prefixed prior to step c). "Prefixing" means here that the provided spacer fabric is heated and, optionally, brought into uniform shape by, for example, stretching the spacer fabric.
As discussed above, is has surprisingly been found that the treated spacer fabrics prepared according to the present inventive method exhibit a good flame retardancy even if no additional flame retardants are used when treating the spacer fabrics.
This means, it is preferred that no flame retardants are added to the provided liquid treating composition and/or to the provided spacer fabric and/or to the treated spacer fabric. It is particularly preferred that no flame retardants are added at all to the provided liquid treating composition and to the provided spacer fabric and to the treated spacer fabric.
"Flame retardants" in the sense of the present invention are the minerals, namely aluminium hydroxide, magnesium hydroxide, huntite and hydromagnesite, red phosphorus, and boron compounds; the organohalogen compounds, namely chlorendic acid derivatives and chlorinated paraffins, decabromodiphenyl ether, decabromodiphenyl ethane, brominated polystyrenes, brominated carbonate oligomers, brominated epoxy oligomers, tetrabromophthalic anyhydride, tetrabromobisphenol A and hexabromocyclododecane; the organophosphorus compounds, namely organophosphate, tris(2,3-dibromopropyl) phosphate, TPP, RDP, BPADP, tricresyl phosphate, phosphonates as DMMP and phosphinates.
The present invention is also directed to a treated spacer fabric obtainable by the method described above. In a preferred embodiment of the invention the treated spacer fabric obtainable by the method described above comprises at least a spacer fabric and about 0.03 to about 1.0 % by weight, preferably about 0.04 to about 0.8 % by weight, and most preferably in the range of from about 0.05 to about 0.6 % by weight, of C6-perfluoralkyl based fluoropolymer(s), based on the weight of the spacer fabric. The amount of C6-perfluoralkyl based fluoropolymer(s) can be determined according to the procedures described in DIN SPEC 1038:2010. The person skilled in the art is able to identify and select those signals in the LC-MS (Liquid chromatography-mass spectrometry) measurements that origin from the C6-perfluoralkyl based fluoropolymer(s) and to calibrate the measurements to obtain correct results for the amount of C6-perfluoralkyl based fluoropolymer(s). Depending on the chosen procedural details of the procedures described in DIN SPEC 1038:2010 an acceptable variation of the results may occur. A variation of up to ± 20 % in the measured amount of the C6-perfluoralkyl based fluoropolymer(s) is acceptable within the present invention.
The spacer fabric obtainable by the method described above is practically free of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS) and perfluorooctane sulfonate (PFOS). "Practically free of" perfluorooctanoic acid, perfluorooctanesulfonic acid and perfluorooctane sulfonate means here that the spacer fabric comprises not more than 100 ppb, preferably not more than 10 ppb, most preferably not more than 1 ppb, of the sum of perfluorooctanoic acid, perfluorooctanesulfonic acid and perfluorooctane sulfonate, based on of the total weight of the spacer fabric.
More general, the present invention is directed to any treated spacer fabric comprising at least a spacer fabric and one or more C6-perfluoralkyl based fluoropolymer(s), the treated spacer fabric being free of perfluorooctanesulfonic acid, perfluorooctane sulfonate and perfluorooctanoic acid and/or being free of any flame retardants. In a preferred embodiment of the invention the treated spacer fabric comprises 0.03 to 1.0 % by weight, preferably 0.04 to 0.8 % by weight, and most preferably in the range of from 0.05 to 0.6 % by weight, of the C6-perfluoralkyl based fluoropolymer(s) based on the weight of the spacer fabric.
"Free of any flame retardants" means here that the spacer fabric comprises less than 3 % by weight, preferably less than 1 % by weight, most preferably less than 0.1 % by weight, of the sum of all flame retardants falling under the above definition, based on of the total weight of the spacer fabric.
The treated spacer fabric of the invention has a velocity of burning (the most important criterion of flame retardancy according to FMVSS 302) of less than 100 mm/minute, preferably less than 85 mm/minute, most preferably less than 70 mm/minute, in at least five of six measurements in cross direction, three measurements on the first and three measurements on the second side, and has a total emission according to VDA 277 (5 hours, 120 °C) of less than 100 µgC/g, preferably less than 90 µgC/g.
Preferably, and in addition to the above good velocity of burning and the low total emission, the treated spacer fabric according to the invention has a spraytest rating according to AATCC 22 of at least 70, preferably at least 75, most preferably at least 80.
Preferably, and in addition to the above good velocity of burning and the low total emission and, optionally, good spray test rating, the treated spacer fabric according to the invention has an oil repellency rating according to AATCC 118 of at least 4, preferably at least 5, most preferably at least 6.
More preferably, and in addition to the above good velocity of burning, the low total emission and the optional good spray test rating and oil repellency rating, the treated spacer fabric according to the invention has a fogging according to DIN 75201-B (16 hours, 100 °C) of less than 100 mg, preferably less than 90 mg, most preferably less than 80 mg, and/or a smell according to VDA 270-2 (40 °C) of not worse than grade 3, preferably of grade 2, most preferably of grade 1, and/or a emission of formaldehyde according to VDA 275 of less than 3.0 mg/kg, preferably less than 2.5 mg/kg, most preferably less than 2.0 mg/kg.
The present invention is also directed to the use according to claim 8 of a liquid treating composition comprising one or more C6-perfluoralkyl based fluoropolymer(s) for preparing a treated spacer fabric of a thermoplastic material, preferably a treated spacer fabric as described above in more detail. In a preferred embodiment of the invention the liquid treating composition comprises the C6-perfluoralkyl based fluoropolymer(s) in a concentration range of from 0.3 to 10 g/l, preferably in the range of from 0.4 to 8 g/l, and most preferably in the range of from 0.5 to 6 g/l.
In a preferred embodiment of the invention the liquid treating composition used as mentioned above preferably comprises water as solvent and additionally one or more emulsifier(s) or surfactant(s).
Figure 1 shows a flow chart with the typical and preferred method steps when preparing a treated spacer fabric according to the invention. One or more of the steps of pre-fixing, removing, drying and fixing can be optional if not needed for achieving customized requirements.

Examples

Methods of determining selected properties of the spacer fabrics:

The flame retardancy of the spacer fabrics has been measured according to FMVSS 302 (corresponds to DIN 75200). The total emission of the spacer fabrics has been measured according to VDA 277 (5 hours, 120 °C). The fogging of the spacer fabrics has been measured according to DIN 75201-B (16 hours, 100 °C). The smell of the spacer fabrics has been measured according to VDA 270-2 (40 °C). The emission of formaldehyde of the spacer fabrics has been measured according to VDA 275. The spraytest rating of the spacer fabrics has been measured according to AATCC 22. The oil repellency rating of the spacer fabrics has been measured according to AATCC 118.

Method of preparing the treated spacer fabrics:

The untreated raw spacer fabrics are conducted via rolls through a bath containing the treating composition at a speed of 6 m/min whereby each section of the spacer fabrics is in contact with the treating composition in the bath for about 3 to 5 seconds. The bath containing the treating composition is heated to a temperature of 23 °C. The treating composition is an aqueous emulsion containing about 2 gram per liter of a C6-perfluoralkyl based fluoropolymer (in form of BAYGARD EFN which is a liquid composition containing about 30 % by weight of the C6-perfluoralkyl based fluoropolymer, BAYGARD EFN is available from Tanatex Chemicals B.V., Netherlands). After leaving the bath the spacer fabrics are conducted through two stainless steel rolls having a separation distance of 0.2 mm for removing excessive treating composition from the spacer fabrics. Discharge means are arranged below the rolls which separate the removed treating composition from the bath containing the liquid treating composition. Thereafter, the treated spacer fabrics are dried with hot blowing air at a temperature of about 165 °C. Finally, the spacer fabrics are conducted through a device fixing the treated spacer fabrics. The final treated spacer fabrics have been analyzed. The results are summarized in table 1.

Table 1

spacer fabric article	5944-3,4 (treated)	5944-3,4 (untreated)
material	unchanged	polyester
thickness	unchanged	3,4 mm
weight per unit area (DIN EN 12127)	274.2 g/m²	273.1 g/m²
velocity of burning (one side, cross direction)	0 mm/min	0 mm/min
	0 mm/min	54 mm/min
	113 mm/min	0 mm/min
velocity of burning (other side, cross direction)	0 mm/min	0 mm/min
	80 mm/min	0 mm/min
	61 mm/min	56 mm/min
total emission	83.0 µgC/g	72.0 µgC/g
fogging	0.25 mg	0.85 mg
smell	grade 1	grade 1
emission of formaldehyde	1.13 mg/kg	3.24 mg/kg
oil repellency rating	6-7	--
spraytest rating	80	--

Table 2

spacer fabric article	5977-3,7 (treated)	5977-3,7 (untreated)
material	unchanged	polyester
thickness	unchanged	3,7 mm
weight per unit area (DIN EN 12127)	285.6 g/m²	284.5 g/m²
velocity of burning (one side, cross direction)	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
velocity of burning (other side, cross direction)	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
total emission	39.0 µgC/g	26.7 µgC/g
fogging	0.6 mg	1.8 mg
smell	grade 2	grade 2
emission of formaldehyde	0.0 mg/kg	0.4 mg/kg
oil repellency rating	4-5	--
spraytest rating	70-80	--

Table 3

spacer fabric article	5944-4,5 (treated)	5944-4,5 (untreated)
material	unchanged	polyester
thickness	unchanged	4,5 mm
weight per unit area (DIN EN 12127)	298.2 g/m²	297.2 g/m²
velocity of burning (one side, cross direction)	76 mm/min	84 mm/min
	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
velocity of burning (other side, cross direction)	0 mm/min	0 mm/min
	0 mm/min	80 mm/min
	0 mm/min	74 mm/min
total emission	8.4 µgC/g	12.4 µgC/g
fogging	0.4 mg	0.4 mg
smell	grade 1-2	grade 1-2
emission of formaldehyde	0.0 mg/kg	0.0 mg/kg
oil repellency rating	5	--
spraytest rating	80	--

Table 4

spacer fabric article	9002-3,3 (treated)	9002-3,3 (untreated)
material	unchanged	polyester
thickness	unchanged	3,3 mm
weight per unit area (DIN EN 12127)	255.9 g/m²	254.8 g/m²
velocity of burning (one side, cross direction)	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
velocity of burning (other side, cross direction)	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
total emission	2.0 µgC/g	4.0 µgC/g
fogging	0.15 mg	0.4 mg
smell	grade 1-2	grade 1-2
emission of formaldehyde	0.0 mg/kg	0.0 mg/kg
oil repellency rating	7	--
spraytest rating	90	--

Table 5

spacer fabric article	9003-3,1 (treated)	9003-3,1 (untreated)
material	unchanged	polyester
thickness	unchanged	3,1 mm
weight per unit area (DIN EN 12127)	211.2 g/m²	210.5 g/m²
velocity of burning (one side, cross direction)	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
velocity of burning (other side, cross direction)	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
	0 mm/min	0 mm/min
total emission	1.6 µgC/g	8.0 µgC/g
fogging	0.25 mg	0.45 mg
smell	grade 1-2	grade 1-2
emission of formaldehyde	0.0 mg/kg	0.0 mg/kg
oil repellency rating	6	-
spraytest rating	80	-

Claims

Method of preparing a treated spacer fabric comprising the steps:
a) providing a spacer fabric of a thermoplastic polymer;

b) providing a liquid treating composition comprising one or more C6-perfluoralkyl based fluoropolymer(s) and a solvent;

c) treating the spacer fabric by immerging the spacer fabric into a bath of the liquid treating composition;

d) removing excessive treating composition from the treated spacer fabric;

e) drying the treated spacer fabric; and

f) fixing the treated spacer fabric,
wherein the concentration of the C6-perfluoralkyl based fluoropolymer(s) in the provided liquid treating composition is in the range of 0.3 to 10 g/l, and wherein the treated spacer fabric obtained after method step f) has a velocity of burning according to FMVSS 302 of less than 100 mm/minute in at least five of six measurements in cross direction, three measurements on the first and three measurements on the second side, and has a total emission according to VDA 277 of less than 100 µgC/g.
Method according to claim 1, wherein the thermoplastic polymer is selected from the group consisting of polyester, polyamid and a combination thereof.
Method according to one or more of the preceding claims, wherein the solvent is water and the liquid treating composition additionally comprises one or more emulsifier(s).
Method according to one or more of the preceding claims, wherein no flame retardants are added to the provided liquid treating composition and/or to the provided spacer fabric and/or to the treated spacer fabric.
Method according to one or more of the preceding claims, wherein at least a major part of the removed treating composition is separated from the bath containing the liquid treating composition which is used in step c) for treating the spacer fabric.
Treated spacer fabric comprising at least a spacer fabric and one or more C6-perfluoralkyl based fluoropolymer(s), the treated spacer fabric being free of perfluorooctanesulfonic acid, perfluorooctane sulfonate and perfluorooctanoic acid and/or being free of any flame retardants, wherein the treated spacer fabric has a velocity of burning according to FMVSS 302 of less than 100 mm/minute in at least five of six measurements in cross direction, three measurements on the first and three measurements on the second side, and has a total emission according to VDA 277 of less than 100 µgC/g.
Treated spacer fabric according to claim 6, wherein the spacer fabric comprises 0.03 to 1.0 % by weight of the C6-perfluoralkyl based fluoropolymer(s) based on the weight of the spacer fabric.
Use of a liquid treating composition comprising one or more C6-perfluoralkyl based fluoropolymer(s) and a solvent for preparing a treated spacer fabric of a thermoplastic polymer, wherein the treated spacer fabric has a velocity of burning according to FMVSS 302 of less than 100 mm/minute in at least five of six measurements in cross direction, three measurements on the first and three measurements on the second side, and has a total emission according to VDA 277 of less than 100 µgC/g.
Use according to claim 8, wherein the solvent is water and the liquid treating composition additionally comprises one or more emulsifier(s).
Use according to claim 8 or 9, wherein the treated spacer fabric has a spraytest rating according to AATCC 22 of at least 70 and/or an oil repellency rating according to AATCC 118 of at least 4 and/or a fogging according to DIN 75201-B of less than 100 mg and/or a smell according to VDA 270-2 of not worse than grade 3 and/or a emission of formaldehyde according to VDA 275 of less than 3.0 mg/kg.
Use according to one or more of the claims 8 to 10, wherein the liquid treating composition comprises the C6-perfluoralkyl based fluoropolymer(s) in a concentration range of from 0.3 to 10 g/l.