CARLIER, Luc, Regis, Leon (Hippodroomstraat 54, Waregem, B-8790, BE)
CLAIMS
1. A process of manufacturing a laminated flame-retardant treated fabric comprising a front fabric layer and a flame-retardant back-layer, characterized in that one surface of a back-layer is provided with a flame- retardant powder and a thermal glue powder, and the back-layer is connected to the front fabric layer by heat treatment of the superimposed layers.
2. A process according to claim 1 , characterized in that the front fabric layer is a non-woven fabric layer.
3. A process according to claims 1 or 2, characterized in that the back layer is a non-woven fabric layer.
4. A process according to any one of the claims 1 - 3, characterized in that the front fabric layer comprises 100 % by weight of synthetic fabrics.
5. A process according to any one of the claims 1 - 4, characterized in that the back-layer is made of pure cellulose fibres or a mixture of cellulose and polyester fibres.
6. A process according to any one of the proceeding claims, characterized in that, the flame-retardant powder and the thermal glace powder are applied to the surface of the back-layers as a scattered mix of powders.
7. A process according to anyone of the claims 1-5, characterized in that the flame retardant powder and the thermal glue powder are applied to the surface of the back-layer by means of a flock process.
8. A process according to claim 7, characterized in that the surface of the back-layer is coated with a stable foam or a non foam able coating and the scattered mix of powder is applied while the stable foam or the non foam able coating is still in a wet condition.
9. A process according to any one of the preceding claims, characterized in that the back-layer is provided with a coating containing at least a flame- retardant.
10. Back layer to be used with a front layer characterized in that one surface of the black layer is provided with a scattered mix of powders containing a flame-retardant powder and a thermal glue powder.
11. Back layer according to claim 10, characterized in that the back layer comprises a fabric layer one surface of being provided with a coating containing at least one flame retardant component.
12. Assembly comprising an amount of back layer comprising a fabric layer of which one surface being provided with a coating comprising a flame retardant component, and a package contained a mixture of a flame retardant powder and a thermal glue powder. |
Process of manufacturing a laminated flame-retardant fabric.
The invention relates to a process of manufacturing a laminated flame-retardant treated fabric comprising a front fabric layer and a flame-retardant back-layer.
In the prior art several methods have been described for producing laminated flame-retardant treated fabrics.
In a first method the fabric, more especially upholstery fabric has been provided with a back coating based upon a collapsible foam, a half collapsible foam, a stable foam, or a paste, either low or high viscosity paste, in which the applied coating contains at least one flame-retardant compound.
The application of such a coating is commonly done by means of lik-roll coating (such as a kiss roll), knife coating (such as knife over air or knife over roll), screen coating or any other commonly known coating method.
In some cases, especially for flat fabrics, the coating can be done by so-called padding (Foulard). However in this system the chemicals come into direct contact with the front side of the fabric which makes the method less attractive.
When using one of the above cited methods the chemicals used in the coating need to be dried and fixed to the fabric, which can be done by guiding the coated fabric through an over (Stenter) in which the fabric is submitted to temperatures of at least 120 0 C up till temperatures of about 200 0 C. The length of the oven determines the speed of drying and fixing to the fabric. This operation requires a good air exhaustion system with sophisticated filtration equipment to reduce the emission.
As these technologies are well known for years they offer a number of advantages in that a wide scope of applications are available. It is therefore possible with this method to coat synthetic and natural fibres. Furthermore a substantial number of coating equipment is available in the market and present in vertically integrated companies.
A disadvantage of this process however is that the equipment to be used is relatively expensive and requires high investment costs, the equipment is large requiring substantial space and must be handled by skilled people.
In this type of process halogen containing coatings are commonly used because they are more efficient and more economical. However mostly they only achieve low or no water resistances like in the soaking test BS. It is therefore difficult to achieve permanent systems which allow a wash ability of the fabric and it is also difficult to achieve high flame retardant standards like BS 5852 part XX Crib 5 or 7 on 100% synthetic materials. With halogen the recycling of water generates an additional problem.
In EP-A-O 752 458 there is described another system and process for producing flame retardant fabric. In general terms this is called a lamination process in which a non-woven fabric is provided with a thermal glue layer and the flame retardant powder is sprayed over this glue layer. Subsequently an additional glue layer may be applied over this first glue layer or another protective layer can be applied. The thermal glue layer can be of the type PES, PP, TPU ot mixtures thereof whereas as flame retardant compound use can be made of graphite particles.
For this process it is needed to have a heated laminator (e.g. of the type Kleverik or Reliant), allowing the assemblage of the front and back fabric, whereas further one or two scatters must be available in order to apply the flame retardant and the thermal glue powder powder.
By using this system and process it became possible to have halogen free flame retardant powders and reach high standards on synthetic fabrics like Crib 5 or Crib 7. Furthermore there is a wash ability of 5 to 10 times depending upon the synthetic fabrics and the thermal glue used. Moreover the type of machine to be used is much cheaper and smaller than in the previous method as no oven is needed.
Otherwise the system has some very specific disadvantages. The investment for a laminator is still important as is the cost for scattering equipment as the application is difficult in view of the static electricity. During confection there are still particles leaving the fabric. Graphite is containing heavy metals (chromium) so that there is pollution problem and it is a expensive product that can only produced in circumstances which are environmentally unfriendly. In some application also the colour of the graphite constitutes a problem.
It is therefore an object of the invention to provide a process for manufacturing a laminated flame-retardant fabric in which the above mentioned problems and disadvantages have been avoided.
This object is achieved by means of the process according to claim 1.
The obtained fabric can be any within a wide range of fabrics such as upholstery, carpets, mattress ticking, curtains, black-out and dim-out curtains, sun protection fabrics, gardening furniture fabrics, wall paper fabrics, protective clothing, automotive applications, decoration fabrics, banners and all kind of technical fabrics. The end fabric maintains mainly its original flexibility, its air permeability, its hand touch which is even improved by giving a full soft body, and its appearance of the original front fabric which has the behaviour to be flame-retardant without any direct flame-retardant composition being present on both the front and rear face of the end fabric. This has the advantage that people working with this type of fabric have no direct contact with any chemical composition thereby avoiding a number of environmental problems. It is also possible to use lighter front fabrics than usually, as the total strength and other characteristics of the ultimate fabric will be provided by the combination of the front and back layer bound together.
In the following a number of examples of front and back layers will be described as well as possible combinations thereof. Moreover in the following description different methods for applying the thermal glue particles will be described.
In most circumstances the back layer thermo-adhesive pre-treated flame retardant fabric will be composed as follows:
Part i : A blend mainly of cellulose containing fibres and a defined percentage of synthetic fibres is assembled in a non-woven fabric produced by hydro jet. The weight of this fabric will vary between 15g/m 2 and 100 g/m 2 . This does not exclude the use of 100% cellulose containing fibres and of different types of weavings like non-woven, woven, knitted
Part 2:
A stable or semi-stable or unstable coating or even a non foam able coating which is produced of flame-retardant raw-materials, binders , special additives. IN addition it is possible to add other special additives like anti-bacterial, anti dust mite, anti-waves, temperature reflex ion,....
Part 3:
The scattered mix of powders can be a mono product or blends of flame retardant compounds such as vermiculite, powder thermo glue like PES, PP, PA, or mixtures thereof, and chemical powders which can provide all kind of properties like anti-bacterial, anti-dust mite,...
Those powders can have particle sizes ranging from the 50μ to 500 μ.
The method of production is characterized in that it comprises the following steps:
The fabric (part 1) is installed in a coating line (knife over air) or a printing line (CT4) which all provides the possibility to apply stable foam, semi stable foam and unstable foam and paste (non foam able). The special flame-retardant coating (part 2) is applied on the fabric (part 1). The powders (part 3) are scattered above the coating (part 2) before entering the stenter (oven). The powders fall Jn and on the front side of the coating.
A second method of application of the powders on the coatings is to use the technology of flocking . This has for advantage that it attracts and fix better the powder in the coating and gives a stronger fixation between the powder and the coating. After this operation, the coating (part 2) and the powders (part 3) can be dried and fixed at a temperature between 90 0 C and 160 0 C. In the case of stable foam or semi-stable foam , the fabric will be crushed just after the oven.
The end result is a back layer thermo-adhesive pre-treated flame retardant fabric .
This back layer thermo-adhesive pre-treated flame retardant fabric is ready to be sold, shipped and applied by the end customer which can be a manufacturer of normal woven or non woven front fabric composed of synthetic fibres (smelting/splitting type).
The customer can laminate this layer thermo-adhesive pre-treated flame retardant fabric with a classical laminator from the type Kleverik, Reliant, ...and even with existing material like heated calendars. This will provide a low cost, easy to apply, flexible solution to synthetic fabrics with flame retardant properties.
In a third method the back layer (part 1 ) and the coating (part 2) are prepared as described above but without the application of the mix of powders containing the flam retardant powder and the thermal glue powder. However apart from the back layer an adequate amount of a powder mix (part 3 ) is supplied to the end user together with the back layer. This allows the end user to apply the scattered mix of powder to the back layer and in the same process adhere the front layer to the back layer provided with the scattered mix of powder.
The present invention will now be explained by means of a number of examples, in which connection it should be noted, however, that the present invention is by no means limited to such a special example:
Q
Examples of trials:
Types of tested back fabrics:
1. Flat non woven
Quality A:
Material name : Jet non-woven
Material composition : 60% Polyester/40% Viscose
Weight: : 45g/m 2 Thickness: : 0,65 mm
Max tensile strength
Longitudinal : 79 N/5cm Transversal: : 74 N/5cm Elongation at max tensile strength Longitudinal : 40 %
Transversal : 54 %
Quality B:
Material name : Jet non-woven Material composition : 100% Viscose
Weight: : 45g/m 2
Thickness: : 0,62 mm
Max tensile strength
Longitudinal : 76 N/5cm Transversal: : 61 N/5cm
Elongation at max tensile strength Longitudinal : 31 % Transversal : 47 %
Quality C:
Material name : jet non-woven
Material composition : 35% Polyester/65% Viscose
Weight: : 50g/m 2
Thickness: : 0,54 mm
Max tensile strength
Longitudinal : 74 N/5cm Transversal: : 24 N/5cm
Elongation at max tensile strength Longitudinal : 30 % Transversal : 120 %
Quality D
Material name :wall papers backing Material composition : 100% cellulose Weight : 100g/m 2
Quality E
Material name : glass fiber non-woven
Material composition :glass fiber Weight : 100 g/m 2
2. Flat woven fabrics: Quality A:
Material composition: 100 % Co Weight: :100 g/m 2
Thickness: : 0,70 mm
Quality B:
Material composition: 95% Co + 5% Elastane Weight : 100 g/m -. 2 2
Thickness : 0,75 mm
Quality C:
Material composition : 65%Co + 35% Pes Weight : 100 g/m 2
Thickness : 0, 70 mm
Quality D:
Material composition :100% glass fibre Weight : 100 g/m 2
Thickness : 0,80 mm
Quality E:
Material composition: 100% basalt Weight : 120 g/m 2
Thickness : 0,9 mm
Types of tested coatings or glues for the treatment of the back fabric:
Quality A: Material composition : Bromine/Antimony /binder/+additives compound
Type of treatment : foamable coating or paste coating
Weight of dry add on: 40-50 g/m 2
Quality B:
Material composition : Bromine/Antimony /binder/+additives compound
Type of treatment : padding coating Weight of dry add on: 40-50 g/m 2
Quality C:
Material composition : Phosphore/Nitrogen/binder /+ additives compound
Type of treatment : Foamable coating or paste coating Weight of dry add on : 40- 50 g/m 2
Quality D:
Material composition : Phosphore/Nitrogen/binder / additives compound
y
Type of treatment : Padding coating Weight of dry add on : 20 g/m 2
Quality E: Material composition : Phosphore/Nitrogen/crosslinker
Type of treatment : Padding coating Weight of dry add on : 10-15g/m 2
Types of powder glue and flame retardant powder mixtures (scattering application or Flock application technique):
Quality A:
Material composition: EVA glue powder + Vermiculite powder
Quality B:
Material composition: Polyurethane glue powder + Vermiculite powder
Quality C:
Material composition : polyamide glue powder +Vermiculite powder
Quality D
Material composition : Polyolefin glue powder + Vermiculite powder
Quality E : Material composition : Polyester glue powder + Vermiculite powder
Quality F and :
Material composition : mixture in different ratio's of all A/B/C/D/E powders+ Vermiculite powder
Those mixtures are possibly used for both type of flame retardant rolls, first in the case of use of a flame retardant treated back fabric which is assembled by
scattering and lamination and second as powder which must be glued in the flame retardant coating composed of see here above.
Types of front fabrics which have given good results on FR Standards:
Quality A:
Material composition: 100% Polyester
Types of fabrics : non-woven and woven Flat and short and medium length pile fabrics
Quality B:
Material composition: 100% Trevira
Types of fabrics : non-woven and woven Flat and short and medium length pile
Quality C:
Material composition: 100% Polyamide
Types of fabrics : non-woven and woven Flat and short and medium length pile
Quality D:
Material composition: 100% Polypropylene
Types of fabrics : non-woven and woven Flat and short and medium length pile
Quality E:
Material composition: 100% acrylic
Types of fabrics : non-woven and woven Flat and short and medium length pile
Quality F and ....
Material composition: Mixtures of all above listed products, A 1 B 1 C 1 D 1 E must be splitting when flame is burning material)
Types of fabrics : non-woven and woven Flat and short and medium length pile
It has been found that all combinations of the above cited materials in a product according to the invention has resulted in a product with good flame retardant properties and easy to handle process.