GB2222608A - Infra-red absorbing textiles - Google Patents

Description

n_ i),, n,2 6 0 0 14- I- Case 150-5262 INFRA RED ABSORBING TEXTILE

MATERIAL Apparatus for detecting I.R. signals have been available for some time. These signals may be emitted by the object itself (e.g. hot mechanical parts, heated rooms in houses, exhaust gases of vehicles and the body temperature of humans and animals) or they may be reflected by the object.

Such apparatuses are mainly used for military purposes. They enable surveillance of troop movements at night for example even in pitch black conditions to occur. The I.R. detecting apparatuses work by contrasting the I.R. emission of the object with the background thereby making detection possible.

It has been a problem to develop textile materials which do not emit I.R. signals above that of the background.

According to the invention, there is provided a textile material to which a conjugated polymer containing a 5 or 6 membered heterocyclic or carbocyclic group and having a molecular weight preferably of at least 500 (herein referred to as the I.R. absorbing polymer) has been applied, preferably from an aqueous dispersion.

Preferably, the I.R. absorbing polymer penetrates the substrate.

Preferably the particle size of the I.R. absorbing polymer is below 1p on average.

Case 150-5262 Further according to the invention there is provided a process for treating textile material so that the material does not substantially emit infra red signals comprising applying to the material an IR suppressing amount of a conjugated polymer containing a 5 or 6 membered heterocyclic or carbocyclic group having a molecular weight preferably of at least 500 (herein referred to as the I. R. absorbing polymer).

Application may be carried out by exhaustion, padding or printing preferably so that the polymer penetrates the fibres.

Preferably the IR absorbing polymer is:

a) a homo or co-polymer of a 5 membered heterocyclic compound with a conjugated n electron system having one heteroatom selected from oxygen, nitrogen and sulphur (hereinafter described as component a) b) a homo- or co-polymer derived from aniline and derivatives thereof (hereinafter described as component b); and c) a homo- or co-polymer of a 5 membered heterocyclic compounds with a conjugated n electron system having two heteroatoms, selected from oxygen, nitrogen and sulphur (hereinafter described as component 0 - More preferably the I.R absorbing polymer is a homo-polymer derived from monomers selected from the aniline, pyrrole, thiophene, furan series or copolymers derived from a monomer selected from the pyrrole, thiophene and furan series and a co-monomer, selected from those of the benzthiazole, thiazole, oxazole, imidazole, phenanthrene, benzidine and aminochrysene series.

Preferably component a) is a polymer derived from monomers selected from. the pyrrolie, thiophene and furan series. More preferably such polymers are those derived from monomers selected from pyrrole, 1 Case 150-5262 3,4-dimethyl and diethyl pyrrole, 3,4-dichloropyrrole, 2-aminothiophene, 2-amino 3-cyanthiophene, 2,3-diethyl thiophene and 3-methyl and 3-ethyl furan. The monomers may be also copolymerised with up to 20 % of a comonomer selected from thiazole, benzthiazole, oxazole,. imidazole, aminophenanthrene, benzidine, aminochrysene, aniline, paraphenyleneaniline-compounds and/or other comonomers.

Preferably component b) is a polymer derived from monomers selected from aniline, ortho anilinic sulphonic acid, 2-methylaniline, 2-chloroaniline, 2-C 1-3 alkoxyaniline, 2-hydroxyaniline, 2,5-dimethylaniline, 2-methoxy 5methylaniline, 4-amino carbazole and 1-C 1-3 -alkyl 4-aminocarbazole, more preferably from monomers selected from aniline or from aniline and orthoanilinic-sulphonic acid.

Preferably component c) is a polymer derived from monomers selected from 2-amino thiazole, 2-aminobenzthiazole and 2-amino-5-methoxy benzthiazole.

Components a to c can also exist in oxidised (or partially oxidised form) in which the anions are selected from Cl-,SO 4 c 1-4 alkyl-, phenyl- and benzyl- sulphonates or C 1-4 alkyl-, phenyl-, and benzyl-carboxylates.

The I.R. absorbing polymers are worked in preparations in the same way as for disperse dyes. The compounds can be milled in a glass pearl mill or a ball mill until the average particle size is under 1 p. Milling is preferably carried out in the presence of dispersing agents, for example a ligninsulphonate or a synthetic dispersing agent eg. the sodium salt of dinaphthylmethane-disulphonic acid.

The I.R. absorbing polymers can be applied to both hydrophobic and hydrophilic fibres and resulting textile material, for example cellulose fibres (eg. fibres of cotton, linen, jute, regenerated cellulose), cellulose ester fibres, all types of polyamide fibres (both natural and synthetic), polyester fibres and polyacrylonitrile fibres.

Case 150-5262 The I.R. absorbing polymers can be applied by the usual methods, preferably being heat-fixed.

The I.R. absorbing polymer can be applied to the substrate by exhaustion, impregnation (slop padding and printing) with a short bath or as a printing paste.

When the I.R. absorbing polymers are applied by impregnation, it is preferable to use an impregnation liquor of 0.3 to 5 g/1, more preferably 0.5 to 4 g11, most preferably about 2 g11 of polymer in the liquor.

When the I.R. absorbing polymer is in the form of a paste, the paste preferably contains 10-50 g of I.R. absorbing polymer per kg of paste.

Preferably, the amount of IR absorbing polymer taken up on the substrate is 0.015% to 1% based on the weight of substrate.

In a process of padding, after impregnation, 60-120 % of the impregnation liquor, based on the dry weight of substrate is left on the substrate and the substrate may then be dried (hot air or under steam drying) at usual drying temperatures for such substrates, for example when the substrate is cotton or polyester fibres at 2000C for 60 seconds, when the substrate is synthetic polyamide at 180C for 60 seconds and when the substrate is polyacrylonitrite at 160C for 60 seconds.

Application of the IR-absorbing compounds is preferably carried out after dyeing of the corresponding substrates.The substrates to which the IRabsorbing compound has been fixed have very good fastness properties (fastness to water, washing, dry cleaning, light and heat),so much so that they can subsequently be dyed or printed (with daylight camouflage colours).

- Case 150-5262 Further, it is also possible to apply the IR-absorbing compounds at the same time as applying the dyestuffs themselves. It is also advantageous to apply one or more conventional resin or other finishes once the IR absorbing polymer and any dyes have been applied. Such finishes are described, for example in DE-OS 34 46 284, 35 25 104 or 31 05 897, and these will additionally increase in particular the wet fastness properties of the substrates.

The IR-absorbing polymers are known or may be produced from known compounds by known methods. They are generally produced by means of oxidative polymerisation of the monomers, whether in a purely chemical way (e.g. with FeCl 3 as the oxidation agent) or in an electro-chemical way.

Case 150-5262 In the following Examples, all parts and percentages are by weight, unless indicated to the contrary. One part by volume corresponds to the volume of one part by weight of water. All temperatures are given in OC.

Example 1 a) Production of polypyrrole:

33.5 parts of pyrrole and 50 parts of a commercial C 13 -alkanesulphonate are homogenised in 1500 parts of water and the pH is set at pH 4 by the addition of glacial acetic acid. To this mixture is added over the course of 90 minutes a solution of 150 parts of FeCl 3 6H 2 0 in 300 parts of water. This is stirred for a further two hours, the black residue is filtered off, washed with 1000 parts of water and vacuum dried at 501. Ca. 40 parts of polypyrrole are thus obtained in the form of a black powder.

b) Production of polyaniline:

23 parts of aniline and 100 parts of ice are mixed whilst cooling with 31 parts by volume of 30% hydrochloric acid, and then added, over the course of 90 minutes, to a solution of 114 parts of ammonium peroxide disulphate in 1000 parts of water. The temperature is maintained at 0 to 50 by adding ca. 500 parts of ice. The resultant black suspension is then stirred for 3 hours at room temperature, then filtered off through two soft filters, the residue is washed with ca. 1000 parts by volume of 1 N HCl and is then vacuum dried at ca. 600. The polyaniline obtained is similarly a black powder.

c) Grinding of the product according to a) above and production of a preparation for the impregnation of textile fibre material parts of a commercial dispersing agent based on lignin sulphonate (11Reax 8511) are stirred up in a grinding bowl with 20 parts Case 150-5262 of water, and then 10 parts of polypyrrole (as prepared in example la), 80 parts of water and 122 parts of glass beads are added. The product is ground (ca. 24 hours) until the average particle size lies below 1 pm. The mixture is then filtered from the glass beads, the glass beads are washed with water and the filtrate is adjusted to 400 parts by volume.

d) Pad-dyeing of a polyester fabric:

parts of the dispersion obtained according to Example 1c) above is mixed with 1.5 parts of sodium alginate and 3 parts of sodium dinaphylmethane disulphonate, and is adjusted with water to 500 parts (= 0.2% IRabsorbing compound). An olive-dyed polyester fabric is then padded with this liquor at 25', squeegeed out to so as to leave ca. 100% dry weight increase, dried for 60 seconds with air of 100 to 130, and subsequently fixed for 60 seconds with hot dry air of 2001C. A fabric is obtained, whose spectral luminance factor in the range from 750 to 1500 nm has a value of about 30%. The olive polyester polyester substrate which is not treated with the IR-absorbing compound in the said range has a spectral luminance factor of ca. 85%.

Cotton and nylon fabrics, as well as polyester/cotton mixed fabrics, may also be finished analogously using the IR-absorbing compound prepared according to Example 1a) or Example 1b) above.

Example 2 a) From Polypyrrole made according to Example la except that it is not dried, a 12.2% polypyrrole containing dispersion is produced.

To 400 mls of distilled water in a 2 litre vessel, 800 g of silicaquartz, 8 g of 2, 4, 7, 9-tetramethyl-S-decin-4,7-diol (Surfinol GA) and 8 g antifoaming agent (Antimussol UP) are then added and are stirred with a single paddle at 800 revs. per min. Slowly 171 g of a 65.5% presscake of polypyrrole is added and the rate of mixing is increased to 2800 revlmin. Grinding is carried out for 8 hours at the Case 150-5262 same time adding 3 g of antifoaming agent. The mixture is stirred a further 2 hours and 100 mls of distilled water and 225 g of formaldehyde/ditolylether sulphonate condensation product (Lyocol OL) is then added and ground a further 24 hours. The dispersion is filtered from the glass beads, the beads are washed and the washings are added to the filtrate and added to distilled water to give 500 ml of distilled water.

b) A cotton fabric (Tricot) which has been dyed with 0.16% of C.I. Direct Yellow 162 (commercially available) 0.17% of C.I. Direct Red 161 (commercially available) 0.58% of C.I. Direct Green 69 (commercially available) is treated with 16g/1 of the dispersion according to a (here above), dried, impregnated in a bath containing g1l of a commercially available softening agent 20 g/l of a polyethylene dispersion 1 g1l of a commercially available crosslinking agent 130 g1l of the product of Example 1 of D.O.S. 31 05 897 the balance being water and the fabric is squeegeed to leave an increase in the weight of the fabric of 80% by weight.

2-4% of residual water is dried off and the fabric is then heated for 3045 seconds at 180C.

The treated fabric has a spectral luminance factor of 30% (approximately) in the 800 to 1500 nm range. This does not significantly change after treating for 100 hours with a Xenon lamp.

After a 601C wash (C2S) the spectral luminance factor is increased to about 33% at about 1300 nm.

Example 3 a) Preparation of a Presscake Case 150-5262 Example 1 a) is repeated omitting the addition of the c 13 - alkansulphonate and the final drying step of the polypyrrole to form a presscake.

b) Preparation of an impregnation composition In an 1.5 liter support container, 100 g of polypyrrole in the form of a 35% presscake (as made in Example 2a) is added. 100 ml demineralised water, 8 g of a commercial available product of 2,4,7,9tetramethyl-5- decin-4,7 diol (Surfinol GA), 60 g of a commercially available formaldehyde/ditolylether sulphonate condensation product (Lyocol OL) is poured over and stirred in by hand until a pourable paste results. The mixture is stirred with a single blade stirrer at 90 rev. per minute and slowly 500 g of siliquartzite beads are added. After the addition of 0.5 g of a commercially available antifoaming agent (Antimussol UP), a further 119 g of the formaldehyde/ ditolyethersulphonate condenstation product and 155.5 g of polypyrrole presscake (35%) are slowly added, so that the suspension remains pourable. The speed of the stirrer is then increased to 2800 revs per minute and a further 0.5 g of antifoaming agent is added.

Using a conventional filter test, the fineness of the dispersion is evaluated. After stirring for 20 hours, the dispersion is separated from the glass beads and the glass beads are washed twice with 50 C of distilled water. The water of the wash is then added to the dispersion. A 13.9% aqueous dispersion of polypyrrol is obtained.

c) Dyeing containing I.R. absorbing polymer.

A polyamide fabric (Helanca) is impregnated using a short dyebath containing, per litre of dyebath 1 - 10 6 0.5 10 14 2 0.5 g of CI Acid Orange 127 (commercially available) g of CI Acid Red 263 (commercially available) g of CI Acid Blue 280 (commercially available) g of the dispersion of Example 3b) above; M1 of Sansapol AM liq. and g of Sandopan DTC paste, Case 150-5262 and the fabric is squeegeed to allow an 80% increase in the weight of the substrate. The substrate is dried for 3 minutes at 1800C, steamed at 1020C for 10 minutes and soaped at 701C with 1 g/l of a non-ionic washing medium (Ekalin F). The fabric is washed warm and then cold and then dried.

The resulting dyeing has a spectral luminance factor of about 27% in the 750-1500 nm range. This is only insignificantly raised after dry cleaning (D01) as well as exposing for 100 hours to a Xenon lamp (the increase in the spectral luminance factor is still under than 30%). When the fabric is washed at 600C (C2S) the spectral luminance factor is raised to about 43%.

Example 4

Example 3 is repeated using the same amount of polyaniline instead of polypyrrole.

The heated cotton fabric has a spectral luminance of about 35% and after dryed cleaning and exposure to a Xenon lamp for 100 hours is raised to about 50%. The 601C wash does not significantly affect the spectral luminance factor.

I. - 11 - Case 150-5262

Claims (23)

Claims:

1. A textile material to which a conjugated polymer containing a 5 or 6 membered heterocyclic or carbocyclic group having a molecular weight preferably of at least 500 (herein referred to as the I.R. absorbing polymer) has been applied.

2. A textile material according to Claim 1 in which the I.R. absorbing polymer penetrates at least in part the substrate.

3. A textile material according to Claim 1 or Claim 2 in which the average particle size of the I.R. absorbing polymer is below 1p.

4. A textile material according to any one of the preceding claims in which the IR absorbing polymer is:

a) a homo or co-polymer of a 5 membered heterocyclic compound with a conjugated n electron system in which the heteroatom is oxygen, nitrogen or sulphur (hereinafter described as component a) b) a polymer derived from aniline or derivatives thereof (hereinafter described as component b); and c) a polymer derived from amino substituted 5 membered heterocyclic compounds (hereinafter described as component c).

5. A textile material according to Claim 4 in which the I.R absorbing compound is a homo- or co-polymer derived from monomers selected from aniline, pyrrole, thiophene, furan, benzthiazole and thiazole, oxazole, imidazole, phenanthrene benzidine or crysene.

6. A textile material according to Claim 4 or Claim 5 in which component a) is a polymer derived from monomers selected from the pyrrole, thiophene and furan series.

7. A textile material according to Claim 6 in which component a) is a Case 150-5262 polymer derived from monomers selected from pyrrole, 3,4-dimethyl or diethyl pyrrole, 3,4-dichloropyrrole, 2,3-diethyl thiophene, 3-methyl and 3-ethyl furan, in which the monomers may be also copolymerised with up to 20 % of a comonomer selected from thiazole, oxazole, imidazole, aminophenanthrene, benzidine, aminocrysene, aniline, para-phenylene aniline and/or other comonomers.

8. A textile material according to any one of Claims 4 to 7 in which component b) is a polymer derived from monomers selected from 2methylaniline, 2-chloroaniline, 2-C 1-3 alkoxyaniline, 2-hydroxyaniline, 2,5-dimethylaniline, 2-methoxy 5-methylaniline, 4-amino carbazole and 1-C 1-3 alkyl 4-aminocarbazole.

9. A textile material according to Claim 8 in which component b) is a polymer derived from monomers selected from aniline and anilineorthoanilinic acid copolymers.

10. A textile material according to any one of Claims 4 to 9 in which component c) is a polymer derived from monomers selected from 2aminothiophene, 2-amino 3-cyanthiophene, 2-amino thiazole, 2aminobenzthiazole and 2-amino-5-methoxy benzthiazole.

11. A process for treating textile material so that the material does not emit infra red signals comprising applying to the material a conjugated polymer containing a 5 or 6 membered heterocyclic or carbocyclic group having a molecular weight preferably of at least 2000 (herein referred to as the I.R. absorbing polymer) from an aqueous dispersion.

12. A process according to Claim 11 in which application of the polymer is carried out by exhaustion, padding or printing.

13. A process according to Claim 11 or 12 in which the IR absorbing polymer is:

Case 150-5262 a) a homo or co-polymer of a 5 membered heterocyclic compound with a conjugated n electron system in which the heteroatom is oxygen, nitrogen or sulphur (hereinafter described as component a) b) a polymer derived from aniline or derivatives thereof (hereinafter described as component b); and c) a polymer derived from amino substituted 5 membered heterocyclic compounds (hereinafter described as component c).

14. A process according to Claim 13 in which the I.R absorbing compound is a homo- or co-polymer derived from monomers selected from aniline, pyrrole, thiophene, furan, benzthiazole and thiazole, oxazole, imidazole, phenanthrene, benzidine or crysene.

15. A process according to Claim 13 or 14 in which component a) is a polymer derived from monomers selected from the pyrrole, thiophene and furan series.

16. A process according to Claim 15 in which component a) is a polymer derived from monomers selected from pyrrole, 3,4-dimethyl or diethyl pyrrole, 3,4-dichloropyrrole, 2,3-diethyl thiophene, 3-methyl and 3-ethyl furan, in which the monomers may be also copolymerised with up to 20 % of a comonomer selected from thiazole, oxazole, imidazole, aminophenanthrene, benzidine, aminocrysene, aniline, para-phenylene aniline and/or other comonomers.

17. A process according to any one of Claims 13 to 16 in which component b) is a polymer derived from monomers selected from 2-methylaniline, 2chloroaniline, 2-C 1-3 alkoxyaniline, 2-hydroxyaniline, 2,5dimethylaniline, 2-methoxy 5-methylaniline, 4-amino carbazole and 1-C 1-3 alkyl 4-aminocarbazole.

18. A process according to Claim 17 in which component b) is a polymer derived from monomers selected from aniline and aniline-orthoanilinic acid copolymers.

Case 150-5262

19. A process according to any one of Claims 13 to 18 in which component c) is a polymer derived from monomers selected from 2-aminothiophene, 2- amino 3-cyanthiophene, 2-amino thiazole, 2-aminobenzthiazole and 2-amino- 5-methoxy benzthiazole.

20. A process according to any one of Claims 11 to 19 in which the I.R. absorbing polymer is applied to the substrate by exhaustion, impregnation with a short bath or as a printing paste.

21. A textile substrate to which a polymer substantially as herein described with reference to Example 1 has been applied.

22. A process for applying a polymer substantially as herein described with reference to any one of Examples 2 to 4.

23. A substrate treated substantially as herein described with reference to any one of examples 2 to 4.

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