CRABTREE, Alan John (54 New Park Road, Queensbury, Bradford Yorkshire BD13 1PP, GB)
THOMAS, Paul (134 Bradford Road, Liversedge, Bradford Yorkshire WF15 6LW, GB)
BRIGGS, Brendan Karle (19 Westbourne Road, Marsh, Huddersfield Yorkshire HD1 4LQ, GB)
CRABTREE, Alan John (54 New Park Road, Queensbury, Bradford Yorkshire BD13 1PP, GB)
THOMAS, Paul (134 Bradford Road, Liversedge, Bradford Yorkshire WF15 6LW, GB)
| What is claimed is
1. An aqueous dispersion containing
(A) a polymer formec by polymerization of
(a) 1 - 100 % by weight of a compound of formula (1 )
R 1
(1 ).
H 2 C=C- ^ Uil I I 2 o U ( /rL^-\M I 2 γL^-\M I 2 γUλ\; n—R 2 wherein R 1 denotes hydrogen or methyl, R 2 is C 8 -C 3 o-alkyl, C 6 -C 36 -aryl, C 7 -C 36 -aralkyl or C 6 -C 36 -cycloalkyl and n is 0 or an integer from 1 to 100,
(b) 0 - 90 % by weight of at least one ethylenically unsaturated non-ionic monomer different from component (a),
(c) 0 - 90 % by weight of at least one ethylenically unsaturated ionic monomer, and
(d) 0 - 1 % by weight of a copolymerisable polyethylenically unsaturated monomer, the sum of the amounts of components (a) - (d) being 100 % by weight;
(B) an anionic or nonionic surfactant; and (C) a defoaming agent.
2. An aqueous dispersion according to claim 1 , containing as component (A) a polymer formed by polymerization of monomers (a) and optionally (b), (c) and (d), characterised in that monomer (a) is a compound of formula (1 ) wherein R 2 is Ci O -C 24 -alkyl or Ci O -C 24 -aryl.
3. An aqueous dispersion according to claim 1 , containing as component (A) a polymer formed by polymerization of monomers (a) and optionally (b), (c) and (d), characterised in that monomer (a) is a compound of formula (1 ) wherein R 2 is stearyl, lauryl, docosyl or 4-octylphenyl.
4. An aqueous dispersion according to claim 1 , containing as component (A) a polymer formed by polymerization of monomers (a) and optionally (b), (c) and (d), characterised in that monomer (a) is a compound of formula (1 ) wherein n is an integer from 8 to 30.
5. An aqueous dispersion according to claim 1 , containing as component (A) a polymer formed by polymerization of monomers (a), (b) and optionally (c) and (d), characterised in that monomer (b) is methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate or n-butyl methacrylate.
6. An aqueous dispersion according to claim 1 , containing as component (A) a polymer formed by polymerization of monomers (a), (c) and optionally (b) and (d), characterised in that monomer (c) is acrylic acid or methacrylic acid.
7. An aqueous dispersion according to claim 1 , containing as component (A) a polymer formed by polymerization of monomers (a), (d) and optionally (b) and (c), characterised in that monomer (d) is diallyl phthalate, allyl acrylate, allyl methacrylate, divinyl benzene, ethylene glycol dimethacrylate or methylene bis acrylamide.
8. An aqueous dispersion according to claim 1 , containing as component (B) a fatty alcohol polyglycol ether or a fatty alcohol polyglycol ether sulfate.
9. An aqueous dispersion according to claim 1 , containing as component (B) sodium lauryl sulfate or ethoxylated sodium lauryl sulfate.
10. An aqueous dispersion according to claim 1 , containing as component (C) a preparation containing anionic surfactants, C 9 -Cnalcohols, and ethoxylated C 9 -Cnalcohols in dipropylene glycol monomethylether.
1 1. An aqueous dispersion according to claim 1 , containing
1 - 20 % by weight, based on the total composition, of component (A), 0.1 - 6.0 % by weight, based on the total composition, of component (B), and 0.05 - 4.0 % by weight, based on the total composition, of component (C), the remainder being water and, optionally, additives.
12. An aqueous dispersion according to claim 1 1 , additionally containing
1 - 50 % by weight, based on the total composition, of urea.
13. An aqueous dispersion according to claim 1 1 , additionally containing 0.1 - 5.0 % by weight, based on the total composition, of an oxidant.
14. A printing paste containing an aqueous dispersion according to claim 1 and 0.1 - 5.0 % by weight, based on the total composition, of a reactive dye.
15. A method for printing textile material characterised in that at least one coat containing a printing paste according to claim 14 is applied. |
Printing Paste
The invention relates to an aqueous dispersion containing polymeric thickeners, a printing paste based on said aqueous dispersion and a method for printing textile material.
Printing pastes for textile materials require a defined rheology to make sure that the paste can be processed by means of squeegees or rolls, can be pressed through the printing screen and afterwards sufficiently adheres to the fabric.
The rheology of the paste is usually adjusted by addition of polymeric thickeners which should be swellable but not soluble in water and crosslinkable to an extent that achieves the required viscoelastic properties. Over-crosslinking leads to high penetration and strong colors but poor definition of the printed mark whereas under-crosslinking provides excellent definition but pale colors due to low paste transfer.
Conventional thickeners for printing pastes are copolymers of acrylic acid, sodium or ammonium acrylate and acrylamide dispersed as emulsion particles in a continuous oil phase. Traditional aqueous dispersions containing polymeric thickeners do not allow for efficient flow control and rapid viscosity build-up during the printing process.
It has now been found that a stable aqueous dispersion suitable for the preparation of printing pastes is obtained when a polymer that is substantially non swelling and insoluble in neutral water and is prepared from allyl ether monomers is combined with an anionic or non- ionic surfactant and a defoaming agent.
Accordingly, the invention relates to an aqueous dispersion containing (A) a polymer formed by polymerization of
(a) 1 - 100 % by weight of a compound of formula (1 )
(1 ). H 2 C=C CH 2 — O (CH 2 CH 2 O) n -R 2 wherein R 1 denotes hydrogen or methyl, R 2 is C 8 -C 3 o-alkyl, C 6 -C 36 -aryl, C 7 -C 36 -aralkyl or C 6 -C 36 -cycloalkyl and n is 0 or an integer from 1 to 100,
(b) 0 - 90 % by weight of at least one ethylenically unsaturated non-ionic monomer different from component (a),
(c) 0 - 90 % by weight of at least one ethylenically unsaturated ionic monomer, and
(d) 0 - 1 % by weight of a copolymerisable polyethylenically unsaturated monomer,
the sum of the amounts of components (a) - (d) being 100 % by weight;
(B) an anionic or nonionic surfactant; and
(C) a defoaming agent.
Polymers according to component (A) generally are substantially non swelling and insoluble in neutral water but swellable or soluble in aqueous alkali and have an intrinsic viscosity of at least 0.5 (measured as single point at 0.05 % concentration in methanol) and normally prepared by emulsion polymerisation of the allyl ether and, optionally, the ethylenically unsaturated non-ionic monomer and/or the ethylenically unsaturated ionic monomer. Such polymers are known and described, for instance, in EP-A 0 216 479, hereby incorporated by reference.
Preferably, polymer (A) is prepared by oil-in-water emulsion polymerisation using an appropriate emulsifier, as is conventional. The final polymer is insoluble and substantially unswollen in the aqueous phase of the polymerisation mixture but is soluble or swellable upon appropriate pH adjustment. The solubility of the monomers in the aqueous phase may be conventional for oil-in-water emulsion polymerisation. Generally the blend of monomers, and often each monomer, is insoluble in the aqueous phase but some water solubility can be tolerated provided the monomers all migrate during the polymerisation into the micelles of the emulsifier.
Monomer (a) includes a polyethoxy chain and by appropriate choice of the values of n and R 2 it is possible to control the solubility of the monomer and the properties of the final polymer. Ri is generally hydrogen. R 2 is a hydrocarbyl group containing 6 to 36, preferably 8 to 30, more preferably 10 to 24 and most preferably 12 to 18 carbon atoms. It may be selected from C 8 -C 30 -alkyl, for instance n-octyl, lauryl, stearyl or docosyl, C 6 -C 36 -aryl such as phenyl or naphthyl, C 7 -C 36 -aralkyl such as benzyl or 2-phenylethyl, or C 6 -C 36 -cycloalkyl such as cyclohexyl.
Preferably monomer (a) is a compound formula (1 ) wherein R 2 is Ci O -C 24 -alkyl or Ci 0 -C 24 - aryl.
Particularly preferred monomers (a) are compounds of formula (1 ) wherein R 2 is stearyl, lauryl, docosyl or 4-octylphenyl.
Further preferred monomers (a) are compounds of formula (1 ) wherein n is an integer from 8 to 30, in particular from 10 to 15.
The amount of monomer (a) must be such that the blend of components (a) and optionally (b), (c) and/or (d) can be polymerized by by oil-in-water emulsion polymerisation to form an emulsion of the polymeric thickener in which the polymer is insoluble and substantially unswollen and non-thickening but that, after polymerisation, the emulsion can be converted by addition of alkali into a viscous system thickened by the polymer.
The amount of monomer (a) is at least 1 % by weight and usually at least 2 % by weight. It is generally below 50 % by weight and usually below 30 % by weight. Amounts in the range 5 to 20 % by weight are preferred.
Monomer (b) is a vinyl monomer, preferably an acrylic monomer and may be a blend of monomers. The monomers are are generally water insoluble but a minor proportion of monomer (b) may be a water soluble monomer such as acrylamide. By water insoluble monomer in the context of the present specification we mean monomer that is soluble in water to a degree of up to 5 % at room temperature.
Suitable monomers are styrene and alkyl- and/or halogen-subtituted styrenes, acrylonitrile, methacrylonitrile, vinyl alkanoates (especially the chloride), hydroxyalkyl acrylates, hydroxyalkyl methacrylates, alkoxyalkyl acrylates, alkoxyalkyl methacrylates, alkyl acrylates and alkylmethacrylates.
Preferred monomers are styrene, 2-hydroxyethyl acrylate, acrylonitrile, vinyl chloride, vinyl acetate and the alkyl acrylates and alkyl methacrylates. Preferably at least 50 % by weight of component (b), and most preferably 100 % is alkyl acrylate or alkyl methacrylate. In all these monomers any alkyl groups may contain 1 to 8 carbon atoms, but particularly preferred monomers are CrC 4 alkyl acrylates and CrC 4 alkyl methacrylates such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate and n-butyl methacrylate.
Monomer (c) is a vinyl monomer, preferably an acrylic monomer and may be a co-ionic blend of monomers. When monomer (c) is anionic upon addition of alkali, the monomer and its amount must be such that addition of alkali renders the polymer soluble or swellable. The monomer is generally a carboxylic monomer as free acid during the polymerization. The monomer generally contains 3 to 8 carbon atoms. It may be a monocarboxylic acid, a
- A -
dicarboxylic acid or, for instance, a monoalkyl ester of a dicarboxylic acid. The acid may be selected from acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, citraconic acid, acryloxypropionic acid and maleic acid. Preferably at least 50 %, and most preferably 100 % of component (c) is provided by acrylic acid and/or methacrylic acid, with methacrylic acid particularly preferred.
Monomer (d) is optional and serves as a crosslinker. Suitable crosslinkers for emulsion polymerised ethylenically unsaturated monomers are well-known. They are generally polyethylenically unsaturated monomer materials such as diallyl phthalate, allyl acrylate allyl methacrylate, divinyl benzene, ethylene glycol dimethacrylate and methylene bisacrylamide. If the crosslinker is present, its amount is generally in the range 0.0005 to 1 % (5 to 10000 ppm), most preferably 0.001 to 0.2 %.
Particularly preferred components (A) are those formed from 20 to 60 % by weight acrylic acid and/or methacrylic acid (preferably methacrylic acid alone), 5 to 60 % ethyl acrylate or other suitable alkyl acrylate or alkyl methacrylate and 2 to 50 % of the allyl ether (compound of formula (1 )), optionally with crosslinker.
The intrinsic viscosity (namely the single point intrinsic viscosity as measured at 0.05 % polymer concentration in methanol) of linear polymers is generally at least 0.5 and when there is no solid phase, the intrinsic viscosity is preferably at least 1 , more preferably at least 2, 3 or even 5, for instance it may be 5 - 10 or higher.
Anionic surfactants which can be used as component (B) of the dispersions according to the invention are well-known to the skilled artisan. Suitable anionic surfactants are, for example, alkali metal or ammonium salts of fatty acids, alkylbenzene sulfonates, C 1 0-C 2 0- alkane sulfonates, Ci 2 -Ci 8 -fatty alcohol sulfates, ethoxylated Ci 2 -Ci 8 -fatty alcohol sulfates, fatty acid methyl taurides, alkylisothionates, fatty acid polypeptide condensates, fatty alcohol phosphoric acid esters, sulfo succinates, olefin sulfonates and methyl ester sulfonates.
Noionic surfactants are likewise well-known. Suitable nonionic surfactants are, for example, alcohol ethoxylates, in particular fatty alcohol ethoxylates, alkylphenol ethoxylates, fatty acid alkanolamides, alkyl polyglycosides and fatty acid N-methylglucamides.
Preferably, the dispersions contain as component (B) a fatty alcohol sulfate or a fatty alcohol polyglycol ether sulfate, in particular sodium lauryl sulfate or ethoxylated sodium lauryl sulfate.
Basically any customary defoaming agent can be used as component (C ) in the dispersions according to the invention. Suitable defoaming agents can be natural fats and oils, long chain alcohols such as 2-ethylhexanol, hexadecanol and octadecanol, polymeric glycols, fatty acid polyglycols, fatty acid polyglycolester, carboxylic acid alkyl amides, silica and silicones. Further suitable defoaming agents are dispersions of the products known as metallic soaps, which may be obtained by reaction of stearic and oleic acid with metal hyroxides, in organic solvents, for example a dispersion of aluminium distearate in a liquid hydrocarbon.
Preferably, component (C) is a preparation containing anionic surfactants, C 9 -Cnalcohols, and ethoxylated C 9 -Cnalcohols in dipropylene glycol monomethylether. The total amount of ingredients in dipropylene glycol monomethylether is preferably 10 - 20 % by weight, in particular 14 - 16 % by weight.
The amounts of components (A), (B) and (C) may vary within wide ranges. Preferably, the claimed aqueous dispersions contain 1 - 20 %, in particular 2 - 10 %, most preferably 3 - 6 %, by weight, based on the total composition, of component (A),
0.1 - 6.0 %, in particular 0.2 - 3.0 %, most preferably 0.5 - 2.0 %, by weight, based on the total composition, of component (B), and
0.05 - 4.0 % by weight, in particular 0.1 - 3.0 %, most preferably 0.2 - 2.0 %, based on the total composition, of component (C), the remainder being water and, optionally, additives.
For the preparation of printing pastes the aqueous dispersion according to the invention can be combined with customary additives, such as further antifoams, antifrosting agents, biocides, acids or bases to give any required pH in the printing paste, surfactants to improve the dispersion of the product when it is stirred in water, stabilisers to improve the storage stability of the product etc.
The printing paste will normally comprise at least one pigment or dye. However, when the design includes a white area, it is often advantageous to print a blank paste, -i.e. a paste with no dye, in this area. This helps to prevent dye bleeding from adjacent coloured areas into the white. To improve this effect even further, the blank paste may comprise a so-called reserving agent. Reserving agents are colourless or virtually colourless chemicals with structural resemblances to the dyes. They block available dye sites in the fibre, particularly at the surface of the fibre, so that these sites are not available for the dyes.
Preferably, the printing pastes contain at least one dye, in particular a reactive dye. The amount of reactive dye in the printing paste is preferably 0.1 - 5.0 %, in particular 0.2 - 3.0 % and most preferably 0.5 - 2.0 % by weight, based on the total composition.
Further components which may be present in the printing pastes are e.g. additional natural or synthetic thickeners, pigments, acids, bases and/or salts to adjust the pH to the desired value, solvents, further anionic or nonionic surfactants, antifoaming and antifrosting agents, dispersing agents, fixing agents, oxidising agents, wetting agents, polyhydroxy compounds, reaction products of hydroxyl compounds and isocyanates, polyesters prepared by reaction of terephthalic acid and one or more polyethylene glycols. These components are commonly used or recommended for textile printing or finishing.
Urea has proved to be especially useful as a dyestuff solvent. Therefore, a further embodiment of the invention is an aqueous dispersion containing 1 - 20 % by weight, based on the total composition, of component (A), 0.1 - 6.0 % by weight, based on the total composition, of component (B), 0.05 - 4.0 % by weight, based on the total composition, of component (C), and
1 - 50 %, preferably 2 - 40 %, in particular 5 -20 %, by weight, based on the total composition, of urea, the remainder being water and, optionally, additives.
Purposively, the printing paste contains a mild oxidant in order to prevent reduction of the reactive dye. A preferred oxidant is sodium 3-nitrobenzene sulfonate.
Accordingly, the invention further relates to an aqueous dispersion containing 1 - 20 % by weight, based on the total composition, of component (A),
0.1 - 6.0 % by weight, based on the total composition, of component (B), and 0.05 - 4.0 % by weight, based on the total composition, of component (C), and 0.1 - 5.0 %, preferably 0.2 - 3.0 %, in particular 0.5 -2.0 %, by weight, based on the total composition, of an oxidant, the remainder being water and, optionally, additives.
The aqueous dispersions and the printing pastes according to the invention can be prepared by any suitable method known to those of ordinary skill in the art. For example, the components of the composition and, where appropriate, further additives can be combined and mixed in a suitable mixer or blender.
The following method of preparation has proved to be quite effective:
1 ) component (C), urea and the oxidant are dissolved in water;
2) 75 % of the required quantity of component (A) is added subsequently to the solution obtained in step 1 );
3) sodium carbonate is then added to the solution obtained in step 2;
4) stirring is continued until a homogeneous mixture is obtained;
5) the remaining 25 % of component (A) is added and then stirred until uniform.
6) component (B) is then added with stirring; the stock is mixed until the final viscosity has been reached.
The printing pastes according to the invention can be applied in conventional manner using conventional equipment.
A further aspect of the invention is a method for printing textile material characterised in that at least one coat containing a printing paste as described above is applied.
The method according to the invention is preferably suitable for printing silk, wool, synthetic polyamides and natural or synthetic cellulose fibres, such as for example viscose, linen and in particular cotton.
The essential printing process is normally followed by a thermal drying and fixation step. Preferably, the printed textile material is dried for 30 s to 3 min at a temperature of 50 to 140 0 C and subsequently fixed at a temperature of 80 to 200 0 C over a period of 30 s to
5 min. Effective fixation can be achieved by steaming, for example at 102 0 C for 8 min at 100 % steam saturation.
The dispersion according to the present invention distinguishes by high storage stability, delivers good rheological behaviour and ensures a rapid viscosity build-up during the printing process.
The following non-limitative Examples illustrate the invention in more detail. Parts and percentages are by weight, unless otherwise stated. In the Examples the following components are applied:
Thickener 1 : Copolymer prepared by emulsion polymerisation of 9.5 parts of ethyl acrylate, 6.2 parts of methacrylic acid and 1 part of allyl ether of ethoxylated stearyl alcohol (10 mol ethylene oxide per mol stearyl alcohol)
Oxidant: sodium 3-nitrobenzene sulfonate
Defoaming agent: a preparation containing anionic surfactants, C 9 -Cnalcohols, and ethoxylated Cg-Cnalcohols in dipropylene glycol monomethylether
Anionic surfactant: sodium lauryl sulphate
Example 1
A stock containing the ingredients listed in Table 1 is prepared:
12.5 g oxidant, 125.0 g urea and 3.3 g defoaming agent are dissolved in 383.35 g water. 75
% of the required quantity of component (A) (33.75 g) is added under stirring. Afterwards 37.5 g sodium carbonate is added to the solution and stirring is continued until a homogeneous mixture is obtained. The remaining 25 % (11.25 g) of component (A) is added and the mixture is stirred up to uniformity. Component (B) (10.0 g) is then added with stirring.
The stock is mixed until the final viscosity has been reached.
Table i :
Application Example
700 g of stock obtained in Example 1 is mixed in each case with 300 g of one of the dye preparations listed in Table 2.
A 70 square cotton fabric is printed with the pastes so obtained using a blade rotary printing machine. The fabric is printed at 20 m/min and subsequently the fabric is dried in a stenter at
140 0 C for approximately 1 min followed by steaming for 8 min at 102 0 C.
After fixation a small quantity of each quality of cottonis washed off by hand for visual rating.
The levelness of the printings so obtained is very good.
Table 2: