SOFTENING AGENTS

Abstract: A method for the treatment of natural or synthetic fibres, such as wool, cotton, nylon or acrylic, so as to impart a softer handle comprises treating the fibres with a polymer or prepolymer as defined. The method may be performed as either a continuous process or as a batch process.

Description: SOFTENING AGENTS This invention relates to the novel use of known polymers and prepolymers as softening agents to improve the handle of both natural and synthetic fibres. Traditionally employed softening agents have as their basis either fatty acid or reactive siloxane chemistry. In both cases, the use of such agents imparts a degree of hydrophobicity to the treated fibres. While attempts have been made to overcome this effect by the incorporation of hydrophilic groups, such as amino, quaternary ammonium and polyethylene oxide groups, these generally have the effect of reducing the softness of handle that can be achieved and some hydrophobicity nevertheless remains. In addition, particularly in the case of fatty amide based softening agents, the effects are transitory and tend to be readily removed upon subsequent wet processing of the treated fibres or during domestic washing of the finished product. Consequently, it has been necessary either to re-soften the material by re-applying a softening agent (which is inefficient and uneconomic) or to tolerate a reduction in the level of softness following washing of the product. British Patent Nos. 1470243 and 1533343 describe compounds containing aziridine radicals and their use for reducing the shrinkage and felting of protein fibres. One of the compounds disclosed is that sold under the trade name Basolan SW, and which is marketed as a hydrophilic polymer that is said to achieve a soft hydrophilic finish when applied to synthetic fibres. The.present invention seeks to provide improved softening agents suitable for use with both natural and synthetic fibres. The polymers and prepolymers employed for this purpose are the subject of our co-pending European Patent Application No. 90307951.5. The present invention relates to the use as a softening agent for natural or synthetic fibres of a compound of any one of the following formulae:- i) Z-UA] m -N(R 1 ) n >r (I ) which may be expressed more simply as: ( ID or ii) structure involving crosslinking or bridging of the above groups (I) or (II) : ( II) which ' may be expressed more simply as: (IV) or iii) a low molecular weight polymeric structure formed from the above groups (I) or (II) : {K} X -(B}y-K (V) wherein Z represents a residue of a polyol, preferably a di- or trivalent polyol; - A represents a polyalkylene oxide residue, that is a polyether chain produced by polymerisation of, for example, ethylene, propylene or butylene oxides or tetrahydrofuran; B is the residue created by bi- or polyfunctional reaction between any polyfunctional reactive group and the parent amine of the title compounds (formula (I) where R. is hydrogen in all cases), or is the residue of a reactive amino-acrylic polymer (e.g. of the type described in EP-A-0129322) o r a reactive polyamide polymer (e.g. of the type described in EP-A-0260017A or a Hercosett polymer), and may be taken, for example, to represent a group -E-(R 3 ) p N-[D]-N(R 3 ) p -E- (VI) a group (VII) a group resulting from the reaction of a bi- or polyfunctional species capable of reacting with amino groups, for example: epihalohydrins, alkyl di- and polyhalides, di- or polycarboxylic acids or their acyl halides and anhydrides, dicyandiamide, urea and formaldehyde, a group derived from low molecular weight reactive resins such as the Bisphenol A type, or a group derived from reaction of a cationic polymeric reactive species such as where R g and R_ are selected from C_.-C 5 alkyl and C 2 -C 5 hydroxyalkyl radicals, γ -- selected from C 2 -C 8 alkylene radicals, 2-hydroxy-1 ,3-propylene radicals, and the radicals: -CH 2 CH 2 NHCONHCH 2 CH 2 - and -CH 2 CH 2 CH 2 NHCONHCH 2 CH 2 CH 2 - and q is an integer of from 0 to 20, provided that when q is greater than 2, each of the symbols Y need not necessarily have the same significance; D represents a straight or branched chain hydrocarbon, polysiloxane or polyalkylene oxide residue, and which may also either bear functional groups or may contain functional groups, such as amino groups, which may in turn either bear one or more groups R 1 or, where B is polyfunctional rather than bifunctional, may represent a further functional reaction point of the group B with the rest of the molecular structure; E represents a group resulting from the reaction of a bi- or polyfunctional species capable of reacting with amino groups, for example: epihalohydrins, alkyl di- and polyhalides, dicarboxylic acids or their acyl halides and anhydrides, dicyandiamide, urea and formaldehyde; J represents a residue derived from a polyfunctional polyether; K represents the monofunctional or polyfunctional residue derived from partial reaction of the basic prepolymers in formulae (I) or (II), i.e. it represents the shaded area in formula (III) as follows: R. represents a fibre reactive grouping such as the residue derived from monofunctional reaction of an epihalohydrin, an alkyl or alkyl aryl polyhalide or a methylol grouping derived from monofunctional reaction of formaldehyde, or is alkyl, hydroxyalkyl or hydrogen, with the proviso that at least one group R 1 per polyoxyalkyleneamine residue, and preferably at least one for each nitrogen, retains residual fibre reactivity; R„ represents a fibre reactive grouping such as the residue derived from monofunctional reaction of an epihalohydrin, an alkyl or alkyl aryl polyhalide or is a methylol grouping derived from monofunctional reaction of formaldehyde, or alkyl, hydroxyalkyl or hydrogen; R, represents hydrogen or C..-C. alkyl or hydroxyalkyl; R. represents halogen or a group (VIII) . or one of alkylamino, hydroxyalkylamino, alkoxy, alkylarylamino or a group -(R 3 ) p N-[D]-R 5 or a functional reaction point of the group B with the rest of the molecular structure, where B is polyfunctional rather than bifunctional; R 5 represents hydrogen or a group -N(R 2 ) n or -N(R 3 ) n ; m is between 4 and 50; n is 2 or 3, with the proviso that, where n is 3, the nitrogen atom involved also bears a formal positive charge; p is 1 or 2, with the proviso that, where p is 2, the nitrogen atom involved also bears a formal positive charge; r equals the functionality of group Z; t is a number representing the functionality of reaction of the residue B; s is a number between 1 and r-1; x is between 2 and 30; and y is from x to x, t-1 with the general proviso that, in any given instance, the significance of a particular group Z, A, B, R, J or K in any given structure shall not be dictated by the significance of any other such group in the same formula, and further, wherever a formal positive charge is present in the structure, then an appropriate counter anion is taken to be present, for example chloride ion. The term "fibre reactive grouping" as used herein is to be understood as meaning a group having residual chemical reactivity such that it will be capable of causing a molecule to be bound to the surface of a fibre in such a way as not to be readily removable therefrom. Examples include the fibre reactive dyes in which a variety of reactive halogen groupings are sited on the molecule and which, during dyeing, react with hydroxy or amino functionalities on the fibre surface to produce a chemical bond. It will be understood that electrical bonding forces, rather than chemical forces, could be involved and that a "reaction" as such need not occur. The terminology further includes species which will be attracted to a fibre surface and bind themselves thereto by means of cross-linking mechanisms. The term "polyfunctional reactive group" as used herein is to be understood as meaning a group which is capable of reacting with the amino functionality of compounds of formula I or II. The reactivity of group B needs to be complimentary to that of group R. in those compounds. It will be understood that the polymers and prepolymers may be derived from mixtures of one or more polyoxyalkyleneamines and that these may be joined by bridging groups. The bridging groups serve to link the polyoxyalkyleneamines and some examples of suitable groups were mentioned above. The bridging groups themselves could, of course, bear reactive species capable of reacting with fibres. It will also be appreciated that the bridging group B could be incorporated into the molecular structure, whilst the prepolymer is being applied to the fibre, as a separate reactive crosslinking agent. The present invention further provides a method for the treatment of natural or synthetic fibres so as to impart a softer handle and which comprises treating the fibres with a polymer or prepolymer compound of the aforementioned type. The softening agents and method of this invention may be applied to all types of natural and synthetic fibres, including nylon and acrylic. They are particularly suited to use with wool and cotton, including 100% cotton terry loop towelling, and to cotton or wool blends with synthetic fibres. The softening agents of the invention may be presented for use in solution in a non aqueous solvent, such as perchloroethylene. More preferably, however, they are in the form of an aqueous solution, optionally with the addition of suitable dispersing agents to reduce the viscosity of the solution. The total amount of polymer solids applied to the fibres is generally from 0.005 to 10.0% by weight, most preferably from 0.05 to 2.0%. The method of this invention can be performed as either a batch or continuous process using conventional equipment. For example, the softening agent may be applied aqueously by exhaustion on to the goods in a traditional long bath method using suitable machinery, or may be padded onto fabric continuously or applied in foam or by suction- slot techniques. In addition, the agent may be applied to piece goods or fabric from a solvent such as perchloroethylene in suitable machinery. If desired, the softening agents may be applied in combination with other resins, further softening agents, emulsifiers, pigments, binders fluorescent whitening agents or other materials to confer additional properties or benefits to the material. It has surprisingly and advantageously been found that the use of polymers and prepolymers of this type as softening agents imparts rather different, and improved, properties to the treated fibres compared with conventional softeners. Not only is a very soft handle achieved, but the finish is also extremely hydrophilic and substantially more durable to subsequent washing or wet processing. The durable softness thus imparted results also in dimensional retention and elasticity in knit cotton structures without recourse to conventional cotton resin finishes. As will be appreciated, this results in considerable benefits for both manufacturers and users of, for example, cotton towelling, bathrobes, underwear and leisurewear. A further advantage of the softening agents of this invention arises from their extreme water dispersibility. Conventionally employed softening agents are emulsions which create problems of shear instability in such high shear situations as jet dyeing machines, suction slot evacuators, and filtration problems when treating yarn in package dyeing machines, when filtration effects can cause difficulties. These problems are reduced, or totally avoided, with the present softening agents. A still further surprising aspect of the invention is that these softening agents, when used in combination with one or more conventional softening agents, can result in finishes with considerably superior handle and performance than may be expected. Wash durability, handle and fuming during fabric heat setting, for example, are much improved. In some cases the improvement may be up to or above the levels achieved with either material alone, indicating a synergis ' tic action. Examples of suitable "conventional" fabric softening agents include: oxidised polyethylene wax emulsions; silicone emulsions, especially emulsions of reactive organofunctional silicones, and more especially amonosilicones; fatty amide emulsions; and quaternised fatty amine emulsions. The present invention will now be illustrated by the following Examples. Example 1 λ solution was prepared containing 881 g of a blsaminopropyl polytetrahydrofuran of structure H2N CH2.CH2.CH2-f-0(CH2)4-ta 0 CH2.CH2.CH2 NH2 (where a is approximately 28 average) in 2418 g of a mixture of 70% isopropanol in water. To this solution was added 155.3g of eplchlorohydrln with efficient stirring at room temperature in a reaction flask fitted with a water cooled reflux condenser. The mixture was then heated to boiling and reflux maintained for approximately 4 hours or until a clear or slightly turbid homogeneous solution is produced when 5 cm 3 of the reaction mix is mixed with 30 cm 3 water. The reaction mixture was then allowed to cool and used in subsequent experiments. Example 2 Various textile samples were treated with the product of example 1 as follows: scoured goods were placed in a blank bath at a liquor ratio of 30:1 and the bath set to pH 6.5 to 7.0 at 25°C. The required amount of softener was added to the bath in prediluted form 1:10 with water. The bath was raised to 35°C and then allowed to exhaust, as indicated by the disappearance of the slight turbidity from the bath, which usually took between 15 and 30 minutes. The goods were then removed, hydroextracted and dried in a tumble dryer at between 70° and 100°C The results of the tests are presented in Table 1. Example 3 (a) Formulation A formulation was produced containing 20 parts product from Example 1 , 20 parts nonyl phenol 8 mole ethoxylate and 10 parts nonyl phenol 6 mole ethoxylate. (b) Application 1 λ Bowe P421 dry cleaning machine was loaded with 30 kg of 60% mercerised Cotton 40% nylon predyed ens socks. Then 130 litres of perchlorethylene was charged to the machine and the goods tumbled in solvent for 1 minute to wet out. 1.95 kg of the above formulation was then added to the machine via the button trap and the goods tumbled for 5 minutes , then the solvent drained to the still and centrifuged to 1001 expression, then tumble dried. (c) Application 2 The above procedure was repeated, but using 1.43 kg of the above mixture and 1.95 kg water placed in the button trap. (d) Results Example Wetting time* Handle Handle after 7xH CC5 3b 8 sec very soft soft 3c 1 sec very soft soft In addition to the above, the changes im lateral stretching of the sock after washing were measured =and compared with an untreated sock. Percent change in lateral- stretch foot ankle leg welt Example 3c -2.8 -2.2 -1.3 -1.3 Untreated -8.9 -8.5 -7.5 -2.3 This further indicates retention of softmess and sprlngness of the knitted structure after washing. * time taken for a 0.1 cm 3 drop of water to sink into the fabric ** in a Wascator FGM 7 acoocding to Horns laundering Consultative Council procedures Example 4 The product of Example 1 can be prepared as an aqueous solution by distilling out the isopropanol and replacing it with water, thereby minimising fire hazard. 797 parts of the product of Example 1 is distilled at atmospheric pressure until 391 parts of an isopropanol: water distillate is collected. Then, 710 parts of water and 80 parts monoethylene glycol is added to the flask and stirred. The resulting product contains about 20% w/w active solids and only 4-5% isopropanol. The product was applied to wool and acrylic socks by an exhaustion method as in Example 2. Excellent handle and good durability was achieved. Example 5 The softening agent can be mixed with conventional fatty quaternary ammonium-type softeners to give a product which has excellent handle, good durability and superior hydrophilicity to conventional softeners. Such a product is particularly useful for softening cotton/nylon socks. a) Formulation 797 parts of the product ,qf. Example 1 were distilled at atmospheric pressure until 391 parts of an isopropanol: water distillate were collected. 391 parts of water were added to this, stirred and this product blended with 341 parts of a commercial fatty quaternary ammonium softener (PPT Ltd). b) Application The performance of this softener was compared against conventional types on cotton/nylon socks. The softeners were applied as described in Example 2. The results are presented in Table 2. Table 2 Softeners.- applied to cotton/nylon socks Handle 1 . Fatty amide scαftener , Sandoz Products Ltd. 2. Durable siliccone softeners , PPT Ltd, prepared as described in European Paartent Application No. 89312306.7. Example 6 A stable product can be formulated by taking 100 parts of the product of Exaapάle 4 and blending this with 30 parts of a silicone eraulsioππ (eg Finish VP1445E, Wacker Chemicals Ltd). This product wass compared for handle on knitted lambswool swatches against a silicone softener (Wacker VP1445E). The softeners were apcplied by exhaustion, as described in Example 2 using 1-2% producrt on weight of wool. The new softener gave a super-soft handles., less slippy and more natural than with the silicone. The hysόdrophiliclty was also noticeably superior. Example 7 a) To a solution of 254g blsaminopropyl polytetrahydrofuran (of the structure in Example 1 ) in 70Og of a mixture of 70% isopropanol in water was added 39g DER732 (Dow Chemical Co.) and 7.8g eplchlorohydrln. The mixture was refluxed for 4 hours or until a clear or slightly turbid solution was obtained when 5σm 3 of the product was added to 30cm 3 of water. b) A solution containing 238g blsaminopropyl polytetrahydrofuran (of the structure in Example 1) in 712g isopropanol was prepared. To this was added 27g DER732 (Dow Chemical Co.), 16.6g Tego OF3010 (Th. Goldschmidt Ltd) and 7.3g epichlorohydrin. The mixture was refluxed for 4 hours or until a homogeneous, but turbid, solution was obtained when 5cm 3 of the product was added to 30cm 3 of water. Example 8 The products of Example 4 and Examples 7a and 7b were applied to a variety of knitted cotton fabrics (double jersey, single jersey, loopback interlock and pique). The softeners were applied by a) padding: the softeners were applied wet-on-wet to the fabrics from a solution containing 25g/l product, pH7, 25°C at 100% pick-up and b) exhaustion: as given in Example 2- using 2.5% o.w.g. product. The fabrics were stenter dried and commercially finished then compared for handle and durability to washing against a standard fatty amide softener. A co-applied mixture of the product of Example 4 and a polyethylene wax emulsion (Bradsyn G, Hickson & Welch Ltd) was also evaluated. The relative handle and durability assessments were as follows. In general, the handle before and after wash was superior when softeners were applied by a padding technique compared with exhaustion. Before washing the softeners were comparable in softness to the standard silicone softener (Edunlne SE, ICI Colours & Fine Chemicals); after wash, (3 x HLCC4), the standard softener could be readily distinguished by its harsher handle. The Example 4/polyethylene wax mixture performed particularly well on all fabric types, giving a cool, soft handle and excellent drape. Example 9 The softening agents of the invention are particularly suited to use on towels and towelling fabric as a consequence of their superior hydrophilicity. The products were applied by a wet-on- wet continuous pad treatment at 80% pick-up, from solutions containing 20-40g/l softener to Egyptian combed cotton towelling. The fabrics were tumble tried and finished as towels. A warm, soft handle is achieved with excellent rewettability, as compared with silicone- and fatty amide-type softeners. The new softeners impart a fuller, more luxurious feel to towelling and a silkier handle. The durability of the softeners was assessed by subjecting the towels to seven domestic washes, without additional fabric conditioner and line dried. The towels treated with the new softeners retain their original appearance, with a full, soft handle. Example 10 The product of Example 4 was compared for yellowing at high temperatures against standard silicone- and fatty amide-type softeners. The products were applied to 50/50 polyester/cotton by padding from solutions containing 1 g/1 wetting agent (Fullwet PPT Ltd) and 10-40 g/1 softener. The fabrics were padded to 100% pick-up then dried. Yellowing of the fabrics was assessed by heating the fabrics on an electrically-heated press for up to 3 minutes. Temperature Comments 180°C Little difference between products 200 O C Example 4 showed no yellowing at 1,2,3 mins at all levels. Other products yellowed slightly. 220©c Slight yellowing of Example 4. Other products were markedly yellowed.

Claims: CLAIMS 1. A method for the treatment of natural or synthetic fibres so as to impart a softer handle and which comprises treating the fibres with a polymer or prepolymer having one of the following structural formulae: i) J£N ( Rl ) n Jr or (K} χ -{B)y-K iϋ) wherein J represents a residue derived from a polyfunctional polyether; K represents the monofuctional or polyfunctional residue derived from partial reaction of a prepolymer of the formula: Z-UA) B -N(R l)n)r or J[N(R x ) n ) r (I) (ID that is, it represents the shaded area in the following formula: B is the residue created by bi- or polyfunctional reaction between any polyfunctional reactive group and the parent amine of the title compound (formula (I) where R 1 is hydrogen in all cases) or is the residue of a reactive amino-acrylic polymer or a reactive polyamide polymer; Z represents a residue of a polyol; A represents a polyalkylene oxide residue; R 1 represents a fibre reactive grouping such as the residue derived from monofunctional reaction of an epihalohydrin, an alkyl or alkyl aryl polyhalide or a methylol grouping derived from monofunctional reaction of formaldehyde, or is alkyl, hydroxyalkyl or hydrogen, with the proviso that at least one group R. per polyoxyalkyleneamine residue, and preferably at least one for each nitrogen, retains residual fibre reactivity; m is between 4 and 50; n is 2 or 3, with the proviso that, where n is 3, the nitrogen atom involved also bears a formal positive charge; p is 1 or 2, with the proviso that, where p is 2, the nitrogen atom involved also bears a formal positive charge; r equals the functionality of group Z; t is a number representing the functionality of reaction of the residue B; s is a number between 1 and r-1; x is between 2 and 30; and y is from x to x, t-1 with the general proviso that, in any given instance, the significance of a particular group Z, A, B, R, J or K in any given structure shall not be dictated by the significance of any other such group in the same formula, and further, wherever a formal positive charge is present in the structure, then an appropriate counter anion is taken to be present. 2. A method as claimed in claim 1 , wherein the total amount of polymer solids applied to the fibres is from 0.005% to 10.0% by weight. 3. A method as claimed in claim 1 , wherein the total amount of polymer solids applied to the fibres is from 0.05% to 2.0% by weight. 4. A method as claimed in any one of claims 1 to 3, wherein the polymer or prepolymer is presented for use in the form of an aqueous solution. 5. A method as claimed in any one of claims 1 to 3, wherein the polymer or prepolymer is presented for use as a solution in a non-aqueous solvent or is applied from a non-aqueous solvent of an aqueous solution. 6. A method as claimed in any one of claims 1 to 5, wherein the fibres being treated comprise cotton or wool. 7. A method as claimed in any one of claims 1 to 5, wherein the fibres being treated comprise nylon or acrylic. 8. A method as claimed in any one of claims 1 to 5, wherein the fibres being treated comprise a cotton or wool blend with synthetic fibres. 9. A method as claimed in any one of claims 1 to 8, wherein the polymer or prepolymer is applied in conjunction with one or more other softening agents. 10. A method as claimed in any one of claims 1 to 9, and which is carried out as a continuous process. 11. A method as claimed in any one of claims 1 to 9, and which is carried out as a batch process. 12. Use as a softening agent for natural or synthetic fibres of a polymer or prepolymer of the type defined in claim 1. 13. A formulation for the treatment of fibres comprising a polymer or prepolymer of the type defined in claim 1 together with one or more other softening agents.

Inventors: BAMFORD SUSAN, CONNELL DAVID LONGLEY, HUDDLESTONE KENNETH MICHAEL, BAMFORD, SUSAN, CONNELL, DAVID, LONGLEY, HUDDLESTONE, KENNETH, MICHAEL
Applicants: PRECISION PROC TEXTILES LTD, PRECISION PROCESSES (TEXTILES) LIMITED
Application year: 1991
Main classification: D06M15
IPC codes: D06M13, D06M15, D06M101