WO2012104157A1

WO2012104157A1 - Soil release polymers

Info

Publication number: WO2012104157A1
Application number: PCT/EP2012/050942
Authority: WO
Inventors: Martin Charles Crossman; Adam Peter Jarvis; Susanne Henning Rogers; Jeremy Nicholas Winter
Original assignee: Unilever Plc; Unilever N.V.; Hindustan Unilever Limited
Priority date: 2011-01-31
Filing date: 2012-01-23
Publication date: 2012-08-09

Abstract

A soil release polymer with the formula (I) : X-[(EO)_q-block-(PO)_p]-[(A-R¹-A-R²)_n]-A-R¹-A-[(PO)_p-block-(EO)_q] X (I) where EO is predominantly ethylene oxide (CH₂CH₂O) that is to say that at least 75% of the repeat units in the block are ethylene oxide, preferably at least 90% and most preferably 100%; where PO comprises propylene oxide (CH₂CH(CH₃)O), that is the PO block must contain at least 50% propylene oxide repeat units, preferably at least 80% PO units and most preferably 100% PO units; where p is a number from 0 to 60, when present preferably from 2 to 50, more preferably from 5 to 45, even more preferably from 6 to 40, yet more preferably from 7 to 40 and most preferably from 8 to 40, even from 11 to 35; where q is a number from 6 to 120, preferably 18 to 80, most preferably 40 to 70, provided that q is greater than p; where X is a capping moiety, preferably selected from C_1-4 alkyl, branched and unbranched; where n is a number from 2 to 26; where the moieties R¹ are all 1,4 phenylene, where the moieties A are all esters, characterised in that 100% of the moieties R²are substituted ethylene of formula (II) wherein R³ and R⁴are selected from Hydrogen, C_1-4 alkyl and C_1-4 alkoxy, provided that at least one of R³ and R⁴ is not hydrogen and that at least 10, preferably at least 20 mol% of the groups R² have neither R³ nor R⁴ as hydrogen.

Description

SOIL RELEASE POLYMERS

TECHNICAL FIELD This invention relates to improved soil release polymers which may be

incorporated into alkaline liquid detergent compositions to assist with cleaning of oily soils from fabrics, particularly fabrics comprising polyester.

BACKGROUND

US441 1831 (Purex) relates to inclusion of soil release polymer (SRP) in a liquid detergent composition. It has as its object to provide a liquid detergent having soil-release properties and which is stable from separation and precipitation for extended periods of time. The stable aqueous detergent composition consists essentially of (by weight): 0.2 to 20.0% of an ethylene terephthalate/polyethylene oxide terephthalate copolymer; 5 to 40% of specific anionic detergent; Up to 40% of specific nonionic detergent; and a buffer sufficient to maintain the pH of the aqueous composition within the range of 5.0 to 9.0. The preferred soil-release polymers for these liquids are said to be: Zelcon 4780 (DuPont) and Milease T (ICI Americas). It is taught that when formulating the liquids one must protect against high pH or the development of a high pH upon storage. This is because the soil-release agents used will hydrolyze in the alkaline range. For these polymers the hydrolysis is said to become objectionable when the pH begins to exceed 8.5 and it can be a real problem above 9.0.

These types of polyester SRPs have, since then, been developed considerably to improve their performance, especially in powdered compositions. More recent SRPs are, for example, described generally in EP991743 (Clariant) and

EP2135931 (Procter &Gamble). One line of development for soil release polymers (or more accurately oligomers) has been to make them of low molecular weight. In this specification the term polymer is used for both polymers and oligomers irrespective of molecular weight. We have found that while such low molecular weight polymers have excellent performance in powder compositions the low molecular weight seems to have increased their susceptibility to loss of performance via alkaline hydrolysis when included in alkaline liquid detergents. Thus although the SRP exemplified in WO2009/153184 has excellent performance in a freshly made concentrated liquid detergent composition according to that invention, we have now determined that the resistance of the SRP to hydrolysis on storage in the detergent liquid at pH from 7.5 to 9.0 (and consequential loss of soil release performance) is insufficient for a robust commercial detergent liquid. As such an alkaline pH is useful for boosting the performance of the surfactants and other ingredients it is highly desirable to find a new polymer with better storage stability at alkaline pH. The inclusion of triethanolamine (TEA) in the composition makes matters worse as it appears to catalyse the cleavage of ester bonds present in the SRP. Thus stability of the known SRP is insufficient even at neutral pH if TEA is incorporated as part of the buffer system of the detergent liquid. The approach taken in WO2009/153184 is to dose a main wash surfactant at low levels so that the in wash surfactant level is lower than normal. What would be the consequential unsatisfactory wash performance resulting from the low in wash surfactant levels, is boosted by inclusion of high levels of specific polymers and enzymes in the liquid. One of the key polymers that are preferably included at high levels in the composition is a polyester SRP. The one used in the examples of WO2009/153184, and also one of the three preferred on page 39, is of polyester chemistry (terephthalic acid/propandiol copolymer with methoxy PEG 750 end cap). It is sold under the trade name Texcare® SRN 170 by Clariant. It is now thought that this material is substantially linear. Despite attempts to reformulate the concentrated detergent liquids described in WO2009/153184 to eliminate TEA from the composition we have been unable to achieve that for a viable 20ml dose concentrated laundry detergent liquid. Thus, it is necessary to find a new SRP that is resistant to hydrolysis under moderately alkaline conditions, especially in the presence of TEA, under alkaline conditions and yet retains the excellent soil release properties of Texcare® SRN170.

WO 2006/133868 & WO 2006/133867 (Clariant) describe oligoesters of the type that would include Texcare® SRN170. The general formula is:

R¹-(O-R²)a-[OC(O)R³C(O)(OR )b]c-O-C(O)R⁵-C(O)O-(R⁶-O)_d-R⁷

While R⁴ may be alkylene such as ethylene, propylene, butylene; ethylene is preferred. The patent also discloses the used of statistical mixtures of ethylene and 1 ,2 propylene as bridging groups between the esters. Examples use either 1 ,2 propylene glycol alone or mixtures of this material with ethylene glycol.

The use of 1 ,2, propane diol in the polymer backbone, as found in Texcare® SRN 170, is described in many publications, for example, in EP 629690 (P&G). It is also found in the earlier EP 185427 (P&G) where it is said to confer improved polymer solubility when used in place of ethylene glycol in the backbone.

The generic expression for the polymeric soil release agents of EP185427 is: X-[(OCH₂CH2)n(OR⁵)_m]-[(A-R¹-A-R²)_u(A-R³-A-R²)_v]-A-R -A-[(R⁵O)_m(CH2CH₂O)n]-X

In this formula, the moiety [(A-R¹-A-R²)_U(A-R³-A-R²)_V]-A-R -A- forms the

backbone. Groups X-[(OCH₂CH₂)_n(OR⁵)_m] and [(R⁵O)_m (CH₂CH₂O)_n]-X are generally connected at the ends of the backbone. ln the backbone, the moieties A are preferably ester moieties. R¹ moieties are essentially 1 ,4-phenylene moieties. R² moieties are essentially ethylene moieties, or substituted ethylene moieties having C1 -C4 alkyl or alkoxy substituents.

Suitable ethylene or substituted ethylene moieties include ethylene, 1 ,2- propylene, 1 ,2-butylene, 1 ,2-hexylene, 3-methoxy-1 ,2-propylene and mixtures thereof. Preferably, the R² moieties are essentially ethylene moieties, 1 ,2- propylene moieties or mixtures thereof. Inclusion of a greater percentage of ethylene moieties tends to improve the soil release activity of the compounds. Inclusion of a greater percentage of 1 ,2-propylene moieties tends to improve the water solubility of the compounds. Preferred R³ moieties are those which are substituted 1 ,3-phenylene moieties.

In the above list 1 ,2-butylene is thought to mean a substituted ethylene moiety with one ethyl side chain; i.e. it has been made from 1 ,3 butane diol.

EP 1 661 933 (Sasol) describes amphiphilic non-ionic oligoesters that have soil release properties after storage in alkaline detergent liquid.

In the exemplary formulae a PO block of up to 10, but preferably 2 to 4 may be adjacent to the mid block. The tested material has 4 PO. The mid block is essentially 1 ,4 - phenylene and 1 ,2 propylidene. No mention is made of use of 2,3 butane diol for manufacture of the mid block.

US 2002/0042354 (Clariant) recites a similar list of diols. These fall into two groups. The alpha omega diols which will condense to form linear unbranched alkylene moieties of various chain lengths and the 1 ,2 diols which form ethylene moieties with a single alkyl side chain of variable length.

US4463165 (Cassella) mentions at column 4 lines 46 to 51 to use diols selected from a list that includes 1 ,2 butane diol, 1 ,3 butane diol and 1 ,4 butane diol. Because all of these diols have one primary alcohol the resulting alkylene group in the polymer only has one side branch.

2,3 butane diol has been proposed and used to make polyester fibres in

GB1 191499 (ICI). The optically active forms of the 2,3 butane diol are preferred due to their effect on fibre appearance.

2,3 butane diol exists in 3 diastereoisomeric forms. The RS (meso) form has a slightly higher melting point and is more stable in some environments. The other two forms are the optically active RR and SS forms.

Despite the large volume of prior art disclosures of soil release polymers based on polyester there remains a need for a polymer, or polymers that combine resistance to hydrolysis in alkaline liquids with good soil release performance on polyester fabrics.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a soil release polymer with the formula (I):

X-[(EO)_q-block-(PO)p]-[(A-R¹-A-R²)n]-A-R¹-A-[(PO)p-block-(EO)_q] -X (I) where EO is predominantly ethylene oxide (CH₂CH₂O) that is to say that at least 75% of the repeat units in the block are ethylene oxide, preferably at least 90% and most preferably 100%; where PO comprises propylene oxide (CH₂CH(CH₃)O), that is the PO block must contain at least 50% propylene oxide repeat units, preferably at least 80% PO units and most preferably 100% PO units; where p is a number from 0 to 60, preferably when present p is from 2 to 50, more preferably from 5 to 45, even more preferably from 6 to 40, yet more preferably from 7 to 40 and most preferably from 8 to 40, even from 1 1 to 35; when p is present n is preferably at least 5; where q is a number from 6 to 120, preferably 18 to 80, most preferably 40 to 70, provided that q is greater than p and preferably q is at least 1 .5 times as large as p; where X is a capping moiety, preferably selected from Ci_-4 alkyl, branched and unbranched; where n is a number from 2 to 26;

where the moieties R¹ are all 1 ,4 phenylene; and

where the linking moieties A are essentially esters. and characterised in that 100% of the moieties R² are substituted ethylene of formula (II) R³ R⁴

I I (II)

- CH - CH - wherein R³ and R⁴ are selected from Hydrogen, Ci_-4 alkyl and Ci_-4 alkoxy, provided that at least one of R³ and R⁴ is not hydrogen and that at least 10 mol%, preferably at least 20 mol% of the groups R² have neither R³ nor R⁴ as hydrogen. Preferably when R³ and R⁴ are not hydrogen then they are methyl moieties.

Preferably the non H substituents, more preferably the methyl moieties, are arranged in syn configuration on the ethylene backbone -CH-CH- of moieties R². When p is zero it is preferred for q to be at least 40. Furthermore we have determined that for such polymers it is desirable that they are provided with a large mid block where n is at least 5 and preferably at least 8 as this seems to confer advantages for sustained soil release after prolonged storage under alkaline conditions.

The linking moieties A adjacent to the end blocks -[(EO)_q-block-(PO)_p]- and - [(PO)p-block-(EO)_q]- are esters. Most preferably the moieties A are all esters. If the mid block is formed by the condensation of an ester of terephthalic acid with a diol the preferred diol to form the desired group R² is selected from the group of diols of formula (III): syn n+1 ,n+2 alkylene diol (III) n being an integer from 1 to c-3, where c is the number of carbons in the alkylene chain. The most preferred diols are syn 2,3 butane diol and 1 ,2 propane diol.

Because it is an average n is not necessarily a whole number for the polymer in bulk. The same holds true, to a lesser extent, for p and q. Since p and q are made by anionic polymerisation routes (resulting in polymer blocks with very discreet block lengths) as against the mid block made by polycondensation routes (resulting in polymer blocks with more polydisperse block lengths). According to a second aspect of the invention there is provided an alkaline detergent liquid comprising at least 10 wt% non soap surfactant and at least 1 wt% of the soil release polymer according to the first aspect of the invention, preferably the liquid has an undiluted pH of at least 7.4, more preferably at least 7.8. To obtain the benefit of the improved hydrolytic stability it is preferable that the alkaline detergent liquid has an undiluted pH of at most 9, preferably at most 8.4, even at most 8.2. The liquid may comprise at least 1 wt% triethanolamine.

DETAILED DESCRIPTION OF THE INVENTION

All percentages are weight percent except where indicated otherwise or where the context makes it obvious that something else is intended. The invention provides a stable high performance soil release polymer suitable for incorporation in alkaline concentrated detergent liquids, even in the presence of triethanolamine, and having the formula (I):

X-[(EO)_q-block-(PO)p]-[(A-R¹-A-R²)n]-A-R¹-A-[(PO)p-block-(EO)_q]-X (I)

The end blocks may be the conventional capped PEG groups of various molecular weight or alternatively, in the case where p is not zero, they may be blocked mPEG/PPG groups i.e. X-[(EO)_q-block-(PO)_p]- and -[(PO)_p-block-(EO)_q] -X. The end blocks are connected to the polymer mid block by ester moieties, A.

The end blocks of large blocks of EO groups are highly hydrophilic and can be considered to swing away from the fabric to provide the surface modification that promotes soil release. Thus it is an essential feature of the polymers of the present invention to have capped EO end block(s).

Mid block or backbone

The mid block [(A-R¹-A-R²)_r]-A-R¹-A is responsible for making the polymer fabric substantive, particularly towards polyester fabrics. The linking moieties A are essentially esters. In the polymer structure such an ester may be formed either way around and it may thus take the form of the moiety:

0 0 -C 0- or -0 C- The A moieties preferably consist entirely of such ester moieties. The R¹ moieties comprise 1 ,4-phenylene moieties.

It is possible, as taught by the prior art, to partially substitute some of the 1 , 4 phenylene moieties with other arylene or alkarylene moieties, for example 1 ,3- phenylene, 1 ,2-phenylene, 1 ,8-naphthylene, 1 ,4-naphthylene, 2,2'-biphenylene, 4,4'-biphenylene and mixtures thereof. However, such substitution is undesirable as it adversely affects the ability of the mid block to deposit onto polyester fabric. The R² moieties are substituted ethylene moieties having one or two Ci_-4 alkyl or alkoxy substituents, provided that at least 10, preferably at least 20 mol% of the R² moieties have two such substituents, one on each carbon atom in the backbone of the polymer. Alkyl substituents are preferred and methyl substituents are most preferred. R² is typically the residue of a diol used in the polymerisation reaction. To obtain R² which is ethylene substituted on each carbon by a single methyl group the diol is 2,3 butane diol (also known as 2,3 butylene glycol). In most preferred embodiments this is mixed with the corresponding ethylene substituted with only one methyl. Thus the polymer is formed from a mixture of 2,3 butane diol and 1 ,2 propane diol. R² does not consist of any other moieties. It is desirable to avoid oxyalkylene moieties, for best soil release activity.

For the R² moieties, preferred substituted ethylene moieties are mixtures of the monomethyl substituted R² formed from 1 ,2-propylene diol , and the dimethyl substituted R² formed from 2,3 butylene diol. Without wishing to be bound by theory it is thought that the 1 ,2 di methyl substituted ethylene shows superior protection of adjacent ester bonds due to that fact that it is always going to be the case that there is a methyl group on the carbon atom adjacent to the ester. This contrasts with the situation for the monomethyl material formed from 1 ,2 propane diol. In that case the methyl group may arrange itself adjacent to the ester or it may alternatively arrange itself to be on the carbon of the ethylene that is more remote from the ester. 2,3 butylene is a meso stereo isomeric compound. It is thought that once reacted into the polymer chain the different forms behave in similar ways so far as the hindering of hydrolysis is concerned. The optically active RR or SS

diastereoisomers are preferred over the RS (meso) diastereoisomer. Thus, the preferred form of the 2,3 butylene glycol used is the RR or SS optically active forms either isolated, or as a racemic mixture. In practice a mixture of the meso and racemic forms has been found to give satisfactory results.

The polymer should be nonionic as ionic polymers are not phase stable in concentrated alkaline detergent liquids.

It has been found that the value of n needs to be at least 2 in order for the compounds of the present invention to have sufficient polyester substantivity. The maximum value for n is generally determined by the process by which the compound is made, but can range up to 26, i.e. the compounds of the present invention are oligomers or low molecular weight polymers. By comparison, polyesters used in fibre making typically have a much higher molecular weight, with n from 50 to 250. Typically, n ranges from 2 to 16, preferably 4 to 1 1 .

Generally, the larger the n value, the less soluble is the polymer.

Preferred polymers are linear. If required, branching can be created by use of tri substituted phenylene or branched alkylene moieties, as is known to the person skilled in the art.

End blocks The polymer may have two end blocks, one on each end, or a single end block on one or the other end. The end block, when present, will link to a mid block ester moiety. The formulae given throughout the claims and description should be interpreted to include polymers having one or other variant of the single end block and polymers having two end blocks.

In one particularly preferred embodiment the end block(s) is arranged in blocks to obtain a particularly good combination of hydrolytic stability and soil release properties when stored in and delivered from an alkaline liquid. For such a polymer the end blocks have PO groups present and they are arranged in blocks adjacent to the last ester moieties of the mid block and end capped EO groups similarly arranged in blocks more remote from the mid block. Pure, i.e. 100%, EO and PO blocks are preferred. However, it is possible to introduce small qualities of random PO units into the EO block provided it remains hydrophilic. To some extent this depends on how many EO units there are in the EO block. We have determined that there must be at most 25% by number PO units in the EO block, preferably their number is less than 10% of the total units in the EO block and more preferably less than 5%. Most preferably the EO block contains no PO, or other more hydrophobic units, apart from the necessary endcap. Thus a preferred EO block is made using a capped PEG such as methyl capped PEG, or mPEG. The molecular weight Mw of the mPEG may be in the range 700 to 3000 Da. The PO block should comprise at least 50% by number PO units. We have determined that a stat block PO/EO block confers some improvement of resistance to hydrolysis of the end ester moieties. However, to avoid this hydrophobic block becoming unnecessarily large it is preferred that it comprises as much as possible of the ester bond hindering PO units. Preferably it consists of at least 80%, more preferably at least 90% and most preferably 100%, by number, PO units. The number, p, of units in the optional PO block is from 0 to 60, preferably from 2 to 50, more preferably from 5 to 45, even more preferably from 6 to 40, yet more preferably from 7 to 40 and most preferably from 8 to 40, even from 1 1 to 35;

Preferred polymers have an EO block that has more units than the PO block, preferably the EO block has at least 1 .5 times the number of moles or units (q) as the PO block (p).

The terminal end cap X on the EO block is preferably as small as possible, for example C1 -C4 alkyl. X is preferably methyl, ethyl, or n-butyl and most preferably methyl or n-butyl. q is at least 6, but is preferably at least 10. The value for q usually ranges from 12 to 1 13. Typically, the value for q is in the range of from 12 to 70.

As the value for q increases, the value for n should be increased so that the compound will deposit better on the fabric during laundering. Preferred compounds of the present invention are block polyesters having the formula (IV):

X-[(OCH₂CH₂)_q-]-block-[(OCH₂CH(CH3))p]-[(OC(0)-R¹-C(0)0-R²)n]-OC(0)-R¹- C(0)0-[(CH₂CH(CH3)0)p-]-block-[(CH₂CH₂0)_q]-X (IV) wherein the R¹ moieties are all 1 ,4-phenylene moieties; the R² moieties are essentially substituted ethylene moieties, selected from substituted ethylene of formula (II)

R³ R⁴

I I (II)

- CH - CH - wherein R³ and R⁴ are selected from Hydrogen, C1 -4 alkyl and C1 -C4 alkoxy provided that at least one of R³ and R⁴ is not hydrogen and that at least 10 mol%, preferably at least 20 mol% of the groups R² have neither R³ nor R⁴ as hydrogen. Preferably when R³ and R⁴ are not hydrogen then they are methyl moieties.

Preferably the non Hydrogen substituents, more preferably the methyl moieties, are arranged in syn configuration on the ethylene backbone.

If the mid block is formed by the condensation of an ester of terephthalic acid with a diol the preferred diol to form the desired group is selected from the group of diols of formula (III): syn n+1 ,n+2 alkylene diol (III) n being an integer from 1 to c-3, where c is the number of carbons in the alkylene chain. The most preferred diols are syn 2, 3 butane diol and 1 ,2 propane diol.

Especially preferred are mixtures of up to 80 mol% 1 ,2 propylene with the condensation product of SS or RR 2,3 butylene; each X is Ci_-4 alkyl, preferably methyl or n-butyl; each q is from 12 to 80; each p is from 0 to 50; n is from 3 to 10;

Particularly preferred block polyesters are linear block polyesters. For these most preferred linear block polyesters, n typically ranges from 2 to 9, especially for those made by condensation of dimethyl terephthalate, with 2,3 butane diol alone or in a mixture with up to 80 mol% 1 ,2-propylene glycol and having an end blocks of methyl capped polyethylene glycol. The most composition soluble of these linear block polyesters are those where n is from 2 to 7.

In a preferred embodiment, the polymeric soil release agents according to the present invention have the formula (V):

X-[(EO)_q(PO)p]-(OC(0)-R¹-C(0)0-R²)n]-OC(0)-R¹-C(0)0-

-[(PO)_p(EO)_q]-X (V) wherein :

- each of the R¹ moieties is a 1 ,4-phenylene moiety;

- the R² moieties are each selected from the group consisting of monomethyl ethylene and dimethyl ethylene, provided that the dimethyl ethylene has the two methyl groups on separate carbons and that this moiety forms at least 20 mol% of the moieties R²

- each X is Ci-C₄ alkyl; each q is from 40 to 70; each p is from 0 to 50, and n is from 3 to 10. Preferably, in the formula (V), R² moieties comprise a mixture of from 40 to 90 mol% monomethyl substituted ethylene moieties, and from 10 to 60 mol% 1 ,2 dimethyl ethylene moieties. In most preferred embodiments of the present invention, the polymeric soil release agents have the formula (VI) or (VII):

(VI)

Where in formula VII a+b=1 and "a" lies in the range 0 to 0.8 and in both formulae, n has the value from 2 to 20.

The soil release polymers of the present invention can be prepared by methods known to the person skilled in the art. US 4,702, 857 and US 4,71 1 ,730 describe a method of synthesis that may be adapted to produce the block polyesters of the present invention.

The mPEG for variants of the polymer without PO blocks in the end blocks (p=0) may be prepared by methods known to the person skilled in the art. For the case where the end block is a blocked PO/EO copolymer that end block is preferably preformed according to the following reaction scheme. Manufacture of the optional EO/PO end blocks

In a preferred process the optional EO/PO end blocks are preformed by anionic polymerisation of propylene oxide using a preformed mono-functional PEG as the initiator. Such a process is, for example, described in M. I. Malik, B. Trathnigg, CO. Kappe, Macromol. Chem. Phys., 2007, 208, 2510-2524.

The reaction scheme is set forth below:

Reaction A: Sodium hydride reacts with PEG to yield activated chain ends

Reaction B: The addition of PO proceeds at the ends of all the PEG chains to form a block of PO.

An alternative, but less controllable and therefore less preferred, process to construct the end blocks would be to take the mid block and react it with PO and mPEG.

Mid block manufacture It is preferred to manufacture the mid block by condensation of methyl esters of terephthalic acid with the appropriate aliphatic diol, preferably using an excess of one of them as set forth in more detail in the following examples. If the dicarboxylic acid is used in alkyl ester form, the reaction is suitably carried out in the presence of a base catalyst, at an elevated temperature, for example, 120 to 180 °C, and, if desired, under reduced pressure. The lower alcohol, normally methanol, generated during the reaction is distilled off.

Suitable catalysts include alkyl and alkaline earth metals, for example, lithium, sodium, calcium and magnesium, as well as transition and Group MB metals, for example, antimony, manganese, cobalt and zinc. The catalysts are usually used as oxides, carbonates or acetates. A preferred catalyst comprises antimony trioxide and calcium acetate.

The esters and oligomers produced in the condensation (ester interchange) reaction may then be polymerised to the desired molecular weight, by raising the temperature further, typically to 180 to 250°C.

The degree of polymerisation may be monitored by gel permeation

chromatography, NMR, and end-group titrations.

However, it is also possible to obtain a very similar polyester recognition motif with the ester moieties reversed if the starting materials are aliphatic biscarboxylic acids and aromatic bisalcohol.

For example, hydroquinone may be used as the aromatic alcohol and derivatives of succinic acid may be used as the carboxylic acid (in this case, R' and R" = H).

Molecular weight

Preferred polymers for use in liguid detergent compositions have molecular weights Mw within the range of from 1000 to 20 000, preferably from 1500 to 10 000.

The polydispersity of the polymers is preferred to be less than 3.

The polymers of the present invention are suitable for incorporation into alkaline liquid detergent compositions. The polymers may be incorporated into detergent compositions in amounts of from 0.3 to 15 wt%, preferably from 1 to 10 wt%, most preferably 1 .5 to 7 wt%.

The invention will now be further described with reference to the following non- limiting examples.

EXAMPLES

The 2,3-butandiol used was a mixture of the racemic and meso forms from

Aldrich: B84904, 2,3-Butanediol, 98%, CAS no. 513-89-5.

Soil Release (DMO) evaluation:

DMO is dirty motor oil. Soil release polymer was dissolved or dispersed in concentrated alkaline liquid detergent bases to make the concentrated alkaline liquid detergent compositions given in Table 1 .

MPG is mono propylene glycol

TEA is triethanolamine

Neodol 25-7 is nonionic (ex Shell) a C12-15 alcohol with

7 moles EO LAS acid is C12-14 linear alkylbenzene sulphonic acid Prifac ® 5908 is saturated lauric fatty acid ex Croda

SLES 3E0 is sodium lauryl ether sulphate with 3 moles EO

Empigen ® BB is an alkyl betaine ex Huntsman

EPEI is Sokalan ® HP20 - PEI(600) 20EO ex BASF

Perfume is free oil perfume

Table 1 - Liquid detergent compositions

^* comprising NaOH (added from 47% solution) to required pH, and demineralised water balance. Essentially the 3x Composition B is a dilution of the 5x Composition A (i.e. the 5x ingredient percentage concentration x 20/35. A 5x composition is one designed to have a recommended dose per wash of 20ml; A 3x composition is one that has a recommended dose per wash of about 35ml. The exceptions to the scaling between Compositions A and B are the water level and the MPG hydrotrope level which was kept at 20% for both compositions.

The compositions, comprising the polymer, were stored to allow the polymer to be exposed to conditions where it may undergo hydrolysis, with consequent reduction of the soil release performance.

Thus whilst the theoretical level of polymer dosed to the wash is stated to be, say, 50ppm the actual level used after storage would have been lower due to polymer degradation during storage.

Wash Method

All washes and pre-washes were carried out in a Tergotometer containing 1 litre of wash liquor at 25°C. Wash liquors were prepared using 26°FH water. The Tergotometer speed was set at 100 oscillations/minute for all pre-washes and washes.

Product concentration of composition in table 1 added to the wash liquor was 1 .3g/l for Composition A (5x). Two 30 minute pre-washes of knitted polyester test pieces were carried out with polyester and cotton ballast such that the total fabric weight was 40g and the ratio of cotton : polyester was 1 : 1 . After each pre-wash the fabric was rinsed twice (for 20 seconds) in 26°FH water and dried. Fresh ballast was used for each pre-wash (and subsequent wash). After the polyester test pieces had dried, following the second pre-wash, they were stained using one drop of dirty motor oil (DMO) added from a disposable glass pipette. The stains were quickly stretched by hand in order to assist wicking and ensure a uniform stain, and left overnight before washing. Three replicate stained polyester test pieces were included in each wash; three repeat washes were carried out.

ΔΕ of the dried residual stain was measured (relative to clean unstained substrate, i.e. knitted polyester) using a Hunterlab Ultrascan XE reflectance spectrophotometer equipped with a UV filter at 420nm. Specular reflectance was included.

Examples 1 and 2 are two methods for synthesis of SRPs according to the invention. The two stage process of Example 1 is preferred due to the superior properties of the polymer produced. Example 1 Synthesis of PO block EO end-capped terephthalate/2,3 butandiol polyester SRP using a 2-stage reaction process

monobutyl ether Antarox B500 ex Rhodia

Using a 3-necked 100 ml round bottom flask fitted with a digital thermometer, argon inlet and bubbler connected to an air condenser, dimethylterephthalate (1 1 .64g, 59.94 mmol) and 2,3 butandiol (10.80g, 1 19.89 mmol) were weighed into the flask, which also contained a magnetic stirrer bar. Also added were the condensation catalyst titanium tetraisopropylate (3 drops) and sodium acetate (2 small spatulas). The contents of the flask were heated under a constant stream of argon and constant stirring. When the temperature of the molten mixture in the flask reached 160°C, methanol was distilled off, indicating that polycondensation was occurring. Heating continued until the temperature of the mixture reached 240°C, which was held for 2.75 hours. The contents of the flask was then allowed to cool to about 140°C, at which point Antarox B500 (supplied by Rhodia) (1 1.99g, 5.99 mmol) was added to the flask and a further 3 drops of titanium

tetraisopropylate. The mixture was reheated to 250°C and held at this temperature for 2.5 hours. The product was purified by sublimation to remove any residual dimethylterephthalate. Final yield = 18.9g.

¹H-NMR (D₂0) - Accelerated data in concentrated Laundry liquid Composition B buffered with TEA to pH 8 and held at 60°C for 8 days (using ¹H-NMR as the polymer stability tracking tool) has shown the polymer of example 1 to be hydrolytically stable.

TD-SEC (THF) - av Mn = 4,800; av M_w = 14, 150; av PD = 2.95

Example 2 - Synthesis of PO block EO end-capped terephthalate/2,3 butandiol polyester using a 1 -stage reaction process

Using a 3-necked 100ml round bottom flask fitted with a digital thermometer, argon inlet and bubbler connected to an air condenser, dimethylterephthalate (1 1 .64g, 59.94 mmol), 2,3 butandiol (10.80g, 1 19.89 mmol) and Antarox B500 (supplied by Rhodia) (1 1 .99g, 5.99 mmol) were weighed into the flask, which also contained a magnetic stirrer bar. To the mixture was also added the condensation catalyst titanium tetraisopropylate (3 drops) and sodium acetate (2 small spatulas). The contents of the flask were heated under a constant stream of argon and constant stirring. When the temperature of the molten mixture in the flask reached 160°C, methanol was distilled off, indicating that polycondensation was occurring. Heating continued until the temperature of the mixture reached 240°C, which was held for 5 hours. The product was purified by sublimation to remove any residual dimethylterephthalate. Final yield = 19.7g. The product has the same structure as that produced for example 1 , subject to the data below.

¹H-NMR (D₂0) - Accelerated data in concentrated Laundry liquid Composition B buffered with TEA to pH 8 and held at 60°C for 8 days (using ¹H-NMR as the polymer stability tracking tool) has shown the polymer of example 2 to be hydrolytically stable.

TD-SEC (THF) - av Mn = 3,700; av M_w = 4, 150; av PD = 1 .12 Example 3 - Scale up of Example 1

To produce the polymer of example 3 we used the same synthetic procedure as for Examplel with the following:

DMT = 29.1 g, 149.86 mmol

2,3-Butanol = 27. Og, 299.72 mmol

Antarox = 29.98g, 14.99 mmol

Sodium acetate = 2 small spatulas

Titanium isopropoxide (1 st stage) = 3 drops

Titanium isopropoxide (2nd stage) = 3 drops

Yield = 54.2g

The polymer product of Example 3 was shown to have the structure shown for example 1 . The polymer of example 3 was characterised:

TD-SEC (THF) - av Mn = 2,700, av M_w = 3, 100; av PD = 1 .14 The polymer was included in concentrated Laundry liquid Composition B buffered with TEA to pH 8.1 and held at 60°C for 8 days. Using ¹H-NMR as the polymer stability tracking tool showed that this polymer was stable in alkaline detergent liquid.

Example 4

The polymer produced in Example 3 was used in Composition A buffered to pH 6.7 in a full scale wash test in a Miele front loading automatic washing machine dosed at 1 .3 g/L product (50ppm polymer). Controls were the same composition without polymer (water balance) (Table 2) and the same composition using the prior art Texcare® SRN170 polymer (Table 3).

Table 2

Prewash fatty stain data with base as the control

Delta

Stain R LSD95p LSD95n

MakeUp2-CSS3-kPES 0.06 0.63 -0.63

YellowCurry-CSS3-kPES 0.25 0.57 -0.57

W30D-PS16 0.29 0.43 -0.43

W30C-PS16 0.77 1.42 -1.42

C09-PS16 0.97 1.18 -1.18

BlackShoePolish-CSS3-kPES 0.98 3.05 -3.05

W10M-PS16 1.02 1.55 -1.55

W20D-PS16 1.57 2.30 -2.30

E101-PS16 2.15 3.29 -3.29

GreenCurry-CSS3-kPES 3.39 0.59 -0.59

Lipstick-CSS3-kPES 4.72 1.79 -1.79

MechanicalGrease-CSS3-kPES 5.40 2.37 -2.37

TomatoSunflowerOil-CSS3-kPES 7.55 1.69 -1.69

DendeOil-CSS3-kPES 7.65 0.52 -0.52

CookingOilVioletDye-CSS3-kPES 9.28 0.56 -0.56

RedCurry-CSS3-kPES 11.92 1.27 -1.27

RaguSunflowerOil-CSS3-kPES 13.43 2.12 -2.12

LardVioletDye-CSS3-kPES 15.85 3.14 -3.14

DirtyMotorOil-CSS3-kPES 17.58 1.23 -1.23

RedPepperOilWater-CSS3-kPES 23.66 1.46 -1.46 Table 3

Prewash fatty stain data with Texcare®SRN170 as the control

Delta

Stain R LSD95p LSD95n

BlackShoePolish-CSS3-kPES -8.07 3.05 -3.05

Lipstick-CSS3-kPES -6.83 1 .79 -1 .79

DirtyMotorOil-CSS3-kPES -4.43 1 .23 -1 .23

GreenCurry-CSS3-kPES -0.46 0.59 -0.59

W20D-PS16 -0.39 2.30 -2.30

W30C-PS16 -0.32 1 .42 -1 .42

RaguSunflowerOil-CSS3-kPES -0.25 2.12 -2.12

CookingOilVioletDye-CSS3-kPES -0.09 0.56 -0.56

TomatoSunflowerOil-CSS3-kPES -0.08 1 .69 -1 .69

YellowCurry-CSS3-kPES -0.05 0.57 -0.57

DendeOil-CSS3-kPES -0.03 0.52 -0.52

RedPepperOilWater-CSS3-kPES -0.01 1 .46 -1 .46

W10M-PS16 0.00 1 .55 -1 .55

MakeUp2-CSS3-kPES 0.00 0.63 -0.63

E101 -PS16 0.03 3.29 -3.29

W30D-PS16 0.04 0.43 -0.43

RedCurry-CSS3-kPES 0.05 1 .27 -1 .27

LardVioletDye-CSS3-kPES 0.17 3.14 -3.14

C09-PS16 0.38 1 .18 -1 .18

MechanicalGrease-CSS3-kPES 0.43 2.37 -2.37 Example 4 - Synthesis of Polyfethylene glycol) methyl ether 2000 end-capped terephthalate/2,3 butandiol polyester using a 2-stage reaction process

Using a 3-necked 100ml round bottom flask fitted with a digital thermometer, argon inlet and bubbler connected to an air condenser, dimethylterephthalate (1 1 .64g, 59.94 mmol) and 2,3 butandiol (10.80g, 1 19.89 mmol) were weighed into the flask, which also contained a magnetic stirrer bar. Also added were the condensation catalyst titanium tetraisopropylate (3 drops) and sodium acetate (2 small spatulas). The contents of the flask were heated under a constant stream of Argon and constant stirring. When the temperature of the molten mixture in the flask reached 160°C, methanol was distilled off, indicating that polycondensation was occurring. Heating continued until the temperature of the mixture reached 220°C, which was held for 3 hours. The contents of the flask was then allowed to cool to about 140°C, at which point Poly(ethylene glycol) methyl ether 2000 (1 1 .99g, 5.99 mmol) was added to the flask and a further 2 drops of titanium tetraisopropylate. The mixture was then heated to 250°C and held at this temperature for 3 hours. The product was purified by sublimation to remove any residual dimethylterephthalate. Final yield = 20.0g

Characterisation of polymer of Example 4:

TD-SEC (THF) - av Mn = 3,400; av M_w = 4,230; av PD = 1 .23 The polymer of Example 4 was shown to be hydrolytically stable in concentrated Laundry liquid Composition B buffered with TEA to pH 8 at 60°C for 8 days (using ¹H-NMR (D₂0) as the polymer stability tracking tool).

Example 5 - Synthesis of Polyfethylene glycol) methyl ether 2000 end-capped terephthalate/1 ,2 propandiol (80 mol.%) / 2,3-butandiol (20 mol.%) polyester using a 2-stage reaction process

Using a 3-necked 100ml round bottom flask fitted with a digital thermometer, argon inlet and bubbler connected to an air condenser, dimethylterephthalate (10.Og, 51 .50 mmol) and 1 ,2 propandiol (6.27g, 82.40 mmol) and 2,3-butandiol (1.86g, 20.60 mmol) were weighed into the flask, which also contained a magnetic stirrer bar. Also added were the condensation catalyst titanium tetraisopropylate (3 drops) and sodium acetate (1 small spatula). The contents of the flask were heated under a constant stream of argon and constant stirring. When the temperature of the molten mixture in the flask reached 160°C, methanol was distilled off, indicating that polycondensation was occurring. Heating continued until the temperature of the mixture reached 220°C, which was held for 3 hours. The contents of the flask was then allowed to cool to about 140°C, at which point Poly(ethylene glycol) methyl ether 2000 (10.30g, 5.15 mmol) was added to the flask and a further 3 drops of titanium tetraisopropylate. The mixture was then heated to 250°C and held at this temperature for 2 hours. The product was purified by sublimation to remove any residual dimethylterephthalate. Final yield = 14.5g.

In the above schematic some of the ethylene groups were substituted by a second methyl moiety - 2,3 butane diol, as shown.

Characterisation of polymer of Example 5:

¹H-NMR (d⁶-acetone) - Composition PO:BO = 85.9: 14.1

Note that the theoretical ratio of 80:20 is found to be 86: 14 by this NMR study.

TD-SEC (THF) - av Mn = 2, 130; av M_w = 6,890; av PD = 3.24

The polymer of Example 5 was shown to be hydrolytically stable in concentrated Laundry liquid Composition B buffered with TEA to pH 8 at held at 60°C for 8 days (using ¹H-NMR as the polymer stability tracking tool).

Example 6 - Soil Release (DMO) evaluation:

The polymer of Example 5 was pre-dissolved/dispersed in Composition A (5x base). Two pre-washes were carried out prior to staining with DMO and subsequent washing for 30 mins in a tergotometer at 25°C. The experimental polymer was included such that wash liquor cone, was 100ppm.

ΔΕ = 3.15 ± 0.65

The same composition with Texcare SRN170 @ 50 ppm:

ΔΕ = 4.7 (zero means complete stain removal, ΔΕ = 42 for washed stain with no SRP in pre-wash formulation).

Example 7 - Synthesis of Polvfethylene glycol) methyl ether 2000 end-capped terephthalate/1 ,2 propandiol (60 mol.%) / 2,3-butandiol (40 mol.%) polyester using a 2-stage reaction process

Using a 3-necked 100ml round bottom flask fitted with a digital thermometer, argon inlet and bubbler connected to an air condenser, dimethylterephthalate (10.0g, 51 .50 mmol) and 1 ,2 propandiol (4.70g, 61.80 mmol) and 2,3-butandiol (3.71 g, 41 .20 mmol) were weighed into the flask, which also contained a magnetic stirrer bar. Also added were the condensation catalyst titanium tetraisopropylate (3 drops) and sodium acetate (1 small spatula). The contents of the flask were heated under a constant stream of Argon and constant stirring. When the temperature of the molten mixture in the flask reached 160 °C, methanol was distilled off, indicating that polycondensation was occurring. Heating continued until the temperature of the mixture reached 200 °C, which was held for 2 hours. The contents of the flask was then allowed to cool to about 140 °C, at which point Poly(ethylene glycol) methyl ether 2000 (10.30g, 5.15 mmol) was added to the flask and a further 3 drops of titanium tetraisopropylate. The mixture was then heated to 250°C and held at this temperature for 2 hours. The product was purified by sublimation to remove any residual dimethylterephthalate.

Final yield = 13.6g.

In the above schematic some of the ethylene groups were substituted by a second methyl moiety - 2,3 butane diol, as shown. Thus in the polymer the ethylene groups have a 40% probability of having the 2 methyl substituents and a 60% probability of having the more conventional single methyl substituent. Each repeat unit only has one of these possibilities. ¹H-NMR (D₂0) - The polymer of example 7 was shown to be hydrolytically stable in concentrated Laundry liquid Composition B buffered with TEA to pH 8 and held at 60°C for 8 days (using ¹H-NMR as the polymer stability tracking tool).

Characterisation:

¹H-NMR (d⁶-acetone) - Composition PO:BO = 70.3:29.7

Note that the theoretical ratio of 60:40 is found to be 70:30 by this NMR study.

TD-SEC (THF) - av Mn = 2,910; av M_w = 10,530 av PD

Examples 8, 9 and Comparative Example C showing Soil release performance after accelerated aging Polymers from Examples 5 and 7 and a comparative polymer C, Texcare

©SRN170, were stored in concentrated detergent liquid composition A containing 1 % TEA in closed screw-top glass jars in an oven at 60°C for 8 days. Then they were tested for soil release performance in tergotometers using an in wash polymer concentration of 50 ppm. The ΔΕ results are given in Table 4 below.

All polymers show excellent performance at pH6.5; performance was also very good at pH7.5 provided that the butandiol proportion was less than 40% of the total diol. It was noted that after storage the Compositions comprising the butane diol polymers showed better clarity of the liquid.

Table 4

For comparison, a washed stain without SRP has a ΔΕ value of 42. Complete removal of the stain gives a ΔΕ of zero. At alkaline pH the Texcare® SRN170 polymer performance drops significantly. In contrast the polymers according to the invention maintain good performance under alkaline conditions, particularly at a pH below 8.5, even after storage under those alkaline conditions in the presence of TEA. The tested variation in the concentration of TEA does not appear to affect the result significantly.

Claims

1 . A soil release polymer with the formula (I) : X-[(EO)_q-block-(PO)p]-[(A-R¹-A-R²)n]-A-R¹-A-[(PO)p-block-(EO)_q] -X (I) where EO is predominantly ethylene oxide (CH2CH2O) that is to say that at least 75% of the repeat units in the block are ethylene oxide, preferably at least 90% and most preferably 100%; where PO comprises propylene oxide (CH₂CH(CH3)0), that is the PO block must contain at least 50% propylene oxide repeat units, preferably at least 80% PO units and most preferably 100% PO units; where p is a number from 0 to 60, when present preferably from 2 to 50, more preferably from 5 to 45, even more preferably from 6 to 40, yet more preferably from 7 to 40 and most preferably from 8 to 40, even from 1 1 to 35; where q is a number from 6 to 120, preferably 18 to 80, most preferably 40 to 70, provided that q is greater than p; where X is a capping moiety, preferably selected from C1-4 alkyl, branched and unbranched; where n is a number from 2 to 26;

where the moieties R¹ are all 1 ,4 phenylene,

where the moieties A are all esters, characterised in that 100% of the moieties R² are substituted ethylene of formula (II)

R³ R⁴

I I (II)

- CH - CH - wherein R³ and R⁴ are selected from Hydrogen, Ci_-4 alkyl and Ci_-4 alkoxy, provided that at least one of R³ and R⁴ is not hydrogen and that at least 10, preferably at least 20 mol% of the groups R² have neither R³ nor R⁴ as hydrogen.

2. A polymer according to claim 1 in which when R³ and R⁴ are not hydrogen then they are methyl moieties.

3. A polymer according to any preceding claim in which the non H

substituents R³ and R⁴, are arranged in syn configuration on the ethylene backbone of R².

4. A polymer according to any preceding claim in which p is zero and q is at least 40.

5. A polymer according to claim 4 wherein where n is at least 5, preferably at least 8.

6. A polymer according to any preceding claim comprising an EO end block that has more units than the optional PO end block, preferably the EO end block has at least 1.5 times the number of moles or units (q) as the PO end block (p).

7. A polymer according to any preceding claim in which the end cap X is C-i- C₄ alkyl, methyl, ethyl, or n-butyl and most preferably methyl or n-butyl.

8. A polymer according to any preceding claim having the formula (IV):

X-[(OCH2CH2)_q-]-block-[(OCH₂CH(CH3))p]-[(OC(0)-R¹-C(0)0-R²)n]-OC(0)-R¹- C(0)0-[(CH₂CH(CH3)0)p-]-block-[(CH2CH₂0)_q]-X (IV) wherein the R¹ moieties are all 1 ,4-phenylene moieties; the R² moieties are essentially substituted ethylene moieties, selected from substituted ethylene of formula (II) R³ R⁴

I I (II)

- CH - CH - wherein R³ and R⁴ are selected from Hydrogen, C1 -4 alkyl and C1 -C4 alkoxy, provided that at least one of R³ and R⁴ is not hydrogen and that at least 10, preferably at least 20%, of the groups R² have neither R³ nor R⁴ as hydrogen.

9. A polymer according to claim 8 where when R³ and R⁴ are not hydrogen then they are methyl moieties.

10. A polymer according to claim 8 or claim 9 in which, the non H substituents, preferably methyl moieties, are arranged in syn configuration on the ethylene backbone.

1 1 . A polymer according to any preceding claim formed by the condensation of an ester of terephthalic acid with a diol wherein the preferred diol to form the desired group is selected from the group of diols of formula (III): syn n+1 ,n+2 alkylene diol (III) n being an integer from 1 to c-3, where c is the number of carbons in the alkylene chain.

12. A polymer according to claim 1 1 in which the diols are syn 2, 3 butane diol and 1 ,2 propane diol.

13. A polymer according to claim 1 1 or 12 comprising mixtures of up to 90% 1 ,2 propylene with the condensation product of SS or RR 2,3 butylene; wherein each X is Ci_-4 alkyl, preferably methyl or n-butyl; each q is from 12 to 80; each p is from 0 to 50; n is from 3 to 10;

14. A soil release polymer according to any preceding claim and having formula (V): X-[(EO)_q(PO)p]-[(OCH2CH₂CH2)p]-[(OC(0)-R¹-C(0)0-R²)n]-OC(0)-R¹-C(0)0- -[(PO)_p(EO)_q]-X (V) wherein :

- each of the R¹ moieties is a 1 ,4-phenylene moiety;

- each X is Ci-C₄ alkyl; each q is from 40 to 70; each p is from 0 to 50, and n is from 3 to 10.

15. A polymer according to claim 14 in which the R² moieties consist of a mixture of from 40 to 90 mol% monomethyl substituted ethylene moieties, and from 10 to 60 mol% 1 ,2 dimethyl ethylene moieties. A polymer according to any preceding claim and having formula (VI):

(V) where n has the value 2 to 20.

17. A polymer according to any one of claims 1 to 16 and having formula (VII):

where a+b=1 and "a" lies in the range 0 to 0.8 and n has the value 2 to 20.

18. A polymer according to any preceding claim and having a molecular weight Mw within the range of from 1000 to 20 000, preferably from 1500 to 10 000.

19. A polymer according to any preceding claim with a polydispersity of less than 3.

20. An alkaline detergent liquid comprising at least 10 wt% non soap surfactant and at least 1 wt% of the soil release polymer of any preceding claim, preferably the liquid has an undiluted pH of at least 7.4, more preferably at least 7.8.

21 . An alkaline detergent liquid according to claim 20 comprising at least 10 wt% non soap surfactant and at least 1 wt% of the soil release polymer of any preceding claim, wherein the liquid has an undiluted pH of at most 9, preferably at most 8.4, even at most 8.2.

22. A liquid according to claim 20 or claim 21 further comprising at least 1 wt% triethanolamine.