Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Specific organic component
Reexamination Certificate
2001-05-09
2004-07-20
Mruk, Brian P. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Specific organic component
C524S047000, C524S052000, C524S058000, C524S068000, C525S054200, C525S054240, C510S299000, C510S361000, C510S434000, C510S471000, C510S472000, C510S474000, C510S476000, C510S477000, C510S528000
Reexamination Certificate
active
06764992
ABSTRACT:
TECHNICAL FIELD
The present invention relates to novel soil release polymers for detergent formulations capable of enhancing soil removal from cotton or polyester fabric or their blends and a process for the preparation of the same.
BACKGROUND OF THE INVENTION
The washing of soiled fabrics with a laundry detergent is essentially a two step process. In the first stage, the detergent must remove the soil particles from the fabric and suspend them in the soil solution. In the second stage the detergent must prevent soil particles and other insolubles from re-depositing on the cloth before and after the fabric is removed from the soil solution or the rinse solution. Polymers are known to aid both processes—soil release polymers enhance soil removal from the fabric whilst anti-redeposition polymers prevent the deterged soil from depositing on the fabric.
The thrust in recent times has been the development of soil release polymers (SRPs), which can be incorporated into detergent formulations, to enhance the removal of soil from the fabric. SRPs adsorb on the fabric surface, modifying properties like the hydrophilic or hydrophobic nature of the fabric and its surface energy. Consequent soil removal is greater than what is possible with a conventional detergent formulation.
Soil release polymers disclosed in the literature address the problem of removal of oily or fatty soils from polyester. Polyester is a hydrophobic fabric and removal of hydrophobic, oily soils from the fabric has historically been a problem. The problem has been circumvented in part by using soil release polymers which combine hydrophobic and hydrophilic segments. The polymers adsorb strongly on the fabric, are easily dispersed or dissolved in a surfactant and are compatible with the components of the detergent formulation. When incorporated in a detergent formulation, they aid oily soil removal.
Various soil release polymers have been disclosed in the prior art for removal of oily soils from polyester. A vast majority are polyesters that have been hydrophilically modified. U.S. Pat. No. 3,959,230 and U.S. Pat. No. 4,116,885 disclose modified polyesters as soil release agents for detergent formulations.
GB2322137 discloses the hydrophobic modification of starch (starch is the hydrophilic segment) and its use as a soil release polymer, in particular for detergency of oily soil from polyester fabric. Hydrophobic modification was carried out by graft copolymerising starch with hydrophobic monomers.
U.S. Pat. No. 5,227,446 discloses a polysaccharide modified with a) a monoethylenically unsaturated dicarboxylic acid/anhydride/alkali metal salt, b) monoethylenically unsaturated carboxylic acid/alkali metal salt and c) monomer containing two or more ethylenically unsaturated, non-conjugated double bonds in the molecule.
SRPs for removal of oily soil from cotton have also been disclosed. U.S. Pat. No. 3,948,838 discloses the use of copolymers of hydrophobic acrylic monomers and water soluble monomers like acrylic acid, as oily soil release agents for cotton fabrics.
Hence, polymers are known in the prior art for removal of oily soil from cotton or polyester. However, polymers that can aid removal of oily and particulate soil or their mixtures from cotton and polyester have not been disclosed.
SUMMARY OF THE INVENTION
Thus according to the present invention, novel soil release polymers that are anionic, hydrophobic graft copolymers of polysaccharides are provided. The soil release polymers can be incorporated in detergent formulations and aid the removal of oily and particulate soil from cotton, polyester or their blends. The polymers can also be used in rinse conditioners. A process for making these soil release polymers comprising the steps of anionic modification and graft copolymerisation is also provided.
DEFINITION OF THE INVENTION
According to a first aspect of the present invention, there is provided an anionic, hydrophobic polysaccharide which is a graft copolymer of a polysaccharide having anionic substituents with an ethylenically unsaturated monomer, the copolymer having a polysaccharide backbone carrying grafted hydrophobic vinyl polymeric groups derived from the ethylenically unsaturated monomer, and anionic substituents, preferably a group which possesses a carboxylic or a sulphonic acid head group or a salt thereof.
More specifically the invention provides an anionic, hydrophobic polysaccharide having the general formula I:
wherein R is a hydrophobic vinyl polymer, R′ and R″ which may or may not be the same represents a group which possesses a carboxylic or a sulphonic acid head group or a salt thereof and G is a monosaccharide or substituted monosaccharide.
According to a second aspect of the present invention there is provided a process for the preparation of an anionic, hydrophobic polysaccharide as previously defined, comprising the steps of graft copolymerisation and anionic modification of a polysaccharide.
According to a third aspect of the present invention there is provided a fabric treatment composition comprising a fabric treatment agent and from 0.01 to 10 wt % of a anionic, hydrophobic polysaccharide as previously defined.
According to a fourth aspect of the present invention there is provided a detergent composition comprising from 5 to 60 wt % of a detersive surfactant and from 0.01 to 10 wt % of an anionic, hydrophobic polysaccharide as previously defined.
DETAILED DESCRIPTION OF THE INVENTION
The Anionic, Hydrophobic Polysaccharide
The anionic, hydrophobic graft copolymer of polysaccharide of the current invention has the general structure given below:
wherein R is a hydrophobic vinyl polymer, R′ and R″ which may or may not be the same, represent a group which possesses a carboxylic or a sulphonic acid head group or a salt thereof and G is a monosaccharide or substituted monosaccharide.
It is preferable that G is a monosaccharide.
In a first preferred embodiment, R′ and R″ are polymeric vinyl sulphonate groups such as —(CH
2
—CHSO
3
H)
n
and —(CH
2
—CHSO
3
−
M
+
)
n
, wherein M is an alkali or alkaline earth metal and n has a value of from 5 to 100. In a second preferred embodiment, R′ and R″ are alkylene carboxylates of the general form —R
3
—COOH and —R
3
—COO
−
M
+
, wherein R
3
is a C
1
to C
4
alkylene group, C
1
being especially preferred, and M is an alkali or alkaline earth metal.
The hydrophobic vinyl polymer can be attached to the polysaccharide backbone through the hydroxyl group or through any of the carbon atoms on the sugar. The polymer chains can be present at irregular intervals on the polysaccharide chain and it is not critical that they be present at regular intervals. Up to 50% homopolymer may be present without impairing soil release performance. The anionic group is attached to the polysaccharide backbone through the hydroxyl group, either primary or secondary. It is not essential that anionic substituents be present on each of the sugar rings.
It is not essential to remove any unreacted polysaccharide that may be present in the final product obtained by graft copolymerisation and anionic modification of the polysaccharide.
The polysaccharide, which is the hydrophilic part of the molecule, is preferably chosen from cellulose, guar gum, starch and tamarind kernel powder but is not limited by the same. More preferably the polysaccharide is starch. The starch can be any native starch and includes those derived from wheat, rice, oat, tapioca, maize, potato, sorghum, arrowroot or their mixtures thereof. Alternatively, acid or enzymatically degraded starch or oxidised starch or their mixtures or their mixtures thereof with the native starches can also be used.
When starch is the preferred polysaccharide, it may be in the native form or gelatinised form. The term gelatinisation refers to rupture of the starch granule at elevated temperatures in presence of water.
The hydrophobic modification is provided by a hydrophobic vinyl polymer (R in Formula I) grafted onto the polysaccharide backbone. The polyme
Kumar Velayudhan Nair Gopa
Moulee Anuradha
Mitelman Rimma
Mruk Brian P.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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