Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1998-03-24
2001-09-18
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S327700
Reexamination Certificate
active
06291594
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to compositions useful for textile sizes, and in particular to anhydride based graft copolymers which provide lubrication during sizing and a thorough removal of waxes and oils during desizing and scouring.
BACKGROUND OF THE INVENTION
In the textile industry it is common to treat fibers with a sizing composition prior to the weaving process. In the sizing treatment, the size composition adheres to and binds together fibers thereby lubricating and strengthening the fibers. Lubricated fibers allow for faster speeds to be used in the subsequent weaving operation without building up as much static electricity as compared to untreated fibers, and strengthened fibers are more resistant to abrasion and breaking during the weaving operation.
Many types of polymers have been used as sizing agents in the sizing of textiles. These sizing agents include, for instance, starch, starch derivatives, gelatin, polyvinyl alcohol, acrylics, alkali metal salts of maleic anhydride/styrene copolymers, and sulfonic acid metal salt derivatives of polyesters. The disadvantages associated with the use of such sizing agents are that they form brittle hard films on fibers and thus require the addition of waxy type lubricants in order to provide lubrication during sizing. These waxy type lubricants are typically oils and fats which are difficult to remove with water during desizing because they are hydrophobic. Additionally, such sizing agents are characterized by poor soil release properties and thus do not effectively remove the natural and synthetic waxes from the fibers during desizing or scouring. Furthermore, such sizing agents, in particular starch and polyvinyl alcohol, are difficult to resolubilize due to hydrogen bonding even in an alkaline medium and thus are difficult to remove during desizing.
SUMMARY OF THE INVENTION
Accordingly it is an object of the present invention to provide a sizing composition which provides lubrication to fibers during sizing without the addition of waxy type lubricants.
It is also an object of the invention to provide a sizing composition which is effectively removed during desizing.
It is another object of the invention to provide a sizing composition which effectively removes natural and synthetic waxes from fibers during desizing and/or scouring.
With regard to the foregoing and other objects, the present invention provides a sizing composition comprising 1 to 50 weight percent, based on the total weight of the sizing composition, of and anhydride based graft copolymer which comprises the reaction product of an ethylenically unsaturated monomer, an anhydride monomer selected from the group consisting of maleic anhydride, itaconic anhydride, and mixtures thereof, either a monofunctional polyglycol having a hydroxyl or amine terminal group or a polyfunctional polyglycol having a weight average molecular weight of greater than 5,000 and at least one terminal hydroxyl group, and a free radical initiator to form an anhydride based graft copolymer.
According to another aspect the invention provides a sizing composition comprising 1 to 50 weight percent, based on the total weight of the sizing composition, of an anhydride based graft copolymer which is prepared by a two-step process comprising reacting an ethylenically unsaturated monomer and an anhydride monomer selected from the group consisting of maleic anhydride, itaconic anhydride, and mixtures thereof, and a free radical initiator, in the presence of a solvent; and isolating the product from the solvent and reacting the product with either a monofunctional polyglycol having a hydroxyl or amine terminal group or a polyfunctional polyglycol having a weight average molecular weight of greater than 5,000 and at least one terminal hydroxyl group, to form an anhydride based graft copolymer.
An additional aspect of the invention provides an improved process for preparing woven textiles comprising: (a) sizing fibers to be woven with an aqueous solution of an anhydride based graft copolymer which comprises the reaction product of an ethylenically unsaturated monomer, an anhydride monomer selected from the group consisting of maleic anhydride, itaconic anhydride, and mixtures thereof, either a monofunctional polyglycol having a hydroxyl or amine terminal group or a polyfunctional polyglycol having a weight average molecular weight of greater than 5,000 and at least one terminal hydroxyl group, and a free radical initiator; (b) weaving the sized fibers to produce woven textile material; (c) desizing the woven textile material with an aqueous alkaline solution; and (d) washing the alkaline desized woven textile material with water.
Sizing compositions prepared using the anhydride based graft copolymers of the invention form a waxy film on fibers and thus provide effective lubrication without the addition of waxy-type lubricants which are typically added to size compositions in order to lubricate the fibers. In addition, size compositions prepared using the anhydride based graft copolymers of the invention exhibit excellent soil release properties due to the hydrophobic backbone and hydrophillic chains of the anhydride based graft copolymer, and thus provides a more complete removal of natural and synthetic waxes and oils from fabrics during desizing as compared to conventional sizes. During sizing, the anhydride based graft copolymer is preferably in intimate contact with the fibers which enhances the soil removal properties of the sizes prepared therefrom. Moreover, due to the hydrophilic nature of the anhydride based graft copolymer, the copolymer is soluble in alkaline medium and is readily desized. In addition, articles sized with the sizing compositions of the invention may not require a scouring step due to the cleaning ability of the anhydride based graft copolymer during desizing.
DESCRIPTION OF THE INVENTION
This invention provides an improved sizing composition for treating textiles. Suitable textiles are, for example, cotton, polyacrylics, polyamides, polyesters, polyolefins, rayons, wool, and blends thereof. The sizing composition is prepared from an anhydride based graft copolymer. The anhydride based graft copolymer is prepared either by a one-step or a two-step process. In the one-step process, the anhydride based graft copolymer is prepared by reacting an ethylenically unsaturated monomer, an anhydride monomer selected from the group consisting of maleic anhydride, itaconic anhydride, and mixtures thereof, a monofunctional polyglycol having a hydroxyl or amine terminal group, in the presence of a free radical initiator in a polymerization reactor. No solvent is used in the one-step process. In one embodiment of a one-step process, the anhydride based graft copolymers involves heating a mixture containing the monomers, polyglycol, and free radical initiator to cause the monomers to polymerize, and then heating the polymer at a higher temperature in the presence of polyglycol for a sufficient period of time to form the anhydride based graft copolymer. A solventless method for preparing anhydride based graft copolymers is described in U.S. patent application Ser. No. 09/047,032, entitled, “In Situ Solvent Free Method For Making Anhydride Based Graft Copolymers”, filed Mar. 24, 1998, which is hereby incorporated by reference in its entirety.
In the two-step process, the anhydride based graft copolymer is prepared by reacting an ethylenically unsaturated monomer and an anhydride monomer selected from the group consisting of maleic anhydride, itaconic anhydride, and mixtures thereof, in the presence of a solvent and a free radical initiator, to prepare a copolymer which is reacted with a monofunctional polyglycol having a hydroxyl or amine terminal group. In one embodiment of a two-step process, the anhydride based graft copolymers are prepared by solution polymerization in the presence of aromatic hydrocarbon solvents or ketone solvents. In a preferred process, the anhydride based graft copolymers are prepared by solution polymerization using incremental feed addition
National Starch and Chemical Investment Holding Corporation
Rajguru U. K
Roland Thomas F.
Seidleck James J.
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