Soy protein thickener

Details Soy protein thickener Soy protein thickener

1999-05-19

2001-09-18

Seidleck, James J. (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Processes of preparing a desired or intentional composition...

C524S020000

Reexamination Certificate

active

06291559

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to paper coating compositions containing protein and particularly hose containing modified vegetable protein as an adhesive binder.
BACKGROUND OF THE INVENTION
Vegetable protein materials are well known as adhesive binders for paper coating compositions containing pigments. The paper coating compositions provide the paper with a desirable finish, gloss, smoothness, and microporous surface. The functions of the pigment in the coating composition are to fill irregularities of the paper surface and to produce an even and uniformly absorbent surface for printing. The adhesive functions to bind the pigment particles to each other as well as to the surface of the base paper.
Particularly preferred vegetable protein materials for use as adhesive binders in paper coating compositions are modified soy proteins. These adhesive binders are typically prepared from an isolated soy protein modified by hydrolysis and other chemical treatments to prepare a protein adhesive material suitable for use as a binder in paper coating compositions.
Although such compositions have found wide usage in the paper coating industry, it would be desirable to provide improved vegetable protein binders which can be used at lower levels in paper coating compositions to achieve suitable rheological properties in the coating compositions while also exhibiting functional properties comparable to conventional paper coating compositions.
SUMMARY OF THE INVENTION
The present invention provides an improved vegetable protein adhesive binder which can be used in paper coating compositions at much lower levels than conventional vegetable protein adhesive binders while imparting to the paper coating compositions rheological and other properties equivalent to conventional paper coating compositions containing higher levels of vegetable protein adhesive binders. In particular, the vegetable protein adhesive binders of this invention perform an enhanced thickening function which allows lower amounts of the vegetable protein adhesive binder to be utilized to provide a paper coating composition exhibiting desirable rheological properties. More specifically, the vegetable protein adhesive binders of this invention have an enhanced thickening effect so that a lower amount of a vegetable protein adhesive binder in accordance with the invention can be used in a paper coating composition to achieve viscosity levels comparable to conventional paper coating compositions containing a higher level of a conventional vegetable protein adhesive binder.
In accordance with an aspect of the invention, a vegetable protein adhesive binder exhibiting enhanced rheological properties comprises a vegetable protein which is entangled with a polyacrylate.
In another aspect of the invention, the vegetable protein adhesive binder exhibiting enhanced rheological properties comprises a vegetable protein entangled with a polyacrylate which is combined with a pigment or pigments, a polymer latex, and other minor coating additives to form a paper coating composition.
The vegetable protein adhesive binders exhibiting enhanced rheological properties are prepared by coprocessing an alkaline dispersion of a vegetable protein material and a polyacrylate at a temperature and for a time sufficient to entangle the vegetable protein with the polyacrylate, then co-precipitating both protein and entangled polyacrylate. The resulting product has superior properties in a paper coating, application relative to conventional protein adhesives which do not contain an entangled polyacrylate, even in paper coating systems to which a polyacrylate has been added without entangling polyacrylate with the protein adhesive as provided herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Various vegetable protein materials which are suitable as an adhesive binder in paper coating compositions may be used in the practice of this invention. However, the most commonly produced protein isolates and protein concentrates are derived from soy. Accordingly, the preferred embodiments of the invention will be described with respect to soy protein materials because this is the primary area of concern for which the present invention was developed. However, it is apparent that other protein materials and vegetable protein materials can be employed in a similar manner if desired.
For purposes of explanation, the process and product of the present invention will be described in relation to a soy protein material prepared from defatted soybean flakes or flour. Defatted soybean flakes or flour may be produced according to conventional processes in which whole soybeans are cleaned, cracked, flaked, and defatted (either mechanically or chemically), and, in the case of flour, ground. Defatted soybean flakes and flour are commercially available and may be acquired as a starting material for the process of the present invention.
The defatted soybean flakes or flour are used to prepare a dispersion of soy protein. The defatted soybean flakes or flour are extracted with an aqueous alkaline solution to extract and solubilize the protein into the solution The extract containing the protein is then separated from the alkali insoluble solids by conventional filtration or centrifugation. The extract or dispersion of the protein from the soy flakes will typically have a pH of between about 8 to 12. Alternatively, a commercially available soy protein isolate may be used as the starting material for the process of the present invention by forming an alkaline dispersion of the dried protein material, preferably having a pH of from about 8 to about 12, where an alkaline dispersion of the soy protein isolate may be formed by mixing the protein isolate in an aqueous alkaline solution. The particular type of aqueous alkaline solution used to disperse the protein material, either from soy flakes or from a soy protein isolate, is not critical to the practice of the invention and generally any type of aqueous alkali or alkaline earth hydroxide, preferably an aqueous sodium or calcium hydroxide solution, or other materials, such as ammonium hydroxide may be readily employed in preparing the protein dispersion.
A polyacrylate is added to the protein dispersion and the dispersion containing the added polyacrylate is treated at a temperature and for a time sufficient to entangle at least a portion of the polyacrylate in the protein. The polyacrylate can be generally any polymer or copolymer of one or more vinyl carboxylic acid esters, such as alkyl ester acrylate or methacrylate. Copolymers of vinyl carboxylic acid esters containing minor amounts of other copolymerizable monomers may also be employed. Examples of commercially available polyacrylates which are suitable for use in the invention include ACRYSOL® TT-615, available from Rohm & Haas Company; and ALCOGUM® L-289, available from Alco Chemical Industries, Inc. The polyacrylate is preferably added in an amount of from about 1.5% to about 10%, by weight, of the weight of the protein material, although a lower amount or a higher amount may also be employed. It is believed that an optimum balance between improved properties and cost is achieved when the amount of polyacrylate used is from about 5 3% to about 6%, by weight, of the weight of the protein material.
In an alternative embodiment, the polyacrylate may be dispersed in an aqueous solution and the protein may be added to the solution to disperse the protein in the solution. The solution may be made alkaline either before or after the addition of the protein to thoroughly disperse the protein in the solution, and preferably is raised to a pH of from about 8 to about 12 with a suitable alkali, alkaline earth hydroxide, or other base such as ammonium hydroxide. This approach is particularly effective when the protein is a protein isolate from which alkali insoluble materials have been removed since the polyacrylate may be prediluted in the aqueous solution before the protein is added to the solution.
The polyacrylate and protein materials are mixed for a period of time under

Affiliated with

Also associated with

Rating

Soy protein thickener does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Soy protein thickener, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Soy protein thickener will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2490737