Product Code Database
Sizing or size is a substance that is applied to, or incorporated into, other materials—especially papers and textiles—to act as a protective filler or coating. Sizing is used in papermaking and textile manufacturing to change the absorption and wear characteristics of those materials.
Sizing is used for oil-based surface preparation for gilding (sometimes called Mordant in this context). It is used by painters and artists to prepare paper and textile surfaces for some art techniques. Sizing is used in photography Sizing substrates and papers – survey results, alternativephotography.com to increase the sharpness of a print, to change the glossiness of a print, or for other purposes depending on the type of paper and printing technique.
Fibers used in composite materials are treated with various sizing agents to promote adhesion with the matrix material.
Sizing is used during paper manufacture to reduce the paper's tendency when dry to absorb liquid, with the goal of allowing inks and paints to remain on the surface of the paper and to dry there, rather than be absorbed into the paper. This provides a more consistent, economical, and precise printing, painting, and writing surface. This is achieved by curbing the paper fibers' tendency to absorb liquids by capillary action. In addition, sizing affects abrasiveness, creasability, finish, printability, smoothness, and surface bond strength and decreases surface porosity and fuzzing.
There are three categories of papers with respect to sizing: unsized ( water-leaf), weak sized ( slack sized), and strong sized ( hard sized). Waterleaf has low water resistance and includes absorbent papers for blotting paper. Slack sized paper is somewhat absorbent and includes newsprint, while hard sized papers have the highest water resistance, such as coated fine papers and liquid packaging board.
There are two types of sizing: internal sizing, sometimes also called engine sizing, and surface sizing (tub sizing). Internal sizing is applied to almost all papers and especially to all those that are machine made, while surface sizing is added for the highest grade bond paper, ledger, and .
Sizing with starch was introduced quite early in the history of papermaking.Robert Henderson Clapperton and William Henderson. Modern Paper-making. 3rd ed. (Oxford: Basil Blackwell, 1947), 120. Dard Hunter in Papermaking through Eighteen CenturiesDard Hunter, Papermaking through Eighteen Centuries. (New York: William Edwin Rudge, 1930), 141. available on line corroborates this by writing, "The Chinese used starch as a size for paper as early as A.D. 768 and its use continued until the fourteenth century when animal glue was substituted." In the early modern paper mills in Europe, which produced paper for printing and other uses, the sizing agent of choice was gelatin, as Susan Swartzburg writes in Preserving Library Materials': "Various substances have been used for sizing through the ages, from gypsum to animal gelatin."Susan G. Swartzburg, Preserving Library Materials: A Manual. 2nd ed. (Metuchen, NJ: The Scarecrow Press, 1995), 131. Hunter describes the process of sizing in these paper mills in the following:
With the advent of the mass production of paper, the type of size used for paper production also changed. As Swartzburg writes, "By 1850 rosin size had come into use. Unfortunately, it produces a chemical action that hastens the decomposition of even the finest papers."Swartzburg, Preserving Library Materials, 131. In the field of library preservation it is known "that acid hydrolysis of cellulose and related carbo-hydrates sic is one of the key factors responsible for the degradation of paper during ageing."Altaf H. Basta and others, "The Role of Neutral Rosin-Alum Size in the Production of Permanent Paper." Restaurator: International Journal for the Preservation of Library and Archival Material, 27, no. 2 (2006): 67. Some professional work has focused on the specific processes involved in the degradation of rosin-sized paper,Houssni El-Saied, Altaf H. Basta and Mona M. Abdou. "Permanence of Paper 1: Problems and Permanency of Alum-Rosin Sized Paper Sheets from Wood Pulp." Restaurator: International Journal for the Preservation of Library and Archival Material, 19, no. 3 (1998): 155–171. in addition to work on developing permanent paper and sizing agents that will not eventually destroy the paper.Altaf H. Basta and others, "The Role of Neutral Rosin-Alum Size in the Production of Permanent Paper," 67-80. An issue on the periphery to the preservation of paper and sizing, is washing, which is described by V. Daniels and J. Kosek as, "The removal of discolouration ... in water is principally effected by the dissolution of water-soluble material; this is usually done by immersing paper in water."V. Daniels and J. Kosek, . "Studies on the Washing of Paper, Part 1: The Influence of Wetting on the Washing Rate." Restaurator: International journal for the Preservation of Library and Archival Material, 25, no. 2 (2004): 81. In such a process, surface level items applied to the paper, such as size in early paper making processes as seen above, have the possibility of being removed from the paper, which might have some item specific interest in a special collections library. With later processes in paper making being more akin to "engine sizing," as H. Hardman and E. J. Cole describe it, "Engine sizing, which is part of the manufacturing process, has the ingredients added to the furnish or stock prior to sheet formation,"H. Hardman, and E. J. Cole. Paper-making Practice. (Manchester: Manchester University Press, 1960), 112. the concern for the removal of size is less, and as such, most literature focuses on the more pressing issue of preserving acidic papers and similar issues.
With sizing, the strength—abrasion resistance—of the yarn will improve and the hairiness of yarn will decrease. The degree of improvement of strength depends on adhesion force between fiber and size, size penetration, as well as encapsulation of yarn. Different types of water soluble polymers called textile sizing agents/chemicals such as modified starch, polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), and are used to protect the yarn. Also wax is added to reduce the abrasiveness of the warp yarns. The type of yarn material (e.g. cotton, polyester, linen), the thickness of the yarn, and the type of weaving machinery will determine the sizing recipe.
Often, the sizing liquor contain Tallow. Mutton tallow is an animal fat, used to improve abrasion resistance of yarns during weaving.
The sizing liquor is applied on warp yarn with a warp sizing machine. After the weaving process, the fabric is desizing (washed).
Sizing may be done by hand, or in a sizing machine.
target="_blank" rel="nofollow"> History, Chemistry, and Long-Term Effects of Alum-Rosin Size in Paper
|
|
