Disclosed are methods relating to an extruded pregelatinized, partially hydrolyzed starch prepared by mixing at least water, non-pregelatinized starch, and acid to form a starch precursor. The acid can be a weak acid that substantially avoids chelating calcium ions or a strong acid in a small amount. In the method, pregelatinization and acid-modification of the starch precursor occurs in one step in an extruder. Also disclosed are methods of preparing board using the starch prepared according to the methods, as well as starches and boards prepared by various methods of the invention.

A plasterboard comprises a gypsum matrix having particles of agglomerated fibres embedded therein in an amount of at least 1 wt % relative to the gypsum, the gypsum matrix further comprising a polymeric additive, the polymeric additive being present in an amount of at least 1 wt % relative to the gypsum.

A gypsum product has a first polymeric additive and a second polymeric additive distributed therein, wherein the first polymeric additive is a synthetic polymer and the second polymeric additive is starch. It has been found that the combination of starch and a synthetic polymer may result in one or more of the following advantages in the manufacture and performance of gypsum products: —increased strength; —greater ease of manufacturing due to the increased fluidity of stucco slurries containing both additives; and —increased resistance to hygroscopic expansion.

A gypsum slurry includes water, a hydraulic component including calcium sulfate hemihydrate and a linear polycarboxylate dispersant. The linear polycarboxylate anionic dispersant includes a first monomeric repeating unit and a second monomeric repeating unit. The first repeating unit of the linear polycarboxylate dispersant is an olefinic unsaturated carboxylic acid repeating unit or salt thereof. The second repeating unit of the linear polycarboxylate dispersant is a vinyl sulfonate. The slurry can be made into a gypsum panel. Methods of making gypsum slurry and a gypsum panel are also disclosed.

This invention provides low density gypsum products. This invention also provides a method of making the low density gypsum products.

The invention relates to a fibrous mat facer for preparing a gypsum board, to a gypsum board comprising said mat facer and to a system comprising said gypsum board. The fibrous mat comprises at least one ply of a non-woven fabric, and a binder composition, wherein the binder composition represents from 10 to 40 wt % of the total weight of the mat. The binder composition comprises a copolymer comprising a co-monomer unit of a vinyl ester of an alpha branched aliphatic monocarboxylic acid, said copolymer being present in an amount from 25 to 100 wt % of the binder composition weight.

A partition for a building structure comprises a support frame and a plasterboard affixed to the support frame. The support frame comprises a plurality of elongate timber members. The plasterboard comprises a gypsum matrix having fibres embedded therein in an amount of at least 1 wt % relative to the gypsum, as well as a polymeric additive that is present in an amount of at least 1 wt % relative to the gypsum.

A partition for a building structure comprises a support frame and a plasterboard affixed to the support frame with a plurality of screws. The plasterboard comprises a gypsum matrix having fibres embedded therein in an amount of at least 1 wt % relative to the gypsum, as well as a polymeric additive that is present in an amount of at least 1 wt % relative to the gypsum. The support frame comprises a plurality of elongate timber members and the average spacing between nearest-neighbour screws is greater than 400 mm.

A plasterboard comprises a gypsum matrix having a polymeric additive distributed therein in an amount of at least 1 wt % relative to the gypsum, the gypsum matrix further having a first group of fibres and a second group of fibres embedded therein, wherein the fibres of the first group of fibres have an average length that is at least three times the average length of the fibres of the second group of fibres.

In one aspect, a gypsum panel includes a gypsum core, a fiberglass mat, and a wetting agent deposited across an entire thickness of the fiberglass mat. The wetting agent is deposited onto the first fiberglass mat in an uncoated state of the fiberglass mat such that the wetting agent penetrates the entire thickness of the fiberglass mat.