Fiberboard with improved water resistance

一种改性、半水合硫酸钙的技术，应用在气候可持续性、可持续废物处理、固体废物管理等方向，能够解决板材无法达到强度等问题，达到防水性能改进的效果

Inactive Publication Date: 2009-08-12
USG CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, such sheets cannot achieve the desired strength

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The water resistance properties of the fiberboard samples were tested by measuring the amount of water absorbed when the samples were immersed in water for a predetermined period of time. A sample is generally considered waterproof if the weight of the sample after immersion is less than 10% greater than the dry sample weight, although in some embodiments, the target water absorption is less than 5%.

[0036] Table 1 shows the basic composition of the fiberboard. BS94 silicone and dead-burned magnesia were added in the amounts listed in Table II.

[0037] Data were obtained in a pilot plant continuously producing two feet per minute fiberboard comprising 15% by weight primary particles, 10% of which were paper fibers. The gypsum is a synthetic gypsum from Gypsum, OH. The control sample had no water repellent additive. SILRES BS 94 siloxane and dead-burned magnesia were supplied according to Table 2. Liquid alum (48% solids) was added as a crystal modifier at a rate ...

example 2

[0045] Magnesium oxide was used to catalyze siloxane in industrial-scale plant trials, and its 1 / 2" sheet was manufactured at a rate of 40 ft / min (12.3 m / min). The density of the finished product was 67-69 lb / ft 3 (1.13-1.16g / cc). The amount of each ingredient is shown in Table III. Two different sources of magnesium were tested here in slightly different amounts as indicated in the ingredient amounts.

[0046] The gypsum and recycled paper fibers are slurried together and pumped through a continuous calcining autoclave at 295°F (146°C), with a typical residence time of 22 minutes. After a quick return to ambient temperature and pressure, the remaining additives including MgO and siloxanes were pumped into the calcined slurry stream.

[0047]The resulting gypsum slurry is pumped into a Fourdrinier-type headbox and dewatered by forming a porous fabric. Seven vacuum boxes with a vacuum of 4 to 10" Hg were applied to facilitate the removal of white foam. Water was allowed to p...

example 3

[0057] P98 magnesia catalyzed silicone with the composition in Example Two was compared to flashings containing 2.5% wax. All products were manufactured and tested by the same method as taught in Example Two. The target water absorption is less than 5%. Samples 1, 2 and 3 made with SILRES BS94 silicone were compared to conventional fiberboard made with wax.

[0058] Table five

[0059] sample

[0060] This testing proved that a lower water demand could be achieved compared to more traditional waxed fiberboards.

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Abstract

Articles, including fiberboard, are made from a pumpable, flowable slurry including alpha-calcined calcium sulfate hemihydrate anchored in pores of host particles, alpha-calcined calcium sulfate hemihydrate, a silicone compound, magnesium oxide, and water. The magnesium oxide catalyzes the reaction of the silicone compound into a silicone resin. In a preferred method of making a water resistant fiberboard calcium sulfate dihydrate is combined with the host particles and water to form a slurry which is heated under pressure to calcine the calcium sulfate dihydrate to form alpha-calcined calcium sulfate hemihydrate. After relieving the pressure, a silicone compound and magnesium oxide are added to the slurry. The slurry is dewatered to form a filter cake, which is then formed into a desired shape and allowed to set.

Description

Background technique [0001] Gypsum products, particularly gypsum board or wallboard, are commonly used in industrial and construction products due to their availability and low cost. By dehydrating and rehydrating gypsum (also known as calcium sulfate dihydrate or gypsum powder), it can be formed into items in many useful shapes. Gypsum products have fire-resistant properties at least in part because each calcium sulfate molecule is bound to two water molecules. Without reinforcement, the formed dry plaster would be relatively brittle and unable to support heavy loads or withstand impacts of great force. [0002] The addition of a matrix material such as wood or paper fibers can improve the tensile and flexural strength of the wallboard. However, the reduction of calcium sulfate dihydrate and the addition of flammable materials will reduce the flame retardancy of the resulting product, and the cost will be higher. [0003] Attempts to make particle reinforced gypsum product...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B9/04C04B11/00
CPCC04B2111/00146C04B28/146C04B28/148C04B11/024C04B2111/27Y10T428/249933Y10T428/31663Y10T428/249932Y02W30/91C04B11/032C04B18/241C04B18/26C04B22/066C04B24/42C04B40/0089C04B40/0071C04B40/0082
Inventor 戴维·保罗·米勒斯里尼瓦斯·维拉姆森尼
Owner USG CORP
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