阅读说明：本技术 一种石膏制品表面磷酸钙保护层的制备方法 (Preparation method of calcium phosphate protective layer on surface of gypsum product ) 是由 刘妍 杨富巍 于 2019-10-28 设计创作，主要内容包括：本发明提供了一种石膏制品表面磷酸钙保护层的制备方法。其做法是在石膏制品表面先后刷涂钙源和磷源,利用钙、磷源之间的化学反应在石膏制品及文物表面制备一层磷酸钙防护层。由于其良好的耐水性和结合力,制备的磷酸钙保护层能赋予石膏制品及文物一定的耐水性,阻止其因吸潮或遇水溶解而导致的性能劣变。(The invention provides a preparation method of a calcium phosphate protective layer on the surface of a gypsum product. The method comprises brushing calcium source and phosphorus source on the surface of gypsum product, and preparing a calcium phosphate protective layer on the surface of gypsum product and cultural relics by chemical reaction between calcium source and phosphorus source. Due to good water resistance and binding force, the prepared calcium phosphate protective layer can endow gypsum products and cultural relics with certain water resistance, and prevent the gypsum products and the cultural relics from being deteriorated due to moisture absorption or water dissolution.)

1. A preparation method of a calcium phosphate protective layer on the surface of a gypsum product is characterized by comprising the following steps: the calcium source and the phosphorus source are sequentially coated on the surface of the gypsum product, and a calcium phosphate protective layer is prepared on the surface of the gypsum product by utilizing the chemical reaction between the calcium source and the phosphorus source.

2. The method for preparing a calcium phosphate protective layer on the surface of a gypsum product according to claim 1, wherein the method comprises the following steps: the calcium source is suspension dispersion liquid of calcium hydroxide powder in an isopropanol solvent, wherein the particle size range of the calcium hydroxide is 0.05-0.3 mu m, and the suspension concentration of the calcium hydroxide in the isopropanol solvent is 5-15 g/L.

3. The method for preparing a calcium phosphate protective layer on the surface of a gypsum product according to claim 1, wherein the method comprises the following steps: the phosphorus source is the water solution of calcium dihydrogen phosphate, the concentration of which is 0.8 to 1.5 percent; the aqueous solution of calcium dihydrogen phosphate may be replaced by a mixed solution of a soluble calcium salt (e.g. calcium chloride, calcium nitrate) and an acid phosphate (e.g. ammonium dihydrogen phosphate, potassium dihydrogen phosphate, sodium dihydrogen phosphate) at a concentration equivalent to that of the calcium dihydrogen phosphate.

4. The method for preparing a calcium phosphate protective layer on the surface of a gypsum product according to claim 1, wherein the method comprises the following steps: the proportion of the calcium source to the solid content of the phosphorus source is 1: 1.35-1.75.

5. The method for preparing a calcium phosphate protective layer on the surface of a gypsum product according to claim 1, wherein the method comprises the following steps: brushing isopropanol suspension dispersion liquid of calcium hydroxide on the surface of a dried gypsum product, brushing phosphorus sources such as calcium dihydrogen phosphate or a solution of a mixture of soluble calcium salt (such as calcium chloride and calcium nitrate) and acid phosphate (such as ammonium dihydrogen phosphate, potassium dihydrogen phosphate and sodium dihydrogen phosphate) with the concentration equivalent to that of the calcium dihydrogen phosphate after the brushing is finished and isopropanol solvent on the surface of the gypsum product is volatilized, and naturally airing after the brushing.

Technical Field

The invention relates to a preparation method of a calcium phosphate protective layer on the surface of a gypsum product, belonging to the technical field of surface protection of gypsum products.

Background

The gypsum material is widely applied to industries such as buildings, sculptures and the like. It can be used for making decorative plaster line, plaster plate, plaster lamp, plaster image and plaster coloured drawing, etc. However, the gypsum material has the characteristics of easy moisture absorption and water dissolution, which is also the root cause of the moisture resistance and water intolerance of gypsum products. Traditionally, the water resistance of gypsum powder is improved by adding inorganic or organic modifying materials into the gypsum powder. Lime (waterproofing technology for building gypsum products, CN 87102655) and cement (water-resistant powder of gypsum, CN 93101658.4) are common inorganic additive materials. Asphalt [ water-resistant gypsum product, cn93115359. x; the cation emulsified asphalt waterproof agent for gypsum products, CN201310463414.3, organosilicon, an organic-inorganic high-efficiency composite waterproof agent for building gypsum and application thereof, CN201510130741.6 and a polymerized emulsion, water-resistant gypsum and CN201510273533.1, are common hydrophobic organic additives. However, the method of adding a modifier to the gypsum powder has a limited improvement in the water resistance of the gypsum product and cannot be used for the treatment of the gypsum product. In recent years, a method of directly brushing an organic water repellent on the surface of a gypsum product [ a cover gloss water-based paint special for gypsum products and a preparation method thereof, CN 201810999356.9; an enhanced water-proof agent specially used for gypsum, CN201811214997.5, for improving the water-proof property of the gypsum. In contrast, the surface brushing method has lower cost and higher water resistance improvement than the addition modification method, but the organic water repellent has poor weather resistance, is easy to degrade and has limited action time. In addition, the organic water repellent has weak bonding force with the surface of a gypsum product, is easy to run off, and is particularly easy to scour by water flow. Therefore, the protective material with good weather resistance and bonding force and the application technology thereof will be the important research direction in the field.

Disclosure of Invention

The invention provides a preparation method of a calcium phosphate protective layer on the surface of a gypsum product.

Therefore, the technical scheme adopted by the invention is as follows:

the calcium source and the phosphorus source are sequentially coated on the surface of the gypsum product, and a calcium phosphate protective layer is prepared on the surface of the gypsum product by utilizing the chemical reaction between the calcium source and the phosphorus source.

The calcium source is suspension dispersion liquid of calcium hydroxide powder in an isopropanol solvent, wherein the particle size range of the calcium hydroxide is 0.05-0.3 mu m, and the suspension concentration of the calcium hydroxide in the isopropanol solvent is 5-15 g/L.

The phosphorus source is the water solution of calcium dihydrogen phosphate, the concentration of which is 0.8 to 1.5 percent; the above-mentioned aqueous solution of calcium dihydrogen phosphate can also be replaced by mixed solution of soluble calcium salt (such as calcium chloride and calcium nitrate) and acid phosphate (such as ammonium dihydrogen phosphate, potassium dihydrogen phosphate and sodium dihydrogen phosphate) with equivalent concentration, and its effect is equivalent.

The proportion of the calcium source to the solid content of the phosphorus source is 1: 1.35-1.75.

When the surface is brushed, firstly brushing isopropanol suspension dispersion liquid of calcium hydroxide on the surface of a dried gypsum product, brushing phosphorus sources such as calcium dihydrogen phosphate or a mixed solution of soluble calcium salt (such as calcium chloride and calcium nitrate) and acid phosphate (such as ammonium dihydrogen phosphate, potassium dihydrogen phosphate and sodium dihydrogen phosphate) with the same concentration after brushing the isopropanol suspension dispersion liquid on the surface of the dried gypsum product and volatilizing the isopropanol solvent on the surface of the gypsum product, and naturally airing after brushing.

The invention has the beneficial effects that: the prepared calcium phosphate protective layer has good corrosion resistance and binding force, can improve the water resistance of the gypsum product, and can prevent the performance deterioration of the gypsum product and cultural relics caused by moisture absorption or water dissolution.

Drawings

FIG. 1 is a schematic diagram of the preparation principle of a calcium phosphate protective layer

FIG. 2 XRD pattern of calcium phosphate protective layer

Detailed Description

A method for preparing a calcium phosphate protective layer on the surface of a gypsum product is characterized in that a calcium phosphate film layer with a protective effect is prepared on the surface of the gypsum product by brushing isopropanol suspension dispersion liquid of calcium hydroxide and a phosphate aqueous solution on the surface of the gypsum product in sequence. The present invention will be described in detail with reference to the following specific examples: