阅读说明：本技术 一种人造板用pva-磷铝胶粘剂的制备方法 (Preparation method of PVA-phosphorus-aluminum adhesive for artificial board ) 是由 谢拥群 吴振增 李德宏 陈汀杰 魏微 侯鑫均 魏起华 牛敏 林铭 刘景宏 于 2019-10-11 设计创作，主要内容包括：本发明涉及一种人造板用PVA-磷铝胶粘剂的制备方法,由PVA、磷酸和铝化合物反应制备得到粘度为100-600 mPa.S,固含量为40-80%,固化温度为150-200℃的一种无醛环保人造板用胶粘剂。其中,该产品具有强度好、耐高温、阻燃防霉等特点。本发明的优点在于原料来源广泛、价格低廉、操作简便易行、生产过程不产生有毒有害物质,且产品具有良好的力学、阻燃防霉能性能等,有望成为新型的环保型人造板胶粘剂。(The invention relates to a preparation method of PVA-phosphorus aluminum adhesive for artificial boards, which is prepared by reacting PVA, phosphoric acid and aluminum compounds, and the adhesive for formaldehyde-free environment-friendly artificial boards with the viscosity of 100-600 mPa.S, the solid content of 40-80% and the curing temperature of 150-200 ℃ is obtained. Wherein, the product has the characteristics of good strength, high temperature resistance, flame retardance, mildew resistance and the like. The invention has the advantages of wide raw material source, low price, simple and easy operation, no toxic and harmful substances generated in the production process, good mechanical, flame-retardant and mildew-proof performances of the product and the like, and is expected to become a novel environment-friendly artificial board adhesive.)

1. A preparation method of PVA-phosphor aluminum adhesive for artificial boards is characterized by comprising the following steps: the method comprises the following steps:

(1) phosphoric acid or hydrogen phosphate and an aluminum compound with certain concentration are used as raw materials, phosphorus and aluminum elements form a certain phosphorus-aluminum ratio, and the solid content of the adhesive is designed;

(2) heating phosphoric acid or a water-soluble hydrogen phosphate salt bath, and then putting a certain amount of PVA and a catalyst into the heated bath to react for a period of time;

(3) slowly adding a certain amount of aluminum compound into the mixture in the step (2) for reaction for a period of time to prepare the adhesive.

2. The preparation method of the PVA-phosphor-aluminum adhesive for artificial boards according to claim 1, wherein the PVA-phosphor-aluminum adhesive comprises the following steps: the aluminum compound in the step (1) comprises any one of aluminum hydroxide, aluminum oxide and aluminum nitride; the phosphorus-aluminum ratio is the molar ratio of phosphorus element to aluminum element, and ranges from 2.0:1 to 4.0: 1.

3. The preparation method of the PVA-phosphor-aluminum adhesive for artificial boards according to claim 1, wherein the PVA-phosphor-aluminum adhesive comprises the following steps: the solid content of the adhesive in the step (1) is 40-80%.

4. The preparation method of the PVA-phosphor-aluminum adhesive for artificial boards according to claim 1, wherein the PVA-phosphor-aluminum adhesive comprises the following steps: the temperature of the water bath in the step (2) is 70-100 ℃; the addition amount of PVA is 0.1-5.0% of the mass of the phosphor-aluminum solid; the catalyst is urea, and the addition amount of the catalyst is 0.1-10% of the mass of the phosphorus-aluminum solid; the reaction time is as follows: 20-300 min.

5. The preparation method of the PVA-phosphor-aluminum adhesive for artificial boards according to claim 1, wherein the PVA-phosphor-aluminum adhesive comprises the following steps: the reaction time in the step (3) is as follows: 20-300 min.

6. The use method of the PVA-phosphorus-aluminum adhesive for artificial boards prepared by the method of claim 1 is characterized in that: the preparation method specifically comprises the steps of uniformly mixing the prepared phosphorus-aluminum adhesive with a curing agent, and spraying the mixture on the surfaces of wood shavings or fibers or coating the mixture on the surfaces of veneers according to a certain proportion; and carrying out hot pressing on the glued fibers, wood shavings or veneers according to a certain hot pressing condition to form the artificial board.

7. The use method of the PVA-P-Al adhesive for artificial boards according to claim 6, wherein the curing agent is magnesium oxide, aluminum oxide, copper oxide, zinc oxide, iron oxide, aluminum nitride, the addition amount of the curing agent is 3% ~ 3.5.5% of the mass of the adhesive, the glue application amount of the fiber and the wood shavings is 8% -30% of the absolute dry mass of the wood, and the glue application amount of the veneer is 300g/m of double-sided glue application 100-²。

8. The use method of the PVA-phosphor-aluminum adhesive for artificial boards according to claim 6, wherein the PVA-phosphor-aluminum adhesive comprises the following steps: the hot pressing temperature of the fiber and the wood shavings is 150-200 ℃, the hot pressing time is 0.5-2min/mm, and the hot pressing pressure is 0.5-2.0 MPa.

9. The use method of the PVA-phosphor-aluminum adhesive for artificial boards according to claim 6, wherein the PVA-phosphor-aluminum adhesive comprises the following steps: the hot pressing temperature of the single board is 150-200 ℃, the hot pressing time is 0.5-2min/mm, and the hot pressing pressure is 0.5-2.0 MP.

Technical Field

The invention relates to the technical field of artificial board adhesives, in particular to a preparation method of a PVA-phosphorus aluminum inorganic adhesive for artificial boards.

The phosphate radical in the phosphorus-aluminum adhesive has oxygen ions with larger electronegativity, which can attract hydrogen ions in water molecules to break P-O-Al bonds in the adhesive so as to reduce the bonding strength. When the sample is placed in hot water, the water molecules easily separate the interfacial connection between the phosphoaluminium adhesive and the wood fibres, causing it to lose strength. The studies on the change of the moisture absorption strength and the wet strength of the inorganic glue are as follows: organic matters such as ketone, carboxylic acid substances, polyhydric alcohol and the like are introduced into the boron aluminum phosphate, and the storage time is prolonged through an organic carbon chain. The moisture resistance of the phosphate adhesive is improved by using a curing agent (such as ferric oxide, alkaline slag and the like), and the adhesive added with the curing agent has higher strength and better moisture resistance. Adding alkali metal compound to balance oxygen ion electronegativity, reacting to generate complex alkali metal double salt, and improving moisture resistance. However, the above method cannot completely block oxygen ions from attracting hydrogen in water molecules, and the added oxide may have an influence on the regeneration of used sand. Therefore, it is necessary to further explore the problem of improving the moisture resistance of phosphate fundamentally. In the preparation of foundry sand molds, li qing bao, fu ning, zhao national level, phosphate-based organic/inorganic composite foundry binders were first explored [ J ] hot working processes, 2012,41(09):61-64 ] PVA was added to phosphate to participate in the polycondensation reaction. The organic-inorganic reaction consumes a large amount of hydroxyl, and hydrocarbon hydrophobic substances are generated, so that the water entry is reduced, and the water resistance of the molding sand is improved.

Polyvinyl alcohol PVA is one of the most common organic modifiers. It has many advantages such as excellent film-forming properties, better strength and biocompatibility. PVA is non-toxic and non-carcinogenic, has the characteristics of biomass adhesive, and is widely applied to the fields of film preparation, adhesive, paint coating and the like.

Disclosure of Invention

The invention aims to improve the mechanical strength of the phosphorus-aluminum adhesive in plywood by using PVA to modify the phosphorus-aluminum adhesive. During the preparation process of adding PVA into the phosphorus-aluminum adhesive, PVA participates in the polymerization reaction between phosphorus and aluminum to form hydrophobic nodes on some nodes in the phosphorus-aluminum skeleton, so that the chance of forming hydrated molecules by the affinity of-O-and water molecules is reduced. The performance of a sample added with the adhesive prepared by the invention is greatly improved, and particularly, the mechanical and flame retardant properties are obviously enhanced.

In order to realize the purpose of the invention, the invention adopts the following technical scheme:

a preparation method of PVA-phosphor aluminum adhesive for artificial boards comprises the following steps:

(1) phosphoric acid or hydrogen phosphate and an aluminum compound with certain concentration are used as raw materials, phosphorus and aluminum elements form a certain phosphorus-aluminum ratio, and the solid content of the adhesive is designed;

(2) heating phosphoric acid or a water-soluble hydrogen phosphate salt bath, and then putting a certain amount of PVA and a catalyst into the heated bath to react for a period of time;

(3) slowly adding a certain amount of aluminum compound into the mixture in the step (2) for reaction for a period of time.

Further, the aluminum compound in the step (1) comprises any one of aluminum hydroxide, aluminum oxide and aluminum nitride. The phosphorus-aluminum ratio is the molar ratio of phosphorus element to aluminum element, and ranges from 2:1 to 4: 1.

Further, the solid content of the adhesive is 40-85 wt%.

Further, the temperature of the water bath in the step (2) is 70-100 ℃; the addition amount of PVA is 0.1-5.0% of the mass of the phosphor-aluminum solid; the catalyst is as follows: urea; the addition amount is 0.1-10% of the mass of the phosphor-aluminum solid; the reaction time is as follows: 20-300 min.

Further, the reaction time in the step (3) is as follows: 20-300 min.

The use method of the PVA-phosphorus aluminum adhesive for the artificial board comprises the steps of uniformly mixing the prepared phosphorus aluminum adhesive with a curing agent, and spraying the mixture on the surfaces of wood shavings or fibers or coating the mixture on the surfaces of veneers according to a certain proportion; and carrying out hot pressing on the glued fibers, wood shavings or veneers according to a certain hot pressing condition to form the artificial board.

Furthermore, the curing agent is any one of magnesium oxide, aluminum oxide, copper oxide, zinc oxide, iron oxide and aluminum nitride, and the addition amount of the curing agent is ~ 3.5.5 percent of the mass of the adhesive;

furthermore, the glue application amount of the fiber and the wood shavings is 8-30% of the oven-dried quality of the wood, and the glue application amount of the veneer is 300g/m of double-sided glue application amount of 100-²。

Furthermore, the hot pressing temperature of the fiber and the wood shavings is 150-200 ℃, the hot pressing time is 0.5-2min/mm, and the hot pressing pressure is 0.5-2.0 MPa. The hot pressing temperature of the single board is 150-200 ℃, the hot pressing time is 0.5-2min/mm, and the hot pressing pressure is 0.5-2.0 MP.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention improves the relevant physical and chemical properties of the prepared product, such as good mechanical strength, mildew resistance, corrosion resistance and the like, for the formaldehyde-free phosphorus-aluminum adhesive for the artificial board; particularly, the flame retardant property is obviously enhanced, and the flame retardant grade reaches B2 grade specified in the building interior decoration design fire standard;

(2) the product has the advantages of abundant raw material sources, low cost, simple production process, no pollution, no environmental pollution caused by waste, natural degradation, and less smoke generation in the combustion process.

Drawings

FIG. 1 is a flow of a preparation method of a PVA-phosphor-aluminum adhesive for an artificial board.

Detailed Description

In order to make the present invention more comprehensible, the technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited thereto.