阅读说明：本技术 一种胶合板用木塑复合材料及其制备方法 (Wood-plastic composite material for plywood and preparation method thereof ) 是由 余香兰 朱元德 于 2019-10-10 设计创作，主要内容包括：本发明公开了一种胶合板用木塑复合材料,其特征在于,是由如下重量份的各原料制成：基于二苯甲酮三嗪基乙烯基聚酰胺酸45-55份、6-(二丁基氨基)-1,3,5-三唑-2,4-二硫醇/双(乙烯砜基)甲烷缩聚物20-30份、废旧聚氯乙烯塑料粉25-35份、偶联剂1-3份、核桃壳粉5-10份、锯末粉20-30份、填充剂6-10份、引发剂0.5-1.5份。本发明还提供了所述胶合板用木塑复合材料的制备方法。本发明公开的胶合板用木塑复合材料强度高,韧性足,阻燃性、防水性能和耐热性好,尺寸稳定性和耐候性优异,性能稳定性佳,使用寿命长。(The invention discloses a wood-plastic composite material for a plywood, which is characterized by being prepared from the following raw materials in parts by weight: based on 45-55 parts of benzophenone triazinyl vinyl polyamic acid, 20-30 parts of 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol/bis (vinylsulfonyl) methane polycondensate, 25-35 parts of waste polyvinyl chloride plastic powder, 1-3 parts of coupling agent, 5-10 parts of walnut shell powder, 20-30 parts of saw powder, 6-10 parts of filler and 0.5-1.5 parts of initiator. The invention also provides a preparation method of the wood-plastic composite material for the plywood. The wood-plastic composite material for the plywood disclosed by the invention has the advantages of high strength, sufficient toughness, good flame retardance, waterproof performance and heat resistance, excellent dimensional stability and weather resistance, good performance stability and long service life.)

1. The wood-plastic composite material for the plywood is characterized by being prepared from the following raw materials in parts by weight: based on 45-55 parts of benzophenone triazinyl vinyl polyamic acid, 20-30 parts of 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol/bis (vinylsulfonyl) methane polycondensate, 25-35 parts of waste polyvinyl chloride plastic powder, 1-3 parts of coupling agent, 5-10 parts of walnut shell powder, 20-30 parts of saw powder, 6-10 parts of filler and 0.5-1.5 parts of initiator.

2. The wood-plastic composite material for plywood as claimed in claim 1, wherein said filler is at least one of talc powder, sepiolite powder and mica powder; the coupling agent is at least one of a silane coupling agent KH550, a silane coupling agent KH560 and a silane coupling agent KH 570.

3. The wood-plastic composite material for plywood as claimed in claim 1, wherein said initiator is at least one of azobisisobutyronitrile and azobisisoheptonitrile; the granularity of the saw powder is 100-200 meshes, and the water content is less than or equal to 8%.

4. The wood-plastic composite material for plywood according to claim 1, wherein said method for preparing benzophenone triazinyl vinyl polyamic acid comprises the steps of: 2, 4-diamino-6-vinyl-S-triazine is filled into a polymerization bottle containing tetrahydrofuran, stirred at room temperature to be completely dissolved, then 3,3',4,4' -benzophenone tetracarboxylic dianhydride is added under ice water bath, the reaction system is maintained at 0 ℃, the stirring reaction is continuously carried out for 3-5 hours, and then the tetrahydrofuran is removed by rotary evaporation to obtain the benzophenone triazinyl vinyl-based polyamic acid.

5. The wood-plastic composite material for plywood according to claim 4, wherein the mass ratio of 2, 4-diamino-6-vinyl-S-triazine, tetrahydrofuran, and 3,3',4,4' -benzophenonetetracarboxylic dianhydride is 1 (10-15) to 2.35.

6. A wood-plastic composite material for plywood according to claim 1, wherein said 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol/bis (vinylsulfonyl) methane polycondensate is prepared by a method comprising the steps of: adding 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol, bis (vinylsulfonyl) methane and a catalyst into a high-boiling-point solvent, stirring and reacting for 15-20 hours at 100-110 ℃ under the atmosphere of nitrogen or inert gas, then precipitating in water, washing the product with ethanol for 3-7 times, and then placing the product in a vacuum drying oven to be dried to constant weight at 80-90 ℃ to obtain the 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol/bis (vinylsulfonyl) methane polycondensate.

7. The wood-plastic composite material for plywood as claimed in claim 6, wherein the mass ratio of 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol, bis (vinylsulfonyl) methane, catalyst and high-boiling solvent is 1.39:1 (0.3-0.5) to (8-13).

8. The wood-plastic composite material for plywood as claimed in claim 6, wherein said catalyst is at least one of sodium ethoxide, sodium hydride, sodium amide, potassium tert-butoxide; the inert gas is one of helium, neon and argon; the high boiling point solvent is at least one of dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.

9. A wood-plastic composite for plywood according to any one of claims 1 to 8, wherein said method for manufacturing a wood-plastic composite for plywood comprises the steps of: mixing benzophenone triazinyl vinyl-based polyamic acid, 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol/bis (vinylsulfonyl) methane polycondensate, waste polyvinyl chloride plastic powder, a coupling agent, walnut shell powder, saw powder, a filling agent and an initiator according to a proportion, grinding, crushing, sieving by a 50-100-mesh sieve, drying at 100-120 ℃ until the water content is less than or equal to 3%, then putting into a high-speed mixer for premixing, controlling the temperature to be 95-140 ℃, and the premixing time to be 15-25 min, and then naturally cooling to obtain a premix; and then extruding the premix in an extruder, and sequentially carrying out die pressing, shaping and thermal imidization treatment to obtain the wood-plastic composite material for the plywood.

10. The wood-plastic composite material for plywood as claimed in claim 9, wherein said extruding is carried out by extruding the premixed material into a paste-like material at 190-220 ℃ by means of a twin-screw extruder; the die pressing is to place the pasty material in a press die and press the pasty material for 3 to 7 minutes under the pressure of 800 to 1200 tons/M2; the shaping is to shape the pressed and demoulded slab for 35 to 50 minutes under the pressure of 200 to 450 tons/M2; the specific process of the thermal imidization treatment comprises the following steps: firstly heating to 95-110 ℃ at a heating rate of 3-5 ℃/min, preserving heat for 30-50 minutes, then heating to 150-160 ℃ at a heating rate of 5-8 ℃/min, preserving heat for 0.5-1 hour, then heating to 200-210 ℃ at a heating rate of 7-10 ℃/min, preserving heat for 1-2 hours, then heating to 270-280 ℃ at a heating rate of 7-10 ℃/min, preserving heat for 20-40 minutes, and finally heating to 300-310 ℃ at a heating rate of 10 ℃/min, preserving heat for 20-30 minutes.

Technical Field

The invention relates to the technical field of new materials, in particular to a wood-plastic composite material for a plywood and a preparation method thereof.

Background

In recent years, with the rapid development of economy and the continuous progress of society, the living standard of people is steadily improved, the awareness of people on improving the household environment is stronger, and the performance requirement on household materials is higher. As a common material for furniture, the plywood becomes one of three large boards of an artificial board by virtue of the characteristics of large breadth, few abutted seams, light dead weight, easy processing, good integral rigidity and the like, and is widely applied in the fields of furniture interior decoration, airplanes, trains, ships, buildings, automobiles, packing boxes and the like.

Plywood is a three-layer or multi-layer plate material made up by using wood segments and making them be rotary-cut into single board or sliced into thin wood and using adhesive to make them be glued together, and usually using odd number of layers of single board and making the fibre directions of adjacent layers of single board be mutually perpendicular. At present, plywood in the market has various brands, uneven quality and no flame retardant effect, the main materials of the plywood are wood and adhesive, the plywood is extremely easy to burn after meeting open fire, a large amount of harmful gas is generated, and great loss is caused to human bodies and the environment; and the wood in the plywood has very strong water absorption capacity, is very easy to absorb water and mildew in a humid environment, and can greatly damage the plywood due to long-time mildew, so that the service life of the plywood is shortened. On the other hand, the raw material wood for preparing the traditional plywood is sourced from trees, and the existing trees cannot meet the requirements along with the increase of the market demand of the plywood.

The wood-plastic composite material is a composite material processed by utilizing wood fibers and thermoplastic plastics, the raw materials of the wood-plastic composite material can be biomass fibers such as waste wood, crop straws, bamboo wood, hemp scraps and the like, and the recycled thermoplastic plastics such as polyethylene, polypropylene, polyvinyl chloride and the like provide a good way for recycling wastes, have the characteristics of wood and plastics, have good processing performance, strength performance and size stability, are water-resistant and corrosion-resistant, can be used as a substitute of wood in many fields, are low in cost and environment-friendly, have good application prospects, are a 'new favorite' in the material market for plywood at the present stage and in the future for a period of time, and have huge market potential. However, the wood-plastic composite material in the prior art has disadvantages, such as poor rigidity and toughness compared with wood, and particularly, the polyolefin wood-plastic composite material has the problems that the wood-plastic composite material is easy to deform under stress and heating conditions, and the brittle corner part of the material is easy to damage. In addition, they have a high specific gravity, which makes handling difficult.

The Chinese patent application CN1482166A discloses a wood-plastic composite material, which is prepared by mixing raw materials such as thermoplastic resin, wood powder, an auxiliary agent phase solvent, a modifier and the like according to a weight ratio, and the board has high mechanical properties, but cannot prevent water and mildew, and has a limited application range.

Therefore, the development of the wood-plastic composite material for the plywood, which has the advantages of good mechanical property, good heat resistance, good waterproof and mildew-proof properties, good performance stability and long service life, is necessary, and has very important significance for promoting the development of the plywood industry.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides the wood-plastic composite material for the plywood, which has the advantages of high strength, enough toughness, good flame retardance, waterproof performance and heat resistance, excellent dimensional stability and weather resistance, good performance stability and long service life; meanwhile, the invention also discloses a preparation method of the wood-plastic composite material for the plywood, and the method can quickly and safely realize the recycling of the waste wood processing residues and the waste plastics, changes waste into valuable, is suitable for continuous large-scale production, and has higher economic value, social value and ecological value.

In order to achieve the purpose, the invention adopts the technical scheme that the wood-plastic composite material for the plywood is characterized by being prepared from the following raw materials in parts by weight: based on 45-55 parts of benzophenone triazinyl vinyl polyamic acid, 20-30 parts of 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol/bis (vinylsulfonyl) methane polycondensate, 25-35 parts of waste polyvinyl chloride plastic powder, 1-3 parts of coupling agent, 5-10 parts of walnut shell powder, 20-30 parts of saw powder, 6-10 parts of filler and 0.5-1.5 parts of initiator.

Further, the filler is at least one of talcum powder, sepiolite powder and mica powder.

Further, the coupling agent is at least one of a silane coupling agent KH550, a silane coupling agent KH560 and a silane coupling agent KH 570.

Further, the initiator is at least one of azobisisobutyronitrile and azobisisoheptonitrile.

Furthermore, the granularity of the saw powder is 100-200 meshes, and the water content is less than or equal to 8%.

Further, the preparation method of the benzophenone triazinyl vinyl polyamic acid comprises the following steps: 2, 4-diamino-6-vinyl-S-triazine is filled into a polymerization bottle containing tetrahydrofuran, stirred at room temperature to be completely dissolved, then 3,3',4,4' -benzophenone tetracarboxylic dianhydride is added under ice water bath, the reaction system is maintained at 0 ℃, the stirring reaction is continuously carried out for 3-5 hours, and then the tetrahydrofuran is removed by rotary evaporation to obtain the benzophenone triazinyl vinyl-based polyamic acid.

Preferably, the mass ratio of the 2, 4-diamino-6-vinyl-S-triazine to the tetrahydrofuran to the 3,3',4,4' -benzophenone tetracarboxylic dianhydride is 1 (10-15) to 2.35.

Further, the preparation method of the 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol/bis (vinylsulfonyl) methane polycondensate comprises the following steps: adding 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol, bis (vinylsulfonyl) methane and a catalyst into a high-boiling-point solvent, stirring and reacting for 15-20 hours at 100-110 ℃ under the atmosphere of nitrogen or inert gas, then precipitating in water, washing the product with ethanol for 3-7 times, and then placing the product in a vacuum drying oven to be dried to constant weight at 80-90 ℃ to obtain the 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol/bis (vinylsulfonyl) methane polycondensate.

Preferably, the mass ratio of the 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol to the bis (vinylsulfonyl) methane to the catalyst to the high-boiling point solvent is 1.39:1 (0.3-0.5) to (8-13).

Preferably, the catalyst is at least one of sodium ethoxide, sodium hydride, sodium amide and potassium tert-butyl alkoxide; the inert gas is one of helium, neon and argon; the high boiling point solvent is at least one of dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.

The invention also aims to provide a preparation method of the wood-plastic composite material for the plywood, which is characterized by comprising the following steps: mixing benzophenone triazinyl vinyl-based polyamic acid, 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol/bis (vinylsulfonyl) methane polycondensate, waste polyvinyl chloride plastic powder, a coupling agent, walnut shell powder, saw powder, a filling agent and an initiator according to a proportion, grinding, crushing, sieving by a 50-100-mesh sieve, drying at 100-120 ℃ until the water content is less than or equal to 3%, then putting into a high-speed mixer for premixing, controlling the temperature to be 95-140 ℃, and the premixing time to be 15-25 min, and then naturally cooling to obtain a premix; and then extruding the premix in an extruder, and sequentially carrying out die pressing, shaping and thermal imidization treatment to obtain the wood-plastic composite material for the plywood.

Further, the extrusion is to extrude the premix into a pasty material by a double-screw extruder at 190-220 ℃; the die pressing is to place the pasty material in a press die at 800-1200 tons/M²Pressing under pressure for 3-7 min; the shaping is to put the pressed and demoulded slab blank into 200-450 tons/M²Shaping for 35-50 minutes under pressure; the specific process of the thermal imidization treatment comprises the following steps: firstly heating to 95-110 ℃ at a heating rate of 3-5 ℃/min, preserving heat for 30-50 minutes, then heating to 150-160 ℃ at a heating rate of 5-8 ℃/min, preserving heat for 0.5-1 hour, then heating to 200-210 ℃ at a heating rate of 7-10 ℃/min, preserving heat for 1-2 hours, then heating to 270-280 ℃ at a heating rate of 7-10 ℃/min, preserving heat for 20-40 minutes, and finally heating to 300-310 ℃ at a heating rate of 10 ℃/min, preserving heat for 20-30 minutes.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in:

(1) The wood-plastic composite material for the plywood provided by the invention has the advantages of simple and easy operation of the preparation method, rich sources of preparation raw materials, low price, green and environment-friendly preparation process, low energy consumption, high preparation efficiency and high qualification rate of finished products, and is suitable for continuous industrial production; the method can quickly and safely realize the recycling of the waste wood processing residues and the waste plastics, changes waste into valuable, and has higher economic value, social value and ecological value.

(2) The wood-plastic composite material for the plywood provided by the invention overcomes the problems that the traditional wood-plastic composite material is poorer in rigidity and toughness than wood, is easy to deform under stress and heating conditions, is easy to damage fragile corner parts of the material, has higher specific gravity, causes difficulty in transportation and use operation and the like; the flame-retardant waterproof coating has the advantages of high strength, enough toughness, good flame retardance, waterproof performance and heat resistance, excellent dimensional stability and weather resistance, good performance stability and long service life.

(3) According to the wood-plastic composite material for the plywood, provided by the invention, wood processing residues, namely sawdust powder and waste polyvinyl chloride plastic powder, are recycled, so that not only is energy saved, but also the environmental problem caused by random discarding of the wastes is solved, the addition of the peach shell powder can better improve the strength of the material, the source is wide, the value is low, and the cost is effectively reduced; the material has the excellent characteristics of a polyimide structure, and the benzophenone structure and the triazine structure are introduced on a molecular chain, so that the aging resistance and the weather resistance of the material are effectively improved; the introduction of the triazine structure can effectively improve the flame retardance of the material, and the vinyl structure is also introduced on the branched chain, so that a reaction site is provided for the cross-linking reaction in the subsequent material forming stage, the grafting reaction can be carried out on the triazine structure and the waste polyvinyl chloride plastic powder, and the comprehensive performance of the material is further effectively improved.

(4) According to the wood-plastic composite material for the plywood, provided by the invention, a sulfone group structure is introduced on a molecular chain of a 6- (dibutylamino) -1,3, 5-triazole-2, 4-dithiol/bis (vinylsulfonyl) methane polycondensate, so that the mechanical property and the flame retardance of the material can be effectively improved; tertiary amino is introduced, and the material is easy to generate ionization reaction with chlorine on the waste polyvinyl chloride plastic powder in the subsequent material forming stage, so that quaternary ammonium salt cations are introduced to endow the material with an antibacterial effect; based on products of benzophenone triazinyl vinyl polyamic acid after thermal imidization and 6- (dibutyl amino) -1,3, 5-triazole-2, 4-dithiol/bis (vinyl sulfonyl) methane polycondensate, two thermoplastic plastic molecular chains contain more hydrophobic groups, so that the waterproofness of the material is effectively improved, the two thermoplastic plastic molecular chains cooperate with each other to act synergistically, the material can replace a fluorine-silicon material in performance, but the cost is lower than that of the fluorine-silicon material; the raw materials of the material have synergistic effect, so that the comprehensive performance of the material is better, a large amount of additives are not required to be added, and the defects of poor processability and performance stability caused by a large amount of additives are effectively overcome.

Detailed Description

In order to make the technical solutions of the present invention better understood and make the above features, objects, and advantages of the present invention more comprehensible, the present invention is further described with reference to the following examples. The examples are intended to illustrate the invention only and are not intended to limit the scope of the invention.

The raw materials used in the following examples of the present invention were all purchased commercially.