CN116536008A - Starch-based particle board adhesive capable of being quickly cured at medium and low temperatures and preparation method thereof - Google Patents
Starch-based particle board adhesive capable of being quickly cured at medium and low temperatures and preparation method thereof Download PDFInfo
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- CN116536008A CN116536008A CN202310623427.6A CN202310623427A CN116536008A CN 116536008 A CN116536008 A CN 116536008A CN 202310623427 A CN202310623427 A CN 202310623427A CN 116536008 A CN116536008 A CN 116536008A
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- 229920002472 Starch Polymers 0.000 title claims abstract description 181
- 235000019698 starch Nutrition 0.000 title claims abstract description 179
- 239000008107 starch Substances 0.000 title claims abstract description 179
- 239000000853 adhesive Substances 0.000 title claims abstract description 177
- 230000001070 adhesive effect Effects 0.000 title claims abstract description 177
- 239000002245 particle Substances 0.000 title claims abstract description 12
- 238000002360 preparation method Methods 0.000 title abstract description 28
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 114
- 239000003999 initiator Substances 0.000 claims abstract description 81
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 54
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 50
- 239000000178 monomer Substances 0.000 claims abstract description 42
- 239000003995 emulsifying agent Substances 0.000 claims abstract description 38
- 239000003431 cross linking reagent Substances 0.000 claims abstract description 30
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 17
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000011093 chipboard Substances 0.000 claims abstract description 15
- 239000002023 wood Substances 0.000 claims abstract description 9
- 239000011094 fiberboard Substances 0.000 claims abstract description 3
- 239000011120 plywood Substances 0.000 claims abstract description 3
- 238000006116 polymerization reaction Methods 0.000 claims description 46
- 238000006243 chemical reaction Methods 0.000 claims description 40
- 238000007731 hot pressing Methods 0.000 claims description 38
- 235000013336 milk Nutrition 0.000 claims description 38
- 239000008267 milk Substances 0.000 claims description 38
- 210000004080 milk Anatomy 0.000 claims description 38
- 239000000839 emulsion Substances 0.000 claims description 37
- 238000001816 cooling Methods 0.000 claims description 33
- 238000010438 heat treatment Methods 0.000 claims description 29
- 238000002156 mixing Methods 0.000 claims description 23
- XMPZTFVPEKAKFH-UHFFFAOYSA-P ceric ammonium nitrate Chemical compound [NH4+].[NH4+].[Ce+4].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O XMPZTFVPEKAKFH-UHFFFAOYSA-P 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 16
- 238000003756 stirring Methods 0.000 claims description 15
- 238000010559 graft polymerization reaction Methods 0.000 claims description 12
- STMDPCBYJCIZOD-UHFFFAOYSA-N 2-(2,4-dinitroanilino)-4-methylpentanoic acid Chemical group CC(C)CC(C(O)=O)NC1=CC=C([N+]([O-])=O)C=C1[N+]([O-])=O STMDPCBYJCIZOD-UHFFFAOYSA-N 0.000 claims description 11
- LZZYPRNAOMGNLH-UHFFFAOYSA-M Cetrimonium bromide Chemical group [Br-].CCCCCCCCCCCCCCCC[N+](C)(C)C LZZYPRNAOMGNLH-UHFFFAOYSA-M 0.000 claims description 11
- 229920000881 Modified starch Polymers 0.000 claims description 11
- 239000004368 Modified starch Substances 0.000 claims description 11
- 235000019426 modified starch Nutrition 0.000 claims description 11
- 229920002261 Corn starch Polymers 0.000 claims description 4
- 239000008120 corn starch Substances 0.000 claims description 4
- MTJGVAJYTOXFJH-UHFFFAOYSA-N 3-aminonaphthalene-1,5-disulfonic acid Chemical compound C1=CC=C(S(O)(=O)=O)C2=CC(N)=CC(S(O)(=O)=O)=C21 MTJGVAJYTOXFJH-UHFFFAOYSA-N 0.000 claims description 2
- 240000003183 Manihot esculenta Species 0.000 claims description 2
- 235000016735 Manihot esculenta subsp esculenta Nutrition 0.000 claims description 2
- 240000004922 Vigna radiata Species 0.000 claims description 2
- 235000010721 Vigna radiata var radiata Nutrition 0.000 claims description 2
- 235000011469 Vigna radiata var sublobata Nutrition 0.000 claims description 2
- 229920001592 potato starch Polymers 0.000 claims description 2
- 229940100486 rice starch Drugs 0.000 claims description 2
- 229940100445 wheat starch Drugs 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 8
- 238000005265 energy consumption Methods 0.000 abstract description 4
- 238000004132 cross linking Methods 0.000 description 22
- 230000000694 effects Effects 0.000 description 22
- 239000000203 mixture Substances 0.000 description 10
- 238000010521 absorption reaction Methods 0.000 description 8
- 230000035484 reaction time Effects 0.000 description 5
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 229920001187 thermosetting polymer Polymers 0.000 description 4
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- 230000009257 reactivity Effects 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- WZCQRUWWHSTZEM-UHFFFAOYSA-N 1,3-phenylenediamine Chemical compound NC1=CC=CC(N)=C1 WZCQRUWWHSTZEM-UHFFFAOYSA-N 0.000 description 2
- DBCAQXHNJOFNGC-UHFFFAOYSA-N 4-bromo-1,1,1-trifluorobutane Chemical compound FC(F)(F)CCCBr DBCAQXHNJOFNGC-UHFFFAOYSA-N 0.000 description 2
- 229910001870 ammonium persulfate Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- STVZJERGLQHEKB-UHFFFAOYSA-N ethylene glycol dimethacrylate Substances CC(=C)C(=O)OCCOC(=O)C(C)=C STVZJERGLQHEKB-UHFFFAOYSA-N 0.000 description 2
- 231100000206 health hazard Toxicity 0.000 description 2
- 230000000977 initiatory effect Effects 0.000 description 2
- 229940018564 m-phenylenediamine Drugs 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229920000877 Melamine resin Polymers 0.000 description 1
- 229920001807 Urea-formaldehyde Polymers 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- IVJISJACKSSFGE-UHFFFAOYSA-N formaldehyde;1,3,5-triazine-2,4,6-triamine Chemical compound O=C.NC1=NC(N)=NC(N)=N1 IVJISJACKSSFGE-UHFFFAOYSA-N 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 231100000956 nontoxicity Toxicity 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- ODGAOXROABLFNM-UHFFFAOYSA-N polynoxylin Chemical compound O=C.NC(N)=O ODGAOXROABLFNM-UHFFFAOYSA-N 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000005180 public health Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J151/00—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
- C09J151/02—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers grafted on to polysaccharides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/002—Manufacture of substantially flat articles, e.g. boards, from particles or fibres characterised by the type of binder
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
- B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
- B27N3/02—Manufacture of substantially flat articles, e.g. boards, from particles or fibres from particles
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F251/00—Macromolecular compounds obtained by polymerising monomers on to polysaccharides or derivatives thereof
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
- C09J11/02—Non-macromolecular additives
- C09J11/06—Non-macromolecular additives organic
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Wood Science & Technology (AREA)
- Forests & Forestry (AREA)
- Adhesives Or Adhesive Processes (AREA)
Abstract
The invention discloses a starch-based chipboard adhesive capable of being quickly cured at a medium and low temperature and a preparation method thereof, and belongs to the technical field of adhesive preparation. The starch-based adhesive for the particle board comprises a component A and a component B; the component A comprises the following components: 150 parts of starch, 200-300 parts of water, 20-25 parts of concentrated hydrochloric acid, 12-18 parts of dilute nitric acid, 25-40 parts of sodium hydroxide solution, 6-9 parts of initiator, 27-35 parts of grafting monomer and 2-5 parts of emulsifier; the component B comprises: 8-11 parts of post-crosslinking agent ethylenediamine. The starch-based chipboard adhesive effectively solves the problems of high curing temperature and long curing time of the starch adhesive in the prior art, can reduce the curing temperature to 105 ℃ on the premise of keeping a higher curing speed, reduces the production energy consumption of chipboards, and can be widely applied to hot-press bonding of chipboards, plywood, fiberboards and wood blocks.
Description
Technical Field
The invention relates to a starch-based chipboard adhesive capable of being quickly cured at a medium and low temperature and a preparation method thereof, and belongs to the technical field of adhesive preparation.
Background
In recent years, with the rapid development of economy, the domestic wood consumption speed is rapidly increased, and the demand for wood resources is increasing. The artificial board is a product which can fully utilize wood and improve the utilization rate of wood resources, and the demand of the artificial board is also increased. However, as the production scale of the adhesive industry expands, some problems of the wood adhesives used at present are increasingly prominent.
The traditional adhesive used by most artificial boards in the market is mainly 'trialdehyde' resin adhesive, namely phenolic adhesive, urea-formaldehyde adhesive and melamine formaldehyde adhesive, which has low price and better performance, but causes serious pollution and health hazard, formaldehyde is released in the production process and the prepared artificial board products, and the environment pollution and public health hazard are caused. Therefore, there is a need to develop a wood adhesive that is environmentally friendly, excellent in performance, safe and nontoxic.
The starch is a natural degradable, environment-friendly and renewable material, has the characteristics of wide sources, low price, no toxicity, no pollution and the like, and is widely applied to the processing industry. Compared with the common adhesive in the market, the adhesive is prepared by using starch instead of synthetic organic products as raw materials, so that the cost can be reduced, and the environment is not polluted.
At present, the common artificial boards on the market are usually produced by a hot-pressing process, the shaving board is used as one of the categories, the hot-pressing process time of the shaving board is shorter, the adhesive is required to have higher curing activity and can be quickly cured at a certain temperature, the adhesive is required to have lower viscosity and certain water resistance, and the traditional starch adhesive is high in viscosity, lack of thermosetting property and poor in water resistance.
Aiming at the requirements of the particle board on the adhesive performance, the applicant has previously developed a low-viscosity starch-based adhesive with thermosetting property, and the water resistance, the dry strength and the like are greatly improved, but the problems of long curing time, low curing efficiency, high requirement on hot-press curing temperature and the like still exist; the flakeboards are easy to become brittle under long-time high-temperature hot-pressing, the mechanical property is reduced, and the wider and deeper application of the starch-based adhesive is difficult to promote.
Disclosure of Invention
[ technical problem ]
The starch-based adhesive has the problems of long curing time, low curing efficiency, high curing temperature and the like in the hot pressing process, so that the hot pressing time of the shaving board is long, the strength of the prepared shaving board is reduced, the production energy consumption is high, and the preparation requirement of the modern shaving board cannot be met.
Technical scheme
In order to solve the problems, the invention provides a starch-based chipboard adhesive which is quickly solidified at medium and low temperatures and a preparation method thereof; the method is characterized in that starch and a self-crosslinking monomer are subjected to graft polymerization reaction, crosslinking and solidification do not occur in the reaction process, so that the low viscosity of the adhesive is ensured, the retrogradation resistance of the starch is improved by graft modification, and a crosslinkable functional group with higher reactivity is introduced into the starch, thereby being beneficial to improving the reactivity of the crosslinking reaction and reducing the crosslinking temperature; meanwhile, in order to improve the effect of the crosslinking reaction, the process is optimized, the polymerization reaction is firstly carried out on the grafting monomer solution at a lower temperature to generate a monomer oligomer with a certain polymerization degree, which is beneficial to forming a grafting molecular chain with higher molecular weight on starch, so that the crosslinking reaction is easier to carry out, the crosslinking temperature is reduced, the distribution of the grafting molecular chain is more uniform, the reaction site dispersion condition of the crosslinking reaction is improved, and the crosslinking effect is improved; then, a post-crosslinking agent is used, the obtained adhesive is added with the post-crosslinking agent and uniformly mixed when in use, and the adhesive and grafted starch can undergo a quick crosslinking reaction at a lower temperature when in hot pressing to form a three-dimensional network structure, so that the adhesive has better thermosetting property and water resistance; in addition, the crosslinking agent with high reactivity is selected, so that the crosslinking reaction is easier to carry out, and the curing speed is improved.
The invention controls the five key variables of initiator addition, monomer addition, reaction time, crosslinking agent addition and crosslinking pH, and uses a novel grafting reaction preparation method, so that the prepared adhesive has lower curing temperature and faster curing speed when being added with a post-crosslinking agent in hot pressing on the premise of meeting the low viscosity requirement, shortens the hot pressing time, avoids the embrittlement of a shaving board at an excessively high temperature, reduces the energy consumption and the cost of the shaving board production and improves the production efficiency on the premise of ensuring the water resistance, the thermosetting property and the mechanical strength.
The invention performs accurate control aiming at the following key points:
(1) initiator addition amount
The addition amount of the initiator is not less than 5% of the amount of the starch: the addition of dilute nitric acid in the initiator solution can improve the initiation effect, and the addition amount of the initiator is too low, so that the grafting effect of the monomer is reduced, and the curing speed is slowed down; too high an addition of initiator will result in a decrease in graft chain length, a decrease in cross-linking strength, and a decrease in particle board strength; the effect of adding the initiator in portions is improved.
(2) Grafting monomer addition
The addition amount of the grafting monomer should not be lower than 18% of the starch dosage: the small addition amount of the grafting monomer can lead to the reduction of the storage stability, the bonding strength and the water resistance of the starch adhesive;
(3) reaction time
The reaction time is not less than 4 hours: too short or too long a reaction time affects the grafting effect of the monomer on the starch, resulting in a decrease in the adhesive strength and a deterioration in the water resistance of the adhesive.
(4) Crosslinking agent addition amount
The addition amount of the cross-linking agent is not less than 40% of the dosage of the monomer: too little addition of the crosslinking agent results in a decrease in curing activity of the adhesive, and a decrease in final strength.
(5) Cross-linking pH
The pH in the system is not lower than 5.5 during curing and crosslinking: too low a pH during crosslinking can result in slow curing of the adhesive, poor curing effects, and inability to achieve rapid curing at lower temperatures.
The invention provides a starch-based shaving board adhesive which is quickly cured at a medium-low temperature, wherein the starch-based shaving board adhesive comprises a component A and a component B; the component A comprises the following components in parts by mass: 150 parts of starch, 200-300 parts of water, 20-25 parts of concentrated hydrochloric acid, 12-18 parts of dilute nitric acid, 25-40 parts of sodium hydroxide solution, 6-9 parts of initiator ceric ammonium nitrate, 27-35 parts of grafting monomer and 2-5 parts of emulsifier; the component B comprises the following components in parts by mass: 8-11 parts of post-crosslinking agent ethylenediamine.
In one embodiment, the starch is any one or a combination of several of corn starch, waxy corn starch, tapioca starch, wheat starch, potato starch, rice starch, mung bean starch.
In one embodiment, the medium and low temperatures are from 90 ℃ to 120 ℃.
In one embodiment, the concentrated hydrochloric acid is 12 to 15mol/L concentrated hydrochloric acid.
In one embodiment, the sodium hydroxide solution is a sodium hydroxide solution having a concentration of 10 to 15 mol/L.
In one embodiment, the dilute nitric acid is a nitric acid solution of 0.5 to 1 mol/L.
In one embodiment, the emulsifier is cetyltrimethylammonium bromide.
In one embodiment, the grafting monomer is allyl glycidyl ether.
The second object of the invention is to provide a preparation method of the starch-based shaving board adhesive, which comprises the following steps:
(1) In a reaction kettle, starch and water are prepared into starch milk with the concentration of 30-50% based on the dry weight of the starch, after being uniformly stirred, the temperature is raised to 50-60 ℃, and hydrochloric acid diluted to 4-8 mol/L is added for acidolysis; adding sodium hydroxide solution after acidolysis, adjusting the pH to 3-5, and gelatinizing to obtain gelatinized starch emulsion;
(2) Adding an initiator into dilute nitric acid to prepare an initiator solution, adding the initiator solution with the volume ratio of 10-20% into a grafting monomer, uniformly mixing, adding the grafting monomer into a reaction kettle for prepolymerization, and then cooling the system to normal temperature to obtain a prepolymerized solution;
(3) Cooling the gelatinized starch emulsion solution obtained in the step (1) to 50-70 ℃, adding an initiator solution with the volume ratio of 50-80%, and then adding a sodium hydroxide solution to adjust the pH to 3-5;
(4) Dropwise adding the prepolymerization solution obtained in the step (2) into the starch emulsion solution after the initiator is added at a constant speed for graft polymerization, adding the rest initiator solution after the dropwise adding is finished, adding a sodium hydroxide solution, adjusting the pH to 3-5, and preserving the temperature for 30-45 min to obtain a polymerization modified starch-based emulsion;
(5) Dissolving an emulsifier in water to prepare 4% -7% of emulsifier solution, adding the emulsifier solution into the starch-based emulsion obtained in the step (4), heating to 75-85 ℃, and preserving heat for 90-120 min again to obtain a polymerization modified adhesive;
(6) Cooling the polymerization modified adhesive obtained in the step (5) to 30-50 ℃, and adjusting the pH of the adhesive to 6-8 to obtain the starch-based adhesive for the particle board;
(7) And (3) before preparing the shaving board, uniformly stirring and mixing the starch-based adhesive prepared in the step (6) and the post-crosslinking agent, and then carrying out hot pressing on the shaving board.
In one embodiment, the acidolysis time of step (1) is 2 to 4 hours.
In one embodiment, the gelatinization in step (1) is carried out at a temperature of 60 to 90℃for a period of 30 to 60 minutes.
In one embodiment, the prepolymerization temperature in step (2) is 50-60℃and the time is 30-45 min.
In one embodiment, the dripping time in the step (4) is controlled to be 90-120 min.
In one embodiment, the hot pressing in step (7) is performed at a temperature of 90-120 ℃ and a pressure of 6-10 MPa.
The third object of the invention is the use of a starch-based chipboard adhesive as described above for the thermocompression bonding of chipboards, plywood, fiberboard and wood blocks.
In one embodiment, the hot-press bonding method of the shaving board is to uniformly mix and pave the starch-based shaving board adhesive and the shaving, and then press molding the shaving board adhesive and the shaving under the conditions that the hot-press temperature is 90-120 ℃ and the pressure is 6-10 MPa.
The fourth object of the invention is to provide a method for reducing the hot-pressing temperature of the shaving board, which is to use the starch-based shaving board adhesive for hot-pressing and bonding the shaving board.
[ advantageous effects ]
(1) The invention destroys the crystal structure of the starch by gelatinizing the starch, so that monomer molecules can better enter between starch molecules, more monomers react with the starch, and the reaction efficiency and grafting effect are improved. The grafting monomer is subjected to prepolymerization treatment, so that the chain length of a grafted molecular chain is increased, the polymerization degree is increased, the crosslinking is promoted, and the activity on the crosslinking reaction and the crosslinking strength are improved; the grafting efficiency of the monomer is improved by a method of adding the initiator in batches, the selected grafting monomer cannot be self-crosslinked in the reaction and under normal temperature storage after the reaction, and the storage property is improved; after the post-crosslinking agent is added, the cross-linking reaction can be carried out by hot pressing, a three-dimensional reticular structure is formed, and stronger water resistance and bonding strength are ensured;
(2) The grafting monomer used in the invention is matched with the post-crosslinking agent, so that the problems that the starch adhesive is easy to solidify in the reaction process and needs to solidify at high temperature and has slower solidifying speed in use are solved, the solidifying time of the starch adhesive is further reduced to be within 90 seconds, the hot-pressing temperature is reduced to 105 ℃, the production efficiency of the shaving board is improved, and the energy consumption in the production process is reduced;
(3) The particle board prepared by the starch adhesive has the performances meeting the performance requirements of the P2 type shaving board in GB/T4897-2015, can be soaked in water at 20 ℃ for 2 hours without damage, has the water absorption thickness expansion rate of 7 percent, has good water resistance, and further improves the application of the starch-based adhesive.
Detailed Description
The invention will be further described in connection with the following embodiments, it being understood that these examples are for illustrative purposes only and are not intended to limit the scope of the invention.
Determination of adhesive cure time:
respectively adding 30g of adhesive and 3g of post-crosslinking agent into a beaker, fully mixing, transferring 2.0g of the mixture into a test tube, inserting a stirring rod into the test tube, putting into a beaker filled with boiling water, starting timing, and solidifying the sample under stirring; when the stirring rod cannot stir, stopping timing, and taking the measured time as the curing time, performing three parallel experiments on each sample, and taking an average value.
Example 1
A starch-based shaving board adhesive capable of being quickly cured at medium and low temperatures comprises the following components in percentage by weight:
the preparation method of the starch-based shaving board adhesive comprises the following steps:
(1) Preparing starch and water into starch milk with the starch mass fraction of 50%, uniformly stirring and mixing, and heating to 60 ℃;
(2) Preparing 18ml of 12mol/L concentrated hydrochloric acid into 6.5mol/L dilute hydrochloric acid solution, adding the 6.5mol/L dilute hydrochloric acid solution into the starch milk obtained in the step (1) for acidolysis for 2 hours, then adding 10mol/L sodium hydroxide solution, adjusting the pH of the starch milk to 4, and maintaining the pH at 80 ℃ for 30 minutes for gelatinization;
(3) Adding 7.5g of initiator (ceric ammonium nitrate) into 15ml of dilute nitric acid to prepare an initiator solution, adding 2.5ml of the initiator solution into a grafting monomer (allyl glycidyl ether), uniformly mixing, adding into a reaction kettle, heating to 55 ℃, prepolymerizing for 30min, and then cooling the system to normal temperature;
(4) Cooling the gelatinized starch milk obtained in the step (2) to 60 ℃, adding 12ml of the initiator solution prepared in the step (3), and then adding sodium hydroxide solution to adjust the pH to 4;
(5) Dripping the solution obtained after the pre-polymerization treatment in the step (3) into the starch emulsion solution obtained after the initiator is added in the step (4) at a constant speed for graft polymerization, wherein the dripping time is controlled to be 100min, and the reaction temperature is kept to be 60 ℃; after the dripping is completed, adding the rest initiator solution, adding sodium hydroxide solution, adjusting the pH to 4, and preserving the heat for 30min; obtaining a polymerization modified starch-based emulsion;
(6) Dissolving an emulsifier (cetyl trimethyl ammonium bromide) in water to prepare a 5% emulsifier solution, adding the emulsifier solution into the starch-based emulsion obtained in the step (5), heating to 82.5 ℃, and preserving heat for 90 minutes again to obtain a polymerization modified adhesive;
(7) Cooling the polymerization modified adhesive obtained in the step (6) to 45 ℃, and adjusting the pH of the adhesive to 6 to obtain a starch-based adhesive;
(8) Before the preparation of the shaving board, 8.5g of post-crosslinking agent (ethylenediamine) is added into the adhesive prepared in the step (7), and the mixture is stirred and mixed uniformly, and then the shaving board is subjected to hot pressing.
The adhesive product obtained by the embodiment is milky white in appearance, low in viscosity and strong in fluidity, and meets the requirements of a shaving board. The curing time of the adhesive is measured, and the result shows that the curing time of the adhesive for the starch-based shaving board is 90s; and hot-pressing for 5min at 105 ℃ and 10MPa, wherein the water absorption thickness expansion rate of the obtained shaving board is 7%, and the requirements of the national standard P2 type shaving board are met.
Example 2
A starch-based shaving board adhesive capable of being quickly cured at medium and low temperatures comprises the following components in percentage by weight:
the preparation method of the starch-based shaving board adhesive comprises the following steps:
(1) Preparing starch and water into starch milk with the starch mass fraction of 50%, uniformly stirring and mixing, and heating to 60 ℃;
(2) Preparing 18ml of 12mol/L concentrated hydrochloric acid into 6.5mol/L dilute hydrochloric acid solution, adding the 6.5mol/L dilute hydrochloric acid solution into the starch milk obtained in the step (1) for acidolysis for 2 hours, then adding 10mol/L sodium hydroxide solution, adjusting the pH of the starch milk to 4, and maintaining the pH at 80 ℃ for 30 minutes for gelatinization;
(3) Adding 4g of initiator (ceric ammonium nitrate) into 15ml of dilute nitric acid to prepare an initiator solution, adding 2.5ml of the initiator solution into a grafting monomer (allyl glycidyl ether), uniformly mixing, adding into a reaction kettle, heating to 55 ℃, prepolymerizing for 30min, and then cooling the system to normal temperature;
(4) Cooling the gelatinized starch milk obtained in the step (2) to 60 ℃, adding 12ml of the initiator solution prepared in the step (3), and then adding sodium hydroxide solution to adjust the pH to 4;
(5) Dripping the solution obtained after the pre-polymerization treatment in the step (3) into the starch emulsion solution obtained after the initiator is added in the step (4) at a constant speed for graft polymerization, wherein the dripping time is controlled to be 100min, and the reaction temperature is kept to be 60 ℃; after the dripping is completed, adding the rest initiator solution, adding sodium hydroxide solution, adjusting the pH to 4, and preserving the heat for 30min; obtaining a polymerization modified starch-based emulsion;
(6) Dissolving an emulsifier (cetyl trimethyl ammonium bromide) in water to prepare a 5% emulsifier solution, adding the emulsifier solution into the starch-based emulsion obtained in the step (5), heating to 82.5 ℃, and preserving heat for 90 minutes again to obtain a polymerization modified adhesive;
(7) Cooling the polymerization modified adhesive obtained in the step (6) to 45 ℃, and adjusting the pH of the adhesive to 6 to obtain a starch-based adhesive;
(8) Before the preparation of the shaving board, 8.5g of post-crosslinking agent (ethylenediamine) is added into the adhesive, and the mixture is stirred and mixed uniformly, and then the shaving board is subjected to hot pressing.
The adhesive product obtained by the embodiment is milky white in appearance, low in viscosity and strong in fluidity, and meets the requirements of a shaving board. The curing time of the adhesive is measured, and the result shows that the curing time of the adhesive for the starch-based shaving board is 210s; and hot-pressing for 5min at 105 ℃ and 10MPa, wherein the water absorption thickness expansion rate of the obtained shaving board is 17%, and the requirements of the national standard P2 type shaving board are not met.
The influence of the addition amount of the initiator on the viscosity of the adhesive is proved by the examples 1 and 2, and the result shows that the use amount of the initiator is too small, the initiation effect is poor, the grafting effect is poor, the curing performance of the adhesive is influenced, and finally the strength and the water resistance of the particle board are influenced.
Example 3
A starch-based shaving board adhesive capable of being quickly cured at medium and low temperatures comprises the following components in percentage by weight:
the preparation method of the starch-based shaving board adhesive comprises the following steps:
(1) Preparing starch and water into starch milk with the starch mass fraction of 50%, uniformly stirring and mixing, and heating to 60 ℃;
(2) Preparing 18ml of 12mol/L concentrated hydrochloric acid into 6.5mol/L dilute hydrochloric acid solution, adding the 6.5mol/L dilute hydrochloric acid solution into the starch milk obtained in the step (1) for acidolysis for 2 hours, then adding 10mol/L sodium hydroxide solution, adjusting the pH of the starch milk to 4, and maintaining the pH at 80 ℃ for 30 minutes for gelatinization;
(3) Adding 7.5g of initiator (ammonium persulfate) into 15ml of dilute nitric acid to prepare an initiator solution, adding 2.5ml of the initiator solution into a grafting monomer (allyl glycidyl ether), uniformly mixing, adding into a reaction kettle, heating to 55 ℃, prepolymerizing for 30min, and then cooling the system to normal temperature;
(4) Cooling the gelatinized starch milk obtained in the step (2) to 60 ℃, adding 12ml of the initiator solution prepared in the step (3), and then adding sodium hydroxide solution to adjust the pH to 4;
(5) Dripping the solution obtained after the pre-polymerization treatment in the step (3) into the starch emulsion solution obtained after the initiator is added in the step (4) at a constant speed for graft polymerization, wherein the dripping time is controlled to be 100min, and the reaction temperature is kept to be 60 ℃; after the dripping is completed, adding the rest initiator solution, adding sodium hydroxide solution, adjusting the pH to 4, and preserving the heat for 30min; obtaining a polymerization modified starch-based emulsion;
(6) Dissolving an emulsifier (cetyl trimethyl ammonium bromide) in water to prepare a 5% emulsifier solution, adding the emulsifier solution into the starch-based emulsion obtained in the step (5), heating to 82.5 ℃, and preserving heat for 90 minutes again to obtain a polymerization modified adhesive;
(7) Cooling the polymerization modified adhesive obtained in the step (6) to 45 ℃, and adjusting the pH of the adhesive to 6 to obtain a starch-based adhesive;
(8) Before the preparation of the shaving board, 8.5g of post-crosslinking agent (ethylenediamine) is added into the adhesive, and the mixture is stirred and mixed uniformly, and then the shaving board is subjected to hot pressing.
The adhesive product obtained by the embodiment is milky white in appearance, low in viscosity and strong in fluidity, and meets the requirements of a shaving board. The curing time of the adhesive is measured, and the result shows that the curing time of the adhesive for the starch-based shaving board is 220s; and hot-pressing for 5min at 105 ℃ and 10MPa, so that the obtained shaving board is soaked in water and disintegrated, and the requirements of the national standard P2 type shaving board are not met.
The influence of the initiator type on the curing time of the adhesive is proved by the examples 1 and 3, and the results show that the monomer and starch grafting effect is good at the reaction temperature of 60 ℃ by using the ceric ammonium nitrate initiator, the prepared adhesive has good curing performance and can meet the requirement of fast curing of the chipboard adhesive, and the starch adhesive prepared by using ammonium persulfate to initiate monomer grafting has poor grafting effect, so that the adhesive has poor curing performance, longer curing time at 105 ℃ under hot pressing, low curing efficiency and poor water resistance, and the requirements of the chipboard adhesive cannot be met.
Example 4
A starch-based shaving board adhesive capable of being quickly cured at medium and low temperatures comprises the following components in percentage by weight:
the preparation method of the starch-based shaving board adhesive comprises the following steps:
(1) Preparing starch and water into starch milk with the starch mass fraction of 50%, uniformly stirring and mixing, and heating to 60 ℃;
(2) Preparing 18ml of 12mol/L concentrated hydrochloric acid into 6.5mol/L dilute hydrochloric acid solution, adding the 6.5mol/L dilute hydrochloric acid solution into the starch milk obtained in the step (1) for acidolysis for 2 hours, then adding 10mol/L sodium hydroxide solution, adjusting the pH of the starch milk to 4, and maintaining the pH at 80 ℃ for 30 minutes for gelatinization;
(3) Adding 7.5g of initiator (ceric ammonium nitrate) into 15ml of dilute nitric acid to prepare an initiator solution, adding 2.5ml of the initiator solution into a grafting monomer (allyl glycidyl ether), uniformly mixing, adding into a reaction kettle, heating to 55 ℃, prepolymerizing for 30min, and then cooling the system to normal temperature;
(4) Cooling the gelatinized starch milk obtained in the step (2) to 60 ℃, adding 12ml of the initiator solution prepared in the step (3), and then adding sodium hydroxide solution to adjust the pH to 4;
(5) Dripping the solution obtained after the pre-polymerization treatment in the step (3) into the starch emulsion solution obtained after the initiator is added in the step (4) at a constant speed for graft polymerization, wherein the dripping time is controlled to be 100min, and the reaction temperature is kept to be 60 ℃; after the dripping is completed, adding the rest initiator solution, adding sodium hydroxide solution, adjusting the pH to 4, and preserving the heat for 30min; obtaining a polymerization modified starch-based emulsion;
(6) Dissolving an emulsifier (cetyl trimethyl ammonium bromide) in water to prepare a 5% emulsifier solution, adding the emulsifier solution into the starch-based emulsion obtained in the step (5), heating to 82.5 ℃, and preserving heat for 90 minutes again to obtain a polymerization modified adhesive;
(7) Cooling the polymerization modified adhesive obtained in the step (6) to 45 ℃, and adjusting the pH of the adhesive to 6 to obtain a starch-based adhesive;
(8) Before the preparation of the shaving board, 8.5g of post-crosslinking agent (ethylenediamine) is added into the adhesive prepared in the step (7), and the mixture is stirred and mixed uniformly, and then the shaving board is subjected to hot pressing.
The adhesive product obtained by the embodiment is milky white in appearance, low in viscosity and strong in fluidity, and meets the requirements of a shaving board. The curing time of the adhesive is measured, and the result shows that the curing time of the adhesive for the starch-based shaving board is 190s; and hot-pressing for 5min at 105 ℃ and 10MPa, wherein the water absorption thickness expansion rate of the obtained shaving board is 13%, and the requirements of the national standard P2 type shaving board are not met.
The effect of the addition amount of the grafting monomer on the curing performance of the adhesive is proved by examples 1 and 4, and the data show that the addition amount of the grafting monomer is too small, the grafting amount of the monomer on starch is small, so that the crosslinkable groups on the starch adhesive are too small, the curing performance of the adhesive is affected, and finally the strength and the water resistance of the shaving board are reduced.
Example 5
A starch-based shaving board adhesive capable of being quickly cured at medium and low temperatures comprises the following components in percentage by weight:
the preparation method of the starch-based shaving board adhesive comprises the following steps:
(1) Preparing starch and water into starch milk with the starch mass fraction of 50%, uniformly stirring and mixing, and heating to 60 ℃;
(2) Preparing 18ml of 12mol/L concentrated hydrochloric acid into 6.5mol/L dilute hydrochloric acid solution, adding the 6.5mol/L dilute hydrochloric acid solution into the starch milk obtained in the step (1) for acidolysis for 2 hours, then adding 10mol/L sodium hydroxide solution, adjusting the pH of the starch milk to 4, and maintaining the pH at 80 ℃ for 30 minutes for gelatinization;
(3) Adding 7.5g of initiator (ceric ammonium nitrate) into 15ml of dilute nitric acid to prepare an initiator solution, adding 2.5ml of the initiator solution into a grafting monomer (ethylene glycol dimethacrylate), uniformly mixing, adding into a reaction kettle, heating to 55 ℃, prepolymerizing for 30min, and then cooling the system to normal temperature;
(4) Cooling the gelatinized starch milk obtained in the step (2) to 60 ℃, adding 12ml of the initiator solution prepared in the step (3), and then adding sodium hydroxide solution to adjust the pH to 4;
(5) Dripping the solution obtained after the pre-polymerization treatment in the step (3) into the starch emulsion solution obtained after the initiator is added in the step (4) at a constant speed for graft polymerization, wherein the dripping time is controlled to be 100min, and the reaction temperature is kept to be 60 ℃; after the dripping is completed, adding the rest initiator solution, adding sodium hydroxide solution, adjusting the pH to 4, and preserving the heat for 30min; obtaining a polymerization modified starch-based emulsion;
(6) Dissolving an emulsifier (cetyl trimethyl ammonium bromide) in water to prepare a 5% emulsifier solution, adding the emulsifier solution into the starch-based emulsion obtained in the step (5), heating to 82.5 ℃, and preserving heat for 90 minutes again to obtain a polymerization modified adhesive;
(7) Cooling the polymerization modified adhesive obtained in the step (6) to 45 ℃, and adjusting the pH of the adhesive to 6 to obtain a starch-based adhesive;
(8) Before the preparation of the shaving board, 8.5g of post-crosslinking agent (ethylenediamine) is added into the adhesive prepared in the step (7), and the mixture is stirred and mixed uniformly, and then the shaving board is subjected to hot pressing.
The adhesive product obtained by the embodiment is milky white in appearance, low in viscosity and strong in fluidity, and meets the requirements of a shaving board. The curing time of the adhesive is measured, and the result shows that the curing time of the adhesive for the starch-based shaving board is 180s; and hot-pressing for 5min at 105 ℃ and 10MPa, wherein the water absorption thickness expansion rate of the obtained shaving board is 16%, and the requirements of the national standard P2 type shaving board are not met.
The effect of the grafting monomer on the curing time of the adhesive is demonstrated by examples 1, 5. The curing time of the adhesive prepared by using the allyl glycidyl ether and the ethylenediamine under the hot pressing temperature of 105 ℃ is shorter, the requirement of the fast curing of the adhesive for the shaving board can be met, and the curing time of the adhesive prepared by using the ethylene glycol dimethacrylate and the ethylenediamine under the hot pressing temperature of 105 ℃ is longer, the curing efficiency is low, the water resistance is poor, and the requirement of the adhesive for the shaving board cannot be met.
Example 6
A starch-based shaving board adhesive capable of being quickly cured at medium and low temperatures comprises the following components in percentage by weight:
the preparation method of the starch-based shaving board adhesive comprises the following steps:
(1) Preparing starch and water into starch milk with the starch mass fraction of 50%, uniformly stirring and mixing, and heating to 60 ℃;
(2) Preparing 18ml of 12mol/L concentrated hydrochloric acid into 6.5mol/L dilute hydrochloric acid solution, adding the 6.5mol/L dilute hydrochloric acid solution into the starch milk obtained in the step (1) for acidolysis for 2 hours, then adding 10mol/L sodium hydroxide solution, adjusting the pH of the starch milk to 4, and maintaining the pH at 80 ℃ for 30 minutes for gelatinization;
(3) Adding 7.5g of initiator (ceric ammonium nitrate) into 15ml of dilute nitric acid to prepare an initiator solution, adding 2.5ml of the initiator solution into a grafting monomer (allyl glycidyl ether), uniformly mixing, adding into a reaction kettle, heating to 55 ℃, prepolymerizing for 30min, and then cooling the system to normal temperature;
(4) Cooling the gelatinized starch milk obtained in the step (2) to 60 ℃, adding 12ml of the initiator solution prepared in the step (3), and then adding sodium hydroxide solution to adjust the pH to 4;
(5) Dripping the solution obtained after the pre-polymerization treatment in the step (3) into the starch emulsion solution obtained after the initiator is added in the step (4) at a constant speed for graft polymerization, wherein the dripping time is controlled to be 60min, and the reaction temperature is kept to be 60 ℃; after the dripping is completed, adding the rest initiator solution, adding sodium hydroxide solution, adjusting the pH to 4, and preserving the heat for 20min; obtaining a polymerization modified starch-based emulsion;
(6) Dissolving an emulsifier (cetyl trimethyl ammonium bromide) in water to prepare a 5% emulsifier solution, adding the emulsifier solution into the starch-based emulsion obtained in the step (5), heating to 82.5 ℃, and preserving heat for 90 minutes again to obtain a polymerization modified adhesive;
(7) Cooling the polymerization modified adhesive obtained in the step (6) to 45 ℃, and adjusting the pH of the adhesive to 6 to obtain a starch-based adhesive;
(8) Before the preparation of the shaving board, 8.5g of post-crosslinking agent (ethylenediamine) is added into the adhesive prepared in the step (7), and the mixture is stirred and mixed uniformly, and then the shaving board is subjected to hot pressing.
The adhesive product obtained by the embodiment is milky white in appearance, low in viscosity and strong in fluidity, and meets the requirements of a shaving board. The curing time of the adhesive is measured, and the result shows that the curing time of the adhesive for the starch-based shaving board is 260s; and hot-pressing for 5min at 105 ℃ and 10MPa, wherein the water absorption thickness expansion rate of the obtained shaving board is 19%, and the requirements of the national standard P2 type shaving board are not met.
The effect of reaction time on the curing time of the adhesive is demonstrated by examples 1, 6; the above results indicate that reducing the polymerization time for monomer grafting results in a decrease in the grafting rate of the monomer onto the starch, thereby affecting the effect of the crosslinking reaction and the reaction rate, resulting in a longer curing time.
Example 7
Formula (mass/g): a starch-based shaving board adhesive capable of being quickly cured at medium and low temperatures comprises the following components in percentage by weight:
the preparation method of the starch-based shaving board adhesive comprises the following steps:
(1) Preparing starch and water into starch milk with the starch mass fraction of 50%, uniformly stirring and mixing, and heating to 60 ℃;
(2) Preparing 18ml of 12mol/L concentrated hydrochloric acid into 6.5mol/L dilute hydrochloric acid solution, adding the 6.5mol/L dilute hydrochloric acid solution into the starch milk obtained in the step (1) for acidolysis for 2 hours, then adding 10mol/L sodium hydroxide solution, adjusting the pH of the starch milk to 4, and maintaining the pH at 80 ℃ for 30 minutes for gelatinization;
(3) Adding 7.5g of initiator (ceric ammonium nitrate) into 15ml of dilute nitric acid to prepare an initiator solution, adding 2.5ml of the initiator solution into a grafting monomer (allyl glycidyl ether), uniformly mixing, adding into a reaction kettle, heating to 55 ℃, prepolymerizing for 30min, and then cooling the system to normal temperature;
(4) Cooling the gelatinized starch milk obtained in the step (2) to 60 ℃, adding 12ml of the initiator solution prepared in the step (3), and then adding sodium hydroxide solution to adjust the pH to 4;
(5) Dripping the solution obtained after the pre-polymerization treatment in the step (3) into the starch emulsion solution obtained after the initiator is added in the step (4) at a constant speed for graft polymerization, wherein the dripping time is controlled to be 100min, and the reaction temperature is kept to be 60 ℃; after the dripping is completed, adding the rest initiator solution, adding sodium hydroxide solution, adjusting the pH to 4, and preserving the heat for 30min; obtaining a polymerization modified starch-based emulsion;
(6) Dissolving an emulsifier (cetyl trimethyl ammonium bromide) in water to prepare a 5% emulsifier solution, adding the emulsifier solution into the starch-based emulsion obtained in the step (5), heating to 82.5 ℃, and preserving heat for 90 minutes again to obtain a polymerization modified adhesive;
(7) And (3) cooling the polymerization modified adhesive obtained in the step (6) to 45 ℃, and adjusting the pH of the adhesive to 6 to obtain the starch-based adhesive.
(8) Before the preparation of the shaving board, the post-crosslinking agent is not added, and the hot pressing of the shaving board is directly carried out.
The adhesive product obtained by the embodiment is milky white in appearance, low in viscosity and strong in fluidity, and meets the requirements of a shaving board. The measurement of the curing time of the adhesive shows that the starch-based chipboard adhesive cannot be cured and does not meet the use requirement of the chipboard.
Example 8
A starch-based shaving board adhesive capable of being quickly cured at medium and low temperatures comprises the following components in percentage by weight:
the preparation method of the starch-based shaving board adhesive comprises the following steps:
(1) Preparing starch and water into starch milk with the starch mass fraction of 50%, uniformly stirring and mixing, and heating to 60 ℃;
(2) Preparing 18ml of 12mol/L concentrated hydrochloric acid into 6.5mol/L dilute hydrochloric acid solution, adding the 6.5mol/L dilute hydrochloric acid solution into the starch milk obtained in the step (1) for acidolysis for 2 hours, then adding 10mol/L sodium hydroxide solution, adjusting the pH of the starch milk to 4, and maintaining the pH at 80 ℃ for 30 minutes for gelatinization;
(3) Adding 7.5g of initiator (ceric ammonium nitrate) into 15ml of dilute nitric acid to prepare an initiator solution, adding 2.5ml of the initiator solution into a grafting monomer (allyl glycidyl ether), uniformly mixing, adding into a reaction kettle, heating to 55 ℃, prepolymerizing for 30min, and then cooling the system to normal temperature;
(4) Cooling the gelatinized starch milk obtained in the step (2) to 60 ℃, adding 12ml of the initiator solution prepared in the step (3), and then adding sodium hydroxide solution to adjust the pH to 4;
(5) Dripping the solution obtained after the pre-polymerization treatment in the step (3) into the starch emulsion solution obtained after the initiator is added in the step (4) at a constant speed for graft polymerization, wherein the dripping time is controlled to be 100min, and the reaction temperature is kept to be 60 ℃; after the dripping is completed, adding the rest initiator solution, adding sodium hydroxide solution, adjusting the pH to 4, and preserving the heat for 30min; obtaining a polymerization modified starch-based emulsion;
(6) Dissolving an emulsifier (cetyl trimethyl ammonium bromide) in water to prepare a 5% emulsifier solution, adding the emulsifier solution into the starch-based emulsion obtained in the step (5), heating to 82.5 ℃, and preserving heat for 90 minutes again to obtain a polymerization modified adhesive;
(7) Cooling the polymerization modified adhesive obtained in the step (6) to 45 ℃, and adjusting the pH of the adhesive to 6 to obtain a starch-based adhesive;
(8) Before the preparation of the shaving board, 8.5g of post-crosslinking agent (m-phenylenediamine) is added into the adhesive prepared in the step (7), and the mixture is stirred and mixed uniformly, and then the shaving board is subjected to hot pressing.
The adhesive product obtained by the embodiment is milky white in appearance, low in viscosity and strong in fluidity, and meets the requirements of a shaving board. The curing time of the adhesive is measured, and the result shows that the curing time of the adhesive for the starch-based shaving board is 320s; and hot-pressing for 5min at 105 ℃ and 10MPa, wherein the water absorption thickness expansion rate of the obtained shaving board is 35%, and the requirements of the national standard P2 type shaving board are not met.
The effect of the postcrosslinker on the curing time of the adhesive is demonstrated by examples 1, 7, 8, the results indicated above being that: the ethylene diamine which is a post-crosslinking agent is added, so that the adhesive can be quickly cured at a lower temperature, but the adhesive can not be cured without the post-crosslinking agent, and the curing performance of the adhesive can be reduced by adding the m-phenylenediamine which is other post-crosslinking agents, so that the curing speed is reduced, and the performance of the adhesive is influenced.
Example 9
A starch-based shaving board adhesive capable of being quickly cured at medium and low temperatures comprises the following components in percentage by weight:
the preparation method of the starch-based shaving board adhesive comprises the following steps:
(1) Preparing starch and water into starch milk with the starch mass fraction of 50%, uniformly stirring and mixing, and heating to 60 ℃;
(2) Preparing 18ml of 12mol/L concentrated hydrochloric acid into 6.5mol/L dilute hydrochloric acid solution, adding the 6.5mol/L dilute hydrochloric acid solution into the starch milk obtained in the step (1) for acidolysis for 2 hours, then adding 10mol/L sodium hydroxide solution, adjusting the pH of the starch milk to 4, and maintaining the pH at 80 ℃ for 30 minutes for gelatinization;
(3) Adding 7.5g of initiator (ceric ammonium nitrate) into 15ml of dilute nitric acid to prepare an initiator solution, adding 2.5ml of the initiator solution into a grafting monomer (allyl glycidyl ether), uniformly mixing, adding into a reaction kettle, heating to 55 ℃, prepolymerizing for 30min, and then cooling the system to normal temperature;
(4) Cooling the gelatinized starch milk obtained in the step (2) to 60 ℃, adding 12ml of the initiator solution prepared in the step (3), and then adding sodium hydroxide solution to adjust the pH to 4;
(5) Dripping the solution obtained after the pre-polymerization treatment in the step (3) into the starch emulsion solution obtained after the initiator is added in the step (4) at a constant speed for graft polymerization, wherein the dripping time is controlled to be 100min, and the reaction temperature is kept to be 60 ℃; after the dripping is completed, adding the rest initiator solution, adding sodium hydroxide solution, adjusting the pH to 4, and preserving the heat for 30min; obtaining a polymerization modified starch-based emulsion;
(6) Dissolving an emulsifier (cetyl trimethyl ammonium bromide) in water to prepare a 5% emulsifier solution, adding the emulsifier solution into the starch-based emulsion obtained in the step (5), heating to 82.5 ℃, and preserving heat for 90 minutes again to obtain a polymerization modified adhesive;
(7) Cooling the polymerization modified adhesive obtained in the step (6) to 45 ℃, and adjusting the pH of the adhesive to 4 to obtain a starch-based adhesive;
(8) Before the preparation of the shaving board, 8.5g of post-crosslinking agent (ethylenediamine) is added into the adhesive, and the mixture is stirred and mixed uniformly, and then the shaving board is subjected to hot pressing.
The adhesive product obtained by the embodiment is milky white in appearance, low in viscosity and strong in fluidity, and meets the requirements of a shaving board. The curing time of the adhesive is measured, and the result shows that the curing time of the adhesive for the starch-based shaving board is 150s; and hot-pressing for 5min at 105 ℃ and 10MPa, wherein the water absorption thickness expansion rate of the obtained shaving board is 11%, and the requirements of the national standard P2 type shaving board are not met.
The effect of crosslinking pH on the curing time of the adhesive is demonstrated by examples 1, 9. The above results show that, under the condition of ph=6, the ethylenediamine added as the post-crosslinking agent can be rapidly cured at a lower temperature, while the ethylenediamine added as the post-crosslinking agent under the condition of ph=4 has a slower curing speed, and the water resistance after curing is poor, so that the performance of the adhesive is affected.
Claims (10)
1. The starch-based chipboard adhesive is characterized by comprising a component A and a component B;
the component A comprises the following components in parts by mass: 150 parts of starch, 200-300 parts of water, 20-25 parts of concentrated hydrochloric acid, 12-18 parts of dilute nitric acid, 25-40 parts of sodium hydroxide solution, 6-9 parts of initiator ceric ammonium nitrate, 27-35 parts of grafting monomer and 2-5 parts of emulsifier; the component B comprises the following components in parts by mass: 8-11 parts of post-crosslinking agent ethylenediamine.
2. The method of claim 1, wherein the starch is any one or a combination of several of corn starch, waxy corn starch, tapioca starch, wheat starch, potato starch, rice starch, mung bean starch.
3. The method according to claim 1, wherein the concentrated hydrochloric acid is 12-15 mol/L concentrated hydrochloric acid.
4. The method of claim 1, wherein the emulsifier is cetyltrimethylammonium bromide.
5. The method of claim 1, wherein the grafting monomer is allyl glycidyl ether.
6. Use of the starch-based chipboard adhesive according to any one of claims 1 to 5 for the thermocompression bonding of chipboards, plywood, fiberboard, wood blocks.
7. The method for preparing the starch-based shaving board adhesive according to any one of claims 1 to 5, which is characterized by comprising the following steps:
(1) In a reaction kettle, starch and water are prepared into starch milk with the concentration of 30-50% based on the dry weight of the starch, after being uniformly stirred, the temperature is raised to 50-60 ℃, and hydrochloric acid diluted to 4-8 mol/L is added for acidolysis; adding sodium hydroxide solution after acidolysis, adjusting the pH to 3-5, and gelatinizing to obtain gelatinized starch emulsion;
(2) Adding an initiator into dilute nitric acid to prepare an initiator solution, adding the initiator solution with the volume ratio of 10-20% into a grafting monomer, uniformly mixing, adding the grafting monomer into a reaction kettle for prepolymerization, and then cooling the system to normal temperature to obtain a prepolymerized solution;
(3) Cooling the gelatinized starch emulsion solution obtained in the step (1) to 50-70 ℃, adding an initiator solution with the volume ratio of 50-80%, and then adding a sodium hydroxide solution to adjust the pH to 3-5;
(4) Dropwise adding the prepolymerization solution obtained in the step (2) into the starch emulsion solution after the initiator is added at a constant speed for graft polymerization, adding the rest initiator solution after the dropwise adding is finished, adding a sodium hydroxide solution, adjusting the pH to 3-5, and preserving the temperature for 30-45 min to obtain a polymerization modified starch-based emulsion;
(5) Dissolving an emulsifier in water to prepare 4% -7% of emulsifier solution, adding the emulsifier solution into the starch-based emulsion obtained in the step (4), heating to 75-85 ℃, and preserving heat for 90-120 min again to obtain a polymerization modified adhesive;
(6) Cooling the polymerization modified adhesive obtained in the step (5) to 30-50 ℃, and adjusting the pH of the adhesive to 6-8 to obtain the starch-based adhesive for the particle board;
(7) And (3) before preparing the shaving board, uniformly stirring and mixing the starch-based adhesive prepared in the step (6) and the post-crosslinking agent, and then carrying out hot pressing on the shaving board.
8. The method according to claim 7, wherein the dropping time in the step (4) is controlled to be 90 to 120 minutes.
9. The method according to claim 7, wherein the hot pressing in step (7) is carried out at a temperature of 90 to 120℃and a pressure of 6 to 10MPa.
10. A method for reducing the hot-pressing temperature of a particle board, which is characterized in that the starch-based particle board adhesive as claimed in any one of claims 1 to 5 is used for hot-pressing adhesion of particle boards.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310623427.6A CN116536008A (en) | 2023-05-30 | 2023-05-30 | Starch-based particle board adhesive capable of being quickly cured at medium and low temperatures and preparation method thereof |
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|---|---|---|---|
| CN202310623427.6A CN116536008A (en) | 2023-05-30 | 2023-05-30 | Starch-based particle board adhesive capable of being quickly cured at medium and low temperatures and preparation method thereof |
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| CN116536008A true CN116536008A (en) | 2023-08-04 |
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| CN202310623427.6A Pending CN116536008A (en) | 2023-05-30 | 2023-05-30 | Starch-based particle board adhesive capable of being quickly cured at medium and low temperatures and preparation method thereof |
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| Country | Link |
|---|---|
| CN (1) | CN116536008A (en) |
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2023
- 2023-05-30 CN CN202310623427.6A patent/CN116536008A/en active Pending
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