A method for preparing an environmentally friendly adhesive

Abstract

The invention discloses a method for preparing an environmentally friendly adhesive, and belongs to the technical field of glue preparation. The invention comprises the following steps: adding water to cassava flour and mixing into a paste, then adding the paste into glue and mixing, then adding a formaldehyde remover and melamine, heating the mixture to 60-90°C, adding caustic soda flakes, and cooling to 40-50°C after mixing to obtain an environmentally friendly adhesive. The invention can control the formaldehyde emission of the adhesive to above E0 level by reasonably using cassava flour and adjusting various auxiliary materials, and can also improve the adhesive performance of the glue, while reducing the amount of glue used and reducing the cost by about 20%.

Description

Technical Field

[0001] The invention relates to the field of glue preparation, and in particular to a method for preparing an environmentally friendly adhesive. Background Art

[0002] At present, adhesives are widely used in the fields of industry, agriculture, manufacturing, construction and decoration, especially in the construction and decoration industry. The main materials of interior decoration include plywood, particleboard, density board and other artificial boards. The above boards need to use adhesives in the production process. The adhesives used mainly include urea-formaldehyde resin glue, phenolic resin glue and melamine formaldehyde resin glue. Free formaldehyde is inevitably present in the above adhesives. With the continuous release of formaldehyde, it will cause indoor air pollution. Indoor air pollution has become a cause of many diseases, and formaldehyde is a major aspect of indoor air pollution. Formaldehyde is volatile and highly toxic, and has a great impact on the human respiratory system, immune system, nervous system, endocrine system, etc. Long-term, low-concentration exposure to formaldehyde can cause headaches, dizziness, fatigue, sensory disorders, reduced immunity, and drowsiness, memory loss or neurasthenia, and depression; chronic poisoning is also a huge hazard to the respiratory system. Long-term exposure to formaldehyde can cause respiratory dysfunction and liver toxicity, manifested as liver cell damage, abnormal liver radiation energy, etc. Studies have shown that many human diseases are related to the presence of formaldehyde indoors.

[0003] With the improvement of people's living standards, the formaldehyde emission of artificial decorative boards has attracted more and more attention from consumers. How to reduce the formaldehyde emission in artificial decorative boards while maintaining the good performance of the boards has become the research focus of manufacturers. At present, the following measures are usually taken to reduce the formaldehyde emission in artificial boards: 1. Use organic reagents to modify the existing resin adhesives to make them meet environmental protection standards; 2. Add formaldehyde scavengers to the adhesives; 3. Chemically treat the board products. Although the above measures can reduce the formaldehyde emission in the adhesive to a certain extent, they basically do not reach the E0 level. At the same time, due to the use of some special reagents, there may be a risk of secondary pollution and adverse effects on product performance.

[0004] At present, relevant technologies of formaldehyde-free environmentally friendly plant glue have been disclosed. For example, Chinese patent application number CN201220567851.0 discloses a plant oil-finished wooden floor with a single material substrate using formaldehyde-free gluing. The substrate uses biological soybean protein glue as the gluing raw material, which can achieve formaldehyde-free production and is green and environmentally friendly. For example, Chinese patent application number CN201510739974.6 discloses an environmentally friendly plant glue and its preparation method. The raw material is mainly the fermentation liquid of the fruit juice of the natural plant chayote, combined with starch gelatin to enhance the bonding strength and seaweed powder as a water-retaining agent, which can achieve non-toxic and environmentally friendly. , low formaldehyde content; for example, Chinese patent application number CN201911184006.8 discloses an environmentally friendly glue and its production process, which is mainly prepared by a gelatinized slurry of a mixture of various plant colloids such as agar, guar gum, gum arabic, carrageenan and xanthan gum, and a mixture of various plant starches such as glutinous rice flour, soybean flour, corn flour and sweet potato flour, while adding plant green raw materials such as seaweed powder and bamboo charcoal powder. The prepared glue is non-toxic and harmless, and will not produce harmful factors such as formaldehyde, meeting the needs of green environmental protection; although the above-mentioned glue has the advantages of environmental protection and non-toxicity, it generally has the defect of weak adhesion. Summary of the invention

[0005] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and to provide a method for preparing an environmentally friendly adhesive. The present invention can control the formaldehyde emission of the adhesive to above E0 level by reasonably using cassava flour and adjusting various auxiliary materials and additives, and can also improve the bonding performance of the glue and reduce the amount of glue used.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] A method for preparing an environmentally friendly adhesive comprises the following steps: adding water to cassava flour and mixing them into a paste, adding the paste into glue and mixing, then adding a formaldehyde remover and melamine, mixing and heating the mixture to 60-90° C., then adding caustic soda flakes and mixing, cooling, and obtaining the environmentally friendly adhesive.

[0008] Furthermore, the weight ratio of the glue, water and tapioca flour is 10:2-4:0.6-0.8;

[0009] The amount of the formaldehyde remover added is 1-2% of the weight of the glue;

[0010] The amount of melamine added is 0-2% of the weight of the glue;

[0011] The amount of caustic soda added is 0.25-0.5% of the weight of the cassava flour;

[0012] The glue reaches the E1 glue standard and is urea-formaldehyde resin glue.

[0013] Furthermore, the preparation method of the formaldehyde remover comprises the following steps: adding potassium persulfate to water, then adding aluminum dihydrogen phosphate as an activator, stirring and mixing to obtain the formaldehyde remover; the mass ratio of water, potassium persulfate and aluminum dihydrogen phosphate is 1:0.7-1:0.08-0.15.

[0014] Furthermore, in the process of preparing the environmentally friendly adhesive, an auxiliary agent is added, and the auxiliary agent is a raw sugar palm powder. The raw sugar palm powder can be purchased commercially, or can be prepared according to a traditional method, comprising the following steps: peeling the outer bark of a sugar palm tree to obtain the pith, slicing the pith and then crushing it, adding the crushed sugar palm material into water for stirring, and then transferring it to a separator for separation to obtain a sugar palm slurry, and drying the sugar palm slurry to obtain the raw sugar palm powder.

[0015] Furthermore, the sugar palm raw powder is pretreated before being used as an auxiliary agent, specifically, the sugar palm raw powder is prepared into a sugar palm suspension with 45-50°C clean water; the wood vinegar is diluted with clean water to form a wood vinegar dilution; the sugar palm suspension is added to the wood vinegar dilution, and then a high shear mixer is used for mixing, the shear mixing rate is 5000-10000 rpm, the temperature is controlled to be 35-40°C, the mixing treatment time is 1-2min, and then the mixture is allowed to stand and age for 5-8h at a temperature of 15-20°C, after separation, a precipitate is taken and washed with clean water, and the washed precipitate is placed in an oven at 45-50°C for drying to obtain the pretreated sugar palm raw powder, i.e., the auxiliary agent.

[0016] Furthermore, the wood vinegar is refined wood vinegar, the pH of the wood vinegar is 2-3; the volume ratio of the wood vinegar to clean water in the wood vinegar dilution is 1:100-200; the mass fraction of the sugar palm suspension is 15-20%; the volume ratio of the sugar palm suspension to the wood vinegar dilution is 1:15-30.

[0017] Furthermore, the preparation method of the environmentally friendly adhesive comprises the following steps: adding glue to a reactor for standby use; adding water to cassava flour and mixing into a paste, then adding the paste to the reactor containing glue to obtain a mixture, adding formaldehyde remover and melamine to the mixture, mixing and heating the mixture to 60-90° C., then adding caustic soda flakes to mix, and obtaining an adhesive semi-finished product; adjusting the additive to an additive slurry with 40-50° C. clean water to obtain an additive slurry with a mass concentration of 70-80%, adding the additive slurry to the adhesive semi-finished product, mixing evenly, and cooling to obtain an environmentally friendly adhesive; the additive is added in an amount of 0.5-1% by weight of the glue.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. The present invention adds an appropriate amount of cassava flour to the glue. The cassava flour used is cheap, easily available and environmentally friendly. On the basis of maintaining the good performance of the glue, the production cost can be significantly reduced by adding cheap cassava flour, and the cost is reduced by about 20%.

[0020] 2. The present invention first uses a formaldehyde remover to treat the glue. The formaldehyde remover is composed of potassium persulfate and aluminum dihydrogen phosphate. Aluminum dihydrogen phosphate can activate potassium persulfate to produce peroxide ions, thereby increasing the oxidizing ability of aluminum dihydrogen phosphate and improving the effect of removing formaldehyde, thereby removing part of the formaldehyde in the glue; then an auxiliary agent is used for treatment. The auxiliary agent is mainly made of galangal powder. The galangal powder is a specialty of Longzhou, Guangxi. The present invention has found that it has unique adhesion, curing and lubricity. The galangal powder is added to the glue after pretreatment, which can cure the formaldehyde in the glue and greatly reduce the release of formaldehyde. At the same time, it improves the lubricity of the finished adhesive. The present invention first treats the glue with a homemade formaldehyde remover, and then uses regional specialty products as auxiliary regulators for treatment. The resulting glue not only has an extremely low formaldehyde release, but also reaches E. NF The grade meets environmental protection requirements, and the adhesion of the glue is improved to a certain extent, making it very competitive in the market.

[0021] 3. The present invention can improve various properties of glue by rationally using cassava flour and adjusting various auxiliary materials, and the usage of the environmentally friendly adhesive is reduced, and the amount of glue is reduced from 160g / m 2 Reduced to 140g / m 2 The following can effectively reduce costs. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments.

[0023] Example 1

[0024] A method for preparing an environmentally friendly adhesive comprises the following steps: adding 10 tons of glue into a reaction kettle for standby use; adding 3 tons of water into 0.7 tons of cassava flour and mixing into a paste; adding the paste into the reaction kettle containing the glue and mixing; then adding 200 kg of formaldehyde remover and 200 kg of melamine, mixing and heating the mixture to 83° C.; then adding 5 kg of caustic soda flakes and mixing; cooling to 45° C.; after the preparation is completed, extracting and obtaining the environmentally friendly adhesive.

[0025] The glue meets the E1 glue standard (formaldehyde emission 0.112mg / m 3 ), the glue is urea-formaldehyde resin glue.

[0026] The formaldehyde scavenger is commercially available QCJ-001 Oin formaldehyde scavenger.

[0027] Example 2

[0028] A method for preparing an environmentally friendly adhesive comprises the following steps:

[0029] (1) Raw material preparation: Add 10 tons of glue into a reaction kettle and set aside; the glue is the same as that in Example 1.

[0030] (2) Preparation of formaldehyde removal agent: potassium persulfate is added to water, and then aluminum dihydrogen phosphate is added as an activator, and the formaldehyde removal agent is obtained after stirring and mixing, and the mass ratio of water, potassium persulfate and aluminum dihydrogen phosphate is 1:0.8:0.10. The potassium persulfate is produced by Suzhou Lianxiong Fine Chemical Technology Co., Ltd., with a molecular formula of 2KHSO5.KHSO4.K2SO4, and a product name of potassium persulfate, commonly known as potassium persulfate composite salt or potassium monopersulfate, referred to as PMPS or KMPS.

[0031] (3) Preparation of auxiliary agent: The raw sugar palm powder is pretreated, specifically, the raw sugar palm powder is prepared into a sugar palm suspension with a mass fraction of 15% by weight using 48°C clean water; the wood vinegar is diluted with clean water to form a wood vinegar dilution, and the volume ratio of the wood vinegar to water is 1:200; the sugar palm suspension is added to the wood vinegar dilution, and then mixed using a high shear mixer, the shear mixing rate is 8000 rpm, the temperature is controlled to be 38°C, and the mixing time is 1 min, and then the mixture is allowed to stand and age for 5 h at a temperature of 15°C. After separation, the precipitate is taken and washed with clean water, and the washed precipitate is placed in an oven at 50°C and dried for 12 h to obtain the pretreated raw sugar palm powder, i.e., the auxiliary agent.

[0032] The wood vinegar is commercially available Hongsen refined wood vinegar, and the pH value of the wood vinegar is 2-3; the volume ratio of the sugar palm suspension to the wood vinegar dilution is 1:20.

[0033] The sugar palm raw powder is prepared according to a traditional method, comprising the following steps: peeling off the outer bark of a sugar palm tree to obtain the pith, slicing the pith and then crushing it, adding the crushed sugar palm material into water for stirring, then transferring it into a separator for separation to obtain sugar palm slurry, and drying the sugar palm slurry to obtain sugar palm raw powder.

[0034] (4) Preparation of a semi-finished adhesive: 3 tons of water were added to 0.7 tons of cassava flour and mixed into a paste, and the paste was then added to the reaction kettle containing glue in step (1) to obtain a mixture, 150 kg of the formaldehyde removal agent obtained in step (2) was added to the mixture, and then mechanical stirring was performed to mix, the stirring temperature was controlled to be 70° C., the stirring speed was controlled to be 100 r / min, and the stirring time was controlled to be 0.5 h, and then the mixture was heated to 83° C., 5 kg of caustic soda flakes were added to the mixture, and the mixture was mixed to obtain a semi-finished adhesive;

[0035] (5) Preparation of environmentally friendly adhesive: 60 kg of the auxiliary agent obtained in step (3) was adjusted with 45° C. clean water to prepare an auxiliary agent slurry with a mass concentration of 75%, and the auxiliary agent slurry was added to the adhesive semi-finished product, mixed evenly, and then cooled to 45° C. and extracted to obtain the environmentally friendly adhesive.

[0036] Example 3

[0037] A method for preparing an environmentally friendly adhesive comprises the following steps:

[0038] (1) Raw material preparation: Add 10 tons of glue into a reaction kettle and set aside; the glue is the same as that in Example 1.

[0039] (2) Preparation of formaldehyde removal agent: commercially available QCJ-001 Oin formaldehyde scavenger.

[0040] (3) Preparation of auxiliary agent: The raw sugar palm powder is pretreated, specifically, the raw sugar palm powder is prepared into a sugar palm suspension with a mass fraction of 15% by weight using 48°C clean water; the wood vinegar is diluted with clean water to form a wood vinegar dilution, and the volume ratio of the wood vinegar to water is 1:200; the sugar palm suspension is added to the wood vinegar dilution, and then mixed using a high shear mixer, the shear mixing rate is 8000 rpm, the temperature is controlled to be 38°C, and the mixing time is 1 min, and then the mixture is allowed to stand and age for 5 h at a temperature of 15°C. After separation, the precipitate is taken and washed with clean water, and the washed precipitate is placed in an oven at 50°C and dried for 12 h to obtain the pretreated raw sugar palm powder, i.e., the auxiliary agent.

[0041] The wood vinegar is commercially available Hongsen refined wood vinegar, and the pH value of the wood vinegar is 2-3; the volume ratio of the sugar palm suspension to the wood vinegar dilution is 1:20.

[0042] The sugar palm raw powder is prepared according to a traditional method, comprising the following steps: peeling off the outer bark of a sugar palm tree to obtain the pith, slicing the pith and then crushing it, adding the crushed sugar palm material into water for stirring, then transferring it into a separator for separation to obtain sugar palm slurry, and drying the sugar palm slurry to obtain sugar palm raw powder.

[0043] (4) Preparation of a semi-finished adhesive: 3 tons of water were added to 0.7 tons of cassava flour and mixed into a paste, and the paste was then added to the reaction kettle containing glue in step (1) to obtain a mixture, 150 kg of the formaldehyde removal agent obtained in step (2) was added to the mixture, and then mechanical stirring was performed to mix, the stirring temperature was controlled to be 70° C., the stirring speed was controlled to be 100 r / min, and the stirring time was controlled to be 0.5 h, and then the mixture was heated to 83° C., 5 kg of caustic soda flakes were added to the mixture, and the mixture was mixed to obtain a semi-finished adhesive;

[0044] (5) Preparation of environmentally friendly adhesive: 60 kg of the auxiliary agent obtained in step (3) was adjusted with 45° C. clean water to prepare an auxiliary agent slurry with a mass concentration of 75%, and the auxiliary agent slurry was added to the adhesive semi-finished product, mixed evenly, and then cooled to 45° C. and extracted to obtain the environmentally friendly adhesive.

[0045] Example 4

[0046] A method for preparing an environmentally friendly adhesive comprises the following steps:

[0047] (1) Raw material preparation: Add 10 tons of glue into a reaction kettle and set aside; the glue is the same as that in Example 1.

[0048] (2) Preparation of formaldehyde removal agent: potassium persulfate is added to water, and then aluminum dihydrogen phosphate is added as an activator, and the formaldehyde removal agent is obtained after stirring and mixing, and is used for standby; the mass ratio of the water, potassium persulfate, and aluminum dihydrogen phosphate is 1:0.8:0.10. The potassium persulfate is the same as that in Example 2.

[0049] (3) Preparation of environmentally friendly adhesive: 3 tons of water were added to 0.7 tons of cassava flour and mixed into a paste, and the paste was then added to the reaction kettle containing glue in step (1) and mixed to obtain a mixture, 150 kg of formaldehyde removal agent obtained in step (2) was added to the mixture, and then mechanically stirred and mixed, the stirring temperature was controlled to 70° C., the stirring speed was controlled to 100 r / min, the stirring time was controlled to 0.5 h, and then the mixture was heated to 83° C., 5 kg of caustic soda was added to the mixture, and after mixing, the mixture was cooled to 45° C. and extracted to obtain an environmentally friendly adhesive.

[0050] Example 5

[0051] A method for preparing an environmentally friendly adhesive comprises the following steps:

[0052] (1) Raw material preparation: Add 10 tons of glue into a reaction kettle and set aside; the glue is the same as that in Example 1.

[0053] (2) Preparation of formaldehyde removal agent: potassium persulfate is added to water, and then aluminum dihydrogen phosphate is added as an activator, and the formaldehyde removal agent is obtained after stirring and mixing, and is used for standby; the mass ratio of the water, potassium persulfate, and aluminum dihydrogen phosphate is 1:0.8:0.10. The potassium persulfate is the same as that in Example 2.

[0054] (3) Preparation of auxiliary agents: Sugar palm powder is selected as an auxiliary agent. The sugar palm powder is prepared according to a traditional method, comprising the following steps: peeling the bark of a sugar palm tree to obtain the pith, slicing the pith and then crushing it, adding the crushed sugar palm material into water for stirring, and then transferring it to a separator for separation to obtain sugar palm slurry, and drying the sugar palm slurry to obtain sugar palm powder.

[0055] (4) Preparation of a semi-finished adhesive: 3 tons of water were added to 0.7 tons of cassava flour and mixed into a paste, and the paste was then added to the reaction kettle containing glue in step (1) to obtain a mixture, 150 kg of the formaldehyde removal agent obtained in step (2) was added to the mixture, and then mechanical stirring was performed to mix, the stirring temperature was controlled to be 70° C., the stirring speed was controlled to be 100 r / min, and the stirring time was controlled to be 0.5 h, and then the mixture was heated to 83° C., 5 kg of caustic soda flakes were added to the mixture, and the mixture was mixed to obtain a semi-finished adhesive;

[0056] (5) Preparation of environmentally friendly adhesive: 60 kg of the auxiliary agent obtained in step (3) was adjusted with 45° C. clean water to prepare an auxiliary agent slurry with a mass concentration of 75%, and the auxiliary agent slurry was added to the adhesive semi-finished product, mixed evenly, and then cooled to 45° C. and extracted to obtain the environmentally friendly adhesive.

[0057] Example 6

[0058] A method for preparing an environmentally friendly adhesive comprises the following steps:

[0059] (1) Raw material preparation: Add 10 tons of glue into a reaction kettle and set aside; the glue is the same as that in Example 1.

[0060] (2) Preparation of formaldehyde removal agent: potassium persulfate is added to water, and then aluminum dihydrogen phosphate is added as an activator, and the formaldehyde removal agent is obtained after stirring and mixing, and is used for standby; the mass ratio of the water, potassium persulfate, and aluminum dihydrogen phosphate is 1:0.8:0.10. The potassium persulfate is the same as that in Example 2.

[0061] (3) Preparation of auxiliary agent: The raw sugar palm powder is pretreated, specifically, the raw sugar palm powder is prepared into a sugar palm suspension with a mass fraction of 15% by weight using 48°C clean water; the wood vinegar is diluted with clean water to form a wood vinegar dilution, and the volume ratio of the wood vinegar to water is 1:200; the sugar palm suspension is added to the wood vinegar dilution, and then mixed by ordinary mechanical stirring, the stirring speed is 800r / min, and the stirring time is 1h, and then the mixture is allowed to stand and age for 5h at a temperature of 15°C. After separation, the precipitate is taken and washed with clean water, and the washed precipitate is placed in an oven at 50°C and dried for 12h to obtain the pretreated raw sugar palm powder, i.e., the auxiliary agent.

[0062] The wood vinegar is commercially available Hongsen refined wood vinegar, and the pH value of the wood vinegar is 2-3; the volume ratio of the sugar palm suspension to the wood vinegar dilution is 1:20.

[0063] The sugar palm raw powder is prepared according to a traditional method, comprising the following steps: peeling off the outer bark of a sugar palm tree to obtain the pith, slicing the pith and then crushing it, adding the crushed sugar palm material into water for stirring, then transferring it into a separator for separation to obtain sugar palm slurry, and drying the sugar palm slurry to obtain sugar palm raw powder.

[0064] (4) Preparation of a semi-finished adhesive: 3 tons of water were added to 0.7 tons of cassava flour and mixed into a paste, and the paste was then added to the reaction kettle containing glue in step (1) to obtain a mixture, 150 kg of the formaldehyde removal agent obtained in step (2) was added to the mixture, and then mechanical stirring was performed to mix, the stirring temperature was controlled to be 70° C., the stirring speed was controlled to be 100 r / min, and the stirring time was controlled to be 0.5 h, and then the mixture was heated to 83° C., 5 kg of caustic soda flakes were added to the mixture, and the mixture was mixed to obtain a semi-finished adhesive;

[0065] (5) Preparation of environmentally friendly adhesive: 60 kg of the auxiliary agent obtained in step (3) was adjusted with 45° C. clean water to prepare an auxiliary agent slurry with a mass concentration of 75%, and the auxiliary agent slurry was added to the adhesive semi-finished product, mixed evenly, and then cooled to 45° C. and extracted to obtain the environmentally friendly adhesive.

[0066] Example 7

[0067] A method for preparing an environmentally friendly adhesive comprises the following steps:

[0068] (1) Raw material preparation: Add 10 tons of glue into a reaction kettle and set aside; the glue is the same as that in Example 1.

[0069] (2) Preparation of formaldehyde removal agent: potassium persulfate is added to water, and then aluminum dihydrogen phosphate is added as an activator, and the mixture is stirred to obtain a formaldehyde removal agent for use; the mass ratio of water, potassium persulfate, and aluminum dihydrogen phosphate is 1:0.7:0.08.

[0070] (3) Preparation of adjuvant: The commercially available raw sugar palm powder is pretreated, specifically, the raw sugar palm powder is prepared into a sugar palm suspension with a mass fraction of 18% by weight using 45°C clean water; the wood vinegar is diluted with clean water to form a wood vinegar dilution, and the volume ratio of the wood vinegar to water is 1:150; the sugar palm suspension is added to the wood vinegar dilution, and then mixed using a high shear mixer, the shear mixing rate is 10,000 rpm, the temperature is controlled to be 35°C, and the mixing time is 2 min, and then the mixture is allowed to stand and age for 6 h at a temperature of 18°C. After separation, the precipitate is taken and washed with clean water, and the washed precipitate is placed in an oven at 45°C and dried for 12 h to obtain the pretreated raw sugar palm powder, i.e., the adjuvant.

[0071] The wood vinegar is commercially available Hongsen refined wood vinegar, and the pH value of the wood vinegar is 2-3; the volume ratio of the sugar palm suspension to the wood vinegar dilution is 1:30.

[0072] (4) Preparation of a semi-finished adhesive: 2 tons of water are added to 0.6 tons of cassava flour and mixed into a paste, and the paste is then added to the reaction kettle containing glue in step (1) to obtain a mixture, 200 kg of the formaldehyde removal agent obtained in step (2) is added to the mixture, and then mechanical stirring is performed to mix, the stirring temperature is controlled to be 60° C., the stirring speed is controlled to be 90 r / min, and the stirring time is controlled to be 1 hour, and then the mixture is heated to 90° C., 2.5 kg of caustic soda flakes are added to the mixture, and the mixture is mixed to obtain a semi-finished adhesive;

[0073] (5) Preparation of environmentally friendly adhesive: 50 kg of the auxiliary agent obtained in step (3) was adjusted with 45° C. clean water to prepare an auxiliary agent slurry with a mass concentration of 70%, and the auxiliary agent slurry was added to the adhesive semi-finished product, mixed evenly, and then cooled to 45° C. and extracted to obtain the environmentally friendly adhesive.

[0074] Example 8

[0075] A method for preparing an environmentally friendly adhesive comprises the following steps:

[0076] (1) Raw material preparation: Add glue into a reaction kettle and set aside; the glue is the same as that in Example 1.

[0077] (2) Preparation of formaldehyde removal agent: potassium persulfate is added to water, and then aluminum dihydrogen phosphate is added as an activator, and the mixture is stirred to obtain a formaldehyde removal agent for use; the mass ratio of water, potassium persulfate, and aluminum dihydrogen phosphate is 1:1:0.15.

[0078] (3) Preparation of auxiliary agent: The original powder of the sugar palm is pretreated, specifically, the original powder of the sugar palm is prepared into a 20% sugar palm suspension with 50°C clean water; the wood vinegar is diluted with clean water to form a wood vinegar dilution, and the volume ratio of the wood vinegar to water is 1:100; the sugar palm suspension is added to the wood vinegar dilution, and then mixed using a high shear mixer, the shear mixing rate is 5000 rpm, the temperature is controlled to be 40°C, and the mixing time is 1 min, and then the mixture is allowed to stand and age for 8 hours at a temperature of 20°C. After separation, the precipitate is taken and washed with clean water, and the washed precipitate is placed in an oven at 50°C and dried for 12 hours to obtain the pretreated original powder of the sugar palm, i.e., the auxiliary agent.

[0079] The wood vinegar is commercially available Hongsen refined wood vinegar, and the pH value of the wood vinegar is 2-3; the volume ratio of the sugar palm suspension to the wood vinegar dilution is 1:15.

[0080] The sugar palm raw powder is prepared according to a traditional method, comprising the following steps: peeling off the outer bark of a sugar palm tree to obtain the pith, slicing the pith and then crushing it, adding the crushed sugar palm material into water for stirring, then transferring it into a separator for separation to obtain sugar palm slurry, and drying the sugar palm slurry to obtain sugar palm raw powder.

[0081] (4) Preparation of a semi-finished adhesive: 4 tons of water were added to 0.8 tons of cassava flour and mixed into a paste, and the paste was added to the reaction kettle containing glue in step (1) to obtain a mixture, 100 kg of the formaldehyde removal agent obtained in step (2) was added to the mixture, and then mechanical stirring was performed to mix, the stirring temperature was controlled to be 65° C., the stirring speed was controlled to be 100 r / min, the stirring time was controlled to be 0.5 h, the mixture was adjusted to 60° C., 3 kg of caustic soda flakes were added to the mixture, and the semi-finished adhesive was obtained after mixing;

[0082] (5) Preparation of environmentally friendly adhesive: 100 kg of the auxiliary agent obtained in step (3) is mixed with clean water at 45° C. to prepare an auxiliary agent slurry with a mass concentration of 80%, and the auxiliary agent slurry is added to the adhesive semi-finished product. After mixing evenly, the temperature is adjusted to 45° C. and extracted to obtain the environmentally friendly adhesive.

[0083] Example 9

[0084] A method for preparing an environmentally friendly adhesive comprises the following steps:

[0085] (1) Raw material preparation: Add 10 tons of glue into a reaction kettle and set aside; the glue is the same as that in Example 1.

[0086] (2) Preparation of an adjuvant: The raw sugar palm powder is pretreated, specifically, the raw sugar palm powder is prepared into a sugar palm suspension with a mass fraction of 15% by weight using 48° C. clean water; the wood vinegar is diluted with clean water to form a wood vinegar dilution, and the volume ratio of the wood vinegar to water is 1:200; the sugar palm suspension is added to the wood vinegar dilution, and then mixed using a high shear mixer, the shear mixing rate is 8000 rpm, the temperature is controlled to be 38° C., and the mixing time is 1 min, and then the mixture is allowed to stand and age for 5 h at a temperature of 15° C., and after separation, the precipitate is taken and washed with clean water, and the washed precipitate is placed in an oven at 50° C. and dried for 12 h to obtain the pretreated raw sugar palm powder, i.e., the adjuvant.

[0087] The wood vinegar is commercially available Hongsen refined wood vinegar, and the pH value of the wood vinegar is 2-3; the volume ratio of the sugar palm suspension to the wood vinegar dilution is 1:20.

[0088] The sugar palm raw powder is prepared according to a traditional method, comprising the following steps: peeling off the outer bark of a sugar palm tree to obtain the pith, slicing the pith and then crushing it, adding the crushed sugar palm material into water for stirring, then transferring it into a separator for separation to obtain sugar palm slurry, and drying the sugar palm slurry to obtain sugar palm raw powder.

[0089] (3) Preparation of semi-finished adhesive: 3 tons of water were added to 0.7 tons of cassava flour and mixed into a paste, and the paste was added into the reaction kettle containing glue in step (1) to obtain a mixture, and then the mixture was heated to 83° C., 5 kg of caustic soda flakes were added to the mixture, and the mixture was mixed to obtain a semi-finished adhesive;

[0090] (4) Preparation of environmentally friendly adhesive: 60 kg of the auxiliary agent obtained in step (2) is adjusted with 45° C. clean water to prepare an auxiliary agent slurry with a mass concentration of 75%, and the auxiliary agent slurry is added to the adhesive semi-finished product, mixed evenly, and then cooled to 45° C. and extracted to obtain the environmentally friendly adhesive.

[0091] Example 10

[0092] A method for preparing an environmentally friendly adhesive comprises the following steps:

[0093] (1) Raw material preparation: Add 10 tons of glue into a reaction kettle and set aside; the glue is the same as that in Example 1.

[0094] (2) Preparation of auxiliary agent: The auxiliary agent is sugar palm powder, which is prepared according to a traditional method, including the following steps: peeling the bark of a sugar palm tree to obtain the pith, slicing the pith and then crushing it, adding the crushed sugar palm material into water for stirring, and then transferring it to a separator for separation to obtain sugar palm slurry, and drying the sugar palm slurry to obtain sugar palm powder.

[0095] (3) Preparation of semi-finished adhesive: 3 tons of water were added to 0.7 tons of cassava flour and mixed into a paste, and the paste was added into the reaction kettle containing glue in step (1) to obtain a mixture, and then the mixture was heated to 83° C., 5 kg of caustic soda flakes were added to the mixture, and the mixture was mixed to obtain a semi-finished adhesive;

[0096] (4) Preparation of environmentally friendly adhesive: 60 kg of the auxiliary agent obtained in step (2) is adjusted with 45° C. clean water to prepare an auxiliary agent slurry with a mass concentration of 75%, and the auxiliary agent slurry is added to the adhesive semi-finished product, mixed evenly, and then cooled to 45° C. and extracted to obtain the environmentally friendly adhesive.

[0097] In order to verify the technical effect of the present invention, the environmentally friendly adhesives of Examples 1-8 were tested as follows:

[0098] Test material preparation: Poplar veneer and adhesive were used to prepare three-layer plywood; the moisture content of the poplar veneer was 10%, and the amount of double-sided glue was 160g / m 2 ; According to the adhesive used, they are divided into the following groups:

[0099] Test group 1: the adhesive used was the adhesive prepared in Example 1;

[0100] Test group 2: The adhesive used was the adhesive prepared in Example 2;

[0101] Test group 3: The adhesive used was the adhesive prepared in Example 3. Example 3 was based on Example 2, and the formaldehyde remover used was the same as that in Example 1;

[0102] Test group 4: The adhesive used was the adhesive prepared in Example 4, which was based on Example 2 without adding an auxiliary agent;

[0103] Experimental group 5: The adhesive used was the adhesive prepared in Example 5. Example 5 was based on Example 2, and the auxiliary agent was the raw sugar palm powder without pretreatment;

[0104] Test group 6: The adhesive used was the adhesive prepared in Example 6. Example 6 was based on Example 2. In the preparation of the auxiliary agent, ordinary mechanical stirring was used instead of shear mixing.

[0105] Test group 7: The adhesive used was the adhesive prepared in Example 7;

[0106] Test group 8: The adhesive used was the adhesive prepared in Example 8;

[0107] Test Group 9: The adhesive used was the adhesive prepared in Example 9. Example 9 is based on Example 1, and the formaldehyde removal agent is replaced by an auxiliary agent to remove formaldehyde.

[0108] Experimental group 10: The adhesive used was the adhesive prepared in Example 10. Example 10 was based on Example 9, and the auxiliary agent was the raw sugar palm powder without pretreatment.

[0109] The surface bonding strength and formaldehyde emission of the test materials were tested according to GB / T17657-2013 "Test methods for physical and chemical properties of wood-based panels and veneer wood-based panels", and were classified according to GB / T39600-2021 "Classification of formaldehyde emission of wood-based panels and their products" (E1 ≤ 0.124 mg / m 3 、E0 level ≤ 0.050mg / m 3 and E NF Level ≤0.025mg / m 3 ), the results are as follows:

[0110]

[0111]

[0112] It can be seen from the above table that the surface bonding strength of the plywood prepared by the adhesive prepared by the present invention is much greater than the standard surface bonding strength of the decorative veneer veneer artificial board of standard GB / T15104-2021 ≥0.40MPa.

[0113] The present invention has tested and found that the untreated raw powder of the sago palm has agglomeration phenomenon and adhesion problems, while the pretreated raw powder of the sago palm has good dispersibility and good microsphere effect. It can be seen that the use of the raw powder of the sago palm as an auxiliary agent itself has a large defect, so if it is used directly, the adhesion and environmental protection effect of the adhesive will be significantly reduced. In order to improve the performance of the raw powder of the sago palm, the present invention treats the raw powder of the sago palm to obtain an auxiliary agent. It can be seen from the results of test groups 5 and 6 that the auxiliary agent of the present invention is not treated with wood vinegar diluent during the preparation process or the mixing means used is not suitable. The auxiliary agent will have different degrees of agglomeration, and it cannot be evenly dispersed after being added to the semi-finished adhesive and mixed. The auxiliary agent cannot be fully integrated into the glue, resulting in the effect of the auxiliary agent cannot be fully exerted or even not exerted, and the surface bonding strength of the final adhesive product decreases, the curing effect of formaldehyde decreases, and the formaldehyde release increases.

[0114] The auxiliary agent of the present invention is mainly made of nut powder, which is a specialty of Longzhou, Guangxi. The present invention has found that it has unique adhesiveness, curing properties and lubricity. The nut powder is added to the glue after pretreatment to solidify the formaldehyde in the glue and greatly reduce the release of formaldehyde. By comparing the results of test group 1 with test groups 9 and 10, it can be seen that without using a formaldehyde remover, adding the auxiliary agent of the present invention can convert the formaldehyde release of the glue from E1 level to E0 level, and the auxiliary agent of the present invention has a better formaldehyde removal effect than the commercially available formaldehyde remover.

[0115] In addition, after testing, when the amount of glue in test group 1 was 160±5g / square, the amount of glue in test group 2 was 130±5g / square, and the amount of glue in test group 4 was 160±5g / square, the surface bonding strengths of the three were equivalent, indicating that the use of the auxiliary agent in the present invention can effectively reduce the amount of adhesive used.

[0116] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the definition of the claims.

Claims

1. A method for preparing an environmentally friendly adhesive, characterized in that: The method comprises the following steps: adding water to cassava flour and mixing them into a paste, adding the paste into glue to obtain a mixture, adding a formaldehyde remover and melamine into the mixture, mixing and heating the mixture to 60-90° C., then adding caustic soda flakes, mixing, and cooling to obtain an environmentally friendly adhesive; The weight ratio of the glue, water and tapioca flour is 10:2-4:0.6-0.8; The amount of the formaldehyde remover added is 1-2% of the weight of the glue; The amount of melamine added is 0-2% of the weight of the glue; The amount of caustic soda added is 0.25-0.5% of the weight of the cassava flour; The glue meets the E1 glue standard and is urea-formaldehyde resin glue; The preparation method of the formaldehyde remover comprises the following steps: adding potassium persulfate into water, then adding aluminum dihydrogen phosphate as an activator, stirring and mixing to obtain the formaldehyde remover; the mass ratio of water, potassium persulfate and aluminum dihydrogen phosphate is 1:0.7-1:0.08-0.

15.

2. The method for preparing an environmentally friendly adhesive according to claim 1, characterized in that: In the process of preparing the environmentally friendly adhesive, an auxiliary agent is also added, and the auxiliary agent is the original powder of sugar palm.

3. The method for preparing an environmentally friendly adhesive according to claim 2, characterized in that: The sugar palm powder is pretreated before being used as an auxiliary agent, specifically, the sugar palm powder is prepared into a sugar palm suspension with 45-50°C clean water; the wood vinegar is diluted with clean water to form a wood vinegar dilution; the sugar palm suspension is added to the wood vinegar dilution, and then a high shear mixer is used for mixing, the shear mixing rate is 5000-10000 rpm, the temperature is controlled to be 35-40°C, the mixing treatment time is 1-2min, and then the mixture is allowed to stand for aging for 5-8h at a temperature of 15-20°C, and after separation, a precipitate is taken and washed with clean water, and the washed precipitate is placed in an oven at 45-50°C for drying to obtain the pretreated sugar palm powder, i.e., the auxiliary agent.

4. The method for preparing an environmentally friendly adhesive according to claim 3, characterized in that: The wood vinegar is refined wood vinegar, and the pH value of the wood vinegar is 2-3; the volume ratio of the wood vinegar to clean water in the wood vinegar dilution is 1:100-200; the mass fraction of the sugar palm suspension is 15-20%; and the volume ratio of the sugar palm suspension to the wood vinegar dilution is 1:15-30.

5. The method for preparing an environmentally friendly adhesive according to claim 4, characterized in that: The method comprises the following steps: adding glue into a reaction kettle for standby use; adding water into cassava flour and mixing into a paste, adding the paste into the reaction kettle containing glue to obtain a mixture, adding a formaldehyde remover and melamine into the mixture, mixing and heating the mixture to 60-90 DEG C, then adding caustic soda flakes to mix, and obtaining an adhesive semi-finished product; adjusting an auxiliary agent into an auxiliary agent slurry with a mass concentration of 70-80% using clean water at 40-50 DEG C, adding the auxiliary agent slurry into the adhesive semi-finished product, mixing evenly, cooling, and obtaining an environmentally friendly adhesive; the amount of the auxiliary agent added is 0.5-1% of the weight of the glue.

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