Preparation method of camellia oleifera shell powder compound filler modified MUF adhesive

Abstract

The invention discloses a preparation method of a camellia oleifera shell powder compound filler modified MUF adhesive. The preparation method comprises the following steps: S1, preparing raw materials; s2, raw material pretreatment: preparing the oil tea fruit shell powder into modified oil tea fruit shell powder, and mixing the modified oil tea fruit shell powder with other compound fillers to obtain a mixture; s3, preparing an MUF adhesive; s4, preparing a compound filler modified MUF adhesive: adding the mixture in S2 into the MUF adhesive prepolymer in S3 according to a ratio, adding a modifier, and fully and uniformly stirring to obtain the compound filler modified MUF adhesive; and S5, post-processing the product. The camellia oleifera shell powder is used as a filler, so that the production cost of the MUF adhesive can be remarkably reduced; active groups in the modified camellia oleifera shell powder and the MUF adhesive are subjected to chemical reaction, so that the bonding strength and the water resistance of the adhesive are improved; as a natural filler, the camellia oleifera shell powder has the characteristics of reproducibility and degradability, and the release of harmful substances such as formaldehyde and the like is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesives, and in particular relates to a method for preparing a MUF adhesive modified by compounding a filler with oil-tea camellia shell powder. Background Art

[0002] MUF adhesive, full name melamine-urea-formaldehyde co-condensation resin adhesive, is a synthetic adhesive widely used in the wood industry. It is made by the co-condensation reaction of melamine, urea and formaldehyde, combining the high water resistance of melamine resin and the low cost advantage of urea resin. It has good gluing and water resistance and is suitable for indoor and outdoor wood gluing applications.

[0003] With the enhancement of environmental awareness and the effective use of resources, finding green and environmentally friendly materials that can replace traditional chemical raw materials has become a research hotspot. As a by-product of tea processing, camellia oleifera shell has the advantages of large output, renewable, low price, and high lignin content, making it suitable as a filler for wood adhesives. Although traditional MUF adhesives have excellent performance, they have the problem of high formaldehyde emission. Therefore, compounding camellia oleifera shell powder as a filler and using it to modify MUF adhesives can not only improve the performance of the adhesive, but also effectively reduce formaldehyde emission, achieve efficient resource utilization and environmental protection. Therefore, we propose a preparation method for MUF adhesives modified with camellia oleifera shell powder and fillers. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method of a MUF adhesive modified by a composite filler of camellia oleifera shell powder. The camellia oleifera shell powder is used as a filler, which can significantly reduce the production cost of the MUF adhesive. The active groups in the modified camellia oleifera shell powder react chemically with the MUF adhesive, thereby improving the bonding strength and water resistance of the adhesive. The camellia oleifera shell powder, as a natural filler, is renewable and degradable, reduces the release of harmful substances such as formaldehyde, and meets environmental protection requirements, so as to solve the problems in the prior art proposed in the above-mentioned background technology.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a MUF adhesive modified by a compound filler of camellia oleifera shell powder comprises the following steps:

[0007] S1. Raw material preparation: prepare camellia oleifera shell powder raw material, modified MUF adhesive base raw material, modifier and other compound fillers;

[0008] S2, raw material pretreatment: preparing the camellia oleifera shell powder into modified camellia oleifera shell powder, and mixing the modified camellia oleifera shell powder with other compound fillers to obtain a mixture;

[0009] S3, MUF adhesive preparation: preparing MUF adhesive prepolymer using the basic raw materials of MUF adhesive;

[0010] S4, preparing a composite filler-modified MUF adhesive: adding the mixture in S2 to the MUF adhesive prepolymer in S3 according to a proportion, adding a modifier and stirring well to obtain a composite filler-modified MUF adhesive;

[0011] S5. Product post-processing: The prepared composite filler-modified MUF adhesive is filtered, degassed and other treatments are performed to improve its stability and use effect.

[0012] Preferably, in S1, the camellia oleifera shell raw material is washed, dried, and crushed to 350 mesh-550 mesh to obtain the camellia oleifera shell powder raw material; the MUF adhesive basic raw material includes urea, melamine, and formaldehyde solution; the modifier is one of sodium hydroxide, epoxy resin or polyurethane, which can be selected according to needs; other compound fillers are one of silicate fillers or talcum powder.

[0013] Preferably, S2 includes the following steps:

[0014] a. Mix the camellia oleifera shell powder with an appropriate amount of modifier solution, soak the crushed camellia oleifera shell powder in the modifier solution, and stir evenly. The ratio of camellia oleifera shell powder, modifier and water is 1.5:1:1 by mass;

[0015] b. The soaked camellia oleifera shell powder is transferred to an oven for heating to obtain a solid, which is then rinsed with clean water and dried again. The modified camellia oleifera shell powder with uniform particles is obtained by sieving.

[0016] Preferably, in a, the immersion time is adjusted according to the properties of the modifier used and the desired effect. For example, when sodium hydroxide is selected as the modifier (used to enhance the hydrophilicity and reactivity of the powder), the immersion time is 1-1.5 hours; when epoxy resin (used to improve the bonding strength and weather resistance of camellia oleifera shell powder) is selected as the modifier, the immersion time is 1-2 hours; when polyurethane (used to improve the bonding strength and weather resistance of camellia oleifera shell powder) is selected as the modifier, the immersion time is 2-3 hours.

[0017] Preferably, in said b, when the soaked camellia oleifera shell powder is transferred to an oven for heating, it is heated to 100°C-150°C and maintained for 2-3 hours to promote the modification reaction, and then the unreacted modifier is removed by washing with clean water. During the secondary drying, it is dried in an oven at 60°C-100°C to constant weight to remove moisture to obtain the modified camellia oleifera shell powder.

[0018] Preferably, in S2, the modified camellia oleifera shell powder and other fillers are mixed in a weight ratio of 60:40, and the mixture is stirred and mixed for 5 min-10 min by a stirring device.

[0019] Preferably, in S3, urea and melamine are taken in a molar ratio of 1:2:3, added to a formaldehyde solution, and stirred for reaction at a certain temperature of 80°C-90°C for 2h-3h to form a MUF prepolymer. At this temperature, the reactant molecules have sufficient energy to overcome the reaction activation energy and perform a condensation reaction. A lower temperature may result in a too slow reaction rate, while an excessively high temperature may induce side reactions and affect the quality of the prepolymer.

[0020] Preferably, in S4, the mixture obtained in S2 is added to the MUF prepolymer obtained in S3 at 25% of the total mass of the product, and a modifier is added at 0.5%-1% of the total mass of the product, the mixture is fully mixed, and the mixture is reacted at 85° C. for 2.5 hours to obtain a composite filler-modified MUF adhesive.

[0021] Technical effects and advantages of the present invention: The preparation method of the MUF adhesive modified by the compound filler of camellia husk powder proposed by the present invention has the following advantages compared with the prior art:

[0022] 1. Environmental protection: Using tea oil shells, an agricultural and forestry waste, as filler reduces production costs and reduces solid waste pollution.

[0023] 2. Performance improvement: Through the compounding and modification of camellia oleifera shell powder, the bonding strength, water resistance and flame retardancy of MUF adhesive are significantly improved, and the formaldehyde emission is reduced.

[0024] 3. Economic benefits: Using agricultural and forestry processing residues to replace some chemical raw materials reduces the production costs of enterprises and improves economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] Embodiment 1:

[0028] The present invention provides Figure 1 The method for preparing a MUF adhesive modified by a compound filler of camellia husk powder comprises the following steps:

[0029] S1. Raw material preparation: prepare camellia oleifera shell powder raw material, modified MUF adhesive base raw material, modifier and other compound fillers;

[0030] S2, raw material pretreatment: preparing the camellia oleifera shell powder into modified camellia oleifera shell powder, and mixing the modified camellia oleifera shell powder with other compound fillers to obtain a mixture;

[0031] S3, MUF adhesive preparation: preparing MUF adhesive prepolymer using the basic raw materials of MUF adhesive;

[0032] S4, preparing a composite filler-modified MUF adhesive: adding the mixture in S2 to the MUF adhesive prepolymer in S3 according to a proportion, adding a modifier and stirring well to obtain a composite filler-modified MUF adhesive;

[0033] S5. Product post-processing: The prepared composite filler-modified MUF adhesive is filtered, degassed and other treatments are performed to improve its stability and use effect.

[0034] In S1, the oil-tea camellia shell raw material is washed, dried, and crushed to 400 mesh to obtain the oil-tea camellia shell powder raw material; the basic raw materials of MUF adhesive include urea, melamine, and formaldehyde solution; the modifier is one of sodium hydroxide, epoxy resin or polyurethane, which can be selected according to needs; other compound fillers are one of silicate fillers or talcum powder.

[0035] S2 includes the following steps:

[0036] a. Mix the camellia oleifera shell powder with an appropriate amount of modifier solution, soak the crushed camellia oleifera shell powder in the modifier solution, and stir evenly. The ratio of camellia oleifera shell powder, modifier and water is 1.5:1:1 by mass;

[0037] b. The soaked camellia oleifera shell powder is transferred to an oven for heating to obtain a solid, which is then rinsed with clean water and dried again. The modified camellia oleifera shell powder with uniform particles is obtained by sieving.

[0038] In a, the immersion time is adjusted according to the properties of the modifier used and the desired effect. In this embodiment, sodium hydroxide is selected as the modifier (for enhancing the hydrophilicity and reactivity of the powder) and the immersion time is 1.5 h.

[0039] In b, the soaked tea oil husk powder is transferred to an oven for heating, heated to 150°C and maintained for 3 hours to promote the modification reaction, and then the unreacted modifier is removed by rinsing with clean water. During the secondary drying, it is dried in an oven at -100°C to constant weight to remove moisture to obtain the modified tea oil husk powder.

[0040] In S2, the modified camellia oleifera shell powder and other fillers are mixed in a weight ratio of 60:40, and the mixture is stirred for 10 minutes by a stirring device.

[0041] In S3, urea and melamine are taken in a molar ratio of 1:2:3, added to a formaldehyde solution, and stirred for reaction at a certain temperature of 90°C for 3 hours to form a MUF prepolymer. At this temperature, the reactant molecules have enough energy to overcome the reaction activation energy and undergo a condensation reaction. A lower temperature may result in a slow reaction rate, while an excessively high temperature may induce side reactions and affect the quality of the prepolymer.

[0042] In S4, the mixture obtained in S2 is added to the MUF prepolymer obtained in S3 at 25% of the total mass of the product, and a modifier is added at 1% of the total mass of the product, the mixture is fully mixed, and the mixture is reacted at 85° C. for 2.5 hours to obtain a composite filler-modified MUF adhesive.

[0043] In this embodiment, it is concluded that the composite filler modified MUF adhesive has the following effects:

[0044] Good water resistance: MUF adhesive has high water resistance. This is because the addition of melamine makes the molecular structure of the adhesive more stable and able to resist water erosion.

[0045] Gluing strength: MUF adhesive can provide strong bonding strength to ensure the stability and durability of wood products during use.

[0046] Low toxicity: Compared with traditional urea-formaldehyde resin adhesives, MUF adhesives have lower free formaldehyde content and are less harmful to human health.

[0047] Embodiment 2:

[0048] The present invention provides Figure 1 The method for preparing a MUF adhesive modified by a compound filler of camellia husk powder comprises the following steps:

[0049] S1. Raw material preparation: prepare camellia oleifera shell powder raw material, modified MUF adhesive base raw material, modifier and other compound fillers;

[0050] S2, raw material pretreatment: preparing the camellia oleifera shell powder into modified camellia oleifera shell powder, and mixing the modified camellia oleifera shell powder with other compound fillers to obtain a mixture;

[0051] S3, MUF adhesive preparation: preparing MUF adhesive prepolymer using the basic raw materials of MUF adhesive;

[0052] S4, preparing a composite filler-modified MUF adhesive: adding the mixture in S2 to the MUF adhesive prepolymer in S3 according to a proportion, adding a modifier and stirring well to obtain a composite filler-modified MUF adhesive;

[0053] S5. Product post-processing: The prepared composite filler-modified MUF adhesive is filtered, degassed and other treatments are performed to improve its stability and use effect.

[0054] In S1, the oil-tea camellia shell raw material is washed, dried, and crushed to 550 mesh to obtain the oil-tea camellia shell powder raw material; the basic raw materials of MUF adhesive include urea, melamine, and formaldehyde solution; the modifier is one of sodium hydroxide, epoxy resin or polyurethane, which can be selected according to needs; other compound fillers are one of silicate fillers or talcum powder.

[0055] S2 includes the following steps:

[0056] a. Mix the camellia oleifera shell powder with an appropriate amount of modifier solution, soak the crushed camellia oleifera shell powder in the modifier solution, and stir evenly. The ratio of camellia oleifera shell powder, modifier and water is 1.5:1:1 by mass;

[0057] b. The soaked camellia oleifera shell powder is transferred to an oven for heating to obtain a solid, which is then rinsed with clean water and dried again. The modified camellia oleifera shell powder with uniform particles is obtained by sieving.

[0058] In a, the immersion time is adjusted according to the properties of the modifier used and the desired effect. In this embodiment, epoxy resin (used to improve the bonding strength and weather resistance of camellia oleifera shell powder) is selected as the modifier and the immersion time is 1 h.

[0059] In b, the soaked tea oil husk powder is transferred to an oven for heating, heated to 100°C and maintained for 2 hours to promote the modification reaction, and then the unreacted modifier is removed by rinsing with clean water. During the secondary drying, it is dried in an oven at 60°C to constant weight to remove moisture to obtain the modified tea oil husk powder.

[0060] In S2, the modified camellia oleifera shell powder and other fillers are mixed in a weight ratio of 60:40, and the mixture is stirred for 5 minutes by a stirring device.

[0061] In S3, urea and melamine are taken in a molar ratio of 1:2:3, added to a formaldehyde solution, and stirred for reaction at a certain temperature of 80°C for 2 hours to form a MUF prepolymer. At this temperature, the reactant molecules have enough energy to overcome the reaction activation energy and undergo a condensation reaction. A lower temperature may result in a slow reaction rate, while an excessively high temperature may induce side reactions and affect the quality of the prepolymer.

[0062] In S4, the mixture obtained in S2 is added to the MUF prepolymer obtained in S3 at 25% of the total mass of the product, and a modifier is added at 0.5% of the total mass of the product, the mixture is fully mixed, and the mixture is reacted at 85° C. for 2.5 hours to obtain a composite filler-modified MUF adhesive.

[0063] Among them, in S1, fresh tea husks are selected, the tea husks are cleaned to remove surface impurities, the cleaned tea husks are dried in the sun or in an oven until the moisture content is less than 10%, and then crushed to obtain tea husk powder. The crushed tea husk powder should have a certain particle size distribution, preferably above 350 meshes-550 meshes, to ensure cell wall rupture, increase the exposure of active groups, and improve reactivity;

[0064] In this embodiment, it is concluded that the composite filler modified MUF adhesive has the following effects:

[0065] Gluing strength: MUF adhesive can provide strong bonding strength to ensure the stability and durability of wood products during use.

[0066] Aging resistance: MUF adhesive has good aging resistance and can maintain its bonding performance during long-term use.

[0067] Low toxicity: Compared with traditional urea-formaldehyde resin adhesives, MUF adhesives have lower free formaldehyde content and are less harmful to human health.

[0068] In general, the present invention has the following advantages:

[0069] 1. Reduce costs: Using camellia oleifera shell powder as filler can significantly reduce the production cost of MUF adhesive.

[0070] 2. Improve performance: The active groups in the modified camellia oleifera shell powder react chemically with the MUF adhesive, improving the adhesive's bonding strength, water resistance, weather resistance and aging resistance.

[0071] 3. Environmental protection and emission reduction: Camellia oleifera shell powder, as a natural filler, is renewable and degradable, reduces the release of harmful substances such as formaldehyde, and meets environmental protection requirements.

[0072] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a MUF adhesive modified by a compound filler of camellia oleifera shell powder, characterized in that: The following steps are involved: S1. Raw material preparation: prepare camellia oleifera shell powder raw material, modified MUF adhesive base raw material, modifier and other compound fillers; S2, raw material pretreatment: preparing the camellia oleifera shell powder into modified camellia oleifera shell powder, and mixing the modified camellia oleifera shell powder with other compound fillers to obtain a mixture; S3, MUF adhesive preparation: preparing MUF adhesive prepolymer using the basic raw materials of MUF adhesive; S4, preparing a composite filler-modified MUF adhesive: adding the mixture in S2 to the MUF adhesive prepolymer in S3 according to a proportion, adding a modifier and stirring well to obtain a composite filler-modified MUF adhesive; S5. Product post-processing: The prepared composite filler-modified MUF adhesive is filtered, degassed and other treatments are performed to improve its stability and use effect.

2. The method for preparing a MUF adhesive modified by a composite filler of camellia husk powder according to claim 1, characterized in that: In S1, the oil-tea camellia shell raw material is washed, dried, and crushed to 350-550 meshes to obtain the oil-tea camellia shell powder raw material; the MUF adhesive basic raw materials include urea, melamine, and formaldehyde solution; the modifier is one of sodium hydroxide, epoxy resin, or polyurethane, which can be selected according to needs; other compound fillers are one of silicate fillers or talcum powder.

3. The method for preparing a MUF adhesive modified by a composite filler of camellia husk powder according to claim 1, characterized in that: The S2 includes the following steps: a. Mix the camellia oleifera shell powder with an appropriate amount of modifier solution, soak the crushed camellia oleifera shell powder in the modifier solution, and stir evenly. The ratio of camellia oleifera shell powder, modifier and water is 1.5:1:1 by mass; b. The soaked camellia oleifera shell powder is transferred to an oven for heating to obtain a solid, which is then rinsed with clean water and dried again. The modified camellia oleifera shell powder with uniform particles is obtained by sieving.

4. The method for preparing a MUF adhesive modified by a composite filler of camellia husk powder according to claim 3, characterized in that: In the method a, the immersion time is adjusted according to the properties of the modifier used and the desired effect. For example, when sodium hydroxide is selected as the modifier (for enhancing the hydrophilicity and reactivity of the powder), the immersion time is 1-1.5 hours; when epoxy resin (for improving the bonding strength and weather resistance of camellia oleifera shell powder) is selected as the modifier, the immersion time is 1-2 hours; when polyurethane (for improving the bonding strength and weather resistance of camellia oleifera shell powder) is selected as the modifier, the immersion time is 2-3 hours.

5. The method for preparing a MUF adhesive modified by a composite filler of camellia husk powder according to claim 3, characterized in that: In the method b, the soaked camellia oleifera shell powder is transferred to an oven for heating, heated to 100°C-150°C, and maintained for 2-3 hours to promote the modification reaction, and then the unreacted modifier is removed by washing with clean water. During the secondary drying, the modified camellia oleifera shell powder is obtained by drying it in an oven at 60°C-100°C to constant weight to remove moisture.

6. The method for preparing a MUF adhesive modified by a composite filler of camellia husk powder according to claim 1, characterized in that: In S2, the modified camellia oleifera shell powder and other fillers are mixed in a weight ratio of 60:40, and the mixture is stirred for 5-10 minutes by a stirring device.

7. The method for preparing a MUF adhesive modified by a composite filler of camellia husk powder according to claim 1, characterized in that: In S3, urea and melamine are taken in a molar ratio of 1:2:3, added to a formaldehyde solution, and stirred for reaction at a certain temperature of 80° C.-90° C. for 2 h-3 h to form a MUF prepolymer. At this temperature, the reactant molecules have enough energy to overcome the reaction activation energy and undergo a condensation reaction. A lower temperature may result in a too slow reaction rate, while an excessively high temperature may induce side reactions and affect the quality of the prepolymer.

8. The method for preparing a MUF adhesive modified by a composite filler of camellia husk powder according to claim 1, characterized in that: In S4, the mixture obtained in S2 is added to the MUF prepolymer obtained in S3 at 25% of the total mass of the product, and a modifier is added at 0.5%-1% of the total mass of the product, the mixture is fully mixed, and the mixture is reacted at 85° C. for 2.5 hours to obtain a composite filler-modified MUF adhesive.

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