Surface-modified bamboo fiber laminate and preparation method thereof

Abstract

The present invention relates to the technical field of bamboo material processing, and specifically to a surface-modified bamboo fiber laminate and a preparation method thereof. The bamboo fiber laminate comprises a core layer and an upper surface layer and / or a lower surface layer bonded to both sides of the core layer; the upper surface layer and / or the lower surface layer are obtained by impregnating bamboo bundles with a mica-modified resin adhesive. The mica-modified resin adhesive comprises coupling agent-modified mica and a resin adhesive. The present invention uses a mica-modified adhesive to modify only the surface bamboo bundles of the bamboo fiber laminate, without processing the core bamboo bundles, in order to reduce production costs, while achieving an improvement in the surface properties of the bamboo fiber laminate, improving its light aging resistance, cracking resistance and water resistance, and alleviating the problem of its surface being easily deteriorated, thereby expanding the application range and life of the bamboo fiber laminate.

Description

Technical Field

[0001] The invention relates to the technical field of bamboo material processing, in particular to a surface-modified bamboo bundle fiber laminate and a preparation method thereof. Background Art

[0002] As a renewable resource, bamboo boasts fast growth and a short maturity period. The development and utilization of bamboo to produce bamboo panels has significant economic, environmental, and ecological significance. Currently, bamboo fiber laminated lumber (LFL) is a relatively common bamboo panel product. It is made from bamboo curtains, a basic bamboo processing unit made from integrated bamboo veneers, which are laminated, assembled, and hot-pressed. It is an innovative product among reconstituted bamboo materials. Compared to mixed reconstituted bamboo products, LFL composite panels offer excellent properties such as uniform density distribution, light weight, and customizable surface functions. They are widely used in building materials, furniture, packaging, and interior decoration.

[0003] In the production of bamboo-wood recombinant materials, the durability of the board products can be improved by modifying the bamboo-wood units through methods such as steaming, carbonization, and chemical impregnation. However, because the current production of bamboo-wood recombinant materials uses a mixed paving model to assemble the boards, only the overall and indiscriminate modification of the bamboo-wood units can be performed, and controllable, targeted modification of the bamboo-wood units cannot be achieved, which significantly increases the cost of the product.

[0004] The surface of a product is where it interacts with the external environment and is the first area to experience performance degradation. It is also often the area where performance damage is most severe. The quality of the surface performance plays a decisive role in the product's appearance, application areas, and service life. At present, the surface of bamboo fiber laminated lumber products generally directly uses paint or coatings as a finishing protective layer. The paint surface is relatively thin, and there is an interface layer between the paint or coating and the bamboo fiber laminated lumber substrate. As a result, when the product's appearance is exposed to light, moisture, heat, etc., the paint layer is very prone to peeling, bubbling, flaking, and other protective problems. As a result, the bamboo fiber laminated lumber is prone to surface degradation phenomena such as cracking, thread skipping, discoloration, and mildew, which seriously affects the application range and product life of the bamboo fiber laminated lumber products. For example, patent CN201710080696.7 discloses a method for manufacturing bamboo-based laminated decorative panels with different colors, including (1) color-changing bamboo bundles; (2) drying the dyed bamboo bundles; (3) processing bamboo bundle veneers; (4) impregnating and drying the bamboo bundle veneers; (5) assembling the bamboo bundle veneers, which have been impregnated and dried, and then hot-pressing or cold-pressing them to obtain slabs; and (6) processing the decorative panels. This method involves hot-pressing the uniformly impregnated bamboo bundle veneers, and the durability of the surface layer needs to be improved.

[0005] Therefore, it is necessary to provide an improved surface-modified bamboo fiber laminate and a preparation method thereof to solve the above problems. Summary of the Invention

[0006] The present invention aims to provide a surface-modified bamboo fiber laminated lumber and a preparation method thereof. By using a mica-modified resin adhesive to impregnate only the surface bamboo bundles, the light aging resistance, cracking resistance and water resistance of the bamboo fiber laminated lumber can be significantly improved, while also reducing the manufacturing cost.

[0007] To achieve the above objectives, the present invention provides a bamboo fiber laminate, comprising a core layer and an upper surface layer and / or a lower surface layer bonded to both sides of the core layer; the upper surface layer and / or the lower surface layer are obtained by impregnating bamboo bundles with a mica-modified resin adhesive.

[0008] Research in the present invention shows that the mica-modified resin adhesive has a good bonding effect on bamboo bundles, improving the bonding strength between the mica-modified resin adhesive and the core layer. The formed mica-modified resin adhesive layer can provide good protection for the bamboo bundles. It has excellent durability properties such as resistance to light aging, cracking, and water resistance, which can extend the service life of bamboo bundle fiber laminates and expand the product's application range.

[0009] Furthermore, the mica-modified resin adhesive includes coupling agent-modified mica and resin adhesive. The coupling agent-modified mica can improve the compatibility and dispersibility of mica and resin adhesive, thereby improving the protective effect of the adhesive protective layer formed by dipping. By utilizing the unique lamellar structure, film-forming properties and excellent barrier properties of mica, the triple effects of toughening the resin, enhancing bonding and protecting the bamboo bundles (external light, moisture, heat, etc.) are achieved. More importantly, based on the structural characteristics of the bamboo bundles themselves, the mica-modified resin adhesive can play a good protective and adhesive role on the bamboo bundles. The mica-modified resin adhesive penetrates into the interior and surface of the bamboo bundle fibers, and can also form certain chemical bonds and physical adhesive nailing effects with the bamboo bundle fibers during hot pressing and curing, thereby improving the performance of the adhesive layer itself.

[0010] Furthermore, the particle size of the mica is 200-3000 mesh, for example, 300, 500, 800, 1000, 1500, 2000, 2500 mesh, etc.

[0011] Furthermore, the mass ratio of the coupling agent-modified mica to the resin adhesive is 1:(5-200), for example, 1:8, 1:15, 1:20, 1:30, 1:40, 1:50, 1:60, 1:80, 1:90, 1:120, 1:150, 1:200, etc.; preferably 1:(10-100), more preferably 1:(10-50). The amount of coupling agent-modified mica added should not be too much to prevent affecting the bonding properties of the adhesive and further affecting the bonding strength between the layers. If the amount of coupling agent-modified mica added is too little, the surface layer's light aging resistance, crack resistance, water resistance and other properties cannot be effectively improved.

[0012] Furthermore, the mass ratio of the mica to the coupling agent is 1:(0.1-5), for example, 1:0.5, 1:1, 1:2, 1:2.5, 1:3, 1:4, etc., preferably 1:(1-2).

[0013] Furthermore, the resin adhesive includes one or more of phenolic resin, epoxy resin glue, isocyanate glue, polyurethane glue, urea-formaldehyde resin glue, white latex and soybean glue.

[0014] Furthermore, the coupling agent is preferably a silane coupling agent, including one or more of silane coupling agents KH550, KH560, and KH570. Modifying the mica with the coupling agent can achieve the combined effects of enhancing the interfacial bonding between the mica and the adhesive, improving the dispersibility of the mica in the adhesive, and reducing the sedimentation behavior of the mica.

[0015] Furthermore, the core layer is formed by impregnating bamboo bundles with an unmodified resin adhesive; the core layer includes 1-10 layers of bamboo bundles and / or mixed bamboo bundles. Mixed bamboo bundles refer to bundles laid randomly, not in layers. Impregnation with an unmodified resin adhesive ensures hot-press bonding between the bamboo bundles while also addressing the increased costs associated with modification.

[0016] The present invention also provides a method for preparing the bamboo bundle fiber laminated timber as described in any one of the above, comprising the following steps:

[0017] S1, mixing mica and a silane coupling agent in a mass ratio of 1: (0.1-5), reacting at 50° C. to 95° C. to obtain modified mica; mixing the modified mica with a resin adhesive in a mass ratio of 1: (5-200) to obtain a mica-modified resin adhesive;

[0018] S2, impregnating bamboo bundles with the mica-modified resin adhesive to obtain modified bamboo bundles;

[0019] S3, impregnating the bamboo bundle with an unmodified resin adhesive to obtain an unmodified bamboo bundle;

[0020] S4. Placing unmodified bamboo bundles on the core layer, and placing modified bamboo bundles on the upper and / or lower surfaces of the core layer, respectively, and performing assembly and composite hot pressing to obtain bamboo bundle fiber laminates.

[0021] Furthermore, the amount of the modified bamboo bundle impregnated with glue is 8% to 25%, preferably 8% to 18%; the amount of the unmodified bamboo bundle impregnated with glue is 8% to 25%, preferably 10% to 20%.

[0022] Furthermore, the soaking time in steps S2 and S3 is 10 to 45 minutes, usually at room temperature, and the soaked bamboo bundles are drained and dried to obtain modified bamboo bundles or unmodified bamboo bundles.

[0023] Furthermore, the bamboo bundle is bamboo bundle fiber obtained by rolling and decomposing bamboo materials.

[0024] Furthermore, the mass ratio of the modified mica to the resin adhesive is 1:(10-50). Additives such as antiseptics and mildew inhibitors, defoaming agents, etc. can be added as needed to obtain a mica-modified resin adhesive.

[0025] Furthermore, the mass ratio of the mica to the silane coupling agent is 1:(1-2.5).

[0026] Furthermore, step S4 is the assembly and molding, and the temperature of the composite hot pressing is 140±5° C., the pressure is 0.5-30 MPa, and the time is 5-90 minutes.

[0027] The surface modification method provided by the present invention can also be applied to bamboo strips, bamboo strips, etc.

[0028] The beneficial effects of the present invention are as follows:

[0029] 1. The bamboo fiber laminated lumber provided by the present invention uses a mica-modified adhesive to impregnate the surface bamboo bundles of the bamboo fiber laminated lumber, thereby only modifying the surface bamboo bundles of the bamboo fiber laminated lumber while leaving the core bamboo bundles untreated, thereby reducing production costs. At the same time, the surface properties of the bamboo fiber laminated lumber are improved, such as its resistance to light aging, cracking, and water resistance, and the problem of its surface being easily degraded is alleviated, thereby expanding the application range and lifespan of the bamboo fiber laminated lumber.

[0030] 2. The present invention adopts a layered design concept and only modifies the surface bamboo bundles of the bamboo bundle fiber composite material. The process is simple and easy to operate, has strong application practicality, can meet performance requirements and reduce costs.

[0031] 3. Using mica-modified adhesive to impregnate the surface bamboo bundles achieves both bonding and protection. Compared to the currently common surface treatment method of simply applying paint or coating to the surface of bamboo bundle fiber laminates, this can effectively increase the thickness of the surface adhesive layer and the surface bonding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is a schematic structural diagram of a bamboo bundle fiber laminated timber in the prior art;

[0034] Figure 2This is a schematic structural diagram of the bamboo bundle fiber laminated timber provided by the present invention.

[0035] Reference numerals

[0036] 1- modified bamboo bundles on the upper surface; 2- unmodified bamboo bundles on the core layer; 3- modified bamboo bundles on the lower surface. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0038] Figure 1 The invention relates to an overall modified or surface-sprayed bamboo bundle board according to the prior art. Figure 2 This is the surface-modified bamboo fiber laminated lumber of the present invention. The bamboo fiber laminated lumber has a multi-layer structure. For example, a 5-layer slab comprises the upper and lower modified bamboo bundles 1 and 3, which have been modified, and the middle three layers comprise the unmodified core layer of unmodified bamboo bundles 2.

[0039] Example 1

[0040] A method for preparing bamboo fiber laminated timber comprises the following steps:

[0041] S1. 1200 mesh mica and silane coupling agent KH560 were mixed in a mass ratio of 1:1, and the mixture was modified by mechanical stirring at 70°C for 60 minutes. The mixture was washed with clean water and filtered, and then dried at 60°C for 1 hour to obtain modified mica. The modified mica was mixed with phenolic resin adhesive in a mass ratio of 1:20, and the mixture was fully stirred to mix the two to obtain a mica-modified phenolic resin adhesive.

[0042] S2, impregnating the bamboo bundle curtain with mica-modified phenolic resin adhesive at room temperature, with an impregnation amount of about 16% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundle to obtain a modified bamboo bundle curtain;

[0043] S3, impregnating the bamboo bundle curtain with an unmodified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundles to obtain an unmodified bamboo bundle curtain;

[0044] S4. Place two layers of modified bamboo bundle curtains on the upper and lower surface layers of the slab respectively, and place three layers of unmodified bamboo bundle curtains on the core layer for assembly and composite lamination to obtain bamboo bundle fiber laminates; hot pressing parameters are temperature 140±5°C, pressure 19 MPa, and time 30 minutes.

[0045] Example 2

[0046] A method for preparing bamboo fiber laminated timber comprises the following steps:

[0047] S1. 1200 mesh mica and silane coupling agent KH550 were mixed in a mass ratio of 1:2, and the mixture was modified by mechanical stirring at 70°C for 60 minutes. The mixture was washed with clean water and filtered, and then dried at 60°C for 1 hour to obtain modified mica. The modified mica was mixed with phenolic resin adhesive in a mass ratio of 1:10, and the mixture was fully stirred to mix the two to obtain a mica-modified phenolic resin adhesive.

[0048] S2, impregnating the bamboo bundle curtain with mica-modified phenolic resin adhesive at room temperature, with an impregnation amount of about 16% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundle to obtain a modified bamboo bundle curtain;

[0049] S3, impregnating the bamboo bundle curtain with an unmodified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundles to obtain an unmodified bamboo bundle curtain;

[0050] S4. Place two layers of modified bamboo bundle curtains on the upper and lower surfaces of the slab respectively, and place three layers of unmodified bamboo bundle curtains on the core layer for assembly and composite lamination; hot pressing parameters are temperature 140±5°C, pressure 19 MPa, and time 30 minutes.

[0051] Example 3

[0052] A method for preparing bamboo fiber laminated timber comprises the following steps:

[0053] S1. 1200 mesh mica and silane coupling agent KH560 were mixed in a mass ratio of 1:1, and the mixture was modified by mechanical stirring at 70°C for 60 minutes. The mixture was washed with clean water and filtered, and then dried at 60°C for 1 hour to obtain modified mica. The modified mica was mixed with phenolic resin adhesive in a mass ratio of 1:20, and the mixture was fully stirred to mix the two to obtain a mica-modified phenolic resin adhesive.

[0054] S2, impregnating the bamboo bundle curtain with mica-modified phenolic resin adhesive at room temperature, with an impregnation amount of about 15% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundle to obtain a modified bamboo bundle curtain;

[0055] S3, impregnating the bamboo bundle curtain with an unmodified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundles to obtain an unmodified bamboo bundle curtain;

[0056] S4. Place two layers of modified bamboo bundle curtains on the upper surface layer of the slab, and place four layers of unmodified bamboo bundle curtains on the core layer for assembly and composite lamination; hot pressing parameters are temperature 140±5°C, pressure 19 MPa, and time 30 minutes.

[0057] Example 4

[0058] A method for preparing bamboo fiber laminated timber comprises the following steps:

[0059] S1. 1200 mesh mica and silane coupling agent KH570 were mixed in a mass ratio of 1:1, and the mixture was modified by mechanical stirring at 70°C for 60 minutes. The mixture was washed with clean water and filtered, and then dried at 60°C for 1 hour to obtain modified mica. The modified mica was mixed with phenolic resin adhesive in a mass ratio of 1:20, and the mixture was fully stirred to mix the two to obtain a mica-modified phenolic resin adhesive.

[0060] S2, impregnating the bamboo bundle curtain with mica-modified phenolic resin adhesive at room temperature, with an impregnation amount of about 16% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundle to obtain a modified bamboo bundle curtain;

[0061] S3, impregnating the bamboo bundle curtain with an unmodified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundles to obtain an unmodified bamboo bundle curtain;

[0062] S4. Place two layers of modified bamboo bundle curtains on the upper and lower surfaces of the slab respectively, and place one layer of unmodified bamboo bundle curtain on the core layer for assembly and composite lamination; hot pressing parameters are temperature 140±5°C, pressure 19 MPa, and time 30 minutes.

[0063] Example 5

[0064] A method for preparing bamboo fiber laminated timber comprises the following steps:

[0065] S1. Mix 3000 mesh mica and silane coupling agent KH560 in a mass ratio of 1:1.5, modify them by mechanical stirring at 80°C for 120 minutes, wash with clean water and filter, and then dry at 60°C for 1 hour to obtain modified mica; mix the modified mica with phenolic resin adhesive in a mass ratio of 1:10, and stir them thoroughly to mix them evenly to obtain a mica-modified phenolic resin adhesive;

[0066] S2, impregnating the bamboo bundle curtain with mica-modified phenolic resin adhesive at room temperature, with an impregnation amount of about 13% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundle to obtain a modified bamboo bundle curtain;

[0067] S3, impregnating the bamboo bundle curtain with an unmodified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundles to obtain an unmodified bamboo bundle curtain;

[0068] S4. Place two layers of modified bamboo bundle curtains on the upper and lower surfaces of the slab respectively, and place three layers of unmodified bamboo bundle curtains on the core layer for assembly and composite lamination; hot pressing parameters are temperature 140±5°C, pressure 15MPa, and time 30 minutes.

[0069] Example 6

[0070] S1. 1200 mesh mica and silane coupling agent KH560 were mixed in a mass ratio of 1:1, and the mixture was modified by mechanical stirring at 70°C for 60 minutes. The mixture was washed with clean water and filtered, and then dried at 60°C for 1 hour to obtain modified mica. The modified mica was mixed with phenolic resin adhesive in a mass ratio of 1:5, and the mixture was fully stirred to mix the two to obtain a mica-modified phenolic resin adhesive.

[0071] S3, impregnating the bamboo bundle curtain with mica-modified phenolic resin adhesive at room temperature, with an impregnation amount of about 17% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundle to obtain a modified bamboo bundle curtain;

[0072] S3, impregnating the bamboo bundle curtain with an unmodified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundles to obtain an unmodified bamboo bundle curtain;

[0073] S4. Place two layers of modified bamboo bundle curtains on the upper and lower surfaces of the slab, and place three layers of unmodified bamboo bundle curtains on the core layer for assembly and composite lamination; hot pressing parameters are temperature 140±5°C, pressure 19 MPa, and time 30 minutes.

[0074] Example 7

[0075] S1. 1200 mesh mica and silane coupling agent KH550 were mixed in a mass ratio of 1:1, and mechanically stirred at 70°C for 60 minutes for modification. The mixture was washed with clean water and filtered, and then dried at 60°C for 1 hour to obtain modified mica. The modified mica was mixed with epoxy resin adhesive in a mass ratio of 1:10, and the mixture was thoroughly stirred to obtain a mica-modified epoxy resin adhesive.

[0076] S2, impregnating the bamboo bundle curtain with mica-modified epoxy resin adhesive at room temperature, with an impregnation amount of about 17% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundle to obtain a modified bamboo bundle curtain;

[0077] S3, impregnating the bamboo bundle curtain with an unmodified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundles to obtain an unmodified bamboo bundle curtain;

[0078] S4. Place two layers of modified bamboo bundle curtains on the upper and lower surfaces of the slab, and place three layers of unmodified bamboo bundle curtains on the core layer for assembly and composite lamination; hot pressing parameters are temperature 140±5°C, pressure 19 MPa, and time 30 minutes.

[0079] Example 8

[0080] A method for preparing bamboo fiber laminated timber differs from Example 3 in that mica not modified with a coupling agent is used in step S1. Other steps are the same as those in Example 3 and are not described again.

[0081] Example 9

[0082] S1. 1200 mesh mica and silane coupling agent KH560 were mixed in a mass ratio of 1:1, and the mixture was modified by mechanical stirring at 70°C for 60 minutes. The mixture was washed with clean water and filtered, and then dried at 60°C for 1 hour to obtain modified mica. The modified mica was mixed with phenolic resin adhesive in a mass ratio of 1:50, and the mixture was thoroughly stirred to obtain a mica-modified phenolic resin adhesive.

[0083] S3, impregnating the bamboo bundle curtain with mica-modified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundle to obtain a modified bamboo bundle curtain;

[0084] S3, impregnating the bamboo bundle curtain with an unmodified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundles to obtain an unmodified bamboo bundle curtain;

[0085] S4. Place two layers of modified bamboo bundle curtains on the upper and lower surfaces of the slab, and place three layers of unmodified bamboo bundle curtains on the core layer for assembly and composite lamination; hot pressing parameters are temperature 140±5°C, pressure 19 MPa, and time 30 minutes.

[0086] Example 10

[0087] S1. 1200 mesh mica and silane coupling agent KH560 were mixed in a mass ratio of 1:1, and the mixture was modified by mechanical stirring at 70°C for 60 minutes. The mixture was washed with clean water and filtered, and then dried at 60°C for 1 hour to obtain modified mica. The modified mica was mixed with phenolic resin adhesive in a mass ratio of 1:100, and the mixture was fully stirred to mix the two to obtain a mica-modified phenolic resin adhesive.

[0088] S3, impregnating the bamboo bundle curtain with mica-modified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundle to obtain a modified bamboo bundle curtain;

[0089] S3, impregnating the bamboo bundle curtain with an unmodified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundles to obtain an unmodified bamboo bundle curtain;

[0090] S4. Place two layers of modified bamboo bundle curtains on the upper and lower surfaces of the slab, and place three layers of unmodified bamboo bundle curtains on the core layer for assembly and composite lamination; hot pressing parameters are temperature 140±5°C, pressure 19 MPa, and time 30 minutes.

[0091] Example 11

[0092] S1. 1200 mesh mica and silane coupling agent KH560 were mixed in a mass ratio of 1:1, and the mixture was modified by mechanical stirring at 70°C for 60 minutes. The mixture was washed with clean water and filtered, and then dried at 60°C for 1 hour to obtain modified mica. The modified mica was mixed with phenolic resin adhesive in a mass ratio of 1:200, and the mixture was fully stirred to mix the two to obtain a mica-modified phenolic resin adhesive.

[0093] S3, impregnating the bamboo bundle curtain with mica-modified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundle to obtain a modified bamboo bundle curtain;

[0094] S3, impregnating the bamboo bundle curtain with an unmodified phenolic resin adhesive at room temperature, with an impregnation amount of about 18% and an impregnation time of 30 minutes, draining and drying the impregnated bamboo bundles to obtain an unmodified bamboo bundle curtain;

[0095] S4. Place two layers of modified bamboo bundle curtains on the upper and lower surfaces of the slab, and place three layers of unmodified bamboo bundle curtains on the core layer for assembly and composite lamination; hot pressing parameters are temperature 140±5°C, pressure 19 MPa, and time 30 minutes.

[0096] Comparative Example 1

[0097] The bamboo bundle curtain was impregnated with unmodified phenolic resin adhesive at room temperature with an impregnation amount of about 18% for 30 minutes. The impregnated bamboo bundle was drained and dried. Five layers of untreated bamboo bundle curtain were assembled and laminated. The hot pressing parameters were temperature 140±5°C, pressure 19 MPa, and time 30 minutes.

[0098] Comparative Example 2

[0099] The bamboo bundle curtains were impregnated with unmodified phenolic resin adhesive at room temperature with an impregnation amount of about 18% for 30 minutes, and the impregnated bamboo bundles were drained and dried; 5 layers of untreated bamboo bundle curtains were assembled and laminated; the hot pressing parameters were temperature 140±5℃, pressure 19MPa, and time 30 minutes to produce the boards, and the surfaces were coated with paint for protection.

[0100] The durability of the above embodiments and comparative examples, such as the 24h water absorption thickness expansion rate, the surface properties after 14 days of UV accelerated aging, and one year of outdoor natural aging, are shown in Table 1.

[0101] 24h water absorption thickness expansion rate: tested in accordance with the national standard GB / T 17657-2013 "Test methods for physical and chemical properties of wood-based panels and veneered wood-based panels".

[0102] UV accelerated aging for 14 days: Place the plate horizontally with the surface facing up and irradiate with a 500W xenon lamp for 14 days to observe the surface properties of the plate.

[0103] One year of outdoor natural aging: The board was placed horizontally with the surface facing upward on an outdoor open-air platform in Beijing, China. After aging for one year, the surface properties of the board were observed.

[0104] Table 1 Durability of surface modified bamboo fiber composites

[0105]

[0106]

[0107] As can be seen from Table 1, when mica is not added, the crack resistance, aging resistance, and water resistance of bamboo fiber composites obtained with conventional phenolic resin adhesives are reduced. However, adding an appropriate amount of coupling agent-modified mica significantly improves crack resistance, aging resistance, and water resistance. However, when too much mica is added, crack resistance and aging resistance decrease. This shows that the present invention, through the combination of coupling agent-modified mica and resin adhesive, has a synergistic effect on improving the bonding of bamboo fibers.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A bamboo fiber laminated timber, characterized in that: It comprises a core layer and an upper surface layer and / or a lower surface layer bonded to both sides of the core layer; the upper surface layer and / or the lower surface layer are obtained by impregnating bamboo bundles with a mica-modified resin adhesive; The mica-modified resin adhesive comprises coupling agent-modified mica and resin adhesive; The preparation method of the coupling agent modified mica is as follows: mica and a silane coupling agent are mixed in a mass ratio of 1: (0.1-5), and reacted at 50°C-95°C; The particle size of the mica is 200-3000 mesh; The mass ratio of the coupling agent modified mica to the resin adhesive is 1: (5-200); and / or, the mass ratio of the mica to the coupling agent is 1:(0.1-5); The resin adhesive includes one or more of phenolic resin, epoxy resin glue, isocyanate glue, polyurethane glue, urea-formaldehyde resin glue, white latex and soybean glue; And / or, the coupling agent includes one or more of silane coupling agents KH550, KH560 and KH570; The core layer is obtained by impregnating bamboo bundles with unmodified resin adhesive; the core layer comprises 1-10 layers of bamboo bundles and / or mixed paving bamboo bundles; The preparation method of the bamboo bundle fiber laminated timber comprises the following steps: S1, mixing mica and a silane coupling agent in a mass ratio of 1: (0.1-5), reacting at 50°C-95°C to obtain modified mica; mixing the modified mica with a resin adhesive in a mass ratio of 1: (5-200) to obtain a mica-modified resin adhesive; S2, impregnating bamboo bundles with the mica-modified resin adhesive to obtain modified bamboo bundles; S3, impregnating the bamboo bundle with an unmodified resin adhesive to obtain an unmodified bamboo bundle; S4. Placing unmodified bamboo bundles on the core layer, and placing modified bamboo bundles on the upper and / or lower surfaces of the core layer, respectively, and performing composite hot pressing to obtain bamboo bundle fiber laminated materials.

2. The bamboo fiber laminated timber according to claim 1, characterized in that: The amount of the modified bamboo bundle impregnated with glue is 8% to 25%; the amount of the unmodified bamboo bundle impregnated with glue is 8% to 25%; And / or, the immersion time of steps S2 and S3 is 10 to 45 minutes.

3. The bamboo fiber laminated timber according to claim 1, characterized in that: The bamboo bundles are bamboo bundle fibers obtained by rolling and decomposing bamboo materials.

4. The bamboo fiber laminated timber according to claim 1, characterized in that: The mass ratio of the modified mica to the resin adhesive is 1:(10-50); And / or, the mass ratio of the mica to the silane coupling agent is 1:(1-2.5).

5. The bamboo fiber laminated timber according to claim 1, characterized in that: The temperature of the composite hot pressing is 140±5°C, the pressure is 0.5~30 MPa, and the time is 5~90 ​​minutes.

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