A non-formaldehyde shaving board and a preparation method and application thereof

Abstract

The present application provides a kind of formaldehyde-free shaving board and its preparation method and application.The formaldehyde-free shaving board includes upper surface layer, core layer and lower surface layer;Wherein, the raw materials of upper surface layer and lower surface layer include wood shaving fine material, adhesive and water;The raw materials of the core layer include wood shaving coarse material, adhesive, curing agent, softener and water;Wherein, the adhesive includes isocyanate.Curing agent can improve the curing speed of adhesive isocyanate, softener can reduce the hardness of shaving board, improve elasticity, reduce the pre-curing of adhesive before hot pressing, so as to improve the problem that the post-processing section of isocyanate formaldehyde-free shaving board is higher than that of urea-formaldehyde resin shaving board.

Description

Technical Field

[0001] This invention belongs to the field of particleboard technology, and relates to a formaldehyde-free particleboard, its preparation method, and its application. Background Technology

[0002] Particleboard is made from fast-growing or small-diameter timber, so developing particleboard can not only alleviate the demand for timber resources, but also protect the local ecological environment.

[0003] Traditional adhesives used in the engineered wood products industry are "three-aldehyde adhesives," namely urea-formaldehyde resin adhesives, phenolic resin adhesives, and melamine-formaldehyde resin adhesives. When these three adhesives are used in the production of engineered wood products, the boards contain free formaldehyde, which is gradually released into the environment, polluting indoor air and harming human health. Currently, engineered wood products using "three-aldehyde adhesives" mainly reduce formaldehyde release by optimizing the adhesive formula (e.g., changing the ratio of urea to formaldehyde) and adding formaldehyde scavengers. However, these methods still cannot achieve formaldehyde-free production.

[0004] Isocyanates have been widely used in other industries due to their high bonding strength, strong water resistance, and formaldehyde-free properties. They can achieve good physical and mechanical properties with a significantly lower application rate than formaldehyde-free adhesives. Despite these advantages, some problems still need to be addressed in the production process of formaldehyde-free particleboard. For example, the polyurea formed by the reaction of isocyanate with water in wood shavings has excessive hardness and low elasticity, leading to difficulties in sawing and veneering.

[0005] CN114181659A discloses a formaldehyde-free adhesive, which mainly improves the problem of slow curing speed, but fails to solve the problem of excessive hardness and poor elasticity of the finished board. CN115141343A discloses a formaldehyde-free particleboard additive, whose main function is to maintain excellent bonding and mechanical properties while further improving the production efficiency of formaldehyde-free engineered wood products, but it also fails to improve the problem of excessive hardness and poor elasticity of the finished board.

[0006] In summary, the production of formaldehyde-free engineered wood panels using isocyanate as an adhesive still faces several problems that urgently need to be addressed, including severe pre-curing of the adhesive after application, low production efficiency, and excessive hardness of the board blank after hot pressing, which affects subsequent processing. Summary of the Invention

[0007] To address the shortcomings of existing technologies, one of the objectives of this invention is to provide a formaldehyde-free particleboard. This formaldehyde-free particleboard not only eliminates the need for added formaldehyde, but also, under the same processing conditions, exhibits physical and mechanical properties similar to isocyanate-based formaldehyde-free particleboard without added softeners. However, post-processing is more convenient, and the reduced saw blade speed prevents edge clogging, thereby extending saw blade life and improving the board's appearance. Furthermore, it exhibits good dimensional stability after veneering, preventing cracking caused by significant differences in the deformation capabilities of the substrate and veneering material.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] A formaldehyde-free particleboard, comprising an upper surface layer, a core layer, and a lower surface layer; wherein the upper and lower surface layers are made of wood shavings, adhesive, and water; the core layer is made of wood shavings, adhesive, curing agent, softener, and water; wherein the adhesive comprises isocyanate.

[0010] Polyethers in fabric softeners react with isocyanates to produce flexible foam, which has a lower hardness than polyurea, the product of water and isocyanates. Polyether amines in fabric softeners not only react with isocyanates to produce flexible foam, but also react at a faster rate than polyethers, further improving production efficiency. The long-chain hydrocarbons in fabric softeners, with an amino group at one end that can react with isocyanates and a rotatable ether bond at the other end, enhance the product's flexibility. Furthermore, due to the presence of a benzene ring, they exhibit steric hindrance, resulting in lower reactivity before the hot-pressing process, thus reducing the formation of pre-cured material.

[0011] In this invention, the adhesive refers to the adhesive used for the upper surface layer, lower surface layer, and core material. The wood shavings of this invention can be, for example, elongated thin flakes measuring 0.8~12mm * 0.8~1.2mm * 0.1~0.6mm. The wood shavings are sorted by airflow to obtain fine surface wood and coarse core wood. This invention does not impose specific limitations on the exact dimensions of the fine and coarse wood shavings; the finer material obtained after sieving can be used as fine wood shavings, and the coarser material can be used as coarse wood shavings.

[0012] In one embodiment of the present invention, the raw materials of the upper and lower surface layers are, by weight, as follows:

[0013] 100 parts of wood shavings;

[0014] 3-10 parts isocyanate;

[0015] 10-25 parts water.

[0016] In one embodiment of the present invention, the raw material of the core layer is as follows, by weight:

[0017] 100 parts of coarse wood shavings;

[0018] 2-8 parts isocyanate;

[0019] Hardener 0.2-2 parts;

[0020] 0.1-1 part fabric softener;

[0021] Water 2-6 parts.

[0022] In one embodiment of the present invention, the mass ratio of the upper surface layer, the core layer and the lower surface layer is 1:(2.5-4):1, preferably 1:(3-3.5):1.

[0023] In one embodiment of the present invention, the isocyanate has a functionality of 2.6-2.7.

[0024] In one embodiment of the invention, the isocyanate has an -NCO value of 25-35 wt%.

[0025] In one embodiment of the invention, the isocyanate comprises polydiphenylmethane diisocyanate.

[0026] In one embodiment of the present invention, the curing agent comprises an amine curing agent, preferably an aliphatic amine catalyst, more preferably one or more of triethylamine, triethylenediamine, N,N-dimethylcyclohexylamine, N,N-dimethylhexadecanamine, and diethylenetriamine, and even more preferably N,N-dimethylcyclohexylamine.

[0027] In one embodiment of the present invention, the softener comprises three substances A1, A2, and A3; preferably, A1 is a long-chain low-functionality polyether, preferably with a functionality of 2-3 and an average molecular weight of 3000-6000, more preferably with a molecular weight of 5000-6000; preferably, A2 is a polyether amine terminated with a primary amine and / or a secondary amine, preferably with a functionality of 2-3 and an average molecular weight of 230-4000, more preferably with a molecular weight of 230-2000; preferably, A3 is an alkane with one end benzylamino and the other end phenylalkoxy, preferably with the main chain of A3 having ≥4 carbon atoms and the branched phenylalkoxy having ≥3 carbon atoms, more preferably A3 is 6-benzylamino-1-(4'-phenylbutoxy)hexane; preferably, the mass ratio of A1, A2, and A3 is 1:(0.1-0.5):(0.1-1).

[0028] Another object of the present invention is to provide a method for preparing formaldehyde-free particleboard.

[0029] A method for preparing formaldehyde-free particleboard, the method comprising the following steps:

[0030] S1: Dried wood shavings, fine surface material and coarse core material;

[0031] S2: Apply adhesive to wood shavings, add water, and obtain the upper and lower surface preparation materials respectively;

[0032] S3: Apply adhesive, hardener and softener to the wood shavings, add water to obtain the core layer preparation material;

[0033] S4: Place the pre-prepared material for the lower surface layer, the pre-prepared material for the core layer, and the pre-prepared material for the upper surface layer into the laying box in sequence, lay them out and form them, and hot press them to obtain the formaldehyde-free particleboard.

[0034] In one embodiment of the present invention, S1 is dried to a moisture content ≤2wt%.

[0035] In one embodiment of the present invention, the temperature of S3 hot pressing is 180-250°C, the pressure is 0.5-6 MPaG, and the time is 80-140 s.

[0036] Another object of the present invention is to provide a use for preparing formaldehyde-free particleboard.

[0037] An application for preparing formaldehyde-free particleboard, wherein the particleboard is the particleboard described above, or a particleboard prepared by the method described above, and the particleboard is used as a furniture board.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] (1) In this invention, the raw materials for preparing the core layer of the formaldehyde-free board include adhesive isocyanate, curing agent and softener. The curing agent can improve the production efficiency of the formaldehyde-free board, and the use of the softener can improve the elasticity of the board and reduce the hardness of the board, thereby improving the production efficiency of the formaldehyde-free board.

[0040] (2) The particleboard provided by this invention not only achieves formaldehyde-free production, but also, under the same process conditions, has physical and mechanical properties similar to that of isocyanate-based formaldehyde-free particleboard without added softener. However, post-processing is more convenient, and the reduced saw blade speed makes it less prone to edge clogging, thereby improving saw blade life and board appearance. The dimensional stability after veneer is good, and cracking will not occur due to excessive difference in deformation capacity between the substrate and the veneer. Detailed Implementation

[0041] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0042] Table 3

[0043] raw material Manufacturer Brand Isocyanates Wanhua Chemical's CW20 (functionality 2.6-2.7, -NCO content 30.5-32wt%, a mixture of isocyanate and diphenylmethane diisocyanate) curing agent N,N-Dimethylcyclohexylamine softener Polyether: Wuhan Litai Chemical Co., Ltd., DEP-5631D (functionality 3, molecular weight 3000), 10LD76E (functionality 3, molecular weight 5000), 10LD83E (functionality 3, molecular weight 6000) Polyetheramine: Shanghai Aladdin, Polyetheramine D-230 (functionality 2), D-2000 (functionality 2), D-4000 (functionality 2) Alkane: Hubei Hongxin Ruiyu Fine Chemical, 6-benzylamino-1-(4'-phenylbutoxy)hexane; Hangzhou Xunda Biotechnology Co., Ltd., N-benzyl-6-(4-phenylbutoxy)hexane-1-amine oxalate Wood shavings Artificial board factory

[0044] Example 1

[0045] This embodiment provides a formaldehyde-free particleboard, which includes an upper surface layer, a core layer, and a lower surface layer. The raw materials of the upper and lower surface layers, by weight, each include the following components:

[0046] 3000g of wood shavings;

[0047] 120g of isocyanate;

[0048] 600g of water;

[0049] The raw materials for the core layer, by weight, include the following components:

[0050] 3000g of coarse wood shavings;

[0051] 90g of isocyanate;

[0052] 6g of curing agent;

[0053] 30g of fabric softener;

[0054] 120g of water.

[0055] The isocyanate is grade CW20, the curing agent is N,N-dimethylcyclohexylamine, and the softener is graded DEP-5631D (molecular weight 3000), D-230, and N-benzyl-6-(4-phenylbutoxy)hexane-1-amine oxalate, with a mass ratio of 1:0.1:0.1. The mass ratio of the upper surface layer, core layer, and lower surface layer is 1:3:1.

[0056] The preparation method includes the following steps:

[0057] (1) Before the experiment, the wood shavings were placed in a 120℃ oven and dried until the moisture content was 2wt%.

[0058] (1) Pour the wood shavings into the glue mixer, apply isocyanate using a compressed air spray gun, and then add water to obtain the upper and lower surface preparation materials respectively.

[0059] (2) Pour the wood shavings into the glue mixer, apply isocyanate, hardener and softener using a compressed air spray gun, and then add water to obtain the core layer preparation material;

[0060] (3) The preparatory material of the lower surface layer, the preparatory material of the core layer and the preparatory material of the upper surface layer are placed into the laying box in sequence. After laying and forming, the air in the middle is squeezed out. Then, it is placed in the hot press and hot-pressed at 230°C to obtain the formaldehyde-free particleboard.

[0061] The specific hot pressing process is as follows: the hot pressing factor is 6s / mm, and the hot pressing is carried out in sequence according to the following pressure and time: 4MPa(G) / 20s+3.5MPa(G) / 25s+3MPa(G) / 15s+2MPa(G) / 15s+1.5MPa(G) / 20s+0.5MPa(G) / 13s.

[0062] Example 2

[0063] This embodiment provides a formaldehyde-free particleboard, which includes an upper surface layer, a core layer, and a lower surface layer. The raw materials for preparing the upper and lower surface layers each include the following components in parts by weight:

[0064] 3000g of wood shavings;

[0065] 120g of isocyanate;

[0066] 600g of water;

[0067] The raw materials for preparing the core layer include the following components by weight:

[0068] 3000g of coarse wood shavings;

[0069] 90g of isocyanate;

[0070] 6g of curing agent;

[0071] 3g of fabric softener;

[0072] 120g of water.

[0073] The isocyanate is grade CW20, the curing agent is N,N-dimethylcyclohexylamine, and the softener is graded DEP-5631D (molecular weight 3000), D-230, and N-benzyl-6-(4-phenylbutoxy)hexane-1-amine oxalate, with a mass ratio of 1:0.1:0.1. The mass ratio of the upper surface layer, core layer, and lower surface layer is 1:3.5:1.

[0074] The preparation method is the same as in Example 1. Before preparation, the wood shavings were placed in a 120℃ oven and dried until the moisture content was 0.5wt%.

[0075] Example 3

[0076] This embodiment provides a formaldehyde-free particleboard, which includes an upper surface layer, a core layer, and a lower surface layer. The raw materials for preparing the upper and lower surface layers each include the following components in parts by weight:

[0077] 3000g of wood shavings;

[0078] 150g of isocyanate;

[0079] 800g of water;

[0080] The raw materials for preparing the core layer include the following components by weight:

[0081] 3000g of coarse wood shavings;

[0082] 100g of isocyanate;

[0083] 30g of curing agent;

[0084] 30g of fabric softener;

[0085] 150g of water.

[0086] The isocyanate is grade CW20, the curing agent is N,N-dimethylcyclohexylamine, and the softener is graded DEP-5631D (molecular weight 3000), D-4000 and 6-benzylamino-1-(4'-phenylbutoxy)hexane, with a mass ratio of 1:0.1:0.1. The mass ratio of the upper surface layer, core layer and lower surface layer is 1:3:1.

[0087] The preparation method is the same as in Example 1. Before the preparation experiment, the wood shavings were placed in a 120℃ oven and dried until the moisture content was 1wt%.

[0088] Example 4

[0089] This embodiment provides a formaldehyde-free particleboard, which includes an upper surface layer, a core layer, and a lower surface layer. The raw materials for preparing the upper and lower surface layers each include the following components in parts by weight:

[0090] 3000g of wood shavings;

[0091] 240g of isocyanate;

[0092] 300g of water;

[0093] The raw materials for preparing the core layer include the following components by weight:

[0094] 3000g of coarse wood shavings;

[0095] 60g of isocyanate;

[0096] 50g of curing agent;

[0097] 30g of fabric softener;

[0098] 180g of water.

[0099] The isocyanate is grade CW20, the curing agent is N,N-dimethylcyclohexylamine, and the softener is graded DEP-5631D (molecular weight 3000), D-2000 and 6-benzylamino-1-(4'-phenylbutoxy)hexane, with a mass ratio of 1:0.2:0.5. The mass ratio of the upper surface layer, core layer and lower surface layer is 1:3:1.

[0100] The preparation method is the same as in Example 1.

[0101] Example 5

[0102] This embodiment provides a formaldehyde-free particleboard, which includes an upper surface layer, a core layer, and a lower surface layer. The raw materials for preparing the upper and lower surface layers each include the following components in parts by weight:

[0103] 3000g of wood shavings;

[0104] 120g of isocyanate;

[0105] 600g of water;

[0106] The raw materials for preparing the core layer include the following components by weight:

[0107] 3000g of coarse wood shavings;

[0108] 90g of isocyanate;

[0109] 6g of curing agent;

[0110] 30g of fabric softener;

[0111] 120g of water.

[0112] The isocyanate is grade CW20, the curing agent is N,N-dimethylcyclohexylamine, and the softeners are grade 10LD76E (molecular weight 5000), D-230, and 6-benzylamino-1-(4'-phenylbutoxy)hexane, with a mass ratio of 1:0.1:0.1. The mass ratio of the upper surface layer, core layer, and lower surface layer is 1:3:1.

[0113] The preparation method is the same as in Example 1.

[0114] Example 6

[0115] This embodiment provides a formaldehyde-free particleboard, which includes an upper surface layer, a core layer, and a lower surface layer. The raw materials for preparing the upper and lower surface layers each include the following components in parts by weight:

[0116] 3000g of wood shavings;

[0117] 120g of isocyanate;

[0118] 600g of water;

[0119] The raw materials for preparing the core layer include the following components by weight:

[0120] 3000g of coarse wood shavings;

[0121] 90g of isocyanate;

[0122] 6g of curing agent;

[0123] 30g of fabric softener;

[0124] 120g of water.

[0125] The isocyanate is grade CW20, the curing agent is N,N-dimethylcyclohexylamine, and the softeners are grade 10LD76E (molecular weight 5000), D-4000 and 6-benzylamino-1-(4'-phenylbutoxy)hexane, with a mass ratio of 1:0.1:0.1. The mass ratio of the upper surface layer, core layer and lower surface layer is 1:3:1.

[0126] The preparation method is the same as in Example 1.

[0127] Example 7

[0128] This embodiment provides a formaldehyde-free particleboard, which includes an upper surface layer, a core layer, and a lower surface layer. The raw materials for preparing the upper and lower surface layers each include the following components in parts by weight:

[0129] 3000g of wood shavings;

[0130] 120g of isocyanate;

[0131] 600g of water;

[0132] The raw materials for preparing the core layer include the following components by weight:

[0133] 3000g of coarse wood shavings;

[0134] 90g of isocyanate;

[0135] 6g of curing agent;

[0136] 30g of fabric softener;

[0137] 120g of water.

[0138] The isocyanate is grade CW20, the curing agent is N,N-dimethylcyclohexylamine, and the softeners are grade 10LD76E (molecular weight 5000), D-2000 and 6-benzylamino-1-(4'-phenylbutoxy)hexane, with a mass ratio of 1:0.1:0.1. The mass ratio of the upper surface layer, core layer and lower surface layer is 1:3:1.

[0139] The preparation method is the same as in Example 1.

[0140] Example 8

[0141] This embodiment provides a formaldehyde-free particleboard, which includes an upper surface layer, a core layer, and a lower surface layer. The raw materials for preparing the upper and lower surface layers each include the following components in parts by weight:

[0142] 3000g of wood shavings;

[0143] 120g of isocyanate;

[0144] 600g of water;

[0145] The raw materials for preparing the core layer include the following components by weight:

[0146] 3000g of coarse wood shavings;

[0147] 90g of isocyanate;

[0148] 6g of curing agent;

[0149] 30g of fabric softener;

[0150] 120g of water.

[0151] The isocyanate is grade CW20, the curing agent is N,N-dimethylcyclohexylamine, and the softeners are grade 10LD83E (molecular weight 6000), D-230, and 6-benzylamino-1-(4'-phenylbutoxy)hexane, with a mass ratio of 1:0.1:0.1. The mass ratio of the upper surface layer, core layer, and lower surface layer is 1:3:1.

[0152] The preparation method is the same as in Example 1.

[0153] Example 9

[0154] This embodiment provides a formaldehyde-free particleboard, which includes an upper surface layer, a core layer, and a lower surface layer. The raw materials for preparing the upper and lower surface layers each include the following components in parts by weight:

[0155] 3000g of wood shavings;

[0156] 120g of isocyanate;

[0157] 600g of water;

[0158] The raw materials for preparing the core layer include the following components by weight:

[0159] 3000g of coarse wood shavings;

[0160] 90g of isocyanate;

[0161] 6g of curing agent;

[0162] 30g of fabric softener;

[0163] 120g of water.

[0164] The isocyanate is grade CW20, the curing agent is N,N-dimethylcyclohexylamine, and the softeners are grade 10LD83E (molecular weight 6000), D-2000 and 6-benzylamino-1-(4'-phenylbutoxy)hexane, with a mass ratio of 1:0.1:0.1. The mass ratio of the upper surface layer, core layer and lower surface layer is 1:3:1.

[0165] The preparation method is the same as in Example 1.

[0166] Comparative Example 1

[0167] The only difference between this comparative example and Example 1 is that the raw materials used to prepare the core layer do not include a softener.

[0168] A formaldehyde-free particleboard is provided, comprising an upper surface layer, a core layer, and a lower surface layer. The raw materials for preparing the upper and lower surface layers each comprise the following components in parts by weight:

[0169] 3000g of wood shavings;

[0170] 120g of isocyanate;

[0171] 600g of water;

[0172] The raw materials for preparing the core layer include the following components by weight:

[0173] 3000g of coarse wood shavings;

[0174] 90g of isocyanate;

[0175] 6g of curing agent;

[0176] 0g of fabric softener;

[0177] 120g of water.

[0178] The isocyanate grade is CW20, the curing agent is N,N-dimethylcyclohexylamine, and the mass ratio of the upper surface layer, core layer and lower surface layer is 1:3:1.

[0179] The remaining preparation methods are the same as in Example 1.

[0180] Comparative Example 2

[0181] The only difference between this comparative example and Example 1 is that the softener in the raw materials for preparing the core layer is replaced with propyl ether.

[0182] A formaldehyde-free particleboard is provided, comprising an upper surface layer, a core layer, and a lower surface layer. The raw materials for preparing the upper and lower surface layers each comprise the following components in parts by weight:

[0183] 3000g of wood shavings;

[0184] 120g of isocyanate;

[0185] 600g of water;

[0186] The raw materials for preparing the core layer include the following components by weight:

[0187] 3000g of coarse wood shavings;

[0188] 90g of isocyanate;

[0189] 6g of curing agent;

[0190] 30g of fabric softener;

[0191] 120g of water.

[0192] The isocyanate is grade CW20, the curing agent is N,N-dimethylcyclohexylamine, the softener is propyl ether, and the mass ratio of the upper surface layer, the core layer and the lower surface layer is 1:3:1.

[0193] The preparation method is the same as in Example 1.

[0194] The particleboard provided in the embodiments and comparative examples was subjected to performance tests, and the test methods are as follows:

[0195] (1) 2-hour water absorption thickness swelling rate: The test was conducted according to test method 4.4, water absorption thickness swelling rate determination method 1, as specified in GB / T17657-2013;

[0196] (2) Static bending strength and modulus of elasticity: The test shall be conducted in accordance with the test method 4.7 Determination of static bending strength and modulus of elasticity (three-point bending) specified in GB / T17657-2013;

[0197] (3) Internal bond strength: Tested according to test method 4.11 Internal bond (bond) strength determination specified in GB / T17657-2013;

[0198] (4) Physical and mechanical performance requirements: Tested according to GB / T4897.3-2003 Particleboard Part 3: Requirements for furniture and interior decoration boards used in dry state: For boards with a nominal thickness of 13~20mm, static bending strength ≥13Mpa, elastic modulus ≥1600Mpa, internal bond strength ≥0.35Mpa, and thickness expansion rate after 2 hours of water absorption ≤8%.

[0199] The hot press used in the experiment was a universal testing press from Wuxi Dipu, and the instrument used to test the performance was a high-speed rail universal tensile testing machine.

[0200] The thickness and performance test results of the particleboard provided in the examples and comparative examples are shown in Table 4.

[0201] Table 4

[0202] Thickness / mm Internal bond strength / MPa Static bending strength / MPa Elastic modulus / MPa 2-hour water absorption thickness expansion rate / % Saw blade rotation speed r / min Paste the edges Example 1 18.35 0.43 14.7 1945 4 60 no Example 2 18.32 0.46 15.2 2030 3.4 65 no Example 3 18.33 0.45 14.8 1960 3.2 55 no Example 4 18.36 0.48 15.2 2031 4.1 55 no Example 5 18.34 0.46 15.0 2011 4.1 55 no Example 6 18.33 0.46 14.7 1997 3.8 55 no Example 7 18.35 0.48 14.9 2004 3.9 50 no Example 8 18.31 0.47 14.8 2006 4.1 50 no Example 9 18.32 0.46 15.0 2007 3.8 50 no Comparative Example 1 18.62 0.37 13.4 1457 5.6 70 yes Comparative Example 2 18.57 0.38 13.8 1467 5.8 70 yes

[0203] As can be seen from Table 4, the formaldehyde-free particleboard provided in Examples 1-9 of this invention has internal bond strength (0.43-0.48MPa), static bending strength (14.7-15.2MPa), elastic modulus (1945-2031MPa), and 2-hour water absorption thickness expansion rate (3.2-4.1) that all meet the national standard requirements.

[0204] With the increase of the amount of softener, the required rotational speed of the saw blade gradually decreases, and the problem of edge smudging is also solved.

[0205] This invention illustrates the formaldehyde-free particleboard, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A formaldehyde-free particleboard, characterized in that, The formaldehyde-free particleboard includes an upper surface layer, a core layer, and a lower surface layer; wherein, the raw materials of the upper and lower surface layers include fine wood shavings, adhesive, and water; the raw materials of the core layer include coarse wood shavings, adhesive, curing agent, softener, and water; The adhesive comprises isocyanate; The softener contains three substances A1, A2, and A3; A1 is a long-chain, low-functionality polyether with a functionality of 2-3 and an average molecular weight of 3000-6000. A2 is a polyetheramine terminated with primary and / or secondary amines, with an average molecular weight of 230-4000; A3 is an alkane with a benzylamino group at one end and a phenylalkoxy group at the other end.

2. The formaldehyde-free particleboard according to claim 1, characterized in that, The raw materials for the upper and lower surface layers are, by weight, as follows: 100 parts of wood shavings; 3-10 parts isocyanate; 10-25 parts water; And / or, the raw material of the core layer is, by weight, the following: 100 parts of coarse wood shavings; 2-8 parts isocyanate; Hardener 0.2-2 parts; 0.1-1 part fabric softener; Water 2-6 parts.

3. The formaldehyde-free particleboard according to claim 1 or 2, characterized in that, The mass ratio of the upper surface layer, core layer, and lower surface layer is 1:(2.5-4):

1.

4. The formaldehyde-free particleboard according to claim 3, characterized in that, The mass ratio of the upper surface layer, core layer and lower surface layer is 1:(3-3.5):

1.

5. The formaldehyde-free particleboard according to claim 1, characterized in that, The isocyanate has a functionality of 2.6-2.7; And / or, the -NCO value of the isocyanate is 25-35 wt%; And / or, the isocyanate comprises polydiphenylmethane diisocyanate.

6. The formaldehyde-free particleboard according to claim 1, characterized in that, The curing agent includes amine-based curing agents.

7. The formaldehyde-free particleboard according to claim 6, characterized in that, The curing agent contains an aliphatic amine catalyst.

8. The formaldehyde-free particleboard according to claim 7, characterized in that, The curing agent comprises one or more of triethylamine, triethylenediamine, N,N-dimethylcyclohexylamine, N,N-dimethylhexadecanamine, and diethylenetriamine.

9. The formaldehyde-free particleboard according to claim 8, characterized in that, The curing agent is N,N-dimethylcyclohexylamine.

10. The formaldehyde-free particleboard according to claim 1, characterized in that, A1 molecular weight 5000~6000; The functionality of A2 is 2~3, and the molecular weight of A2 is 230~2000; The main chain of A3 contains 4 or more alkane carbons, and the branched chain of phenyl alkoxyl contains 3 or more carbons.

11. The formaldehyde-free particleboard according to claim 10, characterized in that, A3 is 6-benzylamino-1-(4'-phenylbutoxy)hexane; The mass ratio of A1, A2, and A3 is 1:(0.1-0.5):(0.1-1).

12. A method for preparing formaldehyde-free particleboard, said method for preparing particleboard according to any one of claims 1-11, characterized in that, The method includes the following steps: S1: Dried wood shavings, fine surface material and coarse core material; S2: Apply adhesive to wood shavings, add water, and obtain the upper and lower surface preparation materials respectively; S3: Apply adhesive, hardener and softener to the wood shavings, add water to obtain the core layer preparation material; S4: Place the pre-prepared material for the lower surface layer, the pre-prepared material for the core layer, and the pre-prepared material for the upper surface layer into the laying box in sequence, lay them out, and hot-press them to obtain the formaldehyde-free particleboard.

13. The method according to claim 12, characterized in that, S1 dried to a moisture content ≤2wt%; And / or, the temperature of S3 hot pressing is 180-250℃, the pressure is 0.5-6 MPaG, and the time is 80-140s.

14. An application for preparing formaldehyde-free particleboard, wherein the particleboard is the particleboard according to any one of claims 1-11, or the particleboard prepared by the method according to claim 12 or 13, and the particleboard is used as a furniture board.