A fine-surface oriented strand board and its preparation method

Abstract

This invention relates to the technical field of oriented strand board (FOSB), and discloses a fine-surface FOSB and its preparation method. The FOSB comprises a surface layer, a core layer, and another surface layer, which are obtained by applying adhesive, oriented laying, pre-pressing, and hot-pressing of each layer of shavings. The surface layer is made of fine shavings, which are adhesively bonded with 6% isocyanate adhesive and 8-12% urea-formaldehyde resin adhesive. The core layer is made of large shavings, which are adhesively bonded with 4-6% isocyanate adhesive and 0.5-2% paraffin emulsion. This invention achieves higher surface bonding strength and lower 24-hour TS (Total Strength) of FOSB by simultaneously applying isocyanate adhesive and urea-formaldehyde resin adhesive to the fine shavings in the surface layer, and only applying paraffin emulsion to the large shavings in the core layer. Furthermore, the internal bond strength and flexural strength meet the requirements for use.

Description

Technical Field

[0001] This invention relates to the technical field of oriented strand board (OSB), and in particular to a fine-surface OSB and its preparation method. Background Technology

[0002] With the diversified development of the engineered wood products industry and the upgrading of consumer products, the "light luxury" style of customized home furnishing with high environmental protection performance has become a trend. Integrated design and visual integration are becoming increasingly popular, and there is a strong demand for large-format, integrated particleboard products. The boards used should have high strength, resistance to deformation, and light weight to ensure that the products are durable and do not deform. A representative new product that has been recognized by the market is fine-surface oriented strand board, also known as "decorative oriented strand board".

[0003] Fine surface oriented strand board (FOSB) is an oriented strand board made from fine wood shavings or fibers as the surface material. FOSB retains the excellent mechanical properties of oriented strand board, and its smooth surface allows for direct application in finishing, making it widely used in custom furniture and interior decoration. However, due to the small particle size and large surface area of ​​the fine surface layer, the amount of adhesive required increases, and the resulting fine surface layer enhances the hygroscopicity of FOSB. Public information indicates that applying a waterproofing agent to the fine surface layer of FOSB can improve hygroscopicity. However, applying a waterproofing agent to the fine surface layer reduces the interfacial bonding between the fine wood shavings, resulting in decreased surface bond strength, which also negatively impacts surface finishing applications such as veneers and paint finishes. To improve the surface bond strength of FOSB, the amount of isocyanate applied to the fine surface layer can be increased, but this significantly increases costs and reduces installation performance. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a fine-surface oriented strand board (FOSB) and its preparation method. By adjusting the thickness of each FOSB layer, the compounding method of the adhesive, and the addition position of paraffin emulsion in the FOSB blank, a fine-surface oriented strand board with stable surface bonding strength and excellent moisture resistance is prepared.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a fine-surface oriented strand board, comprising a surface layer, a core layer, and a surface layer, which is obtained by applying adhesive, oriented laying, pre-pressing, and hot pressing of each layer of shavings raw material; wherein, the raw material of the surface layer is fine shavings, which are adhesively bonded with 6% by mass of isocyanate adhesive and 8-12% by mass of urea-formaldehyde ester adhesive; the raw material of the core layer is large shavings, which are adhesively bonded with 4-6% by mass of isocyanate adhesive and 0.5-2% by mass of paraffin emulsion.

[0007] This invention improves the surface bonding strength of fine surface oriented strand board (FOSB) by adding a compounded isocyanate adhesive and urea-formaldehyde resin adhesive to the surface fine shavings. Furthermore, by adding paraffin emulsion to the core layer large shavings while simultaneously adding isocyanate adhesive, the internal bonding strength is improved, and the waterproof performance of the FOSB is enhanced. As a result, the overall performance of the FOSB is superior.

[0008] Furthermore, this invention achieves a lower 24h TS and better water resistance by adding paraffin emulsion only to the core layer of FOSB. However, adding paraffin emulsion to both the surface and core layers does not significantly improve the water resistance of the particleboard, and the resulting fine surface oriented strand board has lower surface bond strength and flexural strength. Therefore, the combination of two adhesives applied to the fine surface particles can achieve higher bonding strength, but the addition of paraffin emulsion to the surface layer actually reduces the surface bond strength. This may be because the compatibility of the paraffin emulsion with these two adhesives during application prevents a good synergistic improvement in bond strength and water resistance.

[0009] Preferably, the ratio of the total mass of the upper and lower surface layers to the mass of the core layer in the fine-surface oriented strand board is 20-40%:60-80%, and the upper and lower surface layers have the same mass.

[0010] Preferably, the moisture content of the surface fine wood shavings is 10-12%, wherein the fine wood shavings with a size of 20-100 mesh account for 86-88% of the total mass of the surface fine wood shavings.

[0011] Preferably, fine wood shavings with a size of less than 100 mesh account for 10-11% of the total mass of surface fine wood shavings, and fine wood shavings with a size of more than 20 mesh account for 1-4% of the total mass of surface fine wood shavings.

[0012] The size distribution of the surface fine wood chips will also work synergistically with the ratio of the adhesive applied to achieve better results. Different sizes of surface fine wood chips will have a better synergistic effect on strength. Furthermore, the size distribution of the surface fine wood chips can improve the flatness and smoothness of the particleboard surface, and it can be directly used for secondary veneer processing.

[0013] Preferably, the core layer of large wood shavings has a moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm.

[0014] Preferably, the surface fine wood shavings are applied using an isocyanate adhesive with a mass fraction of 6% and a urea-formaldehyde ester adhesive with a mass fraction of 10-12%.

[0015] Preferably, the core layer of large wood shavings is bonded with 6% isocyanate adhesive and 0.5-2% paraffin emulsion by mass.

[0016] Secondly, the present invention provides a method for preparing fine-surface oriented strand board, comprising the following steps:

[0017] (1) Apply adhesive: Apply isocyanate adhesive and urea-formaldehyde ester adhesive to the surface fine wood shavings, and apply isocyanate adhesive and paraffin emulsion to the core large wood shavings;

[0018] (2) Laying: The surface fine wood shavings and core large wood shavings after applying adhesive are laid layer by layer in a directional manner to obtain the board blank;

[0019] (3) Pre-pressing: Pre-pressing the slab;

[0020] (4) Hot pressing: The slab is then hot pressed again;

[0021] (5) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0022] Preferably, the pre-compression is performed at a pressure of 1.0–1.8 MPa for a duration of 3.5–5 min.

[0023] Preferably, the hot pressing is performed at a temperature of 160–180°C, a pressure of 2–5 MPa, and a time of 0.3–0.5 min / mm.

[0024] Compared with the prior art, the present invention has the following beneficial effects: by simultaneously adding isocyanate adhesive and urea-formaldehyde resin adhesive to the fine surface of FOSB, and adding paraffin emulsion only to the core layer of FOSB, the surface bonding strength of FOSB is higher, its 24h TS is lower, and its internal bond strength and flexural strength can meet the requirements of use. Detailed Implementation

[0025] The technical solution of the present invention will be illustrated below with specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0026] The fine-surface oriented strand board of the present invention comprises, in sequence, a surface layer, a core layer, and a surface layer, and its preparation method includes the following steps:

[0027] (1) Core layer large shavings with an initial moisture content of 8-10%, a length of 5-8cm, and a width of 2-4cm; surface fine shavings with an initial moisture content of 10-12%, fine shavings with a size of 20-100 mesh accounting for 86-88% of the total mass of surface fine shavings, fine shavings with a size of less than 100 mesh accounting for 10-11% of the total mass of surface fine shavings, and fine shavings with a size of more than 20 mesh accounting for 1-4% of the total mass of surface fine shavings;

[0028] (2) Apply adhesive: Apply 6 wt% isocyanate adhesive and 8-12 wt% urea-formaldehyde ester adhesive to the surface fine wood shavings, and apply 4-6 wt% isocyanate adhesive and 0.5-2 wt% paraffin emulsion to the core large wood shavings.

[0029] (3) Laying: The surface fine wood chips and core large wood chips after applying adhesive are laid layer by layer in an oriented manner to obtain a fine surface oriented particleboard blank, and the mass ratio of surface layer: core layer: surface layer in the fine surface oriented particleboard blank is 10-20%: 60-80%: 10-20%;

[0030] (4) Pre-pressing: The slab is pre-pressed at a pressure of 1.0 to 1.8 MPa for 3.5 to 5 minutes.

[0031] (5) Hot pressing: The slab is then hot pressed again. The hot pressing temperature is 160-180℃, the hot pressing pressure is 2-5MPa, and the hot pressing time is 0.3-0.5min / mm.

[0032] (6) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0033] In a specific embodiment of the present invention, the initial moisture content of the surface fine shavings is 10-12%, and the size distribution is: 3.2wt% (greater than 20 mesh), 25.9wt% (20-40 mesh), 22.4wt% (40-60 mesh), 16.9wt% (60-80 mesh), 21wt% (80-100 mesh), and 10.6wt% (less than 100 mesh).

[0034] Comparative Example 1

[0035] (1) The core layer consists of large wood shavings with an initial moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm; the surface consists of fine wood shavings with an initial moisture content of 10-12%, and the size distribution is as follows: 3.2 wt% (greater than 20 mesh), 25.9 wt% (20-40 mesh), 22.4 wt% (40-60 mesh), 16.9 wt% (60-80 mesh), 21 wt% (80-100 mesh), and 10.6 wt% (less than 100 mesh);

[0036] (2) Apply adhesive: Apply 6wt% isocyanate adhesive to the fine wood shavings on the surface and stir evenly; apply 6wt% isocyanate adhesive to the large wood shavings in the core layer and stir evenly.

[0037] (3) Laying: The surface fine wood shavings and core large wood shavings after gluing are laid layer by layer in an oriented manner to obtain fine surface oriented particleboard blanks, and the mass ratio of surface layer: core layer: surface layer is 1:8:1.

[0038] (4) Pre-compression: The paved slab is pre-compressed at a pressure of 1.5 MPa for 4 minutes.

[0039] (5) Hot pressing: The pre-pressed slab is hot pressed at a temperature of 170℃, a pressure of 4MPa, and a time of 0.4min / mm.

[0040] (6) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0041] Comparative Example 2

[0042] (1) The core layer consists of large wood shavings with an initial moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm; the surface consists of fine wood shavings with an initial moisture content of 10-12%, and the size distribution is as follows: 3.2 wt% (greater than 20 mesh), 25.9 wt% (20-40 mesh), 22.4 wt% (40-60 mesh), 16.9 wt% (60-80 mesh), 21 wt% (80-100 mesh), and 10.6 wt% (less than 100 mesh);

[0043] (2) Apply adhesive: Apply 6wt% urea-formaldehyde resin adhesive to the fine wood shavings on the surface and stir evenly; apply 6wt% isocyanate adhesive to the large wood shavings in the core layer and stir evenly.

[0044] (3) Laying: The surface fine wood shavings and core large wood shavings after gluing are laid layer by layer in an oriented manner to obtain fine surface oriented particleboard blanks, and the mass ratio of surface layer: core layer: surface layer is 1:8:1.

[0045] (4) Pre-compression: The paved slab is pre-compressed at a pressure of 1.5 MPa for 4 minutes.

[0046] (5) Hot pressing: The pre-pressed slab is hot pressed at a temperature of 170℃, a pressure of 4MPa, and a time of 0.4min / mm.

[0047] (6) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0048] Comparative Example 3

[0049] (1) The core layer consists of large wood shavings with an initial moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm; the surface consists of fine wood shavings with an initial moisture content of 10-12%, and the size distribution is as follows: 3.2 wt% (greater than 20 mesh), 25.9 wt% (20-40 mesh), 22.4 wt% (40-60 mesh), 16.9 wt% (60-80 mesh), 21 wt% (80-100 mesh), and 10.6 wt% (less than 100 mesh);

[0050] (2) Apply adhesive: Apply 6wt% isocyanate adhesive and 12wt% urea-formaldehyde resin adhesive to the fine wood shavings on the surface and stir evenly; apply 3wt% isocyanate adhesive to the large wood shavings in the core layer and stir evenly.

[0051] (3) Laying: The surface fine wood shavings and core large wood shavings after gluing are laid layer by layer in an oriented manner to obtain fine surface oriented particleboard blanks, and the mass ratio of surface layer: core layer: surface layer is 1:8:1.

[0052] (4) Pre-compression: The paved slab is pre-compressed at a pressure of 1.5 MPa for 4 minutes.

[0053] (5) Hot pressing: The pre-pressed slab is hot pressed at a temperature of 170℃, a pressure of 4MPa, and a time of 0.4min / mm.

[0054] (6) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0055] Comparative Example 4

[0056] (1) The core layer consists of large wood shavings with an initial moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm; the surface consists of fine wood shavings with an initial moisture content of 10-12%, and the size distribution is as follows: 3.2 wt% (greater than 20 mesh), 25.9 wt% (20-40 mesh), 22.4 wt% (40-60 mesh), 16.9 wt% (60-80 mesh), 21 wt% (80-100 mesh), and 10.6 wt% (less than 100 mesh);

[0057] (2) Apply adhesive: Apply 6wt% isocyanate adhesive and 12wt% urea-formaldehyde resin adhesive to the fine wood shavings on the surface and stir evenly; apply 5wt% isocyanate adhesive to the large wood shavings in the core layer and stir evenly.

[0058] (3) Laying: The surface fine wood shavings and core large wood shavings after gluing are laid layer by layer in an oriented manner to obtain fine surface oriented particleboard blanks, and the mass ratio of surface layer: core layer: surface layer is 1:8:1.

[0059] (4) Pre-compression: The paved slab is pre-compressed at a pressure of 1.5 MPa for 4 minutes.

[0060] (5) Hot pressing: The pre-pressed slab is hot pressed at a temperature of 170℃, a pressure of 4MPa, and a time of 0.4min / mm.

[0061] (6) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0062] Comparative Example 5

[0063] (1) The core layer consists of large wood shavings with an initial moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm; the surface consists of fine wood shavings with an initial moisture content of 10-12%, and the size distribution is as follows: 3.2 wt% (greater than 20 mesh), 25.9 wt% (20-40 mesh), 22.4 wt% (40-60 mesh), 16.9 wt% (60-80 mesh), 21 wt% (80-100 mesh), and 10.6 wt% (less than 100 mesh);

[0064] (2) Apply adhesive: Apply 6wt% isocyanate adhesive and 12wt% urea-formaldehyde resin adhesive to the fine wood shavings on the surface and stir evenly; apply 6wt% isocyanate adhesive to the large wood shavings in the core layer and stir evenly.

[0065] (3) Laying: The surface fine wood shavings and core large wood shavings after gluing are laid layer by layer in an oriented manner to obtain fine surface oriented particleboard blanks, and the mass ratio of surface layer: core layer: surface layer is 1:8:1.

[0066] (4) Pre-compression: The paved slab is pre-compressed at a pressure of 1.5 MPa for 4 minutes.

[0067] (5) Hot pressing: The pre-pressed slab is hot pressed at a temperature of 170℃, a pressure of 4MPa, and a time of 0.4min / mm.

[0068] (6) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0069] Comparative Example 6

[0070] (1) The core layer consists of large wood shavings with an initial moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm; the surface consists of fine wood shavings with an initial moisture content of 10-12%, and the size distribution is as follows: 3.2 wt% (greater than 20 mesh), 25.9 wt% (20-40 mesh), 22.4 wt% (40-60 mesh), 16.9 wt% (60-80 mesh), 21 wt% (80-100 mesh), and 10.6 wt% (less than 100 mesh);

[0071] (2) Apply adhesive: Apply 6wt% isocyanate adhesive and 12wt% urea-formaldehyde resin adhesive to the fine wood shavings on the surface and stir evenly; apply 6wt% isocyanate adhesive to the large wood shavings in the core layer and stir evenly.

[0072] (3) Laying: The surface fine wood shavings and core large wood shavings after gluing are laid layer by layer in an oriented manner to obtain a fine surface oriented particleboard blank, and the mass ratio of surface layer: core layer: surface layer is 1.5:7:1.5;

[0073] (4) Pre-compression: The paved slab is pre-compressed at a pressure of 1.5 MPa for 4 minutes.

[0074] (5) Hot pressing: The pre-pressed slab is hot pressed at a temperature of 170℃, a pressure of 4MPa, and a time of 0.4min / mm.

[0075] (6) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0076] Comparative Example 7

[0077] (1) The core layer consists of large wood shavings with an initial moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm; the surface consists of fine wood shavings with an initial moisture content of 10-12%, and the size distribution is as follows: 3.2 wt% (greater than 20 mesh), 25.9 wt% (20-40 mesh), 22.4 wt% (40-60 mesh), 16.9 wt% (60-80 mesh), 21 wt% (80-100 mesh), and 10.6 wt% (less than 100 mesh);

[0078] (2) Apply adhesive: Apply 6wt% isocyanate adhesive and 12wt% urea-formaldehyde resin adhesive to the fine wood shavings on the surface and stir evenly; apply 6wt% isocyanate adhesive to the large wood shavings in the core layer and stir evenly.

[0079] (3) Laying: The surface fine wood shavings and core large wood shavings after gluing are laid layer by layer in an oriented manner to obtain a fine surface oriented particleboard blank, and the mass ratio of surface layer: core layer: surface layer is 2:6:2.

[0080] (4) Pre-compression: The paved slab is pre-compressed at a pressure of 1.5 MPa for 4 minutes.

[0081] (5) Hot pressing: The pre-pressed slab is hot pressed at a temperature of 170℃, a pressure of 4MPa, and a time of 0.4min / mm.

[0082] (6) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0083] Comparative Example 8

[0084] (1) The core layer consists of large wood shavings with an initial moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm; the surface consists of fine wood shavings with an initial moisture content of 10-12%, and the size distribution is as follows: 3.2 wt% (greater than 20 mesh), 25.9 wt% (20-40 mesh), 22.4 wt% (40-60 mesh), 16.9 wt% (60-80 mesh), 21 wt% (80-100 mesh), and 10.6 wt% (less than 100 mesh);

[0085] (2) Apply adhesive: Apply 6wt% isocyanate adhesive, 12wt% urea-formaldehyde resin adhesive and 1wt% paraffin emulsion to the fine wood shavings on the surface and stir evenly; apply 6wt% isocyanate adhesive and 1wt% paraffin emulsion to the large wood shavings in the core layer and stir evenly.

[0086] (3) Laying: The surface fine wood shavings and core large wood shavings after gluing are laid layer by layer in an oriented manner to obtain fine surface oriented particleboard blanks, and the mass ratio of surface layer: core layer: surface layer is 1:8:1.

[0087] (4) Pre-compression: The paved slab is pre-compressed at a pressure of 1.5 MPa for 4 minutes.

[0088] (5) Hot pressing: The pre-pressed slab is hot pressed at a temperature of 170℃, a pressure of 4MPa, and a time of 0.4min / mm.

[0089] (6) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0090] Example 1

[0091] (1) The core layer consists of large wood shavings with an initial moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm; the surface consists of fine wood shavings with an initial moisture content of 10-12%, and the size distribution is as follows: 3.2 wt% (greater than 20 mesh), 25.9 wt% (20-40 mesh), 22.4 wt% (40-60 mesh), 16.9 wt% (60-80 mesh), 21 wt% (80-100 mesh), and 10.6 wt% (less than 100 mesh);

[0092] (2) Apply adhesive: Apply 6wt% isocyanate adhesive and 12wt% urea-formaldehyde resin adhesive to the fine wood shavings on the surface and stir evenly; apply 6wt% isocyanate adhesive and 0.5wt% paraffin emulsion to the large wood shavings in the core layer and stir evenly.

[0093] (3) Laying: The surface fine wood shavings and core large wood shavings after gluing are laid layer by layer in an oriented manner to obtain fine surface oriented particleboard blanks, and the mass ratio of surface layer: core layer: surface layer is 1:8:1.

[0094] (4) Pre-compression: The paved slab is pre-compressed at a pressure of 1.5 MPa for 4 minutes.

[0095] (5) Hot pressing: The pre-pressed slab is hot pressed at a temperature of 170℃, a pressure of 4MPa, and a time of 0.4min / mm.

[0096] (6) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0097] Example 2

[0098] (1) The core layer consists of large wood shavings with an initial moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm; the surface consists of fine wood shavings with an initial moisture content of 10-12%, and the size distribution is as follows: 3.2 wt% (greater than 20 mesh), 25.9 wt% (20-40 mesh), 22.4 wt% (40-60 mesh), 16.9 wt% (60-80 mesh), 21 wt% (80-100 mesh), and 10.6 wt% (less than 100 mesh);

[0099] (2) Apply adhesive: Apply 6wt% isocyanate adhesive and 12wt% urea-formaldehyde resin adhesive to the fine wood shavings on the surface and stir evenly; apply 6wt% isocyanate adhesive and 1wt% paraffin emulsion to the large wood shavings in the core layer and stir evenly.

[0100] (3) Laying: The surface fine wood shavings and core large wood shavings after gluing are laid layer by layer in an oriented manner to obtain fine surface oriented particleboard blanks, and the mass ratio of surface layer: core layer: surface layer is 1:8:1.

[0101] (4) Pre-compression: The paved slab is pre-compressed at a pressure of 1.5 MPa for 4 minutes.

[0102] (5) Hot pressing: The pre-pressed slab is hot pressed at a temperature of 170℃, a pressure of 4MPa, and a time of 0.4min / mm.

[0103] (6) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

[0104] Table 1

[0105]

[0106]

[0107] Table 2

[0108]

[0109] As shown in Tables 1 and 2, Comparative Examples 1 and 2 respectively added isocyanate adhesive and urea-formaldehyde resin adhesive to the surface fine wood shavings. The data shows that the surface bonding strength of the resulting fine surface oriented strand board was relatively low. Comparative Examples 3-5, due to the simultaneous addition of isocyanate adhesive and urea-formaldehyde resin adhesive to the surface fine wood shavings, showed a significant improvement in surface bonding strength, and also improved internal bonding strength compared to Comparative Examples 1-2. Furthermore, Comparative Examples 3-5 demonstrate that increasing the proportion of urea-formaldehyde resin adhesive in the surface fine wood shavings within the scope of this invention can improve surface bonding strength. Comparative Examples 6-7, based on Comparative Example 5, changed the mass ratio of surface layer:core layer:surface layer. The data shows that changing the mass ratio of surface layer:core layer:surface layer within the scope of this invention has little effect on the bonding strength of the particleboard, but significantly reduces the bending strength of the particleboard.

[0110] Examples 1-2 show the fine-surface oriented strand board (FOSB) prepared according to the scheme of the present invention. By simultaneously adding isocyanate adhesive and urea-formaldehyde resin adhesive to the fine surface of FOSB, and adding paraffin emulsion only to the core layer of FOSB, the surface bonding strength of FOSB is higher, and the internal bond strength and flexural strength can meet the usage requirements. At the same time, its 24h TS is lower, and its waterproof performance is better. In contrast, Comparative Example 8 adds paraffin emulsion to both the surface layer and the core layer. Although better waterproof performance can be obtained, the surface bonding strength and flexural strength of the resulting fine-surface oriented strand board are lower. This indicates that the adhesive ratio applied to the fine surface shavings in the present invention can achieve higher bonding strength, and the addition of paraffin emulsion to the surface layer actually reduces the surface bonding strength and does not significantly improve the waterproof performance of the strand board. Furthermore, the size distribution of the surface shavings in this invention will also have a better effect in synergy with the ratio of the applied adhesive. Surface shavings of different sizes will have a better strength synergy effect, and the compounding of isocyanate adhesive and urea-formaldehyde resin adhesive can provide both viscosity and adhesion, thus resulting in higher bonding strength of the surface shavings after adhesive application.

[0111] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A fine surface oriented strand board, characterized in that, It consists of a surface layer, a core layer, and a surface layer, which are made by applying adhesive, directional laying, pre-pressing, and hot pressing of each layer of wood shavings. The surface layer is made of fine wood shavings, which are bonded together with 6% isocyanate adhesive and 8-12% urea-formaldehyde ester adhesive. Of the fine wood shavings, those with a mesh size of 20-100 account for 86-88% of the total mass, those with a mesh size less than 100 account for 10-11%, and those with a mesh size greater than 20 account for 1-4%. The core layer is made of large wood shavings, which are bonded together with 4-6% isocyanate adhesive and 0.5-2% paraffin emulsion by mass.

2. The fine-surface oriented strand board according to claim 1, characterized in that, The ratio of the total mass of the upper and lower surface layers to the mass of the core layer in the fine-surface oriented strand board is 20-40%: 60-80%.

3. The fine-surface oriented strand board according to claim 1, characterized in that, The moisture content of the surface fine wood shavings is 10-12%.

4. The fine-surface oriented strand board according to any one of claims 1-3, characterized in that, The core layer of large wood shavings has a moisture content of 8-10%, a length of 5-8 cm, and a width of 2-4 cm.

5. The fine-surface oriented strand board according to claim 1, characterized in that, The surface fine wood shavings are applied using 6% isocyanate adhesive and 10-12% urea-formaldehyde adhesive by mass.

6. The fine-surface oriented strand board according to claim 1 or 5, characterized in that, The core layer of large-scale wood shavings is bonded together with 6% isocyanate adhesive and 0.5-2% paraffin emulsion.

7. A method for preparing a fine-surface oriented strand board as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) Apply adhesive: Apply isocyanate adhesive and urea-formaldehyde ester adhesive to the surface fine wood shavings, and apply isocyanate adhesive and paraffin emulsion to the core large wood shavings; (2) Laying: The surface fine wood shavings and core large wood shavings after applying adhesive are laid layer by layer in a directional manner to obtain the board blank; (3) Pre-pressing: Pre-pressing the slab; (4) Hot pressing: The slab is then hot pressed again; (5) Post-processing: Cool the hot-pressed board, trim the edges, and sand it to obtain fine-surface oriented strand board.

8. The method for preparing fine-surface oriented strand board according to claim 7, characterized in that, The pre-compression is as follows: the pre-compression pressure is 1.0~1.8MPa, and the time is 3.5~5min.

9. The method for preparing fine-surface oriented strand board according to claim 7 or 8, characterized in that, The hot pressing is characterized by a hot pressing temperature of 160~180℃, a hot pressing pressure of 2~5MPa, and a hot pressing time of 0.3~0.5min / mm.

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