Two-layer solid wood composite floor with high stability and its preparation process

Abstract

The present invention belongs to the technical field of wood floor design and manufacturing, relates to solid wood composite floors, and particularly relates to a two-layer solid wood composite floor with high stability, which is formed by cold pressing and laminating a surface layer and a substrate layer. Among them, a number of stress relief grooves with a depth not greater than 1 / 3 of the thickness of the surface layer are provided on the back of the surface layer, the direction is perpendicular to the texture direction of the surface layer, and the grooves are parallel to each other; through grooves with a width of 10-100 mm and a depth not exceeding 1 / 2 of the thickness of the substrate layer are provided at the 1 / 3 positions of the width of the back of the substrate layer. The present invention also discloses the preparation process of the floor. The floor disclosed by the present invention has a thickness reduced from 14-15 mm to 6-14 mm, which saves more wood resources, has a shorter heat conduction path, helps with the utilization of thermal energy, is particularly suitable for producing floors with relatively small specified sizes, and is easy to achieve the installation of various parquet styles such as herringbone and fishbone patterns, meeting the diverse needs of customers; using the cold pressing formaldehyde-free glue process, the performance of the floor is more stable, there is no formaldehyde release, and it is more environmentally friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of wood floor design and manufacturing, relates to solid wood composite floors, and particularly relates to a two-layer solid wood composite floor with high stability and a preparation process thereof. Background Art

[0002] The three-layer solid wood composite floor includes a surface board, a core board and a back board. The three layers are crisscrossed and bonded and pressed together by glue. The surface board is generally 3-4 mm precious hardwood, and the core board and the back board are mostly fast-growing woods such as poplar and pine. Because of its natural wood texture, easy installation and maintenance, relatively ideal hardness, wear resistance, scratch resistance, and easy cleaning, it is quite popular among consumers. However, there are problems in the use of three-layer solid wood composite floors: for example, it has relatively high requirements for the flatness of the paving ground. If the ground is uneven, there will be easy noise. The three-layer solid wood composite floor has relatively large specification dimensions, with a length of more than 1 m, and a single installation method, which cannot meet the needs of customers for diversified parquet floors; after installation in a floor heating environment, formaldehyde in the floor glue layer will be slowly released, which may pollute the home environment. Since the thickness of the three-layer solid wood composite floor is generally 14-15 mm, the thickness is relatively thick, and the loss of wood materials is large. When paved and used in a floor heating environment, the heat conduction path is long and the heat loss is large; therefore, it is necessary to design a floor that is more resource-saving, more environmentally friendly, more stable, and has more diversified installation methods.

[0003] The existing two-layer solid wood composite floors mainly have the following structures:

[0004] (1) Two-layer solid wood (bamboo wood) composite floor of surface board + integral base material

[0005] CN201343853Y discloses a "carbonized wood bamboo composite floor", which is composed of a surface board made of bamboo and a base material made of fast-growing wood (such as Scotch pine, spruce, southern pine, Douglas fir, eucalyptus, poplar, etc.) through ultra-high temperature heat treatment; the surface board and the base material are bonded into one body with isocyanate glue. The surface layer thickness is 3-7 mm, the base material thickness is 12-18 mm, the floor length is 800-1600 mm, the floor width is 118-120 mm, the thickness is 15-25 mm, and the ultra-high temperature heat treatment temperature is 180-220 °C.

[0006] (2) Two-layer solid wood composite floor of surface board + finger-jointed base material

[0007] CN105672621A discloses an environmentally friendly two-layer solid wood composite floor with high stability and its production method. This floor is composed of a surface board and multiple finger-jointed solid wood boards below the surface board. The thickness of the surface board is 1 - 6 mm, and the thickness of the finger-jointed solid wood boards is 8 - 15 mm. The finger-jointed solid wood boards include multiple identically sized solid wood strips finger-jointed together, with a width of 3 - 5 cm and a length of 20 - 50 cm. The finger-jointed solid wood boards are composed of vertically and horizontally perpendicular plates.

[0008] (3)Two-layer solid wood composite floor with a surface board + an overall substrate with grooves on the back

[0009] CN106182216A and CN201087528Y disclose a two-layer solid wood composite floor and its preparation method. The two-layer solid wood composite floor is made by bonding a surface board and a substrate. The grain directions of the surface board and the substrate are the same. A transverse groove is opened on one side of the substrate, and the substrate with the groove or the other side is bonded to the back of the surface board to make the solid wood composite floor. By opening balance grooves on the back of the floor, the stress problem caused by both layers being in the same direction is solved to ensure the stability of the floor.

[0010] (4)Two-layer solid wood composite floor with a surface board + a finger-jointed substrate with grooves on the back

[0011] CN106150030A discloses a two-layer solid wood composite floor, whose structure is similar to that of CN105672621A, except that the grain direction of the finger-jointed board is the same as that of the surface board, and transverse and longitudinal grooves are opened on the finger-jointed board, and bamboo strips or hardwood strips are filled in the transverse grooves.

[0012] (5)Two-layer solid wood composite floor with a surface board + a frame-type substrate

[0013] CN203569853U discloses a trapezoidal solid wood two-layer floor, including a floor support main body layer and an upper decorative surface layer. The floor support main body layer is formed by inserting and fixing a group of strip-shaped solid wood core materials perpendicular to two parallel side frames and fixed in the middle of the two side frames. Selecting a frame-type substrate board is mainly beneficial to avoid phenomena such as bending deformation caused by internal stress, and can improve the warping deformation or anti-twisting deformation performance during use, especially in dry, humid or geothermal supply environments.

[0014] CN106049820A discloses a two-layer floor based on the "beam bridge" structure, including a core board, side strips, veneers, and strengthening strips; among them, the core board, side strips, and strengthening strips form the floor substrate. The side strips are spliced on both sides of the core board in the width direction, and one or more strengthening strips are added between two core boards. The upper surfaces of the core board, side strips, and strengthening strips are on the same horizontal plane; the lower surfaces of the side strips and strengthening strips protrude more than the lower surface of the core board, and the entire floor substrate forms a "beam bridge" structure.

[0015] CN205875598U discloses a two - layer floor with a base material structure. Its structure is similar to that of CN106049820A, except that the core board, edge strip, and reinforcement strip cooperate with each other through an "S" - shaped arc surface or an arc surface to form the floor base material.

[0016] In summary, among the currently disclosed patent documents, the two - layer solid wood composite floor is composed of a surface layer board and a base material board, and the two are bonded together with glue. The surface layer board is located on the upper part of the floor, and the base material board is located on the lower part of the floor. It is basically similar to the conventional three - layer solid wood composite floor in terms of format specifications and installation methods. The main difference lies in the structure of the base material board, which is mainly divided into three categories: (1) The base material board is a single integral body, with three structures: grooved / ungrooved and high - temperature heat treatment (such as CN201343853Y, CN106182216A, CN201087528Y); (2) The base material board is a finger - jointed board, and then grooved or ungrooved, or with special - shaped grooves on the finger - jointed board (CN105672621A, CN106150030A); (3) The base material is formed by connecting core board strips into an integral body through groove - tenon connections, and no glue is applied between the core board strips (CN203569853U, CN106049820A, CN205875598U).

[0017] Since the wood grain directions of the upper and lower layers of wood are basically in the same direction, the floor stress cannot be balanced, resulting in poor dimensional stability of the two - layer floor. The methods such as high - temperature heat treatment, finger - jointing, and grooving used in the base material are all to reduce the stress in the floor, improve the stability of the floor, and reduce the warping deformation during the use of the floor. The technical problems solved are all the dimensional stability of the two - layer solid wood composite floor. Summary of the Invention

[0018] In view of the problems existing in the two - layer solid wood composite floor in the above - mentioned prior art, such as poor dimensional stability, too thick thickness when used in a floor heating environment, warping deformation, easy cracking, and single installation method, the present invention discloses a two - layer solid wood composite floor with high stability.

[0019] A two - layer solid wood composite floor with high stability is cold - pressed and formed by a surface board layer and a base material layer. Among them, several stress - release grooves with a depth not greater than 1 / 3 of the thickness of the surface board layer are provided on the back of the surface board layer, and the direction is perpendicular to the surface board texture direction, and the grooves are parallel to each other; through - grooves with a width of 10 - 100 mm and a depth not exceeding 1 / 2 of the thickness of the base material layer are provided at 1 / 3 of each width of the back of the base material layer.

[0020] In a preferred disclosure example of the present invention, the stress - release grooves are provided at 1 / 3 of the upper and lower parts in the width direction of the surface board layer, and the inclined directions of the openings of two adjacent stress - release grooves in the width direction are opposite.

[0021] In a preferred disclosed example of the present invention, the width of the stress relief groove is ≤ 5 mm, the length is 3 - 10 mm, the spacing is 5 - 20 mm, and the inclination angle of the notch of the stress relief groove along the thickness direction of the surface board is between 30° and 60°.

[0022] In a preferred disclosed example of the present invention, after applying glue in the through groove, a reinforcing wooden strip is inlaid. The length of the reinforcing wooden strip is equal to the length of the base material layer. The reinforcing wooden strip and the base material board support the surface layer of the floor in a vertical and horizontal lamination manner, improving the dimensional stability of the floor.

[0023] In a preferred disclosed example of the present invention, the surface board layer is a hardwood or wood composite material with a thickness of 2 - 5 mm, which is a single-piece whole surface board or a spliced surface board of multiple panels.

[0024] In a preferred disclosed example of the present invention, the base material layer is a fast-growing wood core board curtain with a thickness of 4 - 9 mm, and the core board curtain is formed by arranging core board strips in sequence.

[0025] In a preferred disclosed example of the present invention, small holes are evenly opened on the core board strip, the diameter of the holes is ≤ 5 mm, and the adjacent holes are spaced 10 - 50 mm apart.

[0026] In a preferred disclosed example of the present invention, a finishing layer formed by applying hot-melt paint is further provided on the surface board layer, with a thickness of 75 - 150 μm.

[0027] Another object of the present invention is to disclose the preparation process of the above two-layer solid wood composite floor with high stability, including surface board preparation → core board preparation → glue application → assembly → cold pressing → curing and aging → splitting, sanding, tenoning → spraying waterproof paraffin on the base material and tenon grooves → grading and packaging processes, where:

[0028] When preparing the surface board, sawn hardwood thin boards with a moisture content of 5.0 - 7.5% and a thickness of 2.0 - 5.0 mm are selected. After sanding, a number of stress relief grooves with a depth not greater than 1 / 3 of the thickness of the surface board layer are opened on one side of the surface board, the direction is perpendicular to the surface board texture direction, and the grooves are parallel to each other;

[0029] When preparing the core board, core board strips with a thickness of 4 - 9 mm, a width of 20 - 50 mm, and a moisture content of 6 - 10% are sorted and mechanically and automatically paved. A tenon board is placed at one end and arranged into a core board curtain. The paved core board is provided with through grooves with a width of 10 - 100 mm and a depth not exceeding 1 / 2 of the thickness of the base material layer at each 1 / 3 of its width, and small holes are opened.

[0030] In a preferred disclosed example of the present invention, in the surface board preparation process, a single-piece whole surface board is selected for the surface board, or a spliced surface board or a composite surface board spliced in the length, width, and thickness of the floor.

[0031] In a preferred disclosure example of the present invention, in the process of preparing the surface board, the core board strips can also be manually laid, and both ends of the core board strips are fixed with two hot melt adhesive lines along the width direction of the core board strips, and a tenon board convenient for tenoning is placed at each end.

[0032] In a preferred disclosure example of the present invention, in the gluing process, a formaldehyde-free resin adhesive is coated on the back of the surface board, and the gluing amount is 150-170 g / m 2 .

[0033] In a preferred disclosure example of the present invention, in the blanking process, the glued surface board and core board are blanked, and the core board strips are uniformly provided with holes ≤5 mm, and the adjacent holes are spaced 10-50 mm apart.

[0034] In a preferred disclosure example of the present invention, in the cold pressing process, the parameters of cold pressing are a pressure of 9-10 kg / cm 2 , a temperature of 18-25 °C, and a time of 40-45 min.

[0035] In a preferred disclosure example of the present invention, the curing and aging time is 3-5 d.

[0036] In a preferred disclosure example of the present invention, in the processes of splitting, sanding, and tenoning, after the floor is split and sanded, a longitudinal double-end milling and a transverse double-end milling are used for tongue-and-groove or lock joint processing.

[0037] In a preferred disclosure example of the present invention, after the tenoning process, hot melt paint is coated, and the hot melt paint coating is divided into two types: a closed-type paint film and an open-type paint film, where:

[0038] The technological process of the closed-type paint film is as follows:

[0039] The floor blank after dyeing, coating the base putty, and sanding → loading → dust removal → hot pressing roller (pressing down the fibers on the surface of the workpiece and heating the blank floor) → infrared heating (heating the blank floor) → hot melt paint roll coating → primer roll coating (rolling 15-20 g / ㎡ UV sanding primer, in two times, 7-10 g / ㎡ each time) → UV lamp curing (curing the sanding primer) → primer sanding (using a sanding belt of 320# or above 400#, sanding off a part of the primer) → dust removal machine → inspection table → UV topcoat finishing (rolling the UV topcoat twice or rolling once and pouring once) → UV lamp curing (curing the topcoat) → inspection → unloading.

[0040] The technological process of the open-type paint film is as follows:

[0041] Floor blank after dyeing, applying primer and sanding → Loading → Dust removal → Hot press roller (press down the fibers on the workpiece surface and heat the blank floor) → Infrared heating (heat the blank floor) → Roller coating of hot melt paint (roller coating 10 - 15 g / ㎡) → Roller coating of topcoat (roller coating 6 - 8 g / ㎡) → UV lamp curing (cure the topcoat) → Inspection → Unloading.

[0042] In a preferred disclosure example of the present invention, in the process of spraying waterproof paraffin on the substrate and tenon groove, the substrate layer of the floor is placed upward, and molten waterproof paraffin is sprayed, with a spraying amount of 40 - 60 g / m 2 .

[0043] Due to the gaps and holes in the core board substrate, during spraying, the waterproof paraffin can enter the two side surfaces of the core board strips, the holes of the core board, and the notch of the tenon groove, achieving coating coverage on the six surfaces of the floor, and waterproof coating can also be realized in the middle of the floor. After being treated with waterproof paraffin, measures are taken to cover and block the water absorption channels on the inner and outer surfaces of the wood, improving the waterproof and moisture-proof performance of the floor and increasing the dimensional stability of the floor.

[0044] The present invention uses a method of cross-laminating the surface layer and the substrate layer in the texture direction for mechanical pressing, and stress grooves are opened on the surface layer and the substrate layer. On the one hand, the stress of the surface layer and the substrate layer is released, and on the other hand, the waterproof coating can penetrate and be applied inside the floor, improving the dimensional stability of the two-layer solid wood composite floor; the surface layer of the floor is coated with hot melt paint, improving the anti-cracking performance of the solid wood surface and reducing the risk of wood cracking on the solid wood surface in a floor heating environment. The waterproof and moisture-proof performance of the hot melt paint is better than that of ultraviolet (UV) light-cured paint.

[0045] Beneficial effects

[0046] The two-layer solid wood composite floor disclosed by the present invention has a thickness reduced from 14 - 15 mm of the general solid wood composite floor to 6 - 14 mm, saving more wood resources, having a shorter heat conduction path, contributing to the utilization of heat energy, especially suitable for producing floors with relatively small specified sizes, facilitating the installation of various parquet styles such as herringbone and fishbone patterns, and being convenient to meet the diverse needs of customers; the two-layer solid wood floor adopts a cold pressing formaldehyde-free glue process, with more stable floor performance, no formaldehyde release, and being more environmentally friendly. Brief description of the drawings

[0047] Figure 1 . Three-dimensional structure schematic diagram of the two-layer solid wood composite floor;

[0048] Figure 2 . Stress release groove on the surface board of the two-layer solid wood composite floor;

[0049] Figure 3. Front view of the stress release groove on the surface board, where 3-1 is the front view of the stress release groove 6-1; 3-2. Front view of the stress release groove 6-2 on the surface board;

[0050] Figure 4 . Schematic diagram of the front side (glue - applying side) of the substrate layer of a two - layer solid wood composite floor;

[0051] Figure 5 . Schematic diagram of the back side of the substrate layer of a two - layer solid wood composite floor;

[0052] Among them, the names of each marked component are: 1. Coating layer; 2. Surface board layer; 3. Substrate layer; 4. Core board strip; 5. Tenon board; 6. Stress - release groove; 7. Penetrating groove. Detailed implementation mode

[0053] The present invention will be described in detail below in conjunction with embodiments, so that those skilled in the art can better understand the present invention. However, the present invention is not limited to the following embodiments.

[0054] Embodiment 1

[0055] A two - layer solid wood composite floor with high stability is cold - pressed and formed by a surface board layer 2 and a substrate layer 3. The surface board layer 2 is made of hardwood with a thickness of 3.2 mm, and the surface board is a double - spliced surface board. The substrate layer 3 is a fast - growing wood core board curtain with a thickness of 6.2 mm, which is formed by arranging core board strips in sequence. Among them, on the back side of the surface board layer (2), there are several stress - release grooves 6 with a depth of 1 mm, the direction is perpendicular to the surface board texture direction, the grooves are parallel to each other, the width of the release groove 6 is 3 mm, the length is 5 mm, and the spacing is 10 mm. The inclination angle of the groove opening of the stress - release groove along the thickness direction of the surface board is between 0° and 30°. The stress - release grooves 6 are arranged at the upper and lower 1 / 3 of the width direction of the surface board layer 2, and the inclination directions of the groove openings of two adjacent stress - release grooves in the width direction are opposite. On the back side of the substrate layer 3, at the 1 / 3 of each width, there is a penetrating groove 7 with a width of 50 mm and a depth of 3 mm. After applying glue in the penetrating groove 7, a reinforcing wood strip is inlaid, and the length of the reinforcing wood strip is equal to the length of the substrate layer. Small holes with a diameter of 2 mm are opened on the core board strip, and the adjacent holes are evenly arranged on the core board strip at an interval of 20 mm. Above the surface board layer 2, there is also a coating layer 1 formed by hot - melt paint coating, with a thickness of 75 μm.

[0056] Embodiment 2

[0057] A two-layer solid wood composite floor with high stability is formed by cold pressing and laminating a surface board layer 2 and a base material layer 3. The surface board layer 2 is made of hardwood with a thickness of 4.2 mm, and the surface board is a single-piece surface board. The base material layer 3 is a fast-growing wood core board curtain with a thickness of 4.3 mm, which is formed by arranging and combining core board strips in sequence. Among them, several stress relief grooves 6 with a depth of 1 mm are provided on the back of the surface board layer 2, and the direction is perpendicular to the surface board texture direction. The grooves are parallel to each other. The width of the relief groove 6 is 4 mm, the length is 8 mm, and the spacing is 15 mm. The inclination angle of the groove opening of the stress relief groove along the thickness direction of the surface board is between 45°. The relief grooves 6 are provided at the upper and lower 1 / 3 of the width direction of the surface board layer 2, and the inclination directions of the groove openings of two adjacent stress relief grooves in the width direction are opposite. On the back of the base material layer 3, through grooves 7 with a width of 60 mm and a depth of 1 mm are provided at the 1 / 3 of each width. After applying glue in the through grooves 7, reinforcing wood strips are inlaid, and the length of the reinforcing wood strips is equal to the length of the base material layer. Small holes with a diameter of 3 mm are opened on the core board strips, and the adjacent holes are evenly arranged on the core board strips at an interval of 30 mm. A finishing layer 1 formed by hot-melt paint coating is further provided on the surface board layer 2, with a thickness of 90 μm.

[0058] Example 3

[0059] A two-layer solid wood composite floor with high stability is formed by cold pressing and laminating a surface board layer 2 and a base material layer 3. The surface board layer 2 is made of hardwood with a thickness of 5 mm, and the surface board is a single-piece surface board. The base material layer 3 is a fast-growing wood core board curtain with a thickness of 9 mm, which is formed by arranging and combining core board strips in sequence. Among them, several stress relief grooves 6 with a depth of 1.5 mm are provided on the back of the surface board layer 2, and the direction is perpendicular to the surface board texture direction. The grooves are parallel to each other. The width of the relief groove 6 is 5 mm, the length is 10 mm, and the spacing is 20 mm. The inclination angle of the groove opening of the stress relief groove along the thickness direction of the surface board is between 60°. The relief grooves 6 are provided at the upper and lower 1 / 3 of the width direction of the surface board layer 2, and the inclination directions of the groove openings of two adjacent stress relief grooves in the width direction are opposite. On the back of the base material layer 3, through grooves 7 with a width of 50 mm and a depth of 3 mm are provided at the 1 / 3 of each width. After applying glue in the through grooves 7, reinforcing wood strips are inlaid, and the length of the reinforcing wood strips is equal to the length of the base material layer. Small holes with a diameter of 2 mm are opened on the core board strips, and the adjacent holes are evenly arranged on the core board strips at an interval of 20 mm. A finishing layer 1 formed by hot-melt paint coating is further provided on the surface board layer 2, with a thickness of 150 μm.

[0060] Example 4

[0061] A manufacturing process for a two-layer solid wood composite floor with high stability includes the following steps:

[0062] 1. Preparation of the surface board: The surface board is made of sawn hardwood thin boards with a moisture content of 5.3% and a thickness of 4.2 mm. The surface board can be a single-piece whole board. After sanding with a 60# sanding belt, the surface board is then transferred to a special grooving device for grooving. The depth of the groove on the back of the surface board is 1 mm. The direction of the stress relief groove is perpendicular to the grain direction of the surface board. The grooves are parallel to each other. The width of the stress relief groove is 1 mm, and the inclination angle of the inclined groove is 45 。 , the spacing between the stress relief grooves is 15 mm. The positions of the stress relief grooves are at the one-third positions in the width direction of the surface board, and the positions of the openings of the two stress relief grooves are opposite;

[0063] 2. Preparation of the core board: The core board is prepared by mechanical automatic paving. The core board is made of fast-growing woods such as pine and poplar. After being transversely precision cut by a preferred saw and divided by a splitting saw, the core board blocks are processed into core board strips with a thickness of 6.2 mm and a width of 18 - 20 mm, and the average moisture content is 9.2%. After the core board strips are manually sorted, they are mechanically automatically paved. Tenon plates are automatically placed at both ends of the core board strips by the equipment to form a core board curtain. The paved core board is passed through a core board grooving machine, and several 1-mm small round holes are punched on the core board strips with a punching machine. A through groove with a width of 50 mm, a depth of 2 mm, and a length of 1000 mm is opened on the core board, and 2 through grooves are evenly arranged in the width of the floor;

[0064] 3. Glue application: An aldehyde-free resin adhesive is selected for glue application on the surface board, and the glue application amount is 155 - 160 g / m 2 ;

[0065] 4. Laminating: The glued surface board and core board are laminated;

[0066] 5. Cold pressing: The cold pressing process is adopted, the cold pressing pressure is 9 kg / cm 2 , the cold pressing temperature is 23 - 25 °C, and the cold pressing time is 45 min;

[0067] 6. Curing and storage: The curing and storage time is 3 days;

[0068] 7. Sawing: The floor is sawn according to the specifications;

[0069] 8. Sanding: The surface board is first coarsely sanded with 80# and 100#, and finally finely sanded with 100#, 120#, and 150#. The fine sanding of the surface board is quantitative sanding;

[0070] 9. Tongue and groove processing: The floor is processed with a tongue and groove and a reverse tongue and groove using a production line of longitudinal double-end milling and transverse double-end milling;

[0071] 10. Hot-melt paint coating: For producing open-type and matte-effect products, the process flow is as follows:

[0072] Rough floorboards that have been dyed, coated with primer, and sanded → Loading → Dust removal → Hot pressing roller (pressing down the fibers that warp the workpiece surface and heating the rough floorboards) → Infrared heating (heating the rough floorboards) → Roller coating of hot-melt paint (roller coating at 10 - 15 g / ㎡) → Roller coating of topcoat (roller coating at 6 - 8 g / ㎡) → UV lamp curing → Post-treatment;

[0073] 11. Spraying waterproof paraffin on the substrate and tenon grooves: Place the substrate layer of the floor upwards, and spray molten waterproof paraffin between and inside the core board strips on the substrate, with the coating amount being 45 - 50 g / m 2 ;

[0074] 12. Packaging: The finished floorboards have a thickness of 10 mm. Place the floorboards face to face on the surface into the packaging box, and package them well with tongue-and-groove and reverse tongue-and-groove.

[0075] Example 5

[0076] A manufacturing process for a two-layer solid wood composite floor with high stability, including the following steps:

[0077] 1. Preparation of the surface board: The surface board is selected as a sawn hardwood thin board with a moisture content of 7.5% and a thickness of 3.2 mm; the surface board is a double-spliced surface board. After sanding with a 60# sanding belt, then transfer the surface board to a dedicated grooving device to groove it. The grooving depth on the back of the surface board is 1 mm, the direction of the stress relief groove is perpendicular to the grain direction of the surface board, the grooves are parallel to each other, the width of the stress relief groove is 3 mm, the length is 5 mm, and the inclination angle of the inclined groove is 30 。 , the spacing between the stress relief grooves is 10 mm, the positions of the stress relief grooves are at each one-third of the width direction of the surface board, and the positions of the two stress relief groove openings are opposite;

[0078] 2. Preparation of the core board: The preparation of the core board is divided into mechanical automatic paving preparation.

[0079] The core board is selected from fast-growing woods such as pine and poplar. After being precisely cross-cut horizontally by a preferred saw and divided by a splitting saw, the core board blocks are processed into core board strips with a thickness of 6.2 mm and a width of 18 - 20 mm, and the average moisture content is 6.5%; after the core board strips are manually sorted, they are mechanically automatically paved. Tenon head boards are automatically placed at both ends by the equipment at both ends of the core board strips to form a core board curtain; the paved core board is passed through a core board grooving machine, and several 2-mm small round holes are punched on the core board strips with a punching machine; a through groove with a width of 20 mm, a depth of 3 mm, and a length of 910 mm is opened on the core board, and 2 through grooves are evenly arranged in the width of the floor;

[0080] 3. Glue application: Select a formaldehyde-free resin adhesive and apply glue to the surface board, with the glue application amount being 160 - 165 g / m 2 ;

[0081] 4. Laminating: Laminating the veneers and core boards after applying glue;

[0082] 5. Cold pressing: Using the cold pressing process, the cold pressing pressure is 7.5 kg / cm 2 , the cold pressing temperature is 23 - 25 °C, and the cold pressing time is 45 minutes;

[0083] 6. Conditioning and storage: The conditioning and storage time is 3 days;

[0084] 7. Sawing: Sawing the floor according to the specifications;

[0085] 8. Sanding: First rough sand the veneer with 80# and 100#, and finally fine sand the veneer with 120#, 150#, and 180#. The fine sanding of the veneer is quantitative sanding;

[0086] 9. Tongue and groove processing: Using a production line with longitudinal double-end milling and transverse double-end milling to process the tongue and groove and reverse tongue and groove of the floor;

[0087] 10. Hot melt paint coating: Producing products with a closed paint film effect, and its process flow is as follows:

[0088] The floor blank after dyeing, applying base putty and sanding → Loading → Dust removal → Hot pressing roller (pressing down the fibers on the surface of the workpiece and heating the blank floor) → Infrared heating (heating the blank floor) → Hot melt paint roller coating → Primer roller coating (roller coating 15 - 18 g / ㎡ UV sanding primer, in two times, 7 - 9 g / ㎡ each time) → UV lamp curing (curing the sanding primer) → Primer sanding (using a 320# sanding belt to sand off a part of the primer) → Dust collector → Inspection table → UV topcoat finishing (one-time roller coating and one-time curtain coating of UV topcoat) → UV lamp curing (curing the topcoat) → Inspection → Unloading.

[0089] 11. Spraying waterproof paraffin on the substrate and tongue and groove: Place the substrate layer of the floor upwards, and spray molten waterproof paraffin between and inside the core board strips on the substrate. The coating amount is 50 - 55 g / m 2 .

[0090] 12. Packaging: The thickness of the finished floor is 9 mm. Place the floors face to face into the packaging box and pack them well according to the tongue and groove and reverse tongue and groove.

[0091] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present invention by the same token.

Claims

1. Preparation process of a two-layer solid wood composite floor with high stability. The floor is formed by cold pressing and laminating a surface board layer (2) and a substrate layer (3). Among them, On the back of the surface board layer (2), there are a number of stress relief grooves (6) with a depth not greater than 1 / 3 of the thickness of the surface board layer, perpendicular to the direction of the surface board texture, and parallel to each other between the grooves; the stress relief grooves (6) are provided at the upper and lower 1 / 3 of the width direction of the surface board layer (2), and the inclined directions of the openings of two adjacent stress relief grooves in the width direction are opposite; on the back of the substrate layer (3), through grooves (7) with a width of 10 - 100 mm and a depth not exceeding 1 / 2 of the thickness of the substrate layer are provided at each 1 / 3 of its width. After applying glue to the through grooves (7), reinforcing wood strips are inlaid, and the length of the reinforcing wood strips is equal to the length of the substrate layer; the preparation process includes surface board preparation → core board preparation → glue application → assembly → cold pressing → curing and aging → splitting, sanding, tenoning → spraying waterproof paraffin on the substrate and tenon grooves → grading and packaging processes, and is characterized in that: When preparing the surface board, sawn hardwood thin boards with a moisture content of 5.0 - 7.5% and a thickness of 2.0 - 5.0 mm are selected. After sanding, a number of stress relief grooves with a depth not greater than 1 / 3 of the thickness of the surface board layer are opened on one side of the surface board, perpendicular to the direction of the surface board texture, and parallel to each other between the grooves; When preparing the core board, core board strips with a thickness of 4 - 9 mm, a width of 20 - 50 mm and a moisture content of 6 - 10% are sorted, mechanically and automatically paved, a tenon board is placed at one end, arranged into a core board curtain, and through grooves with a width of 10 - 100 mm and a depth not exceeding 1 / 2 of the thickness of the substrate layer are opened at each 1 / 3 of its width, and small holes are opened.

2. The preparation process of the two-layer solid wood composite floor with high stability according to claim 1, characterized in that: The width of the stress relief groove (6) ≤ 5 mm, the length is 3 - 10 mm, the spacing is 5 - 20 mm, and the inclination angle of the opening of the stress relief groove along the thickness direction of the surface board is between 30 - 60°.

3. The preparation process of the two-layer solid wood composite floor with high stability according to claim 1, characterized in that: The surface board layer (2) is a hardwood or wood-based composite material with a thickness of 2 - 5 mm, which is a single whole surface board or a spliced surface board of multiple surfaces.

4. The preparation process of the two-layer solid wood composite floor with high stability according to claim 1, characterized in that: The substrate layer (3) is a fast-growing wood core board curtain with a thickness of 4 - 9 mm. The core board curtain is formed by arranging core board strips in sequence. Small holes are evenly opened on the core board strips, the hole diameter ≤ 5 mm, and the adjacent hole spacing is 10 - 50 mm.

5. The preparation process of the two-layer solid wood composite floor with high stability according to claim 1, characterized in that: There is also a coating layer (1) formed by hot-melt paint coating on the surface board layer (2), with a thickness of 75 - 150 μm.

6. The preparation process of the two-layer solid wood composite floor with high stability according to claim 1, characterized in that: In the blanking process, the veneer and the core board after gluing are blanked, wherein the core board strips are uniformly provided with holes ≤5 mm, and the adjacent holes are spaced 10 - 50 mm apart.

7. The preparation process of the two-layer solid wood composite floor with high stability according to claim 1, characterized in that: In the cold pressing process, the cold pressing pressure is 9-10 kg / cm 2 , the temperature is 18-25 °C, and the time is 40-45 minutes.

8. The preparation process of the two-layer solid wood composite floor with high stability according to claim 1, characterized in that: For the process of spraying waterproof paraffin on the substrate and the mortise and tenon groove, place the substrate layer of the floor upward, spray molten waterproof paraffin, and the spraying amount is 40-60 g / m 2 .

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