Secondary gluing method of special recombinant material for independent liquid cargo tanks of LNG, LPG and LEG ships

Abstract

The invention provides a secondary gluing method of special recombined materials for independent liquid cargo tanks of LNG (liquefied natural gas), LPG (liquefied petroleum gas) and LEG (LEG) ships, which comprises the step of performing point crack minimally invasive treatment on to-be-glued surfaces, and the point crack minimally invasive treatment specifically comprises the step of manufacturing point-shaped micro cracks on the two to-be-glued surfaces so as to increase the gluing area and form glue nails on glue layers. Small holes can be symmetrically and dispersedly drilled in the two surfaces to be glued, and wooden plugs are glued and then inserted into the small holes; the shape and the size of the wooden plug are matched with those of the small hole; and the shear strength of the gluing interface is further improved through reinforcement of the interlayer wooden plugs. Meanwhile, the secondary gluing method provided by the invention is matched with a high-strength and high-toughness adhesive, so that the shear strength of a gluing interface is further improved, the local shear strength of the obtained gluing recombination material can reach 50 MPa, and the gluing recombination material is suitable for pressure-bearing wood of a liquid cargo tank of a low-temperature liquid transport ship for liquefied ethylene gas (LEG), liquefied natural gas (LNG), liquefied petroleum gas (LPG) and the like.

Description

Technical Field

[0001] The invention belongs to the field of material processing and also relates to a secondary gluing method of special recombinant materials for independent liquid cargo tanks of LNG, LPG and LEG ships. Background Art

[0002] As the layout of liquefied natural gas (LNG) receiving stations extends to inland rivers, regional transportation demand has steadily increased. Limited by the scale of receiving terminals and navigation conditions, the small and medium-sized LNG shipping market has ushered in development space. This type of ship mainly adopts a C-type independent liquid cargo tank system, with horizontally and longitudinally arranged cargo tank containers supported by supports. The LNG gas tank cannot be in direct contact with the hull to avoid the formation of a low-temperature zone in the hull, which will cause low-temperature brittle failure of the hull steel structure. Therefore, it is necessary to place a cargo hold support between the gas tank and the support. The material must be able to withstand the shear stress generated by the swaying of the hull and the free liquid surface inside the tank during transportation, the thermal stress generated by the temperature difference on both sides of the cargo hold support, and have high water resistance.

[0003] The thickness of the special recombinant materials for LNG ships pressed by a press is usually 2-10 cm, and the thickness of the pressure-bearing wood of the C-type liquid cargo tank is 15-45 cm. The special recombinant materials need to be glued twice to meet the usage requirements.

[0004] The Chinese patent invention application with publication number CN114857486A discloses a support block formed of dense laminated wood, which is formed of veneers, which are polished and / or planed, impregnated with synthetic resin and stacked, and the stack is then densified at high temperature to form the dense laminated wood. The support block obtained by gluing with the method of the invention has the problem of low shear strength of the gluing interface and easy cracking. Summary of the invention

[0005] The present invention provides a secondary bonding method of special recombinant materials for ultra-low temperature, which performs point cracking minimally invasive treatment on the surfaces to be bonded: point-shaped microcracks are created on two surfaces to be bonded, the bonding area is increased, and glue nails are formed, so as to improve the shear strength and prevent cracking.

[0006] The present application adopts the following scheme: a secondary bonding method of special recombinant materials for ultra-low temperature use, including performing point cracking minimally invasive treatment on the surfaces to be bonded, wherein the point cracking minimally invasive treatment specifically comprises: creating point-shaped microcracks on two surfaces to be bonded.

[0007] In some embodiments of the present invention, the diameter of the microcracks is 0.8-1.2 mm. In some embodiments of the present invention, the depth of the microcracks is 0.5-1.5 mm. In some embodiments of the present invention, the microcracks are arranged on the surface to be bonded in a matrix of (1.5 cm×1.5 cm)-(3.0 cm×3.0 cm). The surface to be bonded is subjected to a point-crack minimally invasive treatment to increase the bonding area, and glue nails are formed at the glue layer to increase the shear strength of the bonding interface and prevent cracking. For example, the arrangement of point-shaped microcracks in a 2.0 cm×2.0 cm matrix means that the distance between two adjacent microcracks in the transverse and longitudinal directions is 2.0 cm, and adjacent rows and adjacent columns are parallel.

[0008] In some embodiments of the present invention, in order to further improve the shear strength of the bonding interface, small holes can be symmetrically drilled on the two surfaces to be bonded, and wooden plugs or wooden plugs coated with glue are inserted into the small holes; the shape and size of the wooden plugs match the size of the small holes.

[0009] In some embodiments of the present invention, the aperture of the small hole is 4.5-6.5 mm, and the single-side depth is 6-8 mm of the thickness of a single material to be glued. In some embodiments of the present invention, the small holes are arranged on the surface to be glued in a matrix of (5.0 cm×5.0 cm)-(8.0 cm×8.0 cm). The shear strength of the secondary bonding interface can be improved by reinforcing with interlayer wood plugs. For example, the small holes are arranged in a 6.0 cm×6.0 cm matrix, which means that the distance between two adjacent small holes in the horizontal and vertical directions is 6 cm, and adjacent rows and adjacent columns are parallel.

[0010] In some embodiments of the present invention, the adhesive applied to the surface to be bonded is a high-strength and high-toughness adhesive; preferably, the high-strength and high-toughness adhesive is selected from one or more of phenol-resorcinol-formaldehyde resin, isocyanate, and epoxy resin. In some embodiments of the present invention, the amount of the high-strength and high-toughness adhesive applied is 150-230g / m 2 , preferably 180-200g / m 2 The secondary bonding method provided by the present invention uses a high-strength and high-toughness adhesive for bonding, which can further improve the shear strength of the bonding interface to meet different use requirements.

[0011] The secondary gluing method provided by the present invention can be used to manufacture artificial multilayer boards, such as three-layer boards, five-layer boards, etc., wherein at least one pair of adjacent two gluing surfaces can be glued using the gluing method.

[0012] The present invention has the following beneficial effects: (1) The secondary bonding method provided by the present invention forms point-shaped microcracks after the surface to be bonded is micro-invasively damaged by point cracking, so as to increase the bonding area and form glue nails at the glue layer; it can effectively improve the shear strength of the bonding interface; (2) The secondary gluing method provided by the present invention improves the shear strength of the gluing interface by reinforcing it with interlayer wood plugs; (3) The secondary bonding method provided by the present invention uses a high-strength and high-toughness adhesive for bonding, which can further improve the shear strength of the bonding interface and reduce the cracking rate of the adhesive layer; (4) The secondary gluing method provided by the present invention includes a minimally invasive treatment of the cracking of the bonding surface, combined with interlayer wood plug reinforcement and a high-strength and high-toughness adhesive, which further ensures that the local shear strength of the bonded reconstructed material obtained by gluing is effectively improved and reduces the cracking rate of the adhesive layer.

[0013] The secondary gluing method provided by the present invention is suitable for the secondary gluing of reconstructed materials obtained by gluing veneers, and can effectively improve the interface shear strength of the secondary gluing. For example, the thickness of the veneer reconstructed material pressed by a press is usually 2-10 cm, while the thickness of the pressure-bearing wood of the C-type liquid cargo tank needs to be 15-45 cm. The veneer reconstructed material needs to be secondary gluing to meet the use requirements. At this time, the gluing method of the present invention is used for secondary gluing, which can effectively improve the shear strength of the secondary gluing interface and improve the durability of the pressure-bearing wood. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described in conjunction with specific embodiments below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Example 1

[0016] In this embodiment, a secondary gluing method for special reconstructed materials for ultra-low temperature is provided, wherein reconstructed wood with a thickness of 8 cm is used as the material to be glued, and after secondary gluing, a glued reconstructed material is obtained, which can be used as pressure-bearing wood for liquid cargo tanks of LNG ships.

[0017] In this embodiment, the secondary gluing method comprises the following specific steps: (1) According to the use requirements and the requirements of the drawings, the reconstituted wood is processed into wood blocks of certain sizes; (2) Perform a minimally invasive cracking treatment on the surfaces of the two wood blocks to be glued: Use a needle punch or a drilling machine (set to a diameter of 1.0 mm and a depth of 1.0 mm) to symmetrically create point-shaped microcracks on the surfaces of the two reconstructed materials to be glued. The diameter of the resulting microcracks is 1.0 mm and the depth is 1.0 mm. The point-shaped microcracks are arranged on the surface of the reconstructed materials in a 2.0 cm × 2.0 cm matrix to increase the bonding area and form glue nails at the glue layer. The microcracks are arranged in a 2.0 cm × 2.0 cm matrix, which means that the distance between two adjacent microcracks in the horizontal and vertical directions is 2.0 cm, and adjacent rows and columns are parallel. (3) Drill holes symmetrically and dispersedly on the surfaces of the two recombinant materials to be glued: Use a drilling machine (set the hole diameter to 5mm and the depth to 7.5mm) to symmetrically arrange the surfaces of the two wooden blocks to be glued in a 6.0 cm×6.0 cm matrix, and insert the wooden plugs into the holes after applying glue; the size of the wooden plugs matches the holes, that is, the diameter of the wooden plugs is 5mm and the length is 15mm. The holes are arranged in a 6.0 cm×6.0 cm matrix, which means that the distance between two adjacent holes in the horizontal and vertical directions is 6.0 cm, and adjacent rows and columns are parallel; (4) Phenol-resorcinol-formaldehyde resin (PRF) is evenly applied on the surface of the reconstructed material, and the amount of phenol-resorcinol-formaldehyde resin applied is 200 g / m 2 , and then solidify it by cold pressing gluing, wherein the cold pressing pressure is 0.5-1.5 MPa.

[0018] In this embodiment, the cross section of the wooden plug is circular; those skilled in the art may also choose to replace the drill bit of the drilling machine so that the cross section of the small hole has other shapes, such as regular or irregular polygons, including one or more of squares, triangles, rectangles, pentagons, hexagons, octagons, etc. The wooden plug may be of equal width in the length direction, such as a cylinder, a cuboid, a hexagonal prism, etc., or may be tapered at one or both ends in the length direction, that is, a nail-shaped plug of equal width in the middle and pointed at one or both ends.

[0019] In this embodiment, since the material to be glued is glued reconstructed wood with a relatively large thickness, cold pressing is selected.

[0020] The glued reconstructed material obtained in this embodiment includes the point-shaped microcracks on two adjacent glued surfaces, and also includes small holes symmetrically distributed on the glued surface with respect to the glue layer and wooden plugs inserted into the small holes.

[0021] The local shear strength of the bonded reconstructed material obtained in this embodiment can reach 50 Mpa.

[0022] Example 2

[0023] Different from the first embodiment, instead of coating the wooden cork with glue and then inserting it into the small hole, in the present embodiment, the wooden cork is not coated with glue but is directly inserted into the small hole.

[0024] The glued reconstructed material obtained in the above embodiments can be used as pressure-bearing wood of liquid cargo tanks during the transportation of cryogenic liquids. The cryogenic liquids include but are not limited to LNG, and can also be used for liquefied petroleum gas (LPG), liquefied ethylene gas (LEG), etc. The liquid cargo tank can be type A, type B or type C, especially type C liquid cargo tank.

[0025] Although only an embodiment of phenol-resorcinol-formaldehyde resin as an adhesive is provided, those skilled in the art can expect that the use of isocyanate and epoxy resin can also achieve the purpose of the present invention and improve the shear strength of the secondary bonding interface of the bonded reconstructed material obtained by the secondary bonding method.

[0026] Similarly, although the present invention only provides one kind of microcrack and small hole size and their combination, those skilled in the art can expect, based on Example 1, that the microcrack size and small hole size and their combination provided by the present invention can also be used to achieve the purpose of the invention and improve the shear strength of the secondary bonding interface of the bonded reconstructed material obtained by the secondary bonding method.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A secondary gluing method for special recombinant materials for ultra-low temperature, characterized in that: The method comprises performing a point-crack minimally invasive treatment on the surfaces to be bonded, wherein the point-crack minimally invasive treatment specifically comprises: creating point-shaped microcracks on two surfaces to be bonded.

2. The secondary gluing method according to claim 1, characterized in that: The diameter of the microcracks is 0.8-1.2 mm.

3. The secondary gluing method according to claim 1 or 2, characterized in that: The microcrack depth is 0.5-1.5 mm.

4. The secondary gluing method according to any one of claims 1 to 3, characterized in that: The microcracks are arranged on the surface to be bonded in a matrix of (1.5 cm×1.5 cm)-(3.0 cm×3.0 cm).

5. The secondary gluing method according to claim 1, characterized in that: The method also includes drilling small holes symmetrically and dispersedly on two surfaces to be glued, and inserting wooden plugs or wooden plugs coated with glue into the small holes; the shape and size of the wooden plugs match the shape and size of the small holes.

6. The secondary gluing method according to claim 5, characterized in that The size of the small hole is: hole diameter 4.5-6.5mm, single side depth 6-8mm.

7. The secondary gluing method according to claim 5 or 6, characterized in that: The small holes are arranged on the surface to be bonded in a matrix of (5.0 cm×5.0 cm)-(8.0 cm×8.0 cm).

8. The secondary gluing method according to any one of claims 1 to 7, characterized in that: It involves applying a high-strength and high-toughness adhesive to the surfaces to be bonded.

9. The secondary gluing method according to claim 8, characterized in that: The high-strength and high-toughness adhesive is selected from one or more of phenol-resorcinol-formaldehyde resin, isocyanate, and epoxy resin.

10. The secondary gluing method according to claim 8 or 9, characterized in that: The amount of the high-strength and high-toughness adhesive applied is 150-230 g / m 2 Preferably, the glue application amount is 180-200g / m 2 .