Method for preparing thick composite laminated timber

Abstract

The present invention relates to a method for preparing thick composite laminated timber, comprising the following steps: S100, preparing a blank; S200, forming a finished product, wherein forming the finished product specifically comprises: S210, treating a bonding surface of the blank, and S220, preparing an adhesive, the adhesive comprising 100 parts by weight of an epoxy resin, 25-70 parts by weight of a curing agent, 10-30 parts by weight of a toughening agent, and 0.5-5 parts by weight of a coupling agent, and uniformly mixing said components in proportion; S230, uniformly coating the bonding surface with the adhesive, wherein the adhesive is coated in an amount of 200-1000 g / m2; S240, curing the adhesive; and S300, performing molding. The method for preparing thick composite laminated timber has the advantages that a plurality of prepreg layers are molded to form thin blanks, and then the plurality of blanks are formed into the thick composite laminated timber by means of adhesive curing; thus, the product curing time is shortened, the production efficiency is improved, the product appearance quality and mechanical strength are not affected, and the occurrence of core burning is avoided.

Description

Method for preparing large-thickness composite laminated wood TECHNICAL FIELD

[0001] The present application relates to the technical field of laminated wood preparation, and particularly relates to a method for preparing large-thickness composite laminated wood. BACKGROUND

[0002] Now, as a kind of artificial board, laminated wood has the advantages of high strength, good stability, easy processing, good insulation, good waterproof performance, etc., and has been widely used in many fields, such as the construction industry, furniture manufacturing, electrical insulation, thermal and thermal insulation materials, shipbuilding, etc. In particular, in the field of shipbuilding, laminated wood is used to manufacture ship structures, decks, interior decorations, cabin partitions, and marine furniture. With the rapid development of the low-temperature liquid cargo transportation industry, traditional laminated wood imported from abroad cannot meet the needs of domestic liquid cargo transportation shipbuilding, and many domestic enterprises have begun to develop new composite laminated wood. At present, the production process of composite laminated wood adopts pre-impregnated material molding, which has the advantages of high production efficiency, low cost, flexible design, high strength, light weight, and good surface quality.

[0003] However, pre-impregnated material molding is suitable for the manufacture of relatively thin materials. For example, a laminated wood molding method and laminated wood of composite material are provided in Chinese patent CN117430850A, which includes the following steps: step S1: cutting glass fiber material according to the size of the mold; step S2: adding hollow glass microbeads, flame retardants, coupling agents, and curing agents to the epoxy resin and mixing uniformly to form an epoxy resin glue solution; step S3: uniformly impregnating the glass fiber material in the epoxy resin glue solution to form a pre-impregnated material; step S4: loading the pre-impregnated material into the mold, heating and pressurizing the mold to make the pre-impregnated material cure and shape, forming an epoxy resin composite material; and step S5: demolding the cured and shaped epoxy resin composite material to obtain a composite material type laminated wood. However, various problems may occur in the molding process. (1) Current molding processes mostly use hot plates for heating. When the product thickness is large, the center of the product in the thickness direction is far away from the heating plate, and the heat transfer takes a long time, prolonging the curing time of the product and reducing the production efficiency. (2) The center and surface of the large-thickness product are heated unevenly. In order to completely cure the center without affecting the product performance, the curing time must be increased, and the surface layer in contact with the heating plate may be yellowed due to overheating, seriously affecting the appearance quality and mechanical strength of the product. (3) During the molding process, a large amount of heat is generated during the curing of the product, and the heat at the center of the product cannot be released due to the large thickness, resulting in core burning. In some liquid cargo transportation ships, the application thickness of laminated wood in liquid cargo tanks and liquid cargo tanks is as high as 500-600 mm, and products produced only by molding cannot meet the actual engineering application requirements. SUMMARY

[0004] Therefore, the present application aims to provide a method for preparing large-thickness composite laminated wood, which adopts the method of molding multiple layers of prepreg to form thinner blank, and then curing the multiple blanks by adhesive to form large-thickness composite laminated wood. The method solves the problems of prolonged curing time, low production efficiency, serious influence on product appearance quality and mechanical strength, and core burning phenomenon.

[0005] To solve the above problems, the present application provides a method for preparing large-thickness composite laminated wood, comprising:

[0006] S100, preparing a blank by laminating multiple layers of prepreg and molding by a molding machine;

[0007] S200, forming a finished product, comprising:

[0008] S210, processing the adhesive surface of the blank;

[0009] S220, preparing an adhesive, which comprises: 100 parts by weight of epoxy resin, 25-70 parts by weight of curing agent, 10-30 parts by weight of toughening agent, and 0.5-5 parts by weight of coupling agent, and uniformly mixing the above components in proportion;

[0010] S230, uniformly coating the adhesive on the adhesive surface, and the coating amount of the adhesive is 200-1000 g / m 2 ;

[0011] S240, curing the adhesive;

[0012] S300, machining and forming, removing the excess amount by mechanical machining to meet the design requirements.

[0013] Further, step S100 comprises:

[0014] S110, cutting the prepreg according to the design requirements;

[0015] S120, laminating multiple layers of prepreg to achieve the design thickness;

[0016] S130, placing the laminated prepreg into a molding machine for molding.

[0017] Further, in step S130, the four corners of the laminated prepreg are supported by spacers.

[0018] Further, the laminated thickness is 5-200 mm.

[0019] Further, in step S210, the method for processing the adhesive surface of the blank comprises:

[0020] S211, roughness of the bonding surface is treated to a preset value;

[0021] S212, the bonding surface is cleaned to remove oil stains.

[0022] Further, in step S211, the bonding surface is treated by sandpaper polishing.

[0023] Further, in step S211, the bonding surface is roughened by a release cloth.

[0024] Further, in step S220, the viscosity of the adhesive is 1000-25000 mPa·s.

[0025] Further, the curing agent is an amine curing agent.

[0026] The toughening agent is an epoxy toughening agent.

[0027] The coupling agent is a silane coupling agent.

[0028] Further, the epoxy resin is at least one of E-51 epoxy resin or E-44 epoxy resin. Advantages

[0029] Compared with the prior art, the method for preparing a large-thickness composite material laminated wood has the following advantages:

[0030] The technical solution has the advantages that the multiple layers of pre-impregnated materials are molded to form relatively thin blank materials, and the multiple blank materials are formed into large-thickness composite material laminated wood through adhesive curing, which shortens the product curing time, improves the production efficiency, does not affect the apparent quality and mechanical strength of the product, and avoids the occurrence of the core burning phenomenon. Embodiments of the present application

[0031] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0032] In the present application, the descriptions of "first", "second", "upper", "lower", etc. are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", "upper", "lower" can be explicitly or implicitly included at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but must be based on the realization of ordinary skilled in the art, when the technical solutions of the embodiments can be combined, all within the scope of protection required by the present application.

[0033] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0034] A method for preparing a large-thickness composite laminated wood, comprising:

[0035] S100, preparing a blank by laminating multiple layers of prepreg and then molding by a molding machine through a molding forming method;

[0036] S110, cutting the prepreg according to design requirements;

[0037] S120, laminating multiple layers of prepreg to a designed thickness;

[0038] S130, placing the laminated prepreg into a molding machine, supporting the four corners of the laminated prepreg by pads, and molding under certain temperature, time and pressure, with a laminated thickness of 5mm~200mm.

[0039] S200, product forming, comprising:

[0040] S210, treating the bonding surface of the blank;

[0041] S211, treating the roughness of the bonding surface to a preset value, the treatment method including treating the bonding surface by sandpaper polishing or forming a rough bonding surface by release cloth;

[0042] S212, cleaning the bonding surface to remove oil stains.

[0043] S220, preparing an adhesive, the adhesive comprising: 100 parts by weight of epoxy resin, 25~70 parts by weight of curing agent, 10~30 parts by weight of toughening agent, and 0.5~5 parts by weight of coupling agent, the above components being uniformly mixed in proportion; the curing agent is an amine curing agent, the toughening agent is an epoxy toughening agent, and the coupling agent is a silane coupling agent, and the viscosity of the adhesive is 1000~25000mPa·s.

[0044] S230, uniformly coating the adhesive on the bonding surface, with an adhesive coating amount of 200~1000g / m 2 ;

[0045] S240, curing the adhesive;

[0046] S300, machining forming, polishing to remove the adhesive overflowing around the product, and removing the excess amount by mechanical processing to meet the design requirements.

[0047] In the step S100 of the compression molding, the prepreg is cut according to the design requirements, and the design can correspond to the size of the compression molding equipment. After cutting, the release paper or release film on the upper and lower surfaces of each layer of the prepreg is torn off. In the curing molding process, the preferred curing parameters are: temperature is room temperature ~ 140℃, molding pressure is 5 ~ 20 MPa, and molding time is 2 ~ 6h.

[0048] In the blank bonding surface, a rough surface is manufactured to improve the bonding strength of the adhesive, and then the bonding surface is cleaned with a solvent to remove oil stains, impurities and other factors affecting the bonding effect.

[0049] Generally, the rough surface is manufactured by sanding with sandpaper or laying a layer of release cloth on the upper and lower surfaces of the prepreg during compression molding. The release cloth is a mesh base cloth woven with yarn. After curing molding, the texture of the release cloth is printed on the surface of the product to form a uniform rough surface.

[0050] Preferably, the sanded sandpaper is selected from 40-400 mesh, the cleaning of the bonding surface uses one of ethanol, acetone or ethyl acetate, and the release cloth material is selected from one of nylon, polyester and polytetrafluoroethylene. The gram weight of the release cloth is preferably 80-200g / m 2 .

[0051] The blanks are bonded by adhesive. The adhesive can be one of epoxy adhesive, polyurethane adhesive, vinyl adhesive, acrylate adhesive and polyimide adhesive. Depending on the situation, for example, design requirements, the amount of adhesive, etc., different adhesives can be used for each layer. According to the viscosity of the adhesive, the adhesive can be applied by scraping, brushing or spraying. According to the production efficiency requirement, the adhesive can be applied manually or by automatic adhesive equipment. After bonding, the semi-finished product is placed in a curing oven or drying room for curing. The curing time, temperature and pressure are determined according to the curing characteristics of the adhesive used.

[0052] Preferably, the epoxy resin is E-51 epoxy resin or E-44 epoxy resin or a mixed resin of the two.

[0053] As an example, the proportion of E-51 in the epoxy resin is 0%-100%, the curing agent is a combination of two types of amino curing agents, amine-terminated polyether and m-xylylenediamine, the toughening agent is an epoxy-terminated polyurethane ether, and the coupling agent is one or more of silane coupling agents KH-550, KH-560 and KH-570.

[0054] As an example, the adhesive composition contains 100 parts of epoxy resin, 10-30 parts of epoxy-terminated polyurethane ether, 20-50 parts of amine-terminated polyether, 5-20 parts of m-xylylenediamine and 0.5-5 parts of silane coupling agent.

[0055] The following examples illustrate the preparation method of the present application.

[0056] Example 1

[0057] The prepreg was cut into a size of 1 m x 1 m, and 100 layers were laid up after the release paper and release film were torn off. The laid-up prepreg was placed in a molding machine, 50 mm thick pads were placed around the four sides, and curing was performed at 150°C and 10 MPa for 2 h.

[0058] Two molded blanks were prepared, the adhesive surfaces of the blanks were polished to make rough surfaces using 40 mesh sandpaper, and were cleaned with alcohol. 100 parts by weight of E-51, 25 parts of an epoxy-terminated polyurethane ether, 30 parts of an amino-terminated polyether, 10 parts of m-xylylenediamine, and 1.5 parts of KH-560 were weighed, mixed uniformly, and uniformly coated on the two adhesive surfaces using a doctor blade. The amount of adhesive applied was controlled to be 600 g / m 2 . Then the two blanks were bonded and placed in an oven for curing at 80°C for 2 h.

[0059] Example 2

[0060] The prepreg was cut into a size of 1 m x 1 m, and 100 layers were laid up after the release paper and release film were torn off. A layer of 120 g / m2 polyester release cloth was laid on the upper and lower surfaces of the product, respectively. The laid-up prepreg was placed in a molding machine, 50 mm thick pads were placed around the four sides, and curing was performed at 150°C and 10 MPa for 2 h.

[0061] Two molded blanks were prepared, the release cloth on the upper and lower surfaces was torn off, and the adhesive surfaces were cleaned with alcohol. 100 parts by weight of E-51, 25 parts of an epoxy-terminated polyurethane ether, 30 parts of an amino-terminated polyether, 10 parts of m-xylylenediamine, and 1.5 parts of KH-560 were weighed, mixed uniformly, and uniformly coated on the two adhesive surfaces using a doctor blade. The amount of adhesive applied was controlled to be 600 g / m 2 . Then the two blanks were bonded and placed in an oven for curing at 80°C for 2 h.

[0062] Comparative Example

[0063] The prepreg was cut into a size of 1 m x 1 m, and 100 layers were laid up after the release paper and release film were torn off. The laid-up prepreg was placed in a molding machine, 50 mm thick pads were placed around the four sides, and curing was performed at 150°C and 10 MPa for 2 h. The molded blank was not subjected to adhesive treatment.

[0064] The shear strength, bending strength, and bending modulus of the samples of Example 1, Example 2, and the comparative example were tested, respectively. The shear strength of the adhesive surface was tested for Example 1 and Example 2, and the interlaminar shear strength of the body was tested for the comparative example sample. The specific test results are shown in Table 1.

[0065] It is found by comparison that the shear strength of the adhesive bonding interface and the shear strength of the material body are very small, and both can meet the technical index requirements; the bending strength and bending modulus of the adhesive bonding sample can reach the performance of the body, and meet the technical index requirements.

[0066] Table 1

[0067]

[0068] Although the present application has been disclosed with reference to the above examples, it is not limited to the above examples. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and the scope of protection of the present application should be limited by the scope defined in the claims.

Claims

1. A method of making a large thickness composite laminated wood, characterized in that, Comprise: S100, preparing a blank, stacking multiple layers of prepreg by mold forming method and then molding by a molding machine; S200, product forming, comprising: S210, treating the bonding surface of the blank; S220, preparing an adhesive, the adhesive comprising: 100 parts by weight of epoxy resin, 25-70 parts by weight of curing agent, 10-30 parts by weight of toughening agent, and 0.5-5 parts by weight of coupling agent, and uniformly mixing the above components in proportion; S230, uniformly applying an adhesive on the bonding surface, the adhesive application amount being 200-1000 g / m 2 ; S240, curing the adhesive; S300, machining forming, removing excess amount by machining method to meet design requirements.

2. The method for preparing a large-thickness composite material laminated wood according to claim 1, wherein Step S100 comprises: S110, cutting the prepreg according to design requirements; S120, stacking multiple layers of prepreg to a designed thickness; S130, placing the stacked prepreg into a molding machine for mold forming.

3. The method for preparing a large-thickness composite material laminated wood according to claim 2, wherein In step S130, the four corners of the stacked prepreg are supported by spacers.

4. The method for preparing a large-thickness composite material laminated wood according to claim 2, wherein The stacking thickness is 5-200 mm.

5. The method for preparing a large-thickness composite material laminated wood according to claim 1, wherein In step S210, the method for treating the bonding surface of the blank comprises: S211, treating the roughness of the bonding surface to a preset value; S212, cleaning the bonding surface to remove oil stains.

6. The method for preparing a large-thickness composite material laminated wood according to claim 5, wherein In step S211, the bonding surface is treated by sandpaper polishing.

7. The method for preparing a large-thickness composite material laminated wood according to claim 5, wherein In step S211, the bonding surface is treated by forming a rough surface with release cloth.

8. The method for preparing a large-thickness composite material laminated wood according to claim 1, wherein In step S220, the viscosity of the adhesive is 1000-25000 mPa·s.

9. The method for preparing a large-thickness composite material laminated wood according to claim 8, wherein The curing agent is an amine curing agent; The toughening agent is an epoxy toughening agent; The coupling agent is a silane coupling agent.

10. The method for preparing a large-thickness composite material laminated wood according to claim 8, wherein The epoxy resin is at least one of E-51 epoxy resin or E-44 epoxy resin.

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