Electromagnetic shielding electronic packaging leather and preparation method thereof

Abstract

The invention relates to a preparation method of an electromagnetic shielding material, in particular to electromagnetic shielding electronic packaging leather and a preparation method thereof, and belongs to the technical field of electromagnetic shielding materials. The preparation method of the electromagnetic shielding electronic packaging leather comprises the following steps: S1, coating a surface layer: coating release paper with a surface layer coating to form a surface layer; s2, coating a middle layer: coating the dried surface layer with a middle layer coating; s3, coating a bonding layer: coating the dried middle layer with a bonding layer coating; s4, laminating: laminating the coated three-layer structure with the base cloth layer; and S5, separation: separating the finished product from the release paper. According to the preparation method of the electromagnetic shielding electronic packaging leather, an efficient conductive network in the bonding layer is constructed through the synergistic effect of the multi-wall long carbon nanotubes and pyrrole, the electromagnetic shielding performance is improved, meanwhile, the adding amount of the carbon nanotubes is effectively reduced, and therefore the cost is reduced.

Description

Technical Field

[0001] The invention relates to a method for preparing an electromagnetic shielding material, in particular to an electromagnetic shielding electronic packaging leather and a preparation method thereof, and belongs to the technical field of electromagnetic shielding materials. Background Art

[0002] With the rapid development of the information age, a large number of electronic devices are flooding our lives. While facilitating people's lives, they also bring a lot of electromagnetic pollution. Electromagnetic pollution mainly refers to electromagnetic radiation that is harmful to human production and life, mainly artificially generated microwave electromagnetic waves. Its hazards mainly include interference damage to electronic components, electromagnetic information leakage, and damage to the human body. Among them, microwave frequencies of 8-12GHz, namely the X-band, are the most widely used, so they are highly valued in the field of electromagnetic protection.

[0003] According to the different starting points of electromagnetic wave protection, electromagnetic wave protection materials can be divided into electromagnetic shielding materials and absorbing materials. The former is a radiation protection material that reduces the penetration of electromagnetic waves as much as possible by reflecting and absorbing electromagnetic waves. The latter is to reduce the interference to the radiation source by avoiding the reflection of electromagnetic waves as much as possible on the basis of reducing the transmission of electromagnetic waves as much as possible. The two materials have different characteristics. Electromagnetic shielding materials usually have high conductivity and thin thickness (usually less than 2mm), and the electromagnetic wave loss is mainly reflected. The absorbing material has moderate conductivity (to ensure the matching of dielectric constant and magnetic permeability constant), large thickness (more than 2mm), and the electromagnetic wave loss is mainly absorbed.

[0004] However, existing electromagnetic shielding materials still have some problems, such as insufficient electromagnetic shielding performance, poor mechanical properties, high cost, etc. Therefore, it is of great significance to develop an electromagnetic shielding electronic packaging leather with excellent electromagnetic shielding performance, good mechanical properties and low cost. Summary of the invention

[0005] Based on the above background, the purpose of the present invention is to provide a method for preparing electromagnetic shielding electronic packaging leather to solve the problems described in the background technology.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A method for preparing electromagnetic shielding electronic packaging leather, the method comprising the following steps:

[0008] S1. Coating the surface layer: coating the surface layer coating on the release paper to form a skin layer;

[0009] The surface coating is prepared by mixing surface resin, solvent, leveling agent, defoamer and color paste; the weight composition and dosage of the surface coating are: 100 parts of surface resin, 70 parts of solvent, 0.1-1 parts of leveling agent, 0.1-0.5 parts of defoamer, 3-20 parts of color paste, the viscosity of the surface coating is 1000-10000cps / 25℃, and the coating amount is 100-300g / m 2 ;

[0010] S2. coating the intermediate layer: applying the intermediate layer coating on the dried epidermis layer;

[0011] The weight composition and dosage of the intermediate layer coating are: 100 parts of intermediate layer resin, 70 parts of solvent, 0.1-1 parts of leveling agent, 0.1-0.5 parts of defoaming agent, 10-30 parts of multi-walled short carbon nanotubes, and 3-20 parts of color paste. The viscosity of the intermediate layer coating is 1000-10000cps / 25℃, and the coating amount is 100-300g / m 2 ;

[0012] S3 coating the next layer: the next layer coating is applied to the drying intermediate layer;

[0013] The composition and dosage of the adhesive coating are as follows: 100 parts of adhesive resin, 70 parts of solvent, 0.1-1 parts of leveling agent, 5-10 parts of pyrrole, 10-30 parts of multi-walled long carbon nanotubes, and 3-20 parts of color paste. The viscosity of the adhesive coating is 2000-10000cps / 25℃, and the coating amount is 100-300g / m 2 ;

[0014] S4. Laminating: Laminating the coated three-layer structure with the base fabric layer;

[0015] S5. Separation: Separate the finished product from the release paper.

[0016] The present invention optimizes the composition and dosage of the surface coating to ensure that the surface layer has good mechanical properties such as wear resistance and folding resistance, while ensuring good bonding with the middle layer; by adding multi-walled short carbon nanotubes to the middle layer, a diffuse reflection layer can be formed to improve the loss effect of electromagnetic waves; by adding pyrrole and multi-walled long carbon nanotubes to the bonding layer, an efficient conductive network can be formed to improve the electromagnetic shielding performance.

[0017] Preferably, the surface layer resin is a polycarbonate polyurethane resin with a solid content of 30%-40%. The use of polycarbonate polyurethane resin can improve the mechanical properties of the product, such as wear resistance and folding resistance.

[0018] Preferably, the intermediate layer resin is a polyether polyurethane resin with a solid content of 30%-40%. The polyether polyurethane resin can form a good bond with the adhesive layer.

[0019] Preferably, the adhesive layer resin is a polyether polyurethane resin. The use of a polyether polyurethane resin can improve the bonding performance of the adhesive layer.

[0020] Preferably, the leveling agent is an organosilicon-modified polyether leveling agent such as BYK-346, BYK-348, etc. The use of an organosilicon-modified polyether leveling agent can improve the flatness and leveling property of the coating.

[0021] Preferably, the defoaming agent is an organosilicon-modified anti-bubble agent such as BYK-024, BYK-054, etc. The use of an organosilicon-modified anti-bubble agent can effectively suppress bubbles in the coating and improve the coating quality.

[0022] Preferably, the multi-walled long carbon nanotubes have a diameter of 40-80 nm and a length of 50-200 μm. Selecting multi-walled long carbon nanotubes of appropriate size can form a good conductive network and improve electromagnetic shielding performance.

[0023] Preferably, the multi-walled short carbon nanotubes have a diameter of 40-80 nm and a length of 8-30 μm. Selecting multi-walled short carbon nanotubes of appropriate size can form a diffuse reflection layer and improve the electromagnetic wave loss effect.

[0024] Preferably, in step S1, the coating knife position of the surface coating is 0.03-0.15 mm, and the film thickness of the epidermis after drying is 0.01-0.1 mm. By controlling the coating knife position and film thickness, it can be ensured that the surface layer has good mechanical properties and appearance quality.

[0025] Preferably, in step S2, the coating knife position of the intermediate layer coating is 0.05-0.2 mm, and the intermediate layer film thickness after drying is 0.03-0.1 mm. By controlling the coating knife position and film thickness, it can be ensured that the intermediate layer has good electromagnetic shielding performance and bonding with other layers.

[0026] Preferably, in step S3, the coating knife position of the adhesive layer coating is 0.2-0.4 mm. By controlling the coating knife position, it can be ensured that the adhesive layer has sufficient thickness to form an efficient conductive network.

[0027] Preferably, in step S4, the drying condition before lamination is 120-130° C. By controlling the drying temperature, the penetration degree of the adhesive layer in the base fabric layer can be increased, and the peeling strength can be improved.

[0028] An electromagnetic shielding electronic packaging leather prepared by the preparation method of the invention.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The method for preparing an electromagnetic shielding electronic packaging leather of the present invention constructs a high-efficiency conductive network in the bonding layer through the synergistic effect of multi-walled long carbon nanotubes and pyrrole, thereby effectively reducing the amount of carbon nanotubes added while improving the electromagnetic shielding performance, thereby reducing the cost;

[0031] 2. The bonding layer in the present invention serves as an electromagnetic wave reflection layer, and forms an efficient electromagnetic wave loss structure with the diffuse reflection layer constructed by short multi-walled nanotubes, thereby improving the electromagnetic shielding performance;

[0032] 3. While ensuring the electromagnetic shielding performance, the present invention improves the physical properties of the product such as folding resistance, wear resistance, and hydrolysis resistance by optimizing the surface layer resin and the middle layer resin;

[0033] 4. The present invention solves the mechanical performance problems such as poor peeling force and wear resistance under high filler conditions by optimizing the composition and dosage of each layer of coating, and achieves a balance between the electromagnetic shielding performance and mechanical properties of electromagnetic shielding electronic packaging leather products. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described in detail below through specific embodiments. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any form of modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0035] In the present invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments are all conventional methods in the art unless otherwise specified.

[0036] The reagents used in the following examples, unless otherwise specified, can be purchased from conventional biochemical reagent stores. The solvent described in the following examples is DMF.

[0037] The embodiment of the present invention discloses a method for preparing an electromagnetic shielding electronic packaging leather, comprising preparing a surface coating, an intermediate coating and a bonding coating, and then preparing a final product through steps such as coating, laminating and separating.

[0038] Step 1: Prepare the surface coating:

[0039] 100 parts of polycarbonate type polyurethane resin (surface resin) with a solid content of 35%, 70 parts of solvent, 0.5 parts of BYK-346 leveling agent, 0.3 parts of BYK-024 defoamer and 10 parts of color paste were mixed and stirred evenly to obtain the surface coating. The viscosity of the coating is 5000cps / 25℃, and the coating amount is 200g / m 2 .

[0040] Step 2: Preparation of intermediate layer coating:

[0041] 100 parts of polyether type polyurethane resin (middle layer resin) with a solid content of 35%, 70 parts of solvent, 0.5 parts of BYK-346 leveling agent, 0.3 parts of BYK-024 defoamer, 20 parts of multi-walled short carbon nanotubes (diameter 60nm, length 20μm) and 10 parts of color paste were mixed and stirred evenly to obtain the middle layer coating. The viscosity of the coating is 5000cps / 25℃, and the coating amount is 200g / m 2 .

[0042] Step 3: Prepare the adhesive coating:

[0043] 100 parts of polyether polyurethane resin (adhesive layer resin), 70 parts of solvent, 0.5 parts of BYK-346 leveling agent, 7 parts of pyrrole, 20 parts of multi-walled carbon nanotubes (diameter 60nm, length 150μm) and 10 parts of color paste were mixed and stirred evenly to obtain an adhesive layer coating. The viscosity of the coating is 6000cps / 25℃, and the coating amount is 200g / m 2 .

[0044] Step 4: Apply the surface layer:

[0045] The surface coating was applied on the release paper with a coating knife position of 0.1 mm, and dried at 120°C for 5 minutes to form a skin layer. The film thickness after drying was 0.05 mm.

[0046] Step 5: Apply the middle layer:

[0047] The intermediate layer coating is applied on the dried epidermis layer with a coating knife position of 0.12mm and dried at 120°C for 5 minutes. The film thickness after drying is 0.06mm.

[0048] Step 6: Apply the adhesive layer:

[0049] The second layer coating is applied on the dried middle layer with a coating knife position of 0.3 mm and dried at 120° C. for 5 minutes.

[0050] Step 7: Lamination:

[0051] The coated three-layer structure is laminated with the base fabric layer at 125°C, with a pressure of 0.5 MPa for 30 seconds. Step 8: Separation:

[0052] The finished product is separated from the release paper to obtain the final electromagnetic shielding electronic packaging leather product.

[0053] Example 2

[0054] The method of Example 1 is followed, except that the polyurethane resin in the top layer coating is replaced with a polycarbonate polyurethane resin with a solid content of 40%, the amount of multi-walled short carbon nanotubes in the middle layer coating is changed to 15 parts, the amount of pyrrole in the next layer coating is changed to 6 parts, and the amount of multi-walled long carbon nanotubes is changed to 15 parts.

[0055] Example 3

[0056] The method of Example 1 was followed, except that the leveling agent in the top coating was changed to BYK-348, the defoaming agent was changed to BYK-054, the size of the multi-walled short carbon nanotubes in the middle coating was changed to 50 nm in diameter and 15 μm in length, and the size of the multi-walled long carbon nanotubes in the next coating was changed to 50 nm in diameter and 100 μm in length.

[0057] Example 4

[0058] The method of Example 1 was followed, except that the coating knife position of the top layer coating was changed to 0.05 mm, the coating knife position of the middle layer coating was changed to 0.08 mm, the coating knife position of the next layer coating was changed to 0.25 mm, and the laminating temperature was changed to 130°C.

[0059] Comparative Example 1

[0060] The method of Example 1 was followed, but without adding the short multi-walled carbon nanotubes in the intermediate coating and the long multi-walled carbon nanotubes in the follower coating.

[0061] Comparative Example 2

[0062] The method of Example 1 was followed, but without the addition of pyrrole in the adhesive coating.

[0063] Comparative Example 3

[0064] The method of Example 1 is followed, except that the surface layer resin is changed to polyether polyurethane resin, and the middle layer resin is changed to polyester polyurethane resin.

[0065] The electromagnetic shielding electronic packaging leathers prepared in the above examples and comparative examples were subjected to performance tests, and the results are shown in Table 1:

[0066] Table 1

[0067]

[0068]

[0069] Note: The electromagnetic shielding effectiveness is tested according to GB / T 30142-2013 standard, with a frequency range of 8-12GHz; the peel strength is tested according to GB / T 2790-1995 standard; the folding resistance is tested according to GB / T 2689.1-2008 standard; and the abrasion resistance is tested according to GB / T2689.4-2008 standard.

[0070] As can be seen from Table 1, the electromagnetic shielding electronic packaging leathers prepared in Examples 1-4 of the present invention have excellent electromagnetic shielding effectiveness while maintaining good peel strength, folding resistance and wear resistance. In contrast, the electromagnetic shielding effectiveness of Comparative Example 1 is significantly reduced due to the absence of carbon nanotubes; the electromagnetic shielding effectiveness of Comparative Example 2 is reduced due to the absence of pyrrole; and the mechanical properties of Comparative Example 3 are significantly reduced due to improper selection of resin.

[0071] In Examples 1-4, a highly efficient conductive network in the bonding layer is constructed through the synergistic effect of multi-walled long carbon nanotubes and pyrrole, while the multi-walled short carbon nanotubes in the middle layer form a diffuse reflection layer, and the two work together to form a highly efficient electromagnetic wave loss structure, thereby exhibiting excellent electromagnetic shielding performance. In addition, good mechanical properties are achieved by optimizing the surface layer resin and the middle layer resin.

[0072] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. For example, the composition and amount of each layer of coating can be adjusted according to specific needs, or the coating process parameters can be changed, etc., to obtain electromagnetic shielding electronic packaging leather products with different performances.

Claims

1. A method for preparing electromagnetic shielding electronic packaging leather, characterized in that The method comprises the following steps: S1. Coating the surface layer: coating the surface layer coating on the release paper to form a skin layer; The surface coating is prepared by mixing surface resin, solvent, leveling agent, defoamer and color paste; the weight composition and dosage of the surface coating are: 100 parts of surface resin, 70 parts of solvent, 0.1-1 parts of leveling agent, 0.1-0.5 parts of defoamer, 3-20 parts of color paste, the viscosity of the surface coating is 1000-10000cps / 25℃, and the coating amount is 100-300g / m 2 ; S2. coating the intermediate layer: applying the intermediate layer coating on the dried epidermis layer; The weight composition and dosage of the intermediate layer coating are: 100 parts of intermediate layer resin, 70 parts of solvent, 0.1-1 parts of leveling agent, 0.1-0.5 parts of defoaming agent, 10-30 parts of multi-walled short carbon nanotubes, and 3-20 parts of color paste. The viscosity of the intermediate layer coating is 1000-10000cps / 25℃, and the coating amount is 100-300g / m 2 ; S3 coating the next layer: the next layer coating is applied to the drying intermediate layer; The composition and dosage of the adhesive coating are as follows: 100 parts of adhesive resin, 70 parts of solvent, 0.1-1 parts of leveling agent, 5-10 parts of pyrrole, 10-30 parts of multi-walled long carbon nanotubes, and 3-20 parts of color paste. The viscosity of the adhesive coating is 2000-10000cps / 25℃, and the coating amount is 100-300g / m 2 ; S4. Laminating: Laminating the coated three-layer structure with the base fabric layer; S5. Separation: Separate the finished product from the release paper.

2. The method for preparing the electromagnetic shielding electronic packaging leather according to claim 1, characterized in that: The surface layer resin is a polycarbonate polyurethane resin with a solid content of 30%-40%; the middle layer resin is a polyether polyurethane resin with a solid content of 30%-40%; and the bonding layer resin is a polyether polyurethane resin.

3. The method for preparing the electromagnetic shielding electronic packaging leather according to claim 1, characterized in that: The leveling agent is BYK-346 or BYK-348 silicone-modified polyether leveling agent, and the defoaming agent is BYK-024 or BYK-054 silicone-modified bubble suppressing agent.

4. The method for preparing the electromagnetic shielding electronic packaging leather according to claim 1, characterized in that: The diameter of the multi-walled long carbon nanotube is 40-80 nm, and the length is 50-200 μm; the diameter of the multi-walled short carbon nanotube is 40-80 nm, and the length is 8-30 μm.

5. The method for preparing the electromagnetic shielding electronic packaging leather according to claim 1, characterized in that: In step S1, the coating knife position of the surface coating is 0.03-0.15 mm, and the film thickness of the epidermis after drying is 0.01-0.1 mm.

6. The method for preparing the electromagnetic shielding electronic packaging leather according to claim 1, characterized in that: In step S2, the coating knife position of the intermediate layer coating is 0.05-0.2 mm, and the film thickness of the intermediate layer after drying is 0.03-0.1 mm.

7. The method for preparing the electromagnetic shielding electronic packaging leather according to claim 1, characterized in that: In step S3, the coating knife position of the following layer of coating is 0.2-0.4 mm.

8. The method for preparing the electromagnetic shielding electronic packaging leather according to claim 1, characterized in that: In step S4, the drying condition before lamination is 120-130°C.

9. An electromagnetic shielding electronic packaging leather prepared by the preparation method according to claim 1.

Images