Parchment paper protective sleeve, preparation method thereof and application of parchment paper protective sleeve as packaging assembly

Abstract

The invention relates to the technical field of packaging materials, in particular to a surface protection sleeve for electronic products, cosmetics, gifts and other high-grade products, a preparation method of the surface protection sleeve and a packaging assembly comprising the protection sleeve. The parchment paper protective sleeve comprises a parchment paper surface layer and a functional matt film layer which is directly combined on the inner side of the parchment paper surface layer in a thermal compounding mode, and the composite surface of the parchment paper surface layer is subjected to surface activation treatment; the protective sleeve is provided with a semi-tangent line used for bending forming, and the semi-tangent line completely cuts through the sulfate paper surface layer and ends at the functional matt film layer. The protective sleeve can be easily and accurately bent and formed, and the creases are clear, and the edges and corners are distinct. The preparation method of the parchment paper protective sleeve provided by the invention is environment-friendly in process, simple in step and stable in compounding quality.

Description

Technical Field

[0001] This invention relates to the field of packaging materials technology, specifically to a surface protective sleeve for high-end products such as electronic products, cosmetics, and gifts, a method for preparing the same, and a packaging component including the protective sleeve. Background Technology

[0002] Tracing paper, with its translucent, moisture-proof, and oil-proof properties, is often used in the packaging or protective lining of high-end products to enhance their display. However, there is a significant technical bottleneck when making it into protective sleeves (films) that require folding: commonly used 78g and 107g tracing paper is relatively thin and brittle. If traditional creasing techniques are used to create creases, light pressure results in indistinct creases and blurred edges after forming; slightly heavier pressure easily breaks the paper, rendering the finished product unusable. This contradiction of "ineffective light pressure and breakage under heavy pressure" severely limits the large-scale application of tracing paper in the field of protective sleeves requiring three-dimensional forming.

[0003] In existing technologies, attempts have been made to address the aforementioned problems by laminating ordinary films onto tracing paper or by laminating matte films using adhesives. However, the former fails to effectively solve the molding problem; while the latter offers some relief, it introduces an additional adhesive coating process, potentially leading to solvent emissions, uneven composite thickness, increased costs, and stringing of the adhesive layer during die-cutting. Therefore, a simpler, more environmentally friendly, and more efficient solution is urgently needed, one that can simplify the production process while ensuring excellent molding results and protective performance. Summary of the Invention

[0004] The primary objective of this invention is to overcome the shortcomings of existing technologies and provide a simplified tracing paper protective sleeve that requires no additional adhesive layer. This sleeve can be easily and precisely bent into shape, with clear creases and sharp edges. Another objective of this invention is to provide a method for preparing the aforementioned tracing paper protective sleeve, a method that is environmentally friendly, simple in steps, and produces stable composite quality. A further objective of this invention is to provide a packaging assembly comprising the aforementioned tracing paper protective sleeve.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The first invention provides a tracing paper protective sleeve, comprising a tracing paper surface layer 1 and a functional matte film layer 2 directly bonded to the inner side of the tracing paper surface layer 1 by thermal bonding. The surface of the tracing paper surface layer 1 is surface activated. The protective sleeve is provided with a semi-tangent line 3 for bending and forming. The semi-tangent line 3 completely cuts through the tracing paper surface layer 1 and terminates at the functional matte film layer 2.

[0007] In a specific embodiment of the present invention, the surface activation treatment is corona treatment or plasma treatment.

[0008] As a specific embodiment of the present invention, the functional matte film layer 2 is a multilayer co-extruded film, which includes at least a matte surface layer 21 facing the protected product and a hot-melt bonding layer 22 facing the sulfuric acid paper surface layer 1.

[0009] As a specific embodiment of the present invention, the raw material of the hot-melt bonding layer 22 includes at least one of ethylene-vinyl acetate copolymer, polyolefin elastomer or modified polyolefin.

[0010] As a specific embodiment of the present invention, the total thickness of the functional matte film layer 2 is 15μm-30μm, wherein the thickness of the hot-melt bonding layer 22 accounts for 20%-40% of the total thickness.

[0011] As a specific embodiment of the present invention, the basis weight of the sulfuric acid paper surface layer 1 is 78g / ㎡-107g / ㎡.

[0012] As a specific embodiment of the present invention, the two ends of the semi-tangent 3 are disconnected from the outer contour full tangent 4 of the protective sleeve, and the disconnection distance is 0.5mm-2mm.

[0013] As a specific embodiment of the present invention, the protective sleeve also includes a positioning structure and / or an observation window disposed on one or both sides of the semi-tangent 3.

[0014] Secondly, the method for providing the aforementioned sulfuric acid paper protective sleeve includes the following steps:

[0015] S1. Surface treatment: Surface activation treatment is performed on the surface of the sulfuric acid paper layer 1 to be laminated;

[0016] S2. Hot-press lamination: The sulfuric acid paper surface layer 1 treated in step S1 is aligned with the functional matte film layer 2 and hot-pressed in a hot-press lamination equipment. The hot-press lamination temperature is 80℃-130℃, the pressure is 0.3MPa-0.8MPa, and the time is 1-5 seconds.

[0017] S3. Die-cutting: Die-cutting is performed from the sulfuric acid paper surface layer 1 side of the hot-pressed composite material to the functional matte film layer 2 side, and the die-cutting depth is controlled to form the semi-tangent 3.

[0018] Thirdly, a packaging assembly is provided, characterized in that it includes an outer packaging box and a tracing paper protective sleeve as described in any one of claims 1-8, the tracing paper protective sleeve being adaptably housed within the outer packaging box.

[0019] More specifically:

[0020] Option 1: A protective sleeve made of sulfuric acid paper

[0021] The protective sleeve comprises a tracing paper surface layer and a functional matte film layer directly bonded to the inner side of the tracing paper surface layer via thermal bonding. The composite surface of the tracing paper surface layer undergoes surface activation treatment (such as corona or plasma treatment) to significantly enhance its surface energy and reactivity. The functional matte film layer is not an ordinary matte film, but a specially designed multi-layered thin film, which includes at least a matte surface layer facing the protected product and a heat-fused bonding layer facing the tracing paper surface.

[0022] The protective sleeve has a semi-tangent line for bending and forming. The semi-tangent line completely cuts through the sulfuric acid paper surface layer and terminates at the functional matte film layer, so that the functional matte film layer maintains its structural integrity at the semi-tangent line, thereby playing a continuous "flexible hinge" role when bending.

[0023] Preferably, the surface tension of the sulfuric acid paper composite after surface activation treatment is not less than 40 dynes, so as to ensure that a strong intermolecular force and even partial chemical bond are formed with the hot-melt bonding layer.

[0024] Preferably, the hot-melt bonding layer is made of at least one of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), or modified polyolefin (such as maleic anhydride-grafted polyolefin). These materials have suitable hot-melt temperatures and adhesive properties, enabling them to form a strong and tough bond with the activated sulfuric acid paper surface.

[0025] Preferably, the total thickness of the functional matte film layer is 15 μm to 30 μm, wherein the thickness of the hot-melt bonding layer accounts for 20%-40% of the total thickness. This design ensures both sufficient overall strength and "hinge" function, while also ensuring that the hot-melt bonding layer has sufficient material to achieve reliable adhesion.

[0026] Option 2: A method for preparing a sulfuric acid paper protective sleeve

[0027] The method includes the following steps:

[0028] S1. Surface treatment: The surface of the sulfuric acid paper layer to be laminated is subjected to corona treatment or plasma treatment.

[0029] S2. Hot-press lamination: Align the treated tracing paper surface layer with the functional matte film layer (with the hot-melt bonding layer facing the tracing paper) and feed them into a hot-press lamination device (such as a hot roller laminator or a flatbed hot press). Hot-press for 1-5 seconds at a temperature of 80℃-130℃ and a pressure of 0.3MPa-0.8MPa to melt the hot-melt bonding layer and firmly bond it to the activated tracing paper surface.

[0030] S3. Die-cutting: Using high and low dies, die-cutting is performed from one side of the sulfuric acid paper surface of the composite material, precisely controlling the depth to form a semi-cut line and outer contour.

[0031] Option 3: A packaging component

[0032] The component includes an outer packaging box and a protective sleeve made of tracing paper as described above. This protective sleeve acts as an inner lining, directly wrapping the product and placing it inside the outer packaging box, providing cushioning, scratch protection, and enhancing the display effect.

[0033] Beneficial effects of the present invention

[0034] Simplified process and environmental protection: It abandons the complicated processes of traditional liquid adhesive coating, drying and curing, and adopts one-step hot pressing composite, which greatly simplifies the production process, shortens the production cycle, and has no solvent emissions, making it more environmentally friendly.

[0035] Excellent composite quality: By activating the surface of the sulfuric acid paper and selecting a functional matte film with a special hot-melt bonding layer, high-strength and uniform direct bonding between the two is achieved, with a firm interface bond, completely avoiding problems such as uneven coating, pinholes, and stringing that may occur when using liquid adhesives.

[0036] The forming effect is outstanding and stable: the robust direct composite interface ensures that at the semi-tangent, the functional matte film layer (especially its uncut heat-fused bonding layer and matte surface layer) can effectively wrap and constrain the cut edge of the tracing paper. This makes the "flexible hinge-limiting reinforcement" mechanism more stable and reliable, with a smooth bending feel and extremely sharp forming edges with good retention.

[0037] Overall costs may be reduced: Although the unit price of functional matte film may be slightly higher, the elimination of adhesive costs, investment in coating equipment and energy consumption, as well as related environmental treatment costs, will optimize the overall production cost. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the layered structure of the sulfuric acid paper protective sleeve of the present invention;

[0039] Figure 2 This is a schematic diagram of the layered structure with a support layer of the sulfuric acid paper protective sleeve of the present invention;

[0040] Figure 3 This is a partially enlarged schematic diagram of the protective sleeve's planar unfolding and semi-tangent section according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram illustrating the application of the packaging component of the present invention. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0043] Example 1: Preparation and Structure of Protective Cover

[0044] See Figure 1 The sulfuric acid paper protective sleeve of the present invention is formed by directly bonding the sulfuric acid paper surface layer 1 and the functional matte film layer 2 through hot pressing.

[0045] The surface layer 1 of the sulfuric acid paper uses 107g / ㎡ white sulfuric acid paper. One side of the paper is treated with a corona treatment machine under the following conditions: power 3.5kW, electrode gap 1.5mm, treatment speed 25m / min. The surface tension after treatment is 42 dynes.

[0046] See Figure 2 The functional matte film layer 2 is a three-layer co-extruded film with a total thickness of 20μm. From the outside to the inside, it consists of: matte surface layer 21 (12μm thick, made of PET, with a matte finish), intermediate support layer (4μm thick, made of PET), and hot-melt bonding layer 22 (4μm thick, made of ethylene-vinyl acetate copolymer, EVA, VA content 28%).

[0047] The treated tracing paper (activated side up) and the functional matte film layer (thermal fusion bonding layer 22 facing down) are aligned and fed into a two-roll hot press laminator. The upper roll (contacting the tracing paper) temperature is 100℃, the lower roll (contacting the film) temperature is 110℃, the linear pressure is 50 N / cm, and the lamination speed is 15 m / min. After hot pressing, the two are firmly bonded, and the peel strength is tested to reach 4.0 N / 15 mm.

[0048] See Figure 3 The composite material is die-cut. A high-precision die is used, with a height difference of 0.035mm between the half-cut and full-cut. After die-cutting, the half-cut line 3 is clear, completely cutting through the tracing paper surface layer 1, but leaving only a shallow mark on the surface of the functional matte film layer 2, leaving the matte film layer intact. The two ends of the half-cut line 3 are separated from the full-cut line 4 by 1.2mm.

[0049] Example 2: Comparison Test of Hot-Pressure Composite Process Parameters

[0050] To determine the optimal process window, sulfuric acid paper (107 g, corona treated to 42 dynes / cm) and a functional matte film layer (same as in Example 1) were fixed, and the hot pressing temperature (T) and pressure (P) were varied for lamination. The peel strength (A) and the appearance of the composite were tested (B).

[0051] Table 1 Comparison of Hot-Pressure Composite Process Parameters

[0052]

[0053] As can be seen from the table above, good bonding can be obtained within the temperature range of 90-130℃ and the pressure range of 0.3-0.8MPa. Among them, 110℃ and 0.4-0.6MPa are the preferred parameter ranges, in which the peel strength is high and the appearance quality is the best.

[0054] Example 3: Application as a packaging component

[0055] See Figure 4 A packaging component for a Bluetooth headset charging case is described. The component includes a recycled pulp molded outer box (11) and a tracing paper protective sleeve (12) prepared as in Example 1, shaped to match the charging case. The protective sleeve (12) is manufactured by thermoforming, with a matte and soft inner surface that perfectly protects the glossy shell of the charging case. Its semi-transparent nature allows the product outline to be subtly visible, enhancing its premium feel. During packaging, the charging case is placed in the protective sleeve (12) and then the entire assembly is snapped into the fixing position of the outer box (11), ensuring safe and reliable transportation.

[0056] Verification of proportions and overall effects

[0057] To demonstrate the superiority of this invention, three samples were prepared for parallel testing:

[0058] Comparative Example G (Traditional Adhesive Lamination): 107g of tracing paper (corona-treated) was dry-laminated with 5μm thick water-based acrylic adhesive and ordinary 18μm matte PET film (untreated), and then a half-cut process was used (the half-cut line was broken by 1mm).

[0059] Comparative Example H (simple thermal lamination, no treatment): sulfuric acid paper (107g, without surface treatment) and the functional matte film layer described in Example 1 were hot-pressed together at 110℃ / 0.5MPa, and then the same half-cut process was used.

[0060] Example of the present invention: The scheme of Example 1 (surface treatment + functional matte film hot pressing composite + half cutting) is adopted.

[0061]

[0062] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A protective sleeve for sulfuric acid paper, characterized in that, It includes a sulfuric acid paper surface layer (1) and a functional matte film layer (2) directly bonded to the inner side of the sulfuric acid paper surface layer (1) by thermal bonding. The surface of the sulfuric acid paper surface layer (1) is treated with surface activation. The protective sleeve is provided with a semi-tangent line (3) for bending and forming. The semi-tangent line (3) completely cuts through the sulfuric acid paper surface layer (1) and terminates at the functional matte film layer (2).

2. The sulfuric acid paper protective sleeve according to claim 1, characterized in that, The surface activation treatment is either corona treatment or plasma treatment.

3. The sulfuric acid paper protective sleeve according to claim 1, characterized in that, The functional matte film layer (2) is a multilayer co-extruded film, which includes at least a matte surface layer (21) facing the protected product and a hot-melt bonding layer (22) facing the sulfuric acid paper surface layer (1).

4. The sulfuric acid paper protective sleeve according to claim 3, characterized in that, The raw materials of the hot-melt bonding layer (22) include at least one of ethylene-vinyl acetate copolymer, polyolefin elastomer or modified polyolefin.

5. The sulfuric acid paper protective sleeve according to claim 1, characterized in that, The total thickness of the functional matte film layer (2) is 15μm-30μm, wherein the thickness of the hot melt bonding layer (22) accounts for 20%-40% of the total thickness.

6. The sulfuric acid paper protective sleeve according to claim 1, characterized in that, The basis weight of the sulfuric acid paper surface layer (1) is 78g / ㎡-107g / ㎡.

7. The sulfuric acid paper protective sleeve according to claim 1, characterized in that, The two ends of the semi-tangent (3) are disconnected from the outer contour full tangent (4) of the protective sleeve, with a disconnection distance of 0.5mm-2mm.

8. The sulfuric acid paper protective sleeve according to claim 1, characterized in that, The protective sleeve also includes a positioning structure and / or an observation window located on one or both sides of the semi-tangent (3).

9. A method for preparing a sulfuric acid paper protective sleeve as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Surface treatment: Surface activation treatment is performed on the surface of the sulfuric acid paper layer (1) to be laminated; S2. Hot pressing: The sulfuric acid paper surface layer (1) treated in step S1 is aligned with the functional matte film layer (2), and hot pressing is performed in a hot pressing equipment. The hot pressing temperature is 80℃-130℃, the pressure is 0.3MPa-0.8MPa, and the time is 1-5 seconds. S3. Die-cutting: Die-cutting is performed from the sulfuric acid paper surface layer (1) of the hot-pressed composite material to the functional matte film layer (2) side, and the die-cutting depth is controlled to form the half-cut line (3).

10. A packaging component, characterized in that, It includes an outer packaging box and a tracing paper protective sleeve as described in any one of claims 1-8, the tracing paper protective sleeve being adaptably housed within the outer packaging box.

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