A TPU nitrogen foamed film and its production process

Abstract

A TPU nitrogen foamed film, comprising a foamed TPU main body layer, with an inner protective layer and an outer protective layer fixedly connected to both sides of the foamed TPU main body layer respectively. A plurality of positioning blocks are fixedly connected to both the inner protective layer and the outer protective layer, and the positioning blocks extend into the foamed TPU main body layer. For a TPU nitrogen foamed film and its production process of the present invention, by providing the inner protective layer and the outer protective layer to jointly protect the foamed TPU main body layer, the strength of the foamed film is enhanced. And by providing the positioning blocks to lock the relative positions of the foamed TPU main body layer, the inner protective layer and the outer protective layer, the overall structural stability of the foamed film is enhanced, avoiding the phenomenon of delamination.

Description

Technical Field

[0001] The invention relates to the field of TPU foaming films, in particular to a TPU nitrogen foaming film and a production process thereof. Background Art

[0002] TPU foam film is a commonly used material, often used in luggage products or sporting goods. At present, TPU foam film is often a multi-layer structure, and the layers are mainly connected by bonding. After long-term use, especially after frequent bending, the bent part is prone to delamination, which is not only unsightly but also easy to damage. Summary of the invention

[0003] In order to solve the deficiencies in the prior art, the present invention provides a TPU nitrogen foam film and a production process thereof, wherein an inner protective layer and an outer protective layer are provided to jointly protect a foamed TPU main layer, thereby improving the strength of the foamed film, and a positioning block is provided to lock the relative positions of the foamed TPU main layer, the inner protective layer, and the outer protective layer, thereby improving the overall structural stability of the foamed film and avoiding delamination.

[0004] In order to achieve the above object, the specific scheme adopted by the present invention is:

[0005] A TPU nitrogen foam film comprises a foamed TPU main layer, wherein an inner protective layer and an outer protective layer are fixedly connected to both sides of the foamed TPU main layer, wherein the inner protective layer and the outer protective layer are fixedly connected to a plurality of positioning blocks, and the positioning blocks extend into the foamed TPU main layer.

[0006] Preferably, the foamed TPU main body layer is provided with a plurality of grooves corresponding to the positioning blocks, and the positioning blocks extend into the grooves.

[0007] Preferably, the volume of the positioning block is smaller than the volume of the groove.

[0008] Preferably, the inner protective layer and the outer protective layer are both configured as transparent layers, and the positioning block is formed by consolidating with shadowless adhesive.

[0009] Preferably, a magnetic adsorption layer is fixedly connected to a side of the inner protective layer facing away from the foamed TPU main layer.

[0010] Preferably, the magnetic adsorption layer comprises an adhesive block fixedly connected to the inner protective layer and magnetic particles uniformly distributed in the adhesive block.

[0011] Preferably, a bottom layer is fixedly connected to a side of the magnetic adsorption layer facing away from the inner protective layer.

[0012] Preferably, an inner release layer is provided on one side of the bottom layer facing away from the magnetic adsorption layer, and an outer release layer is provided on one side of the outer protective layer facing away from the foamed TPU main body layer.

[0013] A production process of a TPU nitrogen foamed film includes the following steps:

[0014] S1: Produce the foamed TPU main body layer by using the nitrogen foaming method, and form a groove for cooperating with the positioning block on the surface of the foamed TPU main body layer by using a mold;

[0015] S2: Coat an invisible glue on the outer protective layer, and attach the foamed TPU main body layer to the outer protective layer, so that the invisible glue enters the groove;

[0016] S3: Cure the invisible glue by using ultraviolet light to connect the foamed TPU main body layer and the outer protective layer, and make the part of the invisible glue entering the groove solidify to form the positioning block;

[0017] S4: Connect the foamed TPU main body layer and the inner protective layer according to the methods of S2 and S3.

[0018] Preferably, the following steps are further included:

[0019] S5: Prepare an adhesive and uniformly mix magnetic particles in the adhesive to obtain an adsorption material;

[0020] S6: Coat the adsorption material on the inner protective layer, and the adsorption material forms a magnetic adsorption layer after drying.

[0021] In the present invention, the inner protective layer and the outer protective layer are provided to jointly protect the foamed TPU main body layer, improve the strength of the foamed film, and lock the relative positions of the foamed TPU main body layer, the inner protective layer and the outer protective layer by setting the positioning block, improve the overall structural stability of the foamed film, and avoid the phenomenon of delamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.

[0023] Figure 1 is a schematic diagram of the overall structure of the foamed film;

[0024] Figure 2 is a flowchart of the production process.

[0025] Reference numerals: 1 - outer release layer, 2 - outer protective layer, 3 - foamed TPU main body layer, 4 - groove, 5 - positioning block, 6 - inner protective layer, 7 - adhesive block, 8 - magnetic particles, 9 - bottom layer, 10 - inner release layer. Detailed implementation manners

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] Please refer to Figure 1 and 2 , Figure 1 is a schematic diagram of the overall structure of the foamed film, Figure 2 is a flowchart of the production process.

[0028] A TPU nitrogen foamed film includes a foamed TPU main body layer 3. An inner protective layer 6 and an outer protective layer 2 are respectively fixedly connected to both sides of the foamed TPU main body layer 3. A plurality of positioning blocks 5 are fixedly connected to both the inner protective layer 6 and the outer protective layer 2, and the positioning blocks 5 extend into the foamed TPU main body layer 3.

[0029] In the present invention, by providing the inner protective layer 6 and the outer protective layer 2 to protect the foamed TPU (thermoplastic polyurethane elastomer) main body layer 3, the overall performance of the foamed film is improved. The inner protective layer 6 and the outer protective layer 2 can select appropriate materials according to actual needs. Moreover, in the foamed film of the present invention, by providing the positioning blocks 5 and making the positioning blocks 5 penetrate into the foamed TPU main body layer 3, the relative positions of the foamed TPU main body layer 3, the inner protective layer 6, and the outer protective layer 2 are locked by the positioning blocks 5, so as to fully improve the overall structural stability of the foamed film and avoid the phenomenon of delamination.

[0030] In the present invention, by providing the inner protective layer 6 and the outer protective layer 2 together to protect the foamed TPU main body layer 3, the strength of the foamed film is improved, and by providing the positioning blocks 5 to lock the relative positions of the foamed TPU main body layer 3, the inner protective layer 6, and the outer protective layer 2, the overall structural stability of the foamed film is improved, and the phenomenon of delamination is avoided.

[0031] In order to improve the positioning effect of the positioning block 6, a plurality of grooves 4 corresponding to and cooperating with the positioning block 5 are formed in the foamed TPU main body layer 3, and the positioning block 5 extends into the grooves 4. Although the foamed TPU main body layer 3 itself has good elasticity, the positioning block 5 can directly force the foamed TPU main body layer 3 to produce a depression by extrusion to cooperate with the positioning block 5. However, when the foamed film deforms, the depression on the foamed TPU main body layer 3 may deform, resulting in the dislocation of the positioning block 5, and further causing delamination. By providing the grooves 4 and using the grooves 4 with stable shape to cooperate with the positioning block 5, even if the foamed film deforms during use, the positioning block 5 can stably extend into the grooves 4, thus fully ensuring the positioning effect of the positioning block 5 on the foamed TPU main body layer 3, the inner protective layer 6 and the outer protective layer 2.

[0032] Considering that the grooves 4 will still deform to a certain extent during the deformation of the foamed film, in order to fully ensure that the positioning block 5 can be located in the grooves 4, the volume of the positioning block 5 is smaller than the volume of the grooves 4. Since the volume of the grooves 4 is larger than the volume of the positioning block 5, the grooves 4 will not extrude the positioning block 5 outward when deforming, thus ensuring that the positioning block 5 can be stably located in the grooves 4.

[0033] Since the overall thickness of the foamed film cannot be too high, the size of the positioning block 5 is also very small, and it is very difficult to accurately insert the positioning block 5 into the grooves 4 during the processing. To solve this problem, both the inner protective layer 6 and the outer protective layer 2 are set as transparent layers, and the positioning block 5 is formed by curing with a UV glue. During the processing, first, the UV glue is applied on the inner protective layer 6 and the outer protective layer 2, then the foamed TPU main body layer 3 is attached to the inner protective layer 6 or the outer protective layer 2, and part of the UV glue enters the grooves 4. Subsequently, the UV glue is cured by ultraviolet light irradiation using the light transmission performance of the inner protective layer 6 and the outer protective layer 2. The cured UV glue can not only fixedly connect the foamed TPU main body layer 3 with the inner protective layer 6 and the outer protective layer 2 together, but also form the positioning block 5 in the grooves 4, eliminating the need to specially process the positioning block 5 with a small volume, which can significantly reduce the production difficulty and improve the production efficiency.

[0034] In order to expand the application range of the foamed film and enable the foamed film to be easily fixed to ferromagnetic materials, a magnetic adsorption layer is fixedly connected to the side of the inner protective layer 6 facing away from the foamed TPU main body layer 3. The magnetic adsorption layer can generate magnetism by magnetization, and then the foamed film can be adsorbed on the surface of materials such as iron through the magnetic adsorption layer, eliminating the need for adhesives, making it more convenient to paste and remove, and more environmentally friendly.

[0035] The specific structure of the magnetic adsorption layer is as follows: The magnetic adsorption layer includes an adhesive block 7 fixedly connected to the inner protective layer 6 and magnetic particles 8 evenly distributed in the adhesive block 7. The adhesive block 7 and the magnetic particles 8 can directly adopt the materials of soft magnetic materials in the prior art.

[0036] Although the magnetic adsorption layer expands the fixing methods of the foaming film, in many scenarios, it is still necessary to fix the foaming film by bonding. To facilitate bonding, a bottom layer 9 is fixedly connected to the side of the magnetic adsorption layer facing away from the inner protective layer 6. It should be noted that the thickness of the bottom layer 9 will have a certain impact on the adsorption strength of the magnetic adsorption layer. Therefore, the thickness of the bottom layer 9 cannot be too high.

[0037] To protect the foaming film during packaging and transportation, an inner release layer 10 is provided on the side of the bottom layer 9 facing away from the magnetic adsorption layer, and an outer release layer 1 is provided on the side of the outer protective layer 2 facing away from the foaming TPU main body layer 3. Both the inner release layer 10 and the outer release layer 1 can adopt existing release films, which belong to the conventional technologies in this field and will not be elaborated here. By providing release layers on both sides of the foaming film, the foaming film can be fully protected to avoid damage during packaging and transportation, which may affect its use.

[0038] In a specific embodiment of the present invention, a TPU nitrogen foamed film includes a foamed TPU main body layer 3. Inner protective layers 6 and outer protective layers 2 are respectively and fixedly connected to both sides of the foamed TPU main body layer 3. A plurality of positioning blocks 5 are fixedly connected to both the inner protective layer 6 and the outer protective layer 2, and the positioning blocks 5 extend into the foamed TPU main body layer 3. A plurality of grooves 4 corresponding to and cooperating with the positioning blocks 5 are formed on the foamed TPU main body layer 3. The positioning blocks 5 extend into the grooves 4. Although the foamed TPU main body layer 3 itself has good elasticity and the positioning blocks 5 can directly force the foamed TPU main body layer 3 to produce depressions to cooperate with the positioning blocks 5 by extrusion, when the foamed film is deformed, the depressions on the foamed TPU main body layer 3 may be deformed, resulting in the dislocation of the positioning blocks 5, and thus delamination may occur. By providing the grooves 4 and using the grooves 4 with stable shapes to cooperate with the positioning blocks 5, even if the foamed film is deformed during use, the positioning blocks 5 can stably extend into the grooves 4, thereby fully ensuring the positioning effect of the positioning blocks 5 on the foamed TPU main body layer 3, the inner protective layer 6, and the outer protective layer 2. The volume of the positioning blocks 5 is smaller than the volume of the grooves 4. Since the volume of the grooves 4 is larger than the volume of the positioning blocks 5, when the grooves 4 are deformed, they will not extrude the positioning blocks 5 outward, thus ensuring that the positioning blocks 5 can be stably located in the grooves 4. Both the inner protective layer 6 and the outer protective layer 2 are provided as transparent layers. The positioning blocks 5 are formed by curing with a UV-curable adhesive. During the processing, first, a UV-curable adhesive is coated on the inner protective layer 6 and the outer protective layer 2, then the foamed TPU main body layer 3 is adhered to the inner protective layer 6 or the outer protective layer 2, and part of the UV-curable adhesive enters the grooves 4. Subsequently, the UV-curable adhesive is cured by irradiating with ultraviolet light using the light-transmitting properties of the inner protective layer 6 and the outer protective layer 2. The cured UV-curable adhesive can not only fixedly connect the foamed TPU main body layer 3, the inner protective layer 6, and the outer protective layer 2 together, but also form the positioning blocks 5 in the grooves 4. There is no need to specially process the positioning blocks 5 with a small volume, which can significantly reduce the production difficulty and improve the production efficiency. A magnetic adsorption layer is fixedly connected to the side of the inner protective layer 6 facing away from the foamed TPU main body layer 3. The magnetic adsorption layer can generate magnetism by magnetizing, and thus the foamed film can be adsorbed on the surface of materials such as iron through the magnetic adsorption layer, without using an adhesive, which is more convenient for pasting and removing and is more environmentally friendly. The magnetic adsorption layer includes an adhesive block 7 fixedly connected to the inner protective layer 6 and magnetic particles 8 evenly distributed in the adhesive block 7. A bottom layer 9 is fixedly connected to the side of the magnetic adsorption layer facing away from the inner protective layer 6. An inner release layer 10 is provided on the side of the bottom layer 9 facing away from the magnetic adsorption layer. An outer release layer 1 is provided on the side of the outer protective layer 2 facing away from the foamed TPU main body layer 3. By providing release layers on both sides of the foamed film, the foamed film can be fully protected to avoid damage to the foamed film during packaging and transportation, which may affect its use.

[0039] A production process of the above-mentioned TPU nitrogen foamed film, comprising the following steps:

[0040] S1: Produce the foamed TPU main layer 3 by using the nitrogen foaming method, and form a groove 4 for cooperating with the positioning block 5 on the surface of the foamed TPU main layer 3 by using a mold. The nitrogen foaming method and the mold forming method are both mature existing technologies in the art and will not be elaborated here;

[0041] S2: Coat the ultraviolet curable adhesive on the outer protective layer 2, and bond the foamed TPU main layer 3 to the outer protective layer 2, so that the ultraviolet curable adhesive enters the groove 4;

[0042] S3: Connect the foamed TPU main layer 3 and the outer protective layer 2 by curing the ultraviolet curable adhesive, and the part of the ultraviolet curable adhesive entering the groove 4 solidifies to form the positioning block 5;

[0043] S4: Connect the foamed TPU main layer 3 and the inner protective layer 6 according to the methods of S2 and S3;

[0044] S5: Prepare an adhesive and uniformly mix magnetic particles 8 in the adhesive to obtain an adsorption material.

[0045] S6: Coat the adsorption material on the inner protective layer 6, and a magnetic adsorption layer is formed after the adsorption material dries.

[0046] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0047] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A TPU nitrogen foamed film, characterized in that: It comprises a foamed TPU main body layer (3), the two sides of the foamed TPU main body layer (3) are respectively fixedly connected with an inner protective layer (6) and an outer protective layer (2), the inner protective layer (6) and the outer protective layer (2) are both fixedly connected with a plurality of positioning blocks (5), and the positioning blocks (5) extend into the foamed TPU main body layer (3); The foamed TPU main body layer (3) is provided with a plurality of grooves (4) corresponding to the positioning blocks (5), and the positioning blocks (5) extend into the grooves (4); The volume of the positioning block (5) is smaller than the volume of the groove (4); The inner protective layer (6) and the outer protective layer (2) are both configured as transparent layers, and the positioning block (5) is formed by consolidating with shadowless glue; A magnetic adsorption layer is fixedly connected to the side of the inner protective layer (6) facing away from the foamed TPU main layer (3); The magnetic adsorption layer comprises an adhesive block (7) fixedly connected to the inner protective layer (6) and magnetic particles (8) uniformly distributed in the adhesive block (7).

2. The TPU nitrogen foamed film according to claim 1, characterized in that: A bottom layer (9) is fixedly connected to the side of the magnetic adsorption layer facing away from the inner protective layer (6).

3. The TPU nitrogen foamed film according to claim 2, characterized in that, An inner release layer (10) is provided on the side of the bottom layer (9) facing away from the magnetic adsorption layer, and an outer release layer (1) is provided on the side of the outer protective layer (2) facing away from the foamed TPU main layer (3).

4. A production process of the TPU nitrogen foamed film according to claim 1, characterized in that, The steps include: S1: producing the foamed TPU main layer (3) by a nitrogen foaming method, and forming a groove (4) on the surface of the foamed TPU main layer (3) by a mold for matching with the positioning block (5); S2: applying a shadowless adhesive on the outer protective layer (2), and attaching the foamed TPU main layer (3) to the outer protective layer (2), so that the shadowless adhesive enters the groove (4); S3: using ultraviolet light to cure the shadowless adhesive to connect the foamed TPU main layer (3) with the outer protective layer (2), and allowing the part of the shadowless adhesive that enters the groove (4) to solidify to form the positioning block (5); S4: Connect the foamed TPU main layer (3) and the inner protective layer (6) according to the methods of S2 and S3.

5. The production process of the TPU nitrogen foamed film according to claim 4, characterized in that, The following steps are also included: S5: preparing an adhesive and uniformly mixing the magnetic particles (8) in the adhesive to obtain an adsorption material; S6: coating the adsorption material on the inner protective layer (6); the adsorption material forms a magnetic adsorption layer after drying.

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