A molded popcorn shoe sole with a polyurethane foamed sheet wrapped around and a method for manufacturing the same

Abstract

The present application relates to a kind of polyurethane foaming piece edge covering mould pressing popcorn shoe sole and its preparation method, including by surface modified popcorn particle mould pressing forming shoe sole main body, also including polyurethane foaming piece, above-mentioned polyurethane foaming piece is covered in the side wall surface of above-mentioned shoe sole main body, the side surface of above-mentioned polyurethane foaming piece towards above-mentioned shoe sole main body is covered with color material layer;Above-mentioned polyurethane foaming piece and above-mentioned shoe sole main body are integrally bonded by secondary mould pressing heating melting bonding.This application is modified by popcorn particle surface, so that surface modification layer melts when mould pressing, internal foaming bead does not collapse, popcorn particle does not need to be formed by water vapor, can be directly mould pressing forming, also need not open and make popcorn insole mould, it is favorable to shorten processing flow, reduce production cost;Using ordinary mould pressing equipment and ordinary oil pressure mould can be produced, processing is convenient, it is favorable to reduce the rate of defective products.

Description

Technical Field

[0001] This invention relates to the field of footwear manufacturing technology, specifically to a molded popcorn shoe sole with polyurethane foam edging and its preparation method. Background Technology

[0002] Expanded thermoplastic polyurethane (ETPU, commonly known as "popcorn") granules possess excellent rebound, cushioning, and lightweight properties, making them widely used in footwear products such as athletic shoe soles and insoles. However, if the popcorn granules are directly molded and the sidewalls are exposed, quality issues such as dirt accumulation and granule shedding can easily occur. To avoid the quality risks associated with exposed popcorn granules while retaining the excellent rebound and cushioning performance of the material, existing technology has developed a wraparound popcorn sole structure.

[0003] Referring to patent application number CN202321009843, a novel wrapped shoe sole is disclosed. This solution uses popcorn pellets to form a popcorn midsole as an insole through steam molding, which is then bonded to a rubber or EVA foam outsole with sidewalls using adhesive, so that the popcorn midsole is wrapped on three sides of the outsole. However, this technical solution still has obvious drawbacks: First, the product requires separate molds for the popcorn midsole and the rubber or EVA foam outsole, resulting in high development and manufacturing costs. Second, production requires separate molding of the popcorn midsole and the outer outsole components, followed by roughing, applying adhesive, drying, and pressing, resulting in a lengthy processing flow and low production efficiency. Third, relying on adhesives for interface bonding poses a risk of delamination and separation failure under repeated bending and water exposure, leading to a high product defect rate.

[0004] In addition, the aromatic popcorn pellets commonly used in the market are prone to internal cell collapse when directly molded at high temperatures, resulting in a loss of the rebound performance of the shoe sole. Most of them must rely on steam molding process, and ordinary molding equipment cannot directly complete the molding process, which limits the promotion and application of this material to small products such as insoles and footbeds.

[0005] Therefore, this case arose. Summary of the Invention

[0006] This invention provides a molded popcorn shoe sole with polyurethane foam edging and its preparation method, which solves the above-mentioned problems of existing popcorn shoe soles. It does not require steam molding, can be processed using ordinary molding equipment, the edging is firmly bonded to the main body of the sole, and has the ability to realize rich colors and patterns.

[0007] The present invention adopts the following technical solution: A molded popcorn shoe sole with polyurethane foam edging includes a sole body formed by molding surface-modified popcorn particles, and a polyurethane foam sheet covering the sidewall surface of the sole body. The side surface of the polyurethane foam sheet facing the sole body is covered with a color material layer. The polyurethane foam sheet and the sole body are bonded together by secondary molding and heating.

[0008] Furthermore, the thickness of the aforementioned polyurethane foam sheet is 0.4–3 mm.

[0009] Furthermore, the preparation process of the above-mentioned surface-modified popcorn kernels includes: forming popcorn kernels by supercritical extrusion of thermoplastic polyurethane, entering the cavity after underwater ring cutting, spraying polyurethane resin onto the surface of the above-mentioned popcorn kernels, and obtaining surface-modified popcorn kernels after air drying and bagging; the melting point of the above-mentioned polyurethane resin is 80℃~110℃.

[0010] Furthermore, the aforementioned color layer comprises the following raw materials in parts by weight: 5-60 parts polyurethane ink, 6-15 parts isocyanate curing agent, and 20-50 parts diluent.

[0011] Furthermore, the aforementioned color layer also includes polyurethane adhesive, and the amount of the polyurethane adhesive used is 0 to 20 parts.

[0012] Furthermore, the aforementioned color layer also contains photochromic adhesive, which displays patterns or logos after being exposed to ultraviolet light.

[0013] Furthermore, the aforementioned popcorn particles are foamed thermoplastic polyurethane particles.

[0014] Furthermore, the tensile strength of the aforementioned polyurethane foam sheet is greater than or equal to 0.5 MPa.

[0015] A method for preparing a molded popcorn shoe sole with polyurethane foam edging includes the following steps: Step 1: Cut the polyurethane foam sheet to the set size, cover one side of the sheet with color material, and after air drying or baking, press the uncolored side of the sheet tightly against the inner wall of the middle frame and fix it with the hanging nails on the middle frame. Step 2: Install the middle frame with the hung sheet material onto the lower mold. Half of the middle frame is inside the lower mold, and the other half is inside the upper mold. The hanging pins are on the upper and lower edges of the middle frame. The hanging pins on the upper edge protrude upwards, and the upper mold has small holes corresponding to the hanging pins. The hanging pins on the lower edge extend downwards, and the lower mold has pin grooves corresponding to the hanging pins. Step 3: Pour the weighed popcorn kernels into the cavity, then close the mold, tightening the upper mold, middle frame, and lower mold together. The closing pressure is 0.4 to 1.25 bar. Step 4: Heat the mold to 130-180℃ for 200-600 seconds to make the popcorn kernels stick together, while the polyurethane foam sheet melts and bonds with the popcorn kernels. Step 5: Then move to the cooling station, spray water to cool, open the mold, remove the middle frame, take out the sole, trim the edges to get the finished product.

[0016] As can be seen from the above description of the structure of the present invention, compared with the prior art, the present invention has the following advantages: 1. This application modifies the surface of popcorn kernels so that the surface modification layer melts during molding and the internal foamed beads do not collapse. The popcorn kernels can be directly molded without steam molding and without the need to make popcorn bottom molds, which helps to shorten the processing flow and reduce production costs. Ordinary molding equipment and ordinary hydraulic molds can be used for production, which is convenient and helps to reduce the defect rate.

[0017] 2. The polyurethane foam sheet of this application is bonded to the main body of the shoe sole by secondary molding and heating, which eliminates the need for the glue application process, simplifies the process and ensures a firm bond between the edge covering and the main body of the shoe sole.

[0018] 3. The polyurethane foam sheet of this application has a color layer on the side facing the main body of the sole, which can give the sole edge different colors as needed; after adding photochromic adhesive to the color layer, the sole can display patterns or logos when exposed to ultraviolet light, enriching the appearance.

[0019] 4. The main body of the sole of this application is molded from popcorn kernels, and the side wall surface is covered with polyurethane foam sheet, which can avoid the quality risk caused by exposed popcorn kernels and maintain good rebound and shock absorption performance; the tensile strength of the polyurethane foam sheet is designed to be no less than 0.5MPa, which helps to ensure the durability of the edge covering.

[0020] 5. The aromatic popcorn kernels modified by the present application can be directly molded, which is conducive to expanding the application field of popcorn shoe soles. The soles can be directly covered with textiles to make insoles. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the shoe sole structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the lower mold of the present invention.

[0023] Figure 3 This is a schematic diagram of the upper mold of the present invention.

[0024] Figure 4 This is a structural diagram of the middle frame hanging piece of the present invention.

[0025] Among them, 1. Shoe sole body; 11. Polyurethane foam sheet; 21. Upper mold; 22. Middle frame; 23. Lower mold; 111. Color material layer; 221. Hanging nail. Detailed Implementation

[0026] The specific embodiments of the present invention will now be described with reference to the accompanying drawings. Example 1:

[0027] Reference Figure 1 A molded popcorn shoe sole with polyurethane foam edging includes a sole body 1 formed by molding surface-modified popcorn particles, and a polyurethane foam 11. The polyurethane foam 11 covers the sidewall surface of the sole body 1, and the side surface of the polyurethane foam 11 facing the sole body 1 is covered with a color material layer 111. The polyurethane foam 11 and the sole body 1 are bonded together by secondary molding and heating.

[0028] The thickness of the polyurethane foam sheet 11 is 0.4 to 3 mm, preferably 0.4 mm.

[0029] The preparation process of the above-mentioned surface-modified popcorn kernels includes: forming popcorn kernels by supercritical extrusion of thermoplastic polyurethane, entering the cavity after underwater ring cutting, spraying polyurethane resin onto the surface of the above-mentioned popcorn kernels, and obtaining surface-modified popcorn kernels after air drying and bagging; the melting point of the above-mentioned polyurethane resin is 80℃~110℃, preferably 90℃~95℃.

[0030] The aforementioned color layer 111 comprises the following raw materials by weight: 5 parts polyurethane ink, 6 parts isocyanate curing agent, and 20 parts diluent.

[0031] The popcorn kernels mentioned above are foamed thermoplastic polyurethane kernels; the popcorn kernels mentioned above are foamed thermoplastic polyester polyurethane kernels; the popcorn kernels mentioned above are aliphatic polyurethane kernels.

[0032] The tensile strength of the polyurethane foam sheet 11 is greater than or equal to 0.5 MPa, ensuring that the polyurethane foam sheet is firmly fixed and will not be easily torn.

[0033] Reference Figures 2-4 A method for preparing a molded popcorn shoe sole with polyurethane foam sheet 11 as the edging includes the following steps: Step 1: Cut the polyurethane foam sheet 11 to the set size, cover one side of the sheet with color material, and after air drying or baking, press the uncolored side of the sheet tightly against the inner wall of the middle frame 22 and fix it with the hanging nails 221 on the middle frame 22. Step 2: Install the middle frame 22 with the hung sheet material onto the lower mold 23. Half of the middle frame 22 is inside the lower mold 23, and the other half is inside the upper mold 21. The hanging pins 221 are on the upper and lower edges of the middle frame 22. The hanging pins 221 on the upper edge protrude upwards. The upper mold 21 has small holes corresponding to the hanging pins 221 (not shown in the figure). The hanging pins 221 on the lower edge extend downwards. The lower mold 23 has pin grooves corresponding to the hanging pins 221 (not shown in the figure).

[0034] Step 3: Pour the weighed popcorn kernels into the cavity, then close the mold, tightening the upper mold 21, middle frame 22, and lower mold 23 with a closing pressure of 1.0 bar. Step 4: Heat the mold to 130°C for 200 seconds to make the popcorn kernels stick together, while the polyurethane foam sheet 11 melts and bonds with the popcorn kernels. Step 5: Then move to the cooling station, spray water to cool, open the mold, remove the middle frame 22, take out the sole, trim the edges to get the finished product.

[0035] The resulting product has a smooth sidewall surface, no rat holes, no particle shedding, uniform color, and a translucent visual effect. It is free of wrinkles and creases, and the yield rate is over 98%. The yellowing resistance test (according to HG / T 3689, Method A, 24 hours) results in a grade of 4-5, and the hydrolysis resistance test (refer to GB / T 15905, 70℃, 95%RH, 120 hours) results in a grade of 4-5 with no delamination or discoloration. Example 2:

[0036] Reference Figure 1 A molded popcorn shoe sole with polyurethane foam edging includes a sole body 1 formed by molding surface-modified popcorn particles, and a polyurethane foam 11. The polyurethane foam 11 covers the sidewall surface of the sole body 1, and the side surface of the polyurethane foam 11 facing the sole body 1 is covered with a color material layer 111. The polyurethane foam 11 and the sole body 1 are bonded together by secondary molding and heating.

[0037] The thickness of the polyurethane foam sheet 11 is 0.4 to 3 mm, preferably 3 mm.

[0038] The preparation process of the above-mentioned surface-modified popcorn kernels includes: forming popcorn kernels by supercritical extrusion of thermoplastic polyurethane, entering the cavity after underwater ring cutting, spraying polyurethane resin onto the surface of the above-mentioned popcorn kernels, and obtaining surface-modified popcorn kernels after air drying and bagging; the melting point of the above-mentioned polyurethane resin is 80℃~110℃, preferably 80℃~85℃.

[0039] The aforementioned color layer 111 comprises the following raw materials in parts by weight: 60 parts polyurethane ink, 15 parts isocyanate curing agent, and 50 parts diluent.

[0040] The aforementioned color layer 111 also includes polyurethane adhesive, and the amount of the polyurethane adhesive used is 20 parts.

[0041] The popcorn particles mentioned above are foamed thermoplastic polyurethane particles; the popcorn particles mentioned above are foamed thermoplastic polyether polyurethane particles; the popcorn particles mentioned above are aromatic polyurethane particles.

[0042] The tensile strength of the polyurethane foam sheet 11 is greater than or equal to 0.5 MPa, ensuring that the polyurethane foam sheet is firmly fixed and will not be easily torn.

[0043] Reference Figures 2-4 A method for preparing a molded popcorn shoe sole with polyurethane foam sheet 11 as the edging includes the following steps: Step 1: Cut the polyurethane foam sheet 11 to the set size, cover one side of the sheet with color material, and after air drying or baking, press the uncolored side of the sheet tightly against the inner wall of the middle frame 22 and fix it with the hanging nails 221 on the middle frame 22. Step 2: Install the middle frame 22 with the hung sheet material onto the lower mold 23. Half of the middle frame 22 is inside the lower mold 23, and the other half is inside the upper mold 21. The hanging pins 221 are on the upper and lower edges of the middle frame 22. The hanging pins 221 on the upper edge protrude upwards, and the upper mold 21 has small holes corresponding to the hanging pins 221 (not shown in the figure). The hanging pins 221 on the lower edge extend downwards, and the lower mold 23 has pin grooves corresponding to the hanging pins 221 (not shown in the figure). Step 3: Pour the weighed popcorn kernels into the cavity, then close the mold, tightening the upper mold 21, middle frame 22, and lower mold 23 with a closing pressure of 1.25 bar. Step 4: Heat the mold to 180°C for 600 seconds to make the popcorn kernels stick together, while the polyurethane foam sheet 11 melts and bonds with the popcorn kernels. Step 5: Then move to the cooling station, spray water to cool, open the mold, remove the middle frame 22, take out the sole, trim the edges to get the finished product.

[0044] The resulting product has a smooth sidewall surface, no rat holes, no particle shedding, uniform color, and a translucent visual effect. It is free of wrinkles and creases, and the yield rate is over 98%. The yellowing resistance test (according to HG / T 3689, Method A, 24 hours) results in a level 4 grade, and the hydrolysis resistance test (refer to GB / T 15905, 70℃, 95%RH, 120 hours) results in a level 4 grade with no delamination or discoloration. Example 3:

[0045] A molded popcorn shoe sole with polyurethane foam edging includes a sole body formed by molding surface-modified popcorn particles, and a polyurethane foam sheet covering the sidewall surface of the sole body. The side surface of the polyurethane foam sheet facing the sole body is covered with a color material layer. The polyurethane foam sheet and the sole body are bonded together by secondary molding and heating.

[0046] The thickness of the polyurethane foam sheet is 0.4 to 3 mm, preferably 2.0 mm.

[0047] Furthermore, the preparation process of the above-mentioned surface-modified popcorn kernels includes: forming popcorn kernels by supercritical extrusion of thermoplastic polyurethane, entering the cavity after underwater ring cutting, spraying polyurethane resin onto the surface of the above-mentioned popcorn kernels, and obtaining surface-modified popcorn kernels after air drying and bagging; the melting point of the above-mentioned polyurethane resin is 95℃~100℃.

[0048] The aforementioned color layer comprises the following raw materials by weight: 30 parts polyurethane ink, 12 parts isocyanate curing agent, and 40 parts diluent.

[0049] The aforementioned color layer also includes polyurethane adhesive, and the amount of the polyurethane adhesive used is 10 parts.

[0050] The aforementioned color layer also contains photochromic adhesive, which displays patterns or logos after being exposed to ultraviolet light.

[0051] The popcorn kernels mentioned above are foamed thermoplastic polyurethane kernels; the popcorn kernels mentioned above are foamed thermoplastic polyester polyurethane kernels; the popcorn kernels mentioned above are aromatic polyurethane kernels.

[0052] The tensile strength of the above-mentioned polyurethane foam sheet is greater than or equal to 0.5 MPa.

[0053] A method for preparing a molded popcorn shoe sole with polyurethane foam edging includes the following steps: Step 1: Cut the polyurethane foam sheet to the set size, cover one side of the sheet with color material, and after air drying or baking, press the uncolored side of the sheet tightly against the inner wall of the middle frame 22 and fix it with the hanging nails on the middle frame 22. Step 2: Install the middle frame 22 with the hung sheet material onto the lower mold 23. Half of the middle frame 22 is inside the lower mold 23, and the other half is inside the upper mold 21. The hanging pins 221 are on the upper and lower edges of the middle frame 22. The hanging pins 221 on the upper edge protrude upwards, and the upper mold 21 has small holes corresponding to the hanging pins 221 (not shown in the figure). The hanging pins 221 on the lower edge extend downwards, and the lower mold 23 has pin grooves corresponding to the hanging pins 221 (not shown in the figure). Step 3: Pour the weighed popcorn kernels into the cavity, then close the mold, tightening the upper mold 21, middle frame 22, and lower mold 23 with a closing pressure of 1.0 bar. Step 4: Heat the mold to 150°C for 380 seconds to make the popcorn kernels stick together, while the polyurethane foam sheet melts and bonds with the popcorn kernels. Step 5: Then move to the cooling station, spray water to cool, open the mold, remove the middle frame 22, take out the sole, trim the edges to get the finished product.

[0054] The resulting product has a smooth sidewall surface, free of rat holes and particle shedding, with uniform color and a translucent visual effect. It is free of wrinkles and creases. Under ultraviolet light, the logo on the sidewall is clearly visible, providing a unique visual effect and appeal, thus meeting consumers' demand for personalized shoe materials. The yellowing resistance test (according to HG / T 3689, Method A, 24 hours) results in a grade 4 rating, and the hydrolysis resistance test (referring to GB / T 15905, 70℃, 95%RH, 120 hours) results in a grade 4 rating with no glue separation or discoloration.

[0055] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A molded-in-place, polyurethane-foam-capped, popcorn shoe sole comprising a shoe sole body molded in place from surface-modified popcorn particles, characterized by: It also includes a polyurethane foam sheet, which is wrapped around the side wall surface of the sole body, and the side surface of the polyurethane foam sheet facing the sole body is covered with a color material layer; the polyurethane foam sheet and the sole body are bonded together by secondary molding and heating.

2. The molded popcorn shoe sole with polyurethane foam edging as described in claim 1, characterized in that: The thickness of the polyurethane foam sheet is 0.4 to 3 mm.

3. The molded popcorn shoe sole with polyurethane foam edging as described in claim 1, characterized in that, The color layer comprises the following raw materials by weight: 5-60 parts polyurethane ink, 6-15 parts isocyanate curing agent, and 20-50 parts diluent.

4. The molded popcorn shoe sole with polyurethane foam edging as described in claim 3, characterized in that: The color layer also includes polyurethane adhesive, and the amount of polyurethane adhesive used is 0 to 20 parts.

5. The molded popcorn shoe sole with polyurethane foam edging as described in claim 3, characterized in that: The color layer also contains photochromic adhesive, which displays patterns or logos after being exposed to ultraviolet light.

6. The molded popcorn shoe sole with polyurethane foam edging as described in claim 1, characterized in that: The popcorn kernels are foamed thermoplastic polyurethane kernels.

7. The molded popcorn shoe sole with polyurethane foam edging as described in claim 1, characterized in that: The tensile strength of the polyurethane foam sheet is greater than or equal to 0.5 MPa.

8. A method for preparing a molded popcorn shoe sole with polyurethane foam edging as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: Cut the polyurethane foam sheet to the set size, cover one side of the sheet with color material, and after air drying or baking, press the uncolored side of the sheet tightly against the inner wall of the middle frame and fix it with the hanging nails on the middle frame. Step 2: Install the middle frame with the hung sheet material onto the lower mold. Half of the middle frame is inside the lower mold, and the other half is inside the upper mold. The hanging pins are on the upper and lower edges of the middle frame. The hanging pins on the upper edge protrude upwards, and the upper mold has small holes corresponding to the hanging pins. The hanging pins on the lower edge extend downwards, and the lower mold has pin grooves corresponding to the hanging pins. Step 3: Pour the weighed popcorn kernels into the cavity, then close the mold, tightening the upper mold, middle frame, and lower mold together. The closing pressure is 0.4 to 1.25 bar. Step 4: Heat the mold to 130-180℃ for 200-600 seconds to make the popcorn kernels stick together, while the polyurethane foam sheet melts and bonds with the popcorn kernels. Step 5: Then move to the cooling station, spray water to cool, open the mold, remove the middle frame, take out the sole, trim the edges to get the finished product.

9. The method for preparing a molded popcorn shoe sole with polyurethane foam edging as described in claim 8, characterized in that, The preparation process of the surface-modified popcorn kernels includes: forming popcorn kernels by supercritical extrusion of thermoplastic polyurethane, entering the cavity after underwater ring cutting, spraying polyurethane resin onto the surface of the popcorn kernels, and obtaining surface-modified popcorn kernels after air drying and bagging; the melting point of the polyurethane resin is 80℃~110℃.

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