A TPU hot melt adhesive film for sole lamination and its preparation method and application

Abstract

The invention discloses a TPU hot melt adhesive film for sole lamination, a preparation method and an application thereof. The TPU hot melt adhesive film comprises, by weight, 30 to 80 parts of thermoplastic polyester polyurethane; 3 to 50 parts of thermoplastic polycaprolactone polyurethane; 0.05 to 10 parts of fumed silica; and 0.01 to 5 parts of other additives. The melt index of the thermoplastic polyester polyurethane is 10 to 40 g / 10 min (150° C., 5 kg); the melt index of the thermoplastic polycaprolactone polyurethane is 10 to 100 g / 10 min (170° C., 2.16 kg); the specific surface area of ​​the fumed silica is 50 to 400 m 2 The TPU hot melt adhesive film disclosed in the present invention has a significant advantage in high temperature resistance, especially in the bonding of the rubber outsole of the shoe material and the TPU foamed midsole.

Description

Technical Field

[0001] The invention relates to the technical field of hot melt adhesive films, and in particular to a TPU hot melt adhesive film for sole bonding, a preparation method thereof, and application of the hot melt adhesive film in bonding a rubber outsole of a shoe material and a TPU foamed midsole. Background Art

[0002] At present, the bonding of rubber outsoles and TPU popcorn foam midsoles in the market still mainly uses traditional processes, namely solvent-based chloroprene adhesives (the solvents are mainly toluene and xylene). From production, use to post-processing, a large amount of VOC will be generated, which poses a serious threat to the health of workers and users at the production site, and also causes serious pollution to the environment. In recent years, foreign countries have increasingly stringent requirements on environmental protection indicators for shoe materials. my country has also formulated the latest mandatory standards for shoe glue, which has strict regulations on VOC volatile solvents such as benzene and toluene. Therefore, environmentally friendly solvent-free hot melt adhesives are used.

[0003] As a large category of environmentally friendly solvent-free hot melt adhesives, TPU is widely used in the adhesive field due to its low cost and wide applicable temperature range. TPU physical properties such as softening point, glass transition temperature, adhesion, etc. can be easily achieved by adjusting the type and molecular weight of polyols. It has the advantages of strong formula applicability and obvious bonding effect on the surface of highly polar substrates, and is widely used in hot melt adhesives and other fields. However, in the bonding of soles, especially the bonding of TPU popcorn foam midsole to rubber outsole, solvent-based adhesives are still used, and hot melt adhesives have not yet been widely used. This is mainly because the polarity of the TPU popcorn midsole and rubber outsole surfaces is relatively low, and it is difficult to achieve a high bonding strength effect simply by bonding with ordinary TPU hot melt adhesives. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention discloses a TPU hot melt adhesive film, which has excellent effect on the bonding of shoe rubber outsole and TPU foam midsole, and the bonding substrate does not need to be surface treated, and the operation process is simple and convenient. The hot melt adhesive film also has the advantages of wear resistance, weather resistance, oil resistance, high bonding strength, environmental protection, etc., and has significant advantages in high temperature resistance.

[0005] The specific technical solutions are as follows:

[0006] A TPU hot melt adhesive film for sole lamination, comprising, by weight, the following raw materials:

[0007]

[0008] Under the test conditions of 150° C. and 5 kg, the melt index of the thermoplastic polyester polyurethane is 10-40 g / 10 min. Specifically, Huafeng HF-3H80A-3, Huafeng HF-3H80A-8, etc. can be used.

[0009] Using the test conditions of 170° C. and 2.16 kg, the melt index of the thermoplastic polycaprolactone polyurethane is 10 to 100 g / 10 min. Specifically, Lubrizol Pearlbond 100, Lubrizol Pearlbond 103, Lubrizol Pearlbond 200, Lubrizol Pearlbond 223, etc. can be used.

[0010] The specific surface area of ​​the fumed silica is 50 to 400 m 2 / g.

[0011] The other additives include antioxidants, heat stabilizers, ultraviolet absorbers, anti-blocking agents, etc., which can be selectively added according to specific application conditions. The types of the above additives can be selected from common types in the field.

[0012] The present invention discloses a TPU hot melt adhesive film, which is mainly composed of thermoplastic polyester polyurethane, thermoplastic polycaprolactone polyurethane and fumed silica. It is found through experiments that the composite system of thermoplastic polycaprolactone polyurethane and thermoplastic polyester polyurethane can optimize the bulk strength of the prepared adhesive layer, the wettability of the interface to be bonded and the bonding strength; and the use of fumed silica as a functional filler can greatly improve the interfacial bonding strength, especially at a high temperature of 80 to 90°C. The TPU hot melt adhesive film prepared by the composite of the three has both high bulk strength and bonding strength at room temperature and a high temperature of 80 to 90°C, and has excellent effects in particular on the bonding of shoe rubber outsoles and TPU foamed midsoles.

[0013] Further comparative tests found that if the functional filler is replaced with inorganic nanofillers commonly found in the adhesive field, such as nano-calcium carbonate, nano-talc, etc., although it will help the bonding strength of the bonded interface at room temperature, it is extremely limited, and at high temperatures of 80 to 90°C, it has almost no help in improving the bonding strength.

[0014] Preferably, the raw material composition of the TPU hot melt adhesive film also includes a lubricant, such as ethylene bis stearamide, stearic acid monoglyceride, paraffin, polyethylene wax, erucic acid amide, oleic acid amide, and the like.

[0015] Preferably, the raw material composition of the TPU hot melt adhesive film includes, by weight:

[0016]

[0017] The specific surface area of ​​the fumed silica is 90 to 330 m 2 / g.

[0018] Further preferred:

[0019] The melt index of the thermoplastic polyester polyurethane is 12 to 31 g / 10 min;

[0020] The specific surface area of ​​the fumed silica is 125 to 175 m 2 / g.

[0021] By weight, the raw material composition includes:

[0022]

[0023] Further optimization:

[0024] By weight, the raw material composition includes:

[0025]

[0026]

[0027] It has been found through experiments that the TPU hot melt adhesive film prepared using the above preferred raw material types and contents has better body strength and bonding strength when used to bond the rubber outsole and TPU foam midsole of shoe materials.

[0028] The present invention also discloses a method for preparing the TPU hot melt adhesive film for sole lamination, comprising:

[0029] Step 1: Mix all the raw materials evenly according to the proportion;

[0030] Step 2: Add the mixed raw materials into a twin-screw extruder for extrusion granulation and drying to obtain hot melt rubber particles;

[0031] Step 3: coating the hot melt adhesive particles on a substrate through a casting or coating process to form a TPU hot melt adhesive film.

[0032] Preferably, the substrate is selected from PET film.

[0033] The invention also discloses a shoe sole, comprising a shoe outsole, a hot melt adhesive film and a shoe midsole;

[0034] The shoe outsole is selected from a rubber outsole, and its components include natural rubber and styrene-butadiene rubber;

[0035] The hot melt adhesive film is selected from the above-mentioned TPU hot melt adhesive film, and has a thickness of 0.03 to 0.3 mm;

[0036] The shoe midsole is selected from a TPU foamed midsole.

[0037] Preferably, in the components of the rubber outsole, the weight ratio of natural rubber to styrene-butadiene rubber is 1:1-3.

[0038] Further preferred:

[0039] When the weight ratio of the natural rubber to the styrene-butadiene rubber is 1:1, the TPU hot melt adhesive film adopts the above-mentioned preferred raw material types and ratios, and the thermoplastic polycaprolactone polyurethane is compounded by a thermoplastic polycaprolactone polyurethane with a melt index of 15 to 30 g / 10min and a thermoplastic polycaprolactone polyurethane with a melt index of 60 to 100 g / 10min; more preferably, it is compounded in a weight ratio of 1:1.

[0040] More preferably, the melt index of the thermoplastic polyester polyurethane is 12 to 17 g / 10 min.

[0041] When the weight ratio of the natural rubber to the styrene-butadiene rubber is 0.5:1.5, the TPU hot melt adhesive film adopts the above preferred raw material types and proportions, and the melt index of the thermoplastic polycaprolactone polyurethane is selected from 15 to 30 g / 10 min;

[0042] More preferably, the melt index of the thermoplastic polyester polyurethane is 12 to 17 g / 10 min.

[0043] It is found through experiments that, in the case of using the above further preferred substrate, the prepared adhesive layer has better bonding performance to the shoe outsole and TPU foamed shoe midsole material of corresponding composition.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The invention discloses a TPU hot melt adhesive film, which is mainly composed of thermoplastic polyester polyurethane, thermoplastic polycaprolactone polyurethane and fumed silica. The hot melt adhesive film prepared by the synergistic combination of the three has the advantages of wear resistance, weather resistance, oil resistance, high bonding strength, environmental protection, etc., especially has significant advantages in high temperature resistance (80-90°C). It has excellent effect on the bonding of sole materials with low surface polarity, especially rubber outsoles of shoes and TPU foamed midsoles. DETAILED DESCRIPTION

[0046] The present invention is further described in detail below in conjunction with examples and comparative examples, but the embodiments of the present invention are not limited thereto.

[0047] Example 1

[0048] Step 1: Mix the raw materials evenly according to the proportions in Table 1;

[0049] Step 2: Add the mixed material into a twin-screw extruder for extrusion, granulation and drying (barrel temperature is set at 130-150°C) to obtain hot melt rubber particles;

[0050] Step 3: The hot-melt adhesive particles are cast on the PET film through a casting process to form an adhesive film with a thickness of 0.1 mm, which is the product prepared in this embodiment.

[0051] Table 1

[0052]

[0053] MI 1 Melt index test method: ASTM D1238, test conditions: 150°C, 5kg;

[0054] MI 2 Melt index test method: ISO 1133, test conditions: 170°C, 2.16kg.

[0055] Example 2

[0056] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 2 below.

[0057] Table 2

[0058] Components Manufacturer Brand Number of copies Thermoplastic Polyester Polyurethane Huafeng HF-3H80A-8 65 Thermoplastic polycaprolactone type polyurethane 1 Lubrizol Pearlbond 100 10 Thermoplastic polycaprolactone polyurethane 2 Lubrizol Pearlbond 223 10 Fumed Silica Evonik Aerosil R711 3 Lubricant Ethylene bisstearamide 1.5 Antioxidants Antioxidant 1010 0.5

[0059] Example 3

[0060] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 3 below.

[0061] Table 3

[0062]

[0063]

[0064] Example 4

[0065] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 4 below.

[0066] Table 4

[0067]

[0068] Example 5

[0069] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 5 below.

[0070] Table 5

[0071]

[0072] Example 6

[0073] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 6 below.

[0074] Table 6

[0075]

[0076] Example 7

[0077] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 7 below.

[0078] Table 7

[0079] Components Manufacturer Brand Number of copies Thermoplastic Polyester Polyurethane Huafeng HF-3H80A-8 65 Thermoplastic polycaprolactone polyurethane Lubrizol Pearlbond 223 20 Fumed Silica Evonik Aerosil R711 3 Lubricant Ethylene bisstearamide 1.5 Antioxidants Antioxidant 1010 0.5

[0080] Example 8

[0081] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 8 below.

[0082] Table 8

[0083]

[0084]

[0085] Example 9

[0086] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 9 below.

[0087] Table 9

[0088] Components Manufacturer Brand Number of copies Thermoplastic Polyester Polyurethane Huafeng HF-3H80A-8 68 Thermoplastic polycaprolactone type polyurethane 1 Lubrizol Pearlbond 100 10 Thermoplastic polycaprolactone polyurethane 2 Lubrizol Pearlbond 220 10 Fumed Silica Evonik Aerosil R711 3 Lubricant Ethylene bisstearamide 1.5 Antioxidants Antioxidant 1010 0.5

[0089] Comparative Example 1

[0090] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 10 below.

[0091] Table 10

[0092] Components Manufacturer Brand Number of copies Thermoplastic Polyester Polyurethane Huafeng HF-3H80A-8 85 Lubricant Ethylene bisstearamide 1.5 Antioxidants Antioxidant 1010 0.5

[0093] Comparative Example 2

[0094] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 11 below.

[0095] Table 11

[0096]

[0097]

[0098] Comparative Example 3

[0099] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 12 below.

[0100] Table 12

[0101] Components Manufacturer Brand Number of copies Thermoplastic Polyester Polyurethane Huafeng HF-3H80A-8 65 Thermoplastic polycaprolactone type polyurethane 1 Lubrizol Pearlbond 100 10 Thermoplastic polycaprolactone polyurethane 2 Lubrizol Pearlbond 223 10 Lubricant Ethylene bisstearamide 1.5 Antioxidants Antioxidant 1010 0.5

[0102] Comparative Example 4

[0103] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 13 below.

[0104] Table 13

[0105]

[0106] Comparative Example 5

[0107] The preparation process is the same as that in Example 1, and the raw material formula composition is shown in Table 14 below.

[0108] Table 14

[0109] Components Manufacturer Brand Number of copies Thermoplastic Polyester Polyurethane Huafeng HF-3H80A-8 65 Thermoplastic polycaprolactone type polyurethane 1 Lubrizol Pearlbond 100 10 Thermoplastic polycaprolactone polyurethane 2 Lubrizol Pearlbond 223 10 Nano talc IMIFABIAG609 3 Lubricant Ethylene bisstearamide 1.5 Antioxidants Antioxidant 1010 0.5

[0110] Test method:

[0111] 1. TPU hot melt adhesive film bonding strength test sample preparation process:

[0112] 1. Place the TPU hot melt adhesive film on the outsole rubber sheet, fit the adhesive surface to the rubber sheet, put it into the outsole mold, and put it into the flat vulcanizer for co-vulcanization. The vulcanization temperature is 165-170°C and the vulcanization time is 180-250 seconds. After the vulcanization is completed, take it out and let it cool, then tear off the PET film;

[0113] 2. Place the preformed TPU foam midsole on the co-vulcanized TPU hot melt adhesive film / rubber outsole, put it into the mold again, and place it in a flat vulcanizer for co-vulcanization. The vulcanization temperature is 165-175°C and the vulcanization time is 180-250 seconds. After vulcanization, let it cool for more than 24 hours before performing the sole circumference peeling force test.

[0114] 2. Sole circumference peeling test method:

[0115] Test purpose: Test the adhesion between the outsole and midsole;

[0116] Test scope: for composite soles with rubber outsole / TPU foam midsole structure laminated with TPU hot melt adhesive film;

[0117] Testing equipment: tensile machine, ruler, knife;

[0118] Test conditions: room temperature (25±2℃);

[0119] Test material: composite sole

[0120] Parameter requirements:

[0121] 1. Cutting test section width: 10±1mm;

[0122] 2.Tensile testing machine test speed: 200mm / min.

[0123] Test steps:

[0124] 1. The sample is placed at room temperature for more than 24 hours;

[0125] 2. Draw a line 10 mm away from the edge of the sole sample (make sure the line is 10 mm wide from the edge of the sample);

[0126] 3. Use a knife to carve along the drawn line, making sure the cut is deep enough (penetrating the rubber outsole to the bottom layer of the EVA foam);

[0127] 4. Use a marker pen to evenly mark points on the cut sample, one point every 20 mm, for a total of 24 test points.

[0128] 5. Use a knife to cut a 10mm wide and 20mm long opening along the edge of the sole where the outsole / midsole meet.

[0129] Cut the sample, clamp it on the tensile machine, and set the speed of the tensile machine to 200mm / min;

[0130] 6. Start the test and record the minimum value between every two points

[0131] 7. If you encounter unqualified points, please note the peeling type (interface delamination / adhesive layer body delamination /

[0132] Delamination of sole material

[0133] Note:

[0134] 1. Pull in clockwise direction;

[0135] 2. If the peel strength value of the test point is greater than the standard value (30N / 10mm), it means that the test point meets the standard.

[0136] 3. High temperature resistance test method for shoe rubber outsole / TPU foam midsole film laminated samples:

[0137] Draw two parallel straight lines in the middle area of ​​the sole (extending from the toe to the heel) with an interval of 10 mm, and use a knife to cut vertically along the drawn lines, ensuring that the cut line is deep enough (penetrating the rubber outsole and cutting into the TPU foamed midsole). Put the shoes into a 95°C oven and take them out after baking for 30 minutes. Use pliers to peel off the cut while it is still hot (10 mm long strips) and observe the peeling type of the midsole and the outsole (interface delamination / adhesive layer body delamination / sole material delamination).

[0138] The above test methods were used to test the adhesive layer products prepared in each embodiment and each comparative example. The test results are shown in Table 15 below.

[0139] Table 15

[0140]

[0141] Comparison of Examples 2, 4 to 5 in Table 1 shows that the specific surface area of ​​125 to 175 m 2 / g of gas silicon, the comprehensive performance of the prepared adhesive layer is better. Continuing to compare Example 2 with Comparative Examples 4-5, it can be found that if the gas silicon is replaced with inorganic nanofillers commonly used in the adhesive field, such as nano calcium carbonate and nano talc, the adhesive layer delamination occurs at high temperature.

Claims

1. A TPU hot melt adhesive film for sole lamination, characterized in that: By weight, the raw material composition includes: 30-80 parts of thermoplastic polyester polyurethane; 3-50 parts of thermoplastic polycaprolactone polyurethane; 0.05-10 parts of fumed silica; Other additives 0.01~5 parts; The thermoplastic polyester polyurethane is selected from Huafeng HF-3H80A-3 and / or Huafeng HF-3H80A-8; Under the test conditions of 170°C and 2.16 kg, the melt index of the thermoplastic polycaprolactone polyurethane is 10-100 g / 10 min; The specific surface area of ​​the fumed silica is 50 to 400 m 2 / g.

2. The TPU hot melt adhesive film for sole lamination according to claim 1, characterized in that: The other auxiliary agents include at least one of an antioxidant, a heat stabilizer, an ultraviolet absorber, and an anti-blocking agent.

3. The TPU hot melt adhesive film for sole lamination according to claim 1, characterized in that: The raw material composition also includes a lubricant.

4. The TPU hot melt adhesive film for sole lamination according to any one of claims 1 to 3, characterized in that: By weight, the raw material composition includes: 45-68 parts of thermoplastic polyester polyurethane; 15-25 parts of thermoplastic polycaprolactone polyurethane; 1-5 parts of fumed silica; Lubricant 0.1~10 parts; Other additives: 0.01~5 parts.

5. The TPU hot melt adhesive film for sole lamination according to claim 4, characterized in that: The specific surface area of ​​the fumed silica is 90-330 m 2 / g.

6. The TPU hot melt adhesive film for sole lamination according to claim 5, characterized in that: The melt index of the thermoplastic polyester polyurethane is 12-31 g / 10min; The specific surface area of ​​the fumed silica is 125-175 m 2 / g.

7. The TPU hot melt adhesive film for sole lamination according to claim 6, characterized in that: By weight, the raw material composition includes: 55-68 parts of thermoplastic polyester polyurethane; 18-22 parts of thermoplastic polycaprolactone polyurethane; 1-5 parts of fumed silica; Lubricant 0.1~10 parts; Other additives: 0.01~5 parts.

8. A method for preparing a TPU hot melt adhesive film for sole lamination according to any one of claims 1 to 7, characterized in that: include: Step 1: Mix all the raw materials evenly according to the proportion; Step 2: Add the mixed raw materials into a twin-screw extruder for extrusion granulation and drying to obtain hot melt rubber particles; Step 3: coating the hot melt adhesive particles on a substrate through a casting or coating process to form a TPU hot melt adhesive film.

9. A shoe sole laminated with a TPU hot melt adhesive film according to any one of claims 1 to 7, comprising a shoe outsole, a hot melt adhesive film and a shoe midsole, characterized in that: The shoe outsole is selected from a rubber outsole, and its components include natural rubber and styrene-butadiene rubber; The hot melt adhesive film is the TPU hot melt adhesive film according to any one of claims 1 to 7, and has a thickness of 0.03 to 0.3 mm; The shoe midsole is selected from a TPU foamed midsole.

10. The TPU hot melt adhesive film bonded sole according to claim 9, characterized in that: In the components of the rubber outsole, the weight ratio of natural rubber to styrene-butadiene rubber is 1:1-3.

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