Hot melt adhesive film, preparation method and application thereof

Abstract

The present invention provides a hot-melt adhesive film comprising the following components by weight: 30-70 parts high-density polyethylene, 10-15 parts low-density polyethylene, 8-20 parts ultra-high molecular weight polyethylene, 5-10 parts hydrogenated petroleum resin, 5-15 parts acrylic copolymer, and 0.2-1 part antioxidant. The addition of the ultra-high molecular weight polyethylene component enables the hot-melt adhesive film to maintain a high cohesive strength even at high temperatures. Furthermore, the ultra-high molecular weight polyethylene has a similar structure to high-density polyethylene and, in a molten state, exhibits good compatibility, facilitating the uniform dispersion of the ultra-high molecular weight polyethylene. The introduction of the ultra-high molecular weight polyethylene broadens the molecular weight distribution of the polyethylene, facilitating the continuous cooling and heat release of the adhesive film, rapidly restoring bonding strength, and meeting the bonding requirements of the product. The present invention also provides a method for preparing and applying the hot-melt adhesive film.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile roof adhesive films, and in particular relates to a hot melt adhesive film, a preparation method and application thereof. Background Art

[0002] Currently, automotive roof production technologies are categorized into dry, one-step, and two-step wet processes. The two-step wet process is the mainstream production process, offering high dimensional stability, excellent rigidity, versatile design options, and the ability to achieve edge hemming.

[0003] The two-step wet process for laminating fabrics usually uses solvent adhesive lamination. However, due to its poor working environment and safety, it has been gradually replaced by water-based adhesive and roller adhesive lamination in recent years.

[0004] The safety of the water-based adhesive process has been greatly improved, but it is still applied by spraying, resulting in a large amount of adhesive waste. At the same time, the airing, activation, and compounding conditions of the water-based adhesive are more stringent, making process control difficult.

[0005] The roller gluing process uses roller coating to apply glue, which effectively improves the utilization rate of glue and has received widespread attention for a period of time. However, it has high requirements for composite fabrics, more stringent process control requirements, and low yield rate, which has affected the promotion of this process.

[0006] In response to the problems existing in the above process, relevant personnel proposed using hot melt adhesive film to composite ceiling fabrics.

[0007] Hot melt adhesive film is made of thermoplastic modified polyolefin material. The material utilization rate is much higher than solvent adhesive and water-based adhesive. It has low requirements for fabric structure, simple and easy processing conditions, and broad application prospects.

[0008] However, hot-melt adhesive films are thermoplastic materials, typically laminated using a hot-slug cold-mold method. They are not suitable for wet-process cold-slug hot-mold processes. Their viscosity is low at high temperatures, resulting in poor bonding performance. This makes it difficult to overcome the high rebound stress of the ceiling fabric, leading to delamination between the fabric and the frame. Summary of the Invention

[0009] The purpose of the present invention is to provide a hot melt adhesive film, a preparation method and application thereof. The hot melt adhesive film of the present invention has excellent cohesive strength at high temperature and achieves the purpose of not delaminating after mold opening.

[0010] The present invention provides a hot melt adhesive film comprising the following components in parts by weight:

[0011] 30-70 parts of high-density polyethylene, 10-15 parts of low-density polyethylene, 8-20 parts of ultra-high molecular weight polyethylene, 5-10 parts of hydrogenated petroleum resin, 5-15 parts of acrylic copolymer, 0.2-1 part of antioxidant;

[0012] The average molecular weight of the ultra-high molecular weight polyethylene is above 1 million, and the melt index is 0.01-0.2 g / 10 min; the average molecular weight of the high-density polyethylene is 300,000-650,000, and the melt index is 5-15 g / 10 min; the average molecular weight of the low-density polyethylene is 50,000-100,000, and the melt index is 40-70 g / 10 min.

[0013] Preferably, the softening point of the hydrogenated petroleum resin is above 110°C.

[0014] Preferably, the acrylic acid copolymer is an ethylene-acrylic acid copolymer and / or an ethylene-acrylic acid-maleic anhydride random terpolymer.

[0015] Preferably, the ethylene-acrylic acid-maleic anhydride random terpolymer has a comonomer content of 15-25% and a melt index of 50 or more at 190°C.

[0016] Preferably, the antioxidant includes antioxidant 1010 and / or antioxidant 168.

[0017] The present invention provides a method for preparing the hot melt adhesive film as described above, comprising the following steps:

[0018] After mixing high-density polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, hydrogenated petroleum resin, acrylic copolymer and antioxidant, extrusion granulation and film making are carried out in sequence to obtain a hot melt adhesive film.

[0019] Preferably, the temperature of the extrusion granulation is 175-190°C; the temperature of the film making is 200-250°C.

[0020] The present invention provides use of the hot melt adhesive film as described above in high-temperature bonding.

[0021] Preferably, the high-temperature bonding is specifically to use the hot melt adhesive film according to claim 1 to laminate the ceiling fabric during the two-step wet production process of the automobile ceiling.

[0022] Preferably, the bonding temperature in the two-step wet process is 115-135°C.

[0023] The present invention provides a hot melt adhesive film, comprising the following components in parts by weight: 30 to 70 parts of high-density polyethylene, 10 to 15 parts of low-density polyethylene, 8 to 20 parts of ultra-high molecular weight polyethylene, 5 to 10 parts of hydrogenated petroleum resin, 5 to 15 parts of acrylic copolymer, and 0.2 to 1 part of antioxidant; the ultra-high molecular weight polyethylene has an average molecular weight of more than 1 million and a melt index of 0.01 to 0.2 g / 10 min; the high-density polyethylene has an average molecular weight of 300,000 to 650,000 and a melt index of 5 to 15 g / 10 min; the low-density polyethylene has an average molecular weight of 50,000 to 100,000 and a melt index of 40 to 70 g / 10 min. The present invention adds an ultra-high molecular weight polyethylene component, so that the hot melt adhesive film can still maintain a high cohesive strength at high temperatures; at the same time, the ultra-high molecular weight polyethylene has a similar structure to high-density polyethylene and has good compatibility in the molten state, which is conducive to the uniform dispersion of the ultra-high molecular weight polyethylene; the introduction of ultra-high molecular weight polyethylene widens the molecular weight distribution range of the polyethylene, helps the film to continuously cool down and release heat, quickly restores the bonding strength, and meets the bonding requirements of the product. DETAILED DESCRIPTION

[0024] The present invention provides a hot melt adhesive film comprising the following components in parts by weight:

[0025] 30-70 parts of high-density polyethylene, 10-15 parts of low-density polyethylene, 8-20 parts of ultra-high molecular weight polyethylene, 5-10 parts of hydrogenated petroleum resin, 5-15 parts of acrylic copolymer, 0.2-1 part of antioxidant;

[0026] The average molecular weight of the ultra-high molecular weight polyethylene is above 1 million, and the melt index is 0.01-0.2 g / 10 min; the average molecular weight of the high-density polyethylene is 300,000-650,000, and the melt index is 5-15 g / 10 min; the average molecular weight of the low-density polyethylene is 50,000-100,000, and the melt index is 40-70 g / 10 min.

[0027] In the present invention, the average molecular weight of the high-density polyethylene is 300,000 to 650,000, more preferably 400,000 to 500,000; the melt index is preferably 5 to 15 g / 10 min, more preferably 6 to 12 g / 10 min; the weight proportion of the high-density polyethylene is preferably 30 to 70 parts, more preferably 40 to 60 parts, such as 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, preferably a range value with any of the above values ​​as the upper or lower limit.

[0028] In the present invention, the average molecular weight of the low-density polyethylene is preferably 50,000 to 100,000, more preferably 60,000 to 80,000; the melt index is preferably 40 to 70 g / 10 min, more preferably 50 to 60 g / 10 min, and the weight proportion of the low-density polyethylene is preferably 10 to 15 parts, more preferably 11 to 14 parts, such as 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, preferably a range value with any of the above values ​​as the upper or lower limit.

[0029] The average molecular weight of the ultra-high molecular weight polyethylene is above 1 million, preferably 1 million to 1.6 million, more preferably 1.1 million to 1.5 million; the melt index of the ultra-high molecular weight polyethylene is preferably 0.01 to 0.2 g / 10 min, more preferably 0.05 to 0.15 g / 10 min; the weight proportions of the ultra-high molecular weight polyethylene are preferably 8 to 20 parts, more preferably 10 to 15 parts, such as 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, and 18 parts, preferably a range value with any of the above values ​​as the upper or lower limit.

[0030] The present invention blends materials with greatly different melt indexes (ultra-high molecular weight polyethylene and high-density polyethylene). During the heating and melting process, the high melt index component (high-density polyethylene) has good fluidity, driving the low melt index component (ultra-high molecular weight polyethylene) to flow toward the ceiling frame and the fabric side, completing the infiltration and forming a mortise and tenon structure. After the product is completed, the ultra-high molecular weight polyethylene can provide high cohesive strength at high temperatures, overcome the tensile stress of the fabric, and maintain the bonding state until the product cools.

[0031] In the present invention, the weight proportion of the hydrogenated petroleum resin is preferably 5 to 10 parts, more preferably 6 to 9 parts, such as 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, preferably a range value with any of the above values ​​as the upper or lower limit, and the softening point of the hydrogenated petroleum resin is preferably above 110°C.

[0032] In the present invention, the acrylic copolymer preferably comprises an ethylene-acrylic acid copolymer and / or an ethylene-acrylic acid-maleic anhydride random terpolymer. The ethylene-acrylic acid-maleic anhydride random terpolymer has a comonomer content of 15-25% and a melt index of 50 or above at 190°C. The weight ratio of the acrylic copolymer is preferably 5-15 parts, more preferably 8-12 parts, such as 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, or 15 parts, preferably within a range with any of the above values ​​as the upper or lower limit.

[0033] In the present invention, the antioxidant is preferably antioxidant 1010 and / or antioxidant 168; the weight portion of the antioxidant is preferably 0.2 to 1 part, more preferably 0.5 to 0.8 part, such as 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part, preferably a range value with any of the above values ​​as the upper or lower limit.

[0034] The present invention provides a method for preparing the hot melt adhesive film described above, comprising the following steps:

[0035] After mixing high-density polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, hydrogenated petroleum resin, acrylic copolymer and antioxidant, extrusion granulation and film making are carried out in sequence to obtain a hot melt adhesive film.

[0036] In the present invention, the types and amounts of the high-density polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, hydrogenated petroleum resin, acrylic copolymer and antioxidant are consistent with the types and amounts of the high-density polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, hydrogenated petroleum resin, acrylic copolymer and antioxidant described above, and the present invention will not be repeated here.

[0037] The invention mixes the above raw materials, performs twin-screw extrusion granulation, and then performs film casting to obtain a hot melt adhesive film.

[0038] In the present invention, the temperature of the extrusion granulation is preferably 175-190°C, more preferably 180-185°C; the temperature of the cast film is preferably 200-250°C, more preferably 210-240°C, most preferably 220-230°C.

[0039] The present invention also provides an application of the hot melt adhesive film described above in high-temperature bonding. Specifically, the high-temperature bonding is to use the hot melt adhesive film described above to laminate the ceiling fabric during a two-step wet production process of a car ceiling.

[0040] In the two-step wet process for producing the automotive roof, the material and the hot-melt adhesive film are heated and laminated within a mold. The mold temperature is preferably 120-160°C, more preferably 130-150°C, and the dwell time is preferably 40-50 seconds, more preferably 45 seconds. After the mold is opened, the temperature of the material within the film is generally above 120°C. The hot-melt adhesive film in this application can withstand the tensile stress of the fabric during and after mold opening, preventing delamination of the surface finish.

[0041] The present invention provides a hot melt adhesive film, comprising the following components in parts by weight: 30 to 70 parts of high-density polyethylene, 10 to 15 parts of low-density polyethylene, 8 to 20 parts of ultra-high molecular weight polyethylene, 5 to 10 parts of hydrogenated petroleum resin, 5 to 15 parts of acrylic copolymer, and 0.2 to 1 part of antioxidant; the ultra-high molecular weight polyethylene has an average molecular weight of more than 1 million and a melt index of 0.01 to 0.2 g / 10 min; the high-density polyethylene has an average molecular weight of 300,000 to 650,000 and a melt index of 5 to 15 g / 10 min; the low-density polyethylene has an average molecular weight of 50,000 to 100,000 and a melt index of 40 to 70 g / 10 min. The present invention adds an ultra-high molecular weight polyethylene component, so that the hot melt adhesive film can still maintain a high cohesive strength at high temperatures; at the same time, the ultra-high molecular weight polyethylene has a similar structure to high-density polyethylene and has good compatibility in the molten state, which is conducive to the uniform dispersion of the ultra-high molecular weight polyethylene; the introduction of ultra-high molecular weight polyethylene widens the molecular weight distribution range of the polyethylene, helps the film to continuously cool down and release heat, quickly restores the bonding strength, and meets the bonding requirements of the product.

[0042] In order to further illustrate the present invention, a hot melt adhesive film provided by the present invention, its preparation method and application are described in detail below with reference to examples, but it should not be understood as limiting the scope of protection of the present invention.

[0043] Example 1

[0044] HDPE with a molecular weight of 400,000 and a melt index of 8 g / 10 min, UHMW-PE with a molecular weight of 1.2 million and a melt index of 0.08 g / 10 min, and LDPE with a molecular weight of 60,000 and a melt index of 70 g / 10 min were selected. The ratio of HDPE: UHMW-PE: LDPE: hydrogenated C5 resin: ethylene-acrylic acid-maleic anhydride copolymer: antioxidant was 50:20:15:7.5:7.5:0.5. After high-speed mixing, the mixture was pelletized by twin-screw extrusion and cast into a film. The extrusion process temperature did not exceed 190°C, and the casting temperature was 220°C. The resulting film was then laminated to fabric in a ceiling mold at a mold temperature of 150°C and a holding pressure of 45 seconds.

[0045] Example 2

[0046] HDPE with a molecular weight of 600,000 and a melt index of 6 g / 10 min, UHMW-PE with a molecular weight of 1,000,000 and a melt index of 0.12 g / 10 min, and LDPE with a molecular weight of 80,000 and a melt index of 50 g / 10 min were selected. The ratio of HDPE: UHMW-PE: LDPE: hydrogenated C5 resin: ethylene-acrylic acid-maleic anhydride copolymer: antioxidant was 60:10:15:7.5:7.5:0.5. The processing and compounding process were carried out according to Example 1.

[0047] Example 3

[0048] HDPE with a molecular weight of 600,000 and a melt index of 6 g / 10 min, UHMW-PE with a molecular weight of 1,000,000 and a melt index of 0.12 g / 10 min, and LDPE with a molecular weight of 80,000 and a melt index of 50 g / 10 min were selected. The ratio of HDPE: UHMW-PE: LDPE: hydrogenated C5 resin: ethylene-acrylic acid-maleic anhydride copolymer: antioxidant was 50:10:15:10:15:0.5. The processing and compounding process were carried out according to Example 1.

[0049] Comparative Example 1

[0050] HDPE with a molecular weight of 400,000 and a melt index of 8 g / 10 min and LDPE with a molecular weight of 80,000 and a melt index of 50 g / 10 min were selected. The ratio of HDPE:LDPE:hydrogenated C5 resin:ethylene-acrylic acid-maleic anhydride copolymer:antioxidant was 70:15:7.5:7.5:0.5. The processing and compounding process were carried out according to Example 1.

[0051] Comparative Example 2

[0052] HDPE with a molecular weight of 600,000 and a melt index of 6 g / 10 min and LDPE with a molecular weight of 80,000 and a melt index of 50 g / 10 min were selected, wherein the ratio of HDPE:LDPE:hydrogenated C5 resin:ethylene-acrylic acid-maleic anhydride copolymer:antioxidant was 60:15:10:15:0.5, and the processing and compounding process were carried out as in Example 1.

[0053] Comparative Example 3

[0054] HDPE with a molecular weight of 400,000 and a melt index of 8 g / 10 min, UHMW-PE with a molecular weight of 1.2 million and a melt index of 0.08 g / 10 min, and LDPE with a molecular weight of 60,000 and a melt index of 70 g / 10 min were selected. The ratio of HDPE: UHMW-PE: LDPE: hydrogenated C5 resin: ethylene-acrylic acid-maleic anhydride copolymer: antioxidant was 40:30:15:7.5:7.5:0.5, and the processing was carried out according to Example 1.

[0055] Comparative Example 4

[0056] HDPE with a molecular weight of 400,000 and a melt index of 8 g / 10 min, UHMW-PE with a molecular weight of 1.2 million and a melt index of 0.08 g / 10 min, and LDPE with a molecular weight of 60,000 and a melt index of 70 g / 10 min were selected. The ratio of HDPE: UHMW-PE: LDPE: hydrogenated C5 resin: ethylene-acrylic acid-maleic anhydride copolymer: antioxidant was 65:5:15:7.5:7.5:0.5. The processing and compounding process were carried out according to Example 1.

[0057] Comparative Example 5

[0058] UHMW-PE with a molecular weight of 1,000,000 and a melt index of 0.12 g / 10 min and LDPE with a molecular weight of 80,000 and a melt index of 50 g / 10 min were selected. The ratio of UHMW-PE:LDPE:hydrogenated C5 resin:ethylene-acrylic acid-maleic anhydride copolymer:antioxidant was 25:60:7.5:7.5:0.5. The processing and compounding process were carried out according to Example 1.

[0059] Table 1 Composite material product properties of the embodiments and comparative examples

[0060] Serial number Film-forming properties Mold opening R angle status Fabric peeling force Remark Example 1 Film formation OK No delamination 20.1N / 5cm Example 2 Film formation OK No delamination 17.3N / 5cm Example 3 Film formation OK No delamination 28.8N / 5cm Comparative Example 1 Film formation OK Delamination 6.5N / 5cm R-corner fabric delamination after 5s Comparative Example 2 Film formation OK Delamination 22.6.2N / 5cm After 12s, the R corner fabric delaminated Comparative Example 3 Poor film formation / / Poor compatibility, uneven surface Comparative Example 4 Film formation OK Delamination 11.1N / 5cm After 21 seconds, the R corner fabric delaminated Comparative Example 5 Film formation OK Delamination 13.7N / 5cm After 17s, the R corner fabric delaminated

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A hot melt adhesive film comprising the following components in parts by weight: 30-70 parts of high-density polyethylene, 10-15 parts of low-density polyethylene, 8-20 parts of ultra-high molecular weight polyethylene, 5-10 parts of hydrogenated petroleum resin, 5-15 parts of acrylic copolymer, 0.2-1 part of antioxidant; The average molecular weight of the ultra-high molecular weight polyethylene is 1 million to 1.6 million, and the melt index is 0.01 to 0.2 g / 10 min; the average molecular weight of the high-density polyethylene is 300,000 to 650,000, and the melt index is 5 to 15 g / 10 min; the average molecular weight of the low-density polyethylene is 50,000 to 100,000, and the melt index is 40 to 70 g / 10 min.

2. The hot melt adhesive film according to claim 1, characterized in that: The softening point of the hydrogenated petroleum resin is above 110°C.

3. The hot melt adhesive film according to claim 1, characterized in that: The acrylic acid copolymer is an ethylene-acrylic acid copolymer and / or an ethylene-acrylic acid-maleic anhydride random terpolymer.

4. The hot melt adhesive film according to claim 3, characterized in that: The ethylene-acrylic acid-maleic anhydride random terpolymer has a comonomer content of 15-25% and a melt index of 50 or more at 190°C.

5. The hot melt adhesive film according to claim 1, characterized in that: The antioxidant includes antioxidant 1010 and / or antioxidant 168.

6. The method for preparing the hot melt adhesive film according to claim 1, comprising the following steps: After mixing high-density polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, hydrogenated petroleum resin, acrylic copolymer and antioxidant, extrusion granulation and film making are carried out in sequence to obtain a hot melt adhesive film.

7. The preparation method according to claim 6, characterized in that The temperature of the extrusion granulation is 175-190°C; the temperature of the film making is 200-250°C.

8. Use of the hot melt adhesive film according to claim 1 in high temperature bonding.

9. The use according to claim 8, characterized in that The high-temperature bonding is specifically to use the hot melt adhesive film according to claim 1 to laminate the ceiling fabric during the two-step wet production process of the automobile ceiling.

10. The use according to claim 9, characterized in that The bonding temperature in the two-step wet process is 115-135°C.