Matte TPU hot melt adhesive film and preparation method therefor

Abstract

The present invention relates to the technical field of hot melt adhesive films, and in particular, to a matte TPU hot melt adhesive film and a preparation method therefor. The matte TPU hot melt adhesive film comprises the following components in parts by weight: 50-70 parts of a polyurethane prepolymer, 10-30 parts of a matting agent, 1-3 parts of a filler, 1-3 parts of an antioxidant, 1-3 parts of a diluent, 5-10 parts of polyvinyl alcohol, and 2-8 parts of tackifying resin. The matte TPU hot melt adhesive film has excellent adhesion strength and tensile strength, has a good matting effect, can achieve the effect of remaining matte after hot pressing, leaves no obvious hot melt adhesive welding trace on the outer edge of a bonding position with a process component, and achieves attractive and beautiful appearance. The preparation method for the matte TPU hot melt adhesive film has a simple process, is easy to operate and control, and is beneficial to industrial mass production.

Description

A matte TPU hot melt adhesive film and its preparation method Technical Field

[0001] The present invention relates to the technical field of hot-melt adhesive films, and in particular to a matte TPU hot-melt adhesive film and a preparation method thereof. Background Art

[0002] Hot melt adhesive films can be used for bonding components of optoelectronic devices, electronic products, home appliances, furniture, shoe parts, finished shoes, sportswear, etc. The application of polyester hot melt adhesive films has attracted attention in this field. However, the current polyester hot melt adhesive films still have some shortcomings. They do not have matte properties. For the devices used, especially organic electroluminescent devices, their reflectivity is enhanced, making it necessary to perform extinction or matte treatment.

[0003] Several methods have been reported in the prior art to achieve a matte effect. However, these methods also have drawbacks. For example, in order to achieve a matte effect, the material's mechanical properties, thermal stability, and hot-melt adhesive bonding performance are often compromised. Therefore, in the art, it is desirable to develop a material that achieves a matte effect while maintaining the mechanical properties of a hot-melt adhesive.

[0004] Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide a matte TPU hot melt adhesive film, which has excellent tensile strength and a good matte effect, achieving the effect of not brightening after hot pressing.

[0006] The preparation method of the matte TPU hot melt adhesive film of the present invention is simple in process and easy to control in operation, which is conducive to large-scale industrial production. The prepared matte TPU hot melt adhesive film has excellent adhesion fastness and tensile strength, and has a good matte effect, achieving the effect of not brightening after hot pressing. There is no obvious trace of hot melt adhesive welding on the outer edge of the joint position with the process component, and the appearance is beautiful and the overall performance is excellent.

[0007] The purpose of the present invention is achieved through the following technical solution: the matte TPU hot melt adhesive film comprises the following components by weight: 50-70 parts of polyurethane prepolymer, 10-30 parts of matting agent, 1-3 parts of filler, 1-3 parts of antioxidant, 1-3 parts of diluent, 5-10 parts of polyvinyl alcohol and 2-8 parts of tackifying resin.

[0008] Furthermore, the polyvinyl alcohol is Japanese Kuraray PVA0588.

[0009] Furthermore, the diluent is at least one of isooctyl acrylate, butyl acrylate, acrylic acid, methyl acrylate, ethyl acetate, toluene, dibutyl phthalate and diisobutyl phthalate.

[0010] Furthermore, the antioxidant includes at least one of antioxidant 1010, antioxidant 1076, antioxidant 168 and 2,6-di-tert-butyl-4-methylphenol.

[0011] Furthermore, the filler is at least one of cryolite, calcium carbonate, wollastonite, talc, fumed silica, quartz sand, aluminum powder and zinc powder.

[0012] Furthermore, the tackifying resin is a mixture of hydrogenated rosin glycerol ester, terpene resin and petroleum resin in a weight ratio of 0.8-1.2:0.1-0.5:0.6-1.0.

[0013] Preferably, the hydrogenated rosin glycerol ester is GEHR-85R produced by Guangxi Wuzhou Richeng Forest Products Chemical Co., Ltd., with a softening point of 80-90°C; the terpene resin is poly-α-pinene produced by Fujian Shaxian Wanli Chemical Co., Ltd., with a softening point of 90-100°C; and the petroleum resin is Mitsui petroleum resin with a model of FTR6100.

[0014] Furthermore, the matte agent is compounded from nitrile rubber, modified epoxy resin and styrene-butadiene rubber.

[0015] Furthermore, the weight ratio of the nitrile rubber, modified epoxy resin and styrene-butadiene rubber is 2-4:5-8:3-5.

[0016] Preferably, the nitrile rubber is the nitrile rubber model 1051 produced by Dongguan Mingyuan Plastic Co., Ltd.; the styrene butadiene rubber is the styrene butadiene rubber model 1502 produced by Qilu Petrochemical.

[0017] Furthermore, the modified epoxy resin comprises the following components in parts by weight: 45-55 parts of epoxy resin, 10-15 parts of polycarbonate diol, 1-3 parts of polymerization inhibitor and 1-3 parts of catalyst B.

[0018] Furthermore, the preparation method of the modified epoxy resin is: dissolving epoxy resin in butyl acrylate, adding polycarbonate diol, polymerization inhibitor and catalyst B, heating to 80-100° C. for reaction for 3-4 hours, and then continuing to keep warm for reaction for 1-2 hours to obtain the modified epoxy resin.

[0019] Furthermore, the polycarbonate diol is PCDL1000.

[0020] Furthermore, the catalyst B is one of tetrabutylammonium bromide and triethylamine.

[0021] Furthermore, the polymerization inhibitor is p-hydroxyanisole.

[0022] Furthermore, the epoxy resin is a bisphenol A epoxy resin. Preferably, the bisphenol A epoxy resin is a bisphenol A epoxy resin with an epoxy value of 0.46 produced by Shanghai Luohe High-tech Materials Co., Ltd.

[0023] Furthermore, the polyurethane prepolymer comprises the following components in parts by weight: 45-55 parts of isophorone diisocyanate, 55-75 parts of polyglycol, 1-2 parts of catalyst A and 1-8 parts of end-capping agent.

[0024] Furthermore, the polyglycol is at least one of polyethylene glycol, polytetramethylene glycol and polycaprolactone glycol.

[0025] Furthermore, the end-capping agent is at least one of glycidol, hydroxyl-terminated polydimethylsiloxane and isopropyl alcohol.

[0026] Furthermore, the catalyst A is at least one of dibutyltin dilaurate and stannous octoate.

[0027] Furthermore, the preparation method of the polyurethane prepolymer comprises the following steps:

[0028] (1) Add polyglycol and catalyst A to a reaction kettle, heat to 130-150°C, remove water under vacuum for 2-2.5 hours, cool to 90-110°C, add catalyst A and isophorone diisocyanate, and react for 2.5-3.5 hours to obtain product A;

[0029] (2) The system temperature is cooled to 80-100°C, and the end-capping agent is slowly added dropwise to the product A. After the addition is completed, the reaction is continued for 1-2 hours, and the temperature is maintained at 80-100°C for 1-2 hours, and then cooled to room temperature to obtain a polyurethane prepolymer.

[0030] A preparation method of the matte TPU hot melt adhesive film, the preparation method comprising: dehumidifying and drying polyvinyl alcohol, tackifying resin, matting agent, antioxidant, diluent and filler, then adding polyurethane prepolymer and mixing evenly, melt blending and extruding, salivating, cooling, trimming and winding to obtain the matte TPU hot melt adhesive film.

[0031] Furthermore, the dehumidification and drying is carried out in a dehumidification dryer, the dehumidification and drying temperature is 70-90° C., and the dehumidification and drying time is 3-4 hours; the melt blending is carried out in a casting machine, and the melt blending temperature is 100-180° C.

[0032] It should be further explained that the raw material of the matte TPU hot melt adhesive film is melted by the screw of the casting machine and pushed into the die head, and is cast from the die head into a film with a certain thickness, and then cast onto the cooling wheel and rapidly cooled into a film.

[0033] Furthermore, the thickness of the matte TPU hot melt adhesive film is 0.05-0.3 mm. As required, the lip gap of the die head can be adjusted to control the thickness of the hot melt adhesive film.

[0034] The preparation method of the matte TPU hot melt adhesive film of the present invention is simple in process and easy to control in operation, which is conducive to large-scale industrial production. The prepared matte TPU hot melt adhesive film has excellent adhesion fastness and tensile strength, and has a good matte effect, achieving the effect of not brightening after hot pressing. There is no obvious trace of hot melt adhesive welding on the outer edge of the joint position with the process component, and the appearance is beautiful and the comprehensive performance is excellent.

[0035] The present invention provides the following beneficial effects: the matte TPU hot-melt adhesive film exhibits excellent tensile and bonding strengths while maintaining a good matte finish, achieving a non-brightening effect even after hot pressing. The outer edge of the film where it meets the process components exhibits no visible hot-melt adhesive weld marks, resulting in an aesthetically pleasing appearance. The preparation method for the matte TPU hot-melt adhesive film is simple and easy to operate, making it suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG1 is a product diagram of Example 1 and Comparative Example 3 (Comparative Example 3 on the left; Example 1 on the right). DETAILED DESCRIPTION

[0037] In order to facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the embodiments. The contents mentioned in the embodiments are not intended to limit the present invention.

[0038] Example 1

[0039] A matte TPU hot melt adhesive film comprises the following components in parts by weight: 65 parts of polyurethane prepolymer, 25 parts of matting agent, 1.5 parts of filler, 2 parts of antioxidant, 2 parts of diluent, 8 parts of polyvinyl alcohol and 7 parts of tackifying resin.

[0040] Furthermore, the polyvinyl alcohol is Japanese Kuraray PVA0588.

[0041] Furthermore, the diluent is dibutyl phthalate.

[0042] Furthermore, the antioxidant is antioxidant 1010.

[0043] Furthermore, the filler is calcium carbonate. Preferably, the average particle size of the calcium carbonate is 4000-6000 mesh.

[0044] Furthermore, the tackifying resin is a mixture of hydrogenated rosin glycerol ester, terpene resin and petroleum resin in a weight ratio of 1:0.3:0.7.

[0045] Furthermore, the hydrogenated rosin glycerol ester uses the model GEHR-85R of Guangxi Wuzhou Richeng Forest Products Chemical Co., Ltd. with a softening point of 80-90°C; the terpene resin uses the main component of poly-α-pinene of Fujian Shaxian Wanli Chemical Co., Ltd. with a softening point of 90-100°C; the petroleum resin uses the petroleum resin of Mitsui model FTR6100.

[0046] Furthermore, the matte agent is compounded from nitrile rubber, modified epoxy resin and styrene-butadiene rubber.

[0047] Furthermore, the weight ratio of the nitrile rubber, modified epoxy resin and styrene-butadiene rubber is 3:6:4.

[0048] Furthermore, the nitrile rubber adopts the nitrile rubber with model number 1051 produced by Dongguan Mingyuan Plastic Co., Ltd.; the styrene butadiene rubber adopts the styrene butadiene rubber with model number 1502 produced by Qilu Petrochemical.

[0049] Furthermore, the modified epoxy resin comprises the following components in parts by weight: 50 parts of epoxy resin, 12 parts of polycarbonate diol, 1.5 parts of polymerization inhibitor and 1.2 parts of catalyst B.

[0050] Furthermore, the polycarbonate diol is PCDL1000.

[0051] Furthermore, the preparation method of the modified epoxy resin is as follows: at room temperature, epoxy resin is dissolved in butyl acrylate, polycarbonate diol, polymerization inhibitor and catalyst B are added, the temperature is raised to 90° C. and the reaction is carried out for 3-4 hours, and the reaction is continued at this temperature for 1.5 hours to obtain the modified epoxy resin.

[0052] Furthermore, the catalyst B is tetrabutylammonium bromide.

[0053] Furthermore, the polymerization inhibitor is p-hydroxyanisole.

[0054] Furthermore, the epoxy resin is a bisphenol A epoxy resin having an epoxy value of 0.46 and is produced by Shanghai Luohe High-tech Materials Co., Ltd.

[0055] Furthermore, the polyurethane prepolymer comprises the following components in parts by weight: 50 parts of isophorone diisocyanate, 70 parts of polyethylene glycol, 1.5 parts of catalyst A and 7 parts of end-capping agent.

[0056] Furthermore, the polyethylene glycol is polyethylene glycol 1000.

[0057] Furthermore, the end-capping agent is glycidol.

[0058] Furthermore, the catalyst A is dibutyltin dilaurate.

[0059] Furthermore, the preparation method of the polyurethane prepolymer comprises the following steps:

[0060] (1) Polyethylene glycol and catalyst A were added to a reaction kettle, heated to 115°C, vacuum-dried for 2 hours, cooled to 100°C, and isophorone diisocyanate was added. The reaction was continued for 3 hours to obtain product A.

[0061] (2) The system temperature was cooled to 90°C, and the end-capping agent was slowly added dropwise to the product A. After the addition was completed, the reaction was continued for 1.5 hours, and the temperature was maintained at 90°C for 1.5 hours. The reaction was then cooled to room temperature to obtain a polyurethane prepolymer.

[0062] A method for preparing the matte TPU hot melt adhesive film comprises the following steps: dehumidifying and drying polyvinyl alcohol, tackifying resin, matting agent, antioxidant, diluent and filler, adding polyurethane prepolymer and mixing evenly, melt blending and extruding, salivating, cooling, trimming and winding to obtain the matte TPU hot melt adhesive film.

[0063] Furthermore, the dehumidification and drying is carried out in a dehumidification dryer, the dehumidification and drying temperature is 85° C., and the dehumidification and drying time is 3.5 hours; the melt blending is carried out in a casting machine, and the melt blending temperature is 165° C.

[0064] Example 2

[0065] In this embodiment, the polyurethane prepolymer comprises the following components in parts by weight: 50 parts of isophorone diisocyanate, 70 parts of polytetramethylene glycol, 1.5 parts of catalyst A, and 7 parts of end-capping agent.

[0066] Further, the polytetrahydrofuran diol adopts polytetrahydrofuran diol 1000.

[0067] Furthermore, the end-capping agent is hydroxyl-terminated polydimethylsiloxane, and the Mn of the hydroxyl-terminated polydimethylsiloxane is 1000.

[0068] Furthermore, the catalyst A is dibutyltin dilaurate.

[0069] Furthermore, the preparation method of the polyurethane prepolymer comprises the following steps:

[0070] (1) Add polytetrahydrofuran diol and catalyst A into a reactor, heat to 115° C., vacuumize and remove water for 2 h, cool to 100° C., add isophorone diisocyanate, and react for 3 h to obtain product A;

[0071] (2) The system temperature was cooled to 95°C, and the end-capping agent was slowly added dropwise to the product A. After the addition was completed, the reaction was continued for 2 hours, and the temperature was maintained at 95°C for 2 hours. Then, the system was cooled to room temperature to obtain a polyurethane prepolymer.

[0072] The rest of the content of this embodiment is the same as that of embodiment 1.

[0073] Example 3

[0074] In this embodiment, the polyurethane prepolymer includes the following components in parts by weight: 50 parts of isophorone diisocyanate, 70 parts of polycaprolactone diol, 1.5 parts of catalyst A, and 7 parts of end-capping agent.

[0075] Furthermore, the polycaprolactone diol is polycaprolactone diol 1000.

[0076] Furthermore, the capping agent is isopropyl alcohol.

[0077] Furthermore, the catalyst A is dibutyltin dilaurate.

[0078] Furthermore, the preparation method of the polyurethane prepolymer comprises the following steps:

[0079] (1) Add polycaprolactone diol and catalyst A to a reaction kettle, heat to 115°C, remove water under vacuum for 2 hours, cool to 100°C, add isophorone diisocyanate, and react for 3 hours to obtain product A;

[0080] (2) The system temperature was cooled to 95°C, and the end-capping agent was slowly added dropwise to the product A. After the addition was completed, the reaction was continued for 2 hours, and the temperature was maintained at 95°C for 2 hours. Then, the system was cooled to room temperature to obtain a polyurethane prepolymer.

[0081] Furthermore, the weight ratio of the nitrile rubber, modified epoxy resin and styrene-butadiene rubber is 4:6:5.

[0082] A preparation method of the matte TPU hot melt adhesive film, the preparation method comprising: dehumidifying and drying polyvinyl alcohol, tackifying resin, matting agent, antioxidant, diluent and filler, then adding polyurethane prepolymer and mixing evenly, melt blending and extruding, salivating, cooling, trimming and winding to obtain the matte TPU hot melt adhesive film.

[0083] Furthermore, the dehumidification and drying is carried out in a dehumidification dryer, the dehumidification and drying temperature is 85° C., and the dehumidification and drying time is 3.8 hours; the melt blending is carried out in a casting machine, and the melt blending temperature is 170° C.

[0084] The rest of the content of this embodiment is the same as that of embodiment 1.

[0085] Comparative Example 1

[0086] The difference between this comparative example and Example 1 is that the modified epoxy resin in the matting agent is replaced by an equal amount of bisphenol A epoxy resin, which is a bisphenol A epoxy resin with an epoxy value of 0.46 and is produced by Shanghai Luohe High-tech Materials Co., Ltd.

[0087] Comparative Example 2

[0088] The difference between this comparative example and Example 1 is that the matting agent contains only styrene-butadiene rubber.

[0089] Comparative Example 3

[0090] The difference between this comparative example and Example 1 is that the hot melt adhesive does not include a matte agent, and the matte agent is replaced by an equal amount of a tackifying resin.

[0091] Performance Testing

[0092] The matte TPU hot melt adhesive films prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance testing. The thickness of the matte TPU hot melt adhesive films prepared in Examples 1-3 and Comparative Examples 1-3 was controlled at 0.05 mm. The tensile strength, high-temperature adhesive strength, and surface gloss (matte effect) at 60° were tested. The test data are shown in Table 1 below:

[0093] Table 1

[0094] The tensile strength was determined according to GB / T 7124-2008 Determination of tensile shear strength of adhesives (rigid material to rigid material).

[0095] High-temperature bonding test: Glue is applied to the substrates, overlapped crosswise, and pressure maintained. Once fully cured, the two substrates are placed in an 85°C oven for 4 hours. The sample is removed and left at room temperature for 2 hours before testing on a tensile testing machine. The substrate used is TPU film / TPU film. The TPU film is model ZD-135CM*85A, 0.7mm thick, from Guangdong Zhongding Technology Development Co., Ltd.

[0096] The surface gloss is measured according to GB / T8807-1988 Test method for plastics specular gloss.

[0097] As shown in Figure 1, the figure on the left is formed by hot pressing the matte TPU hot melt adhesive film without adding a matte agent in Comparative Example 3. The formed pressing edge surface is smooth and delicate but has high reflectivity, no matte effect, and shows obvious traces of hot melt adhesive welding; while the figure on the right is formed by hot pressing the matte TPU hot melt adhesive film in Example 1. The formed pressing edge surface is smooth and delicate and has basically no reflectivity, good matte effect, and no obvious traces of hot melt adhesive welding.

[0098] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention can also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the scope of protection of the present invention.

Claims

1. A matte TPU hot melt adhesive film, characterized in that: The matte hot melt adhesive comprises the following components in parts by weight: 50-70 parts of polyurethane prepolymer, 10-30 parts of matte agent, 1-3 parts of filler, 1-3 parts of antioxidant, 1-3 parts of diluent, 5-10 parts of polyvinyl alcohol and 2-8 parts of tackifying resin.

2. The matte TPU hot melt adhesive film according to claim 1, characterized in that: The matte agent is compounded from nitrile rubber, modified epoxy resin and styrene-butadiene rubber.

3. The matte TPU hot melt adhesive film according to claim 2, characterized in that: The weight ratio of the nitrile rubber, the modified epoxy resin and the styrene-butadiene rubber is 2-4:5-8:3-5.

4. The matte TPU hot melt adhesive film according to claim 2, characterized in that: The modified epoxy resin comprises the following components in parts by weight: 45-55 parts of epoxy resin, 10-15 parts of polycarbonate diol, 1-3 parts of polymerization inhibitor and 1-3 parts of catalyst B.

5. The matte TPU hot melt adhesive film according to claim 1, characterized in that: The diluent is at least one of isooctyl acrylate, butyl acrylate, acrylic acid, methyl acrylate, ethyl acetate, toluene, dibutyl phthalate and diisobutyl phthalate.

6. The matte TPU hot melt adhesive film according to claim 1, characterized in that: The polyurethane prepolymer comprises the following components in parts by weight: 45-55 parts of isophorone diisocyanate, 55-75 parts of polyglycol, 1-2 parts of catalyst A and 1-8 parts of end-capping agent.

7. The matte TPU hot melt adhesive film according to claim 6, characterized in that: The polyglycol includes at least one of polyethylene glycol, polytetrahydrofuran diol and polycaprolactone diol.

8. The matte TPU hot melt adhesive film according to claim 6, characterized in that: The end-capping agent is at least one of glycidol, hydroxy-terminated polydimethylsiloxane and isopropyl alcohol.

9. The matte TPU hot melt adhesive film according to claim 6, characterized in that: The preparation method of the polyurethane prepolymer comprises the following steps: (1) Add polyglycol and catalyst A into a reaction kettle, raise the temperature to 130-150° C., remove water by vacuum for 2-2.5 hours, cool to 90-110° C., add isophorone diisocyanate, react for 2.5-3.5 hours, and obtain product A; (2) The system temperature is cooled to 80-100°C, and the end-capping agent is slowly added dropwise to the product A. After the addition is completed, the reaction is continued for 1-2 hours, and the temperature is maintained at 80-100°C for 1-2 hours, and then cooled to room temperature to obtain a polyurethane prepolymer.

10. A method for preparing the matte TPU hot melt adhesive film according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: dehumidifying and drying polyvinyl alcohol, tackifying resin, matte agent, antioxidant, diluent and filler, adding polyurethane prepolymer and mixing evenly, melt blending and extruding, drooling, cooling, trimming and rolling to obtain the matte TPU hot melt adhesive film.

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