Matt polyurethane hot melt adhesive as well as preparation method and application thereof

Abstract

The invention relates to a matte polyurethane hot melt adhesive as well as a preparation method and application thereof. The matte polyurethane hot melt adhesive is prepared from the following raw material components in parts by mass: 97 to 102 parts of thermoplastic polyurethane, 8 to 25 parts of ethylene propylene diene monomer, 1 to 5 parts of maleic anhydride grafted propylene-ethylene copolymer, 0.1 to 1 part of polyfunctional group acrylate and 0.05 to 0.5 part of thermal initiator. When the matt polyurethane hot melt adhesive is used, under the combined action of the temperature generated by thermocompression bonding and the thermal initiator, the ethylene propylene diene monomer in the matt polyurethane hot melt adhesive and the polyfunctional group acrylate are subjected to a cross-linking reaction, and rubber particles formed in situ after cross-linking are separated from the thermoplastic polyurethane, so that the matt effect is generated; and the adhesive film with good matte effect and bonding strength can be obtained.

Description

Technical Field

[0001] The present application relates to the technical field of hot melt adhesive films, and in particular to a matte polyurethane hot melt adhesive and its preparation and application. Background Art

[0002] Polyurethane hot melt adhesive is a green and environmentally friendly adhesive material that has good bonding effects on materials such as metal, plastic, wood, and cloth. Therefore, it is widely used in packaging, electronics, clothing, footwear, medical care and other fields.

[0003] After being melted by hot pressing, traditional polyurethane hot melt adhesive has high surface gloss and strong reflection. When it is used for bonding products, obvious reflection will appear at the hollow or overflowing positions, affecting the aesthetics of the product.

[0004] In order to solve the above problems, the traditional technology often adds a matting agent to thermoplastic polyurethane (TPU) to give the polyurethane hot melt adhesive a rough micro surface through the matting agent to obtain a polyurethane hot melt adhesive with a matte effect. However, if a good matting effect is required, more matting agent needs to be added, which leads to a decrease in the bonding performance of the polyurethane hot melt adhesive. Summary of the invention

[0005] Based on this, it is necessary to provide a matte polyurethane hot melt adhesive and a preparation method and application thereof to overcome the problem that traditional polyurethane hot melt adhesive cannot have both good matte effect and bonding strength.

[0006] In a first aspect of the present application, a matte polyurethane hot melt adhesive is provided.

[0007] A matte polyurethane hot melt adhesive, wherein the raw materials of the matte polyurethane hot melt adhesive include the following components in parts by mass:

[0008] Thermoplastic polyurethane 97-102 parts;

[0009] 8-25 parts of EPDM rubber;

[0010] 1-5 parts of maleic anhydride grafted propylene-ethylene copolymer;

[0011] 0.1 to 1 part of multifunctional acrylate; and

[0012] Thermal initiator 0.05~0.5 parts.

[0013] In some embodiments, the multifunctional acrylate includes one or more of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triallyl acrylate, dipentaerythritol tetraacrylate, ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and ditrimethylolpropane acrylate.

[0014] In some embodiments, the 0.1 h half-life temperature of the thermal initiator is 120° C. to 200° C.

[0015] In some embodiments, the thermal initiator includes one or more of 1,1'-azo(cyanocyclohexane), 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-amyl peroxy(2-ethylhexyl)carbonate, tert-butyl peroxy-3,5,5-trimethylhexanoate, and tert-butyl peroxy(2-ethylhexyl)carbonate.

[0016] In some embodiments, the EPDM rubber is prepared from raw materials including ethylene, propylene and a third monomer, and the third monomer is ethylidene norbornene or dicyclopentadiene; in terms of the mass percentage of the raw materials of the EPDM rubber, the content of ethylene is 50% to 75%, the content of the third monomer is 0.5% to 6.0%, and the balance is the propylene.

[0017] In some embodiments, the maleic anhydride grafted propylene-ethylene copolymer is prepared from raw materials including maleic anhydride, propylene, and ethylene, and the content of ethylene is 4% to 25%, and the content of maleic anhydride is 0.3% to 2%, based on the mass percentage of the maleic anhydride grafted propylene-ethylene copolymer raw materials.

[0018] In some embodiments, the matte polyurethane hot melt adhesive further comprises, by weight:

[0019] 0.5 to 5 parts of fluidity regulator; and

[0020] Additive 0.1~1 part.

[0021] In a second aspect of the present application, a method for preparing the above-mentioned matte polyurethane hot melt adhesive is provided.

[0022] A method for preparing the above-mentioned matte polyurethane hot melt adhesive comprises the following steps:

[0023] Mixing the thermoplastic polyurethane, the EPDM rubber, the maleic anhydride grafted propylene-ethylene copolymer, the multifunctional acrylate and the thermal initiator according to the raw material ratio to form a mixture;

[0024] The mixture is melted and extruded, the melting temperature is 80°C to 120°C, and the extrusion temperature is 80°C to 120°C.

[0025] In a third aspect of the present application, there is provided an application of the matte polyurethane hot melt adhesive for bonding objects to be bonded. An application of the matte polyurethane hot melt adhesive for bonding objects to be bonded comprises placing the matte polyurethane hot melt adhesive between the objects to be bonded and hot pressing.

[0026] In some embodiments, the temperature of the hot pressing is 150° C. to 200° C.; and / or

[0027] The heat pressing time is 6s to 25s; and / or

[0028] The hot pressing pressure is 2kgf~6kgf.

[0029] The raw materials of the matte polyurethane hot melt adhesive of the present application include thermoplastic polyurethane, EPDM rubber, maleic anhydride grafted propylene-ethylene copolymer (PEC-g-MA), multifunctional acrylate and thermal initiator. When used, under the combined action of temperature and thermal initiator, the multifunctional acrylate will undergo a cross-linking reaction with the EPDM rubber and form an interlaced cross-linking network. At this time, the rubber particles formed in situ after cross-linking will separate from the TPU, thereby producing a matte effect, and obtaining a polyurethane film with a good matte effect. At the same time, since the multifunctional acrylate and EPDM rubber are phase-separated from the TPU only when bonding, before use, under the promotion of PEC-g-MA, the EPDM rubber in the system can be evenly dispersed in the TPU matrix, which is conducive to maintaining a good matte effect at a lower EPDM content, and has little effect on the bonding performance of the polyurethane hot melt adhesive. Through the combination of the above components, the matte polyurethane hot melt adhesive can obtain a film with both good matte effect and bonding strength when used. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0031] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In this application, "at least one" means more than one, such as one, two and more than two. "Multiple" or "several" means at least two, such as two, three, etc.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0033] When a numerical range is disclosed herein, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0034] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0035] In this application, "above" or "below" includes the number itself. For example, "1 below" includes 1.

[0036] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0037] Polyurethane hot melt adhesive is a green and environmentally friendly adhesive material that has good bonding effects on a variety of materials such as metal, plastic, wood, and cloth. Therefore, it is widely used in packaging, electronics, clothing, footwear, medical and other fields.

[0038] Traditional polyurethane hot melt adhesive is a material with a smooth surface, especially after being hot pressed and melted, the surface has high gloss and strong reflection. When the above hot melt adhesive is used for bonding products, obvious reflection will appear at the hollow or overflowing position, affecting the aesthetics of the product.

[0039] In order to solve the above problems, the traditional solutions are as follows: (1) Use the matte roller process to destroy the surface flatness of the film during film casting to reduce its surface gloss. Although a matte adhesive film can be obtained after the matte roller treatment, the hot pressing and melting process will re-destroy the microscopic surface structure of the hot melt adhesive during use, resulting in a weakening or even disappearance of the matte effect. (2) Add matting agents, such as organic matting agents of rubber, acrylate or epoxy resin, or inorganic filler matting agents such as calcium carbonate, talcum powder, and silica, to form a rougher film phase structure through phase separation of the matting agent and TPU. However, since the compatibility of matting agents with TPU is often poor, the amount of matting agent used is often high. When more matting agents are added, it will have a negative impact on the mechanical strength and ductility of the hot melt adhesive, resulting in a decrease in the bonding performance of the product, and it is impossible to take into account both good matte effect and bonding strength.

[0040] In response to the above technical problems, one embodiment of the present application involves a matte polyurethane hot melt adhesive to overcome the problem that traditional polyurethane hot melt adhesives cannot have both good matte effect and bonding strength.

[0041] A matte polyurethane hot melt adhesive, wherein the raw materials of the matte polyurethane hot melt adhesive include the following components in parts by mass:

[0042] Thermoplastic polyurethane 97-102 parts;

[0043] 8-25 parts of EPDM rubber;

[0044] 1-5 parts of maleic anhydride grafted propylene-ethylene copolymer;

[0045] 0.1 to 1 part of multifunctional acrylate; and

[0046] Thermal initiator 0.05~0.5 parts.

[0047] The raw materials of the matte polyurethane hot melt adhesive of the present application include TPU, EPDM rubber, maleic anhydride grafted propylene-ethylene copolymer (PEC-g-MA), multifunctional acrylate and thermal initiator. When in use, under the combined action of the temperature generated by hot pressing and the thermal initiator, the EPDM rubber in the matte polyurethane hot melt adhesive will undergo a cross-linking reaction with the acrylate, and the rubber particles formed in situ after cross-linking will separate from the TPU, thereby producing a matte effect, and obtaining a polyurethane adhesive film with a good matte effect.

[0048] Optionally, the mass fraction of EPDM rubber can be but is not limited to 8, 10, 12, 14, 16, 18, 20, 22, 25 or other fractions within the range of 8 to 25. When the mass fraction of EPDM rubber is within the above range, a polyurethane hot melt adhesive film having both good matte effect and bonding strength can be obtained.

[0049] In the present embodiment, multifunctional acrylate refers to an acrylate compound containing more than two carbon-carbon double bond functional groups in the molecular monomer. In order to cooperate with EPDM rubber to form an effective cross-linked network, the content of multifunctional acrylate is more critical. When the content of multifunctional acrylate is low, an effective cross-linked network cannot be formed, resulting in poor matte effect. When the content of multifunctional acrylate is high, excessive cross-linking may cause the bonding performance of the polyurethane hot melt adhesive film to decline. Optionally, the mass fraction of multifunctional acrylate can be but is not limited to 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 parts or other parameters within the range of 0.1 parts to 1 parts. When the multifunctional acrylate is in the above mass fractions, a polyurethane hot melt adhesive film with good matte effect and bonding strength can be obtained.

[0050] Maleic anhydride grafted propylene-ethylene copolymer (PEC-g-MA) refers to a propylene-ethylene copolymer grafted with maleic anhydride functional groups. In the matte polyurethane hot melt adhesive system, PEC-g-MA can make the pre-reaction EPDM rubber evenly dispersed in TPU, ensuring the uniform distribution of rubber particles produced by in-situ phase separation, thereby achieving a better matte effect at a lower EPDM content.

[0051] Optionally, the mass fraction of PEC-g-MA can be, but is not limited to, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, or other fractions within the range of 1 part to 5 parts. When the mass fraction of PEC-g-MA is within the above range, a matte polyurethane hot melt adhesive in which each component is evenly dispersed can be obtained.

[0052] The thermoplastic polyurethane of the present application may be in the form of pellets, powders, or a combination of multiple different forms. Optionally, the mass fraction of the thermoplastic polyurethane may be, but is not limited to, 97 parts, 98 parts, 99 parts, 100 parts, 101 parts, 102 parts, or other fractions within the range of 97 parts to 102 parts.

[0053] In some embodiments, the thermoplastic polyurethane is a hot melt grade polyester thermoplastic polyurethane.

[0054] In some embodiments, the melt index (MFR) of the thermoplastic polyurethane is 10 g / 10 min to 40 g / 10 min at 150° C. and 2.16 kg. Within the above index range, the matte polyurethane hot melt adhesive has better processing performance and bonding effect.

[0055] In some embodiments, the softening point is 80° C. to 130° C. Within the above index range, the matte polyurethane hot melt adhesive has better processing performance and bonding effect.

[0056] In some embodiments, the Shore hardness of the thermoplastic polyurethane is 70A-95A. Within the above index range, the obtained matte polyurethane hot melt adhesive film has good flexibility.

[0057] In some embodiments, a multifunctional acrylate containing three or more carbon-carbon double bonds is used. In this case, an effective three-dimensional cross-linked network can be constructed at a relatively low addition amount.

[0058] Optionally, the multifunctional acrylate includes one or more of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triallyl acrylate, dipentaerythritol tetraacrylate, ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and ditrimethylolpropane acrylate.

[0059] In some embodiments, the 0.1h half-life temperature of the thermal initiator is 120°C to 200°C. Keeping the parameters of the thermal initiator within the above range can reduce the risk of phase separation of the matte polyurethane hot melt adhesive during the preparation and storage stages, and enable the matte polyurethane hot melt adhesive to phase separate in time during the hot pressing stage.

[0060] Optionally, the 0.1 h half-life temperature of the thermal initiator may be, but is not limited to, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or other parameters within the range of 120°C to 200°C.

[0061] In some embodiments, the thermal initiator includes one or more of 1,1'-azo(cyanocyclohexane), 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-amyl peroxy(2-ethylhexyl)carbonate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxy(2-ethylhexyl)carbonate, and the like.

[0062] In some embodiments, the EPDM rubber is prepared from raw materials including ethylene, propylene and a third monomer, and the third monomer is ethylidene norbornene or dicyclopentadiene. In terms of the mass percentage of the raw materials of the EPDM rubber, the content of ethylene is 50% to 75%, the content of the third monomer is 0.5% to 6.0%, and the balance is the propylene. By controlling the contents of ethylene and the third monomer of the EPDM rubber to be within the above range, an EPDM rubber with good processing performance and reaction performance can be obtained.

[0063] In some embodiments, the EPDM rubber is prepared from raw materials of ethylene, propylene and a third monomer, wherein the third monomer is ethylidene norbornene or dicyclopentadiene. In terms of the mass percentage of the raw materials of the EPDM rubber, the content of ethylene is 50% to 75%, the content of the third monomer is 0.5% to 6.0%, and the balance is the propylene.

[0064] In some embodiments, the maleic anhydride grafted propylene-ethylene copolymer is prepared from raw materials including maleic anhydride, propylene, and ethylene, and the ethylene content is 4% to 25% and the maleic anhydride content is 0.3% to 2% based on the mass percentage of the maleic anhydride grafted propylene-ethylene copolymer raw materials.

[0065] In some embodiments, the maleic anhydride grafted propylene-ethylene copolymer is prepared from maleic anhydride and propylene-ethylene copolymer raw materials, and the ethylene content is 4% to 25% and the maleic anhydride content is 0.3% to 2% based on the mass percentage of the maleic anhydride grafted propylene-ethylene copolymer raw materials.

[0066] In some embodiments, the matte polyurethane hot melt adhesive further comprises, by weight:

[0067] 0.5 to 5 parts of fluidity regulator; and

[0068] Additive 0.1~1 part.

[0069] In some embodiments, the fluidity modifier includes one or more of paraffin wax, liquid paraffin, Fischer-Tropsch wax, microcrystalline wax, polyethylene wax, oxidized polyethylene wax, white oil, paraffin oil, and naphthenic oil.

[0070] In some embodiments, the auxiliary agent includes one or more of an antioxidant, a UV absorber, an inorganic filler, and an opening agent.

[0071] In another embodiment of the present application, a method for preparing the above-mentioned matte polyurethane hot melt adhesive is provided.

[0072] The preparation method of matte polyurethane hot melt adhesive comprises the following steps:

[0073] Thermoplastic polyurethane, EPDM rubber, maleic anhydride grafted propylene-ethylene copolymer, multifunctional acrylate and thermal initiator are mixed according to the raw material ratio to form a mixture;

[0074] The mixture is melted and extruded, the melting temperature is 80°C to 120°C, and the extrusion temperature is 80°C to 120°C.

[0075] In this embodiment, controlling the melting and extrusion within a relatively low temperature range is beneficial to reducing or avoiding the phase separation of the matte polyurethane hot melt adhesive during the preparation process, so that the multifunctional acrylate and EPDM rubber in the system can be evenly distributed in the thermoplastic polyurethane matrix, which further helps to obtain a polyurethane hot melt adhesive film with a good matte effect with a relatively low EPDM rubber addition amount.

[0076] In some embodiments, a mixer is used to mix the above raw materials to form a mixed slurry.

[0077] In some embodiments, the speed of the mixer is 800 r / min to 2000 r / min. Optionally, the speed of the mixer includes but is not limited to 800 r / min, 1000 r / min, 1100 r / min, 1200 r / min, 1300 r / min, 1400 r / min, 1500 r / min, 1700 r / min, 2000 r / min or other parameters within the range of 800 r / min to 2000 r / min.

[0078] In some embodiments, the mixing time is 0.5 min to 5 min. Optionally, the mixing time includes but is not limited to 0.5 min, 0.6 min, 0.7 min, 0.8 min, 0.9 min, 1 min, 2 min, 3 min, 4 min, 5 min or other parameters within the range of 0.5 min to 5 min.

[0079] In some embodiments, the temperature of the mixture is 25° C. to 50° C. Optionally, the temperature of the mixture includes 50° C., 45° C., 40° C., 35° C., 30° C. or 25° C.

[0080] In some embodiments, a twin-screw extruder is used to melt and extrude the mixed slurry.

[0081] It can be understood that the matte polyurethane hot melt adhesive can be obtained by melting and extruding the mixture. In order to make the product more convenient to use, in some embodiments, the preparation method of the matte polyurethane hot melt adhesive also includes the steps of cooling, cutting, dehumidifying and drying, and casting the matte polyurethane hot melt adhesive after melt extrusion.

[0082] In some embodiments, the matte polyurethane hot melt adhesive is cast into a film using a casting machine. The matte polyurethane hot melt adhesive is cast into a film by the casting machine, and then cut into sheets after cooling to obtain the matte polyurethane hot melt adhesive in sheets.

[0083] In some embodiments, the casting temperature is 90°C to 120°C.

[0084] In some embodiments, the cooling temperature is 0°C to 10°C.

[0085] In some embodiments, the thickness of the matte polyurethane hot melt adhesive sheet is 0.05 mm to 0.25 mm. Keeping the thickness of the matte polyurethane hot melt adhesive within the above range is conducive to obtaining better film bonding strength and having higher production efficiency and yield rate during production.

[0086] In another embodiment of the present application, it also relates to an application of the above-mentioned matte polyurethane hot melt adhesive for bonding objects to be bonded.

[0087] Matt polyurethane hot melt adhesive is used to bond objects in the following ways:

[0088] Place matte polyurethane hot melt adhesive between the objects to be bonded and heat press.

[0089] It can be understood that placing the matte polyurethane hot melt adhesive between the objects to be bonded means stacking the substrates to be bonded and the hot melt adhesive film in sequence to obtain a sandwich structure with the substrates on both sides and the hot melt adhesive film in the middle.

[0090] In some embodiments, a heat press is used for heat pressing, and the bonded product after heat pressing is taken out and cooled naturally.

[0091] In some embodiments, the temperature of hot pressing is 150°C to 200°C.

[0092] In some embodiments, the hot pressing time is 6s to 25s.

[0093] In some embodiments, the pressure of the hot pressing is 2 kgf to 6 kgf.

[0094] Exemplarily, in some embodiments, the application method of the matte polyurethane hot melt adhesive film is as follows:

[0095] Cut the polyurethane hot melt adhesive into pieces, take two pieces of polyester cloth of the same size (thickness 0.3mm), and stack them neatly in the order of polyester cloth-hot melt adhesive film-polyester cloth. Then put the stacked objects in a hot press for hot pressing and bonding, with a hot pressing temperature of 150℃, a time of 20s, and a pressure of 5kgf. Take them out and cool them naturally, and the bonding is completed.

[0096] Exemplarily, in other embodiments, the application method of the matte polyurethane hot melt adhesive film is as follows:

[0097] Cut the polyurethane hot melt adhesive into pieces, and take two pieces of cotton cloth (thickness 0.5mm) and thin wood slices (thickness 1mm) of the same size, and stack them neatly in the order of cotton cloth-hot melt adhesive film-thin wood slices. Then put the stacked objects in a hot press for hot pressing and bonding, with a hot pressing temperature of 190℃, a time of 13s, and a pressure of 2kgf. Take them out and cool them naturally, and the bonding is completed.

[0098] The present application is further described in detail below in conjunction with specific embodiments.

[0099] In the following specific embodiments and comparative examples, the raw materials used, unless otherwise specified, are all commercially available products; the instruments used, unless otherwise specified, are all commercially available products; and the processes used, unless otherwise specified, are all routinely selected by those skilled in the art.

[0100] Example 1

[0101] This embodiment provides a matte polyurethane hot melt adhesive.

[0102] The raw materials and amounts of the matte polyurethane hot melt adhesive are shown in Table 1 in parts by weight.

[0103] Table 1

[0104]

[0105] The above components are put into a mixer according to the proportion and mixed evenly to obtain a raw material premix, wherein the mixing speed is 1000 r / min, the mixing time is 0.5 min, and the mixing temperature is 35°C.

[0106] The raw material premix is ​​put into a twin-screw extruder for melting, mixing and extrusion at a temperature of 105°C. The extrudate is cooled and pelletized, and a hot melt adhesive is obtained after dehumidification and drying.

[0107] The hot melt adhesive material was put into a casting machine, heated and melted to form a film, and then cooled and cut to obtain a matte polyurethane hot melt adhesive with a thickness of 0.25 mm. The casting temperature was 105°C and the cooling temperature was 10°C.

[0108] Example 2

[0109] This embodiment provides a matte polyurethane hot melt adhesive.

[0110] The raw materials and amounts of the matte polyurethane hot melt adhesive are shown in Table 2 in parts by weight.

[0111] Table 2

[0112]

[0113] The preparation method of the matte polyurethane hot melt adhesive in this embodiment is the same as that in Embodiment 1.

[0114] Example 3

[0115] This embodiment provides a matte polyurethane hot melt adhesive.

[0116] The raw materials and amounts of the matte polyurethane hot melt adhesive are shown in Table 3 in parts by weight.

[0117] Table 3

[0118]

[0119] The preparation method of the matte polyurethane hot melt adhesive in this embodiment is the same as that in Embodiment 1.

[0120] Example 4

[0121] This embodiment provides a matte polyurethane hot melt adhesive.

[0122] The preparation method of the matte polyurethane hot melt adhesive in this embodiment is the same as that in Embodiment 1.

[0123] The raw materials and amounts of the matte polyurethane hot melt adhesive are shown in Table 4 in parts by weight.

[0124] Table 4

[0125]

[0126] Comparative Example 1

[0127] This comparative example provides a matte polyurethane hot melt adhesive. The raw material composition and preparation method of the matte polyurethane hot melt adhesive in this comparative example are basically the same as those in Example 1. The difference is that EPDM rubber without a third monomer is used to replace EPDM rubber.

[0128] Comparative Example 2

[0129] This comparative example provides a matte polyurethane hot melt adhesive. The raw material composition and preparation method of the matte polyurethane hot melt adhesive in this comparative example are basically the same as those in Example 1, except that: PEC-g-MA is not added.

[0130] Comparative Example 3

[0131] This comparative example provides a matte polyurethane hot melt adhesive. The raw material composition and preparation method of the matte polyurethane hot melt adhesive in this comparative example are basically the same as those in Example 1, except that the mass fraction of the multifunctional acrylate is 4 parts.

[0132] Comparative Example 4

[0133] This comparative example provides a matte polyurethane hot melt adhesive. The raw material composition and preparation method of the matte polyurethane hot melt adhesive in this comparative example are basically the same as those in Example 1, except that no thermal initiator is added.

[0134] Comparative Example 5

[0135] This comparative example uses a commercially available matte polyurethane hot melt adhesive film formed by pressing with a matte roller.

[0136] Comparative Example 6

[0137] This comparative example provides a matte polyurethane hot melt adhesive. The raw material composition of the polyurethane hot melt adhesive in this comparative example is: 100 parts of the TPU in Example 1 and 50 parts of calcium carbonate are mixed together. The preparation method is the same as that in Example 1.

[0138] Test Case

[0139] Test method for bonding strength: Use polyester cloth and cotton cloth as bonding substrates, and stack them neatly in the order of polyester cloth-hot melt adhesive-cotton cloth. Then place the stacked materials in a hot press for hot pressing, with a hot pressing temperature of 170°C, a time of 18s, a pressure of 3kgf, and natural cooling. Cut the bonded cloth pieces into 25mm×100mm test specimens, and test the peel strength of the bonded polyester cloth and cotton cloth by the T-type peeling method described in GB / T 2791. Use a universal mechanical testing machine to test 5 samples in parallel and take the average value. The peeling speed is fixed at 50mm / min.

[0140] Test method for surface gloss: Use release PET film and ordinary PET film as bonding substrates, and stack them neatly in the order of release PET film-hot melt adhesive-ordinary PET film. Then place the stack in a hot press for hot pressing and bonding, with a hot pressing temperature of 170°C, a time of 18s, a pressure of 3kgf, and natural cooling. Cut the bonded film into 100mm×100mm test samples, peel off the release PET film to expose the hot melt adhesive film, and test the surface gloss of the hot melt adhesive film according to the method of GB / T 8807 standard. Test 5 samples in parallel and take the average value. The light source angle is 60°.

[0141] Test method for water washability: Prepare the test sample according to the test sample preparation method in the bonding strength test. Wash using the washing method of GB / T 3921. The washing water temperature is 60°C and the number of washes is 10. After washing and drying, test the bonding strength of the sample according to the test method of the bonding strength test, and compare the changes in bonding strength before and after washing.

[0142] The test data of the bonding strength, surface gloss and water washability of the hot melt adhesives of various embodiments and comparative examples are shown in Table 5.

[0143] Table 5

[0144]

[0145] From the test results in Table 5, it can be seen that the matte hot melt adhesives of Examples 1 to 4 have both high bonding strength and low surface gloss after hot melt bonding. In addition, the samples of Examples 1 to 4 have good water wash resistance after bonding, which can meet the application requirements of hot melt adhesives for textiles.

[0146] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0147] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims, and the description may be used to interpret the content of the claims.

Claims

1. A matte polyurethane hot melt adhesive, characterized in that: The raw materials of the matte polyurethane hot melt adhesive include the following components in parts by mass: Thermoplastic polyurethane 97-102 parts; 8-25 parts of EPDM rubber; 1-5 parts of maleic anhydride grafted propylene-ethylene copolymer; Multifunctional acrylate 0.1~1 part; as well as Thermal initiator 0.05~0.5 parts.

2. The matte polyurethane hot melt adhesive according to claim 1, characterized in that: The multifunctional acrylate includes one or more of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triallyl acrylate, dipentaerythritol tetraacrylate, ethoxylated trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and ditrimethylolpropane acrylate.

3. The matte polyurethane hot melt adhesive according to claim 1, characterized in that: The 0.1h half-life temperature of the thermal initiator is 120°C to 200°C.

4. The matte polyurethane hot melt adhesive according to claim 3, characterized in that: The thermal initiator includes one or more of 1,1'-azo(cyanocyclohexane), 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-amyl peroxy(2-ethylhexyl)carbonate, tert-butyl peroxy-3,5,5-trimethylhexanoate and tert-butyl peroxy(2-ethylhexyl)carbonate.

5. The matte polyurethane hot melt adhesive according to claim 1, characterized in that: The EPDM rubber is prepared from raw materials including ethylene, propylene and a third monomer, wherein the third monomer is ethylidene norbornene or dicyclopentadiene; in terms of the mass percentage of the raw materials of the EPDM rubber, the content of the ethylene is 50% to 75%, the content of the third monomer is 0.5% to 6.0%, and the balance is the propylene.

6. The matte polyurethane hot melt adhesive according to claim 1, characterized in that: The maleic anhydride grafted propylene-ethylene copolymer is prepared from raw materials including maleic anhydride, propylene and ethylene. The ethylene content is 4% to 25%, and the maleic anhydride content is 0.3% to 2%, based on the mass percentage of the maleic anhydride grafted propylene-ethylene copolymer raw materials.

7. The matte polyurethane hot melt adhesive according to any one of claims 1 to 6, characterized in that: In parts by mass, the matte polyurethane hot melt adhesive further comprises: 0.5 to 5 parts of fluidity regulator; and Additive 0.1~1 part.

8. A method for preparing the matte polyurethane hot melt adhesive according to any one of claims 1 to 7, characterized in that: The steps include: Mixing the thermoplastic polyurethane, the EPDM rubber, the maleic anhydride grafted propylene-ethylene copolymer, the multifunctional acrylate and the thermal initiator according to the raw material ratio to form a mixture; The mixture is melted and extruded, the melting temperature is 80°C to 120°C, and the extrusion temperature is 80°C to 120°C.

9. An application of the matte polyurethane hot melt adhesive as claimed in any one of claims 1 to 7 for bonding objects to be bonded, characterized in that: The method comprises placing the matte polyurethane hot melt adhesive between objects to be bonded and hot pressing.

10. The use according to claim 9, characterized in that: The temperature of the hot pressing is 150°C to 200°C; and / or The heat pressing time is 6s to 25s; and / or The hot pressing pressure is 2kgf~6kgf.

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