Polypropylene hot melt adhesive and preparation method and application thereof

Abstract

The present application relates to a kind of polypropylene hot melt adhesive and its preparation method and application, belong to hot melt adhesive technical field.The polypropylene hot melt adhesive of the present application includes maleic anhydride modified polypropylene resin 100 parts, styrene-maleic anhydride copolymer resin 10-20 parts, flame-retardant filler 20-40 parts, curing agent 2-5 parts, solvent 150-200 parts by weight;Maleic anhydride modified polypropylene resin molecular weight Mw is 50000-70000, acid value is 15mgKOH / g-25mgKOH / g, maleic anhydride content is 1wt%-2wt%, melting point is 70℃-100℃.The polypropylene hot melt adhesive of the present application is by compounding styrene-maleic anhydride copolymer resin, so that the maleic anhydride functional group in styrene-maleic anhydride copolymer resin can react or form hydrogen bond with maleic anhydride in maleic anhydride modified polypropylene resin, to enhance the compatibility of both, reduce phase separation, form more uniform composite material.Copolymer resin as a kind of elastomer, can improve the toughness of polypropylene to some extent, improve the impact resistance of material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hot melt adhesives, and particularly relates to a polypropylene hot melt adhesive as well as a preparation method and application thereof. BACKGROUND

[0002] Hot melt adhesives, as a kind of widely used adhesives in various industries, are widely welcomed due to their unique advantages such as non-toxicity and rapid curing. With the development of manufacturing industry, the demand for high adhesive strength hot melt adhesives is increasing. In particular, in the fields of automobiles, electronics, construction and the like, high adhesive strength hot melt adhesives are widely used due to their excellent adhesive properties and durability. Therefore, the application trend of high adhesive strength hot melt adhesives will further expand, and the market demand and technical level will continue to improve.

[0003] Most of the existing polypropylene hot melt adhesives on the market are maleic anhydride grafted modified polypropylene hot melt adhesives. The grafting rate of maleic anhydride grafted polypropylene is generally 0.5%-2.0%. The low grafting rate of maleic anhydride leads to poor adhesive effect and low adhesive strength of the polypropylene hot melt adhesive, and the phenomenon of adhesive delamination easily occurs. However, after increasing the grafting rate of maleic anhydride, the introduction of a large amount of maleic anhydride will accelerate the degradation of polypropylene at high temperature, especially in the process of melt processing. High grafting rate may also lead to a decrease in the toughness of the material, and the impact resistance of the material is significantly weakened at low temperature, and brittle fracture easily occurs. For example, the patent CN 103756595A discloses a modified polypropylene hot melt adhesive, which is prepared by blending maleic anhydride modified polypropylene and ethylene (propylene) copolymer, copolymerized polypropylene, elastomer and the like. However, the melt index of the maleic anhydride functionalized modified polypropylene is high, indicating that it is easy to degrade and has low molecular weight, which will lead to poor adhesive strength, poor temperature resistance and poor weather resistance of the hot melt adhesive. The patent CN 109796912A discloses a modified polypropylene hot melt adhesive, and a low crystallinity ethylene-α-olefin copolymer is added in the process of preparing the functionalized modified polypropylene. Although the low crystallinity ethylene-α-olefin copolymer can improve the toughness of polypropylene, the compatibility between the elastomer and polypropylene is poor in some cases, which may lead to two-phase separation and form a non-uniform microstructure. This not only affects the mechanical properties of the material, but also may cause appearance defects of the product, such as uneven surface or delamination phenomenon, thereby leading to insufficient adhesive force and adhesive failure.

[0004] In summary, the existing hot melt adhesives still have the problem of insufficient adhesive strength, which will affect the use effect and product quality. Therefore, how to improve the adhesive strength of hot melt adhesives is still a problem to be solved at present. SUMMARY

[0005] To solve the above technical problems, the application provides a polypropylene hot melt adhesive and a preparation method and application thereof, by adding styrene-maleic anhydride copolymer resin in the polypropylene hot melt adhesive, by more carboxyl contained therein and the reaction with the surface of the polar material, chemical bonding is formed, the bonding strength of different interfaces is greatly improved, so that the polypropylene hot melt adhesive has excellent bonding strength and adaptability to various materials. At the same time, due to the polarity and reactivity of maleic anhydride, the polypropylene hot melt adhesive has better heat resistance and chemical stability; in addition, the polypropylene hot melt adhesive adds flame-retardant filler with flame-retardant effect, so that the polypropylene hot melt adhesive has excellent flame-retardant function; the polypropylene hot melt adhesive is coated on the substrate layer to form a multifunctional hot melt adhesive film with high strength, high heat resistance, insulation and flame-retardant performance.

[0006] The first object of the application is to provide a polypropylene hot melt adhesive, which comprises maleic anhydride modified polypropylene resin 100 parts, styrene-maleic anhydride copolymer resin 10-20 parts, flame-retardant filler 20-40 parts, curing agent 2-5 parts, and solvent 150-200 parts by weight; the molecular weight Mn of the styrene-maleic anhydride copolymer resin is 4000-10000, the acid value is 110 mgKOH / g-220 mgKOH / g, the maleic anhydride content is 5wt%-20wt%, and the glass transition temperature Tg is 100℃-120℃. Within this molecular weight range, the styrene-maleic anhydride copolymer resin usually has good solubility and can be easily dissolved in various organic solvents, which makes them very suitable for the formulation of coatings, inks and adhesives; due to the high acid value and maleic anhydride content, the styrene-maleic anhydride copolymer resin has more functional groups such as carboxyl and anhydride groups, which can participate in various chemical reactions, such as crosslinking reaction with polyols, amines, epoxy resins, etc., thereby improving the performance of the material; higher Tg indicates that the resin is more stable when heated and is not easy to soften or deform, which is very important for applications that require heat resistance, such as electronic packaging materials or coatings used in high temperature environments; appropriate molecular weight and Tg help to provide better strength and toughness while maintaining a certain flexibility. This is crucial for the manufacture of durable products; this type of SMA resin has moderate melt viscosity and good flowability, which can improve the wettability of the hot melt adhesive to the adherend.

[0007] In an embodiment of the present application, the styrene-maleic anhydride copolymer resin is composed of styrene and maleic anhydride in a molar ratio of (6-8):1. The styrene-maleic anhydride copolymer is a thermoplastic resin synthesized by chemical reaction of styrene and maleic anhydride. By adjusting the ratio of the two monomers, the physical and chemical properties of the copolymer can be changed, thereby affecting its application performance. By selecting a styrene-maleic anhydride copolymer with high styrene content, the glass transition temperature (Tg) of the material will generally increase, which makes the material maintain better dimensional stability and mechanical strength at higher temperatures. At the same time, the copolymer with higher styrene content may have better resistance to certain solvents and chemicals. Increasing the styrene content can improve the flowability of the material, enhance the wetting effect of the hot melt adhesive on the substrate and the adherend, and improve the processing performance.

[0008] Further, the molar ratio of styrene to maleic anhydride in the styrene-maleic anhydride copolymer resin is (6:1), (7:1), (8:1), etc.

[0009] In an embodiment of the present application, the molecular weight Mw of the maleic anhydride modified polypropylene resin is 50000-70000, the acid value is 15mgKOH / g-25mgKOH / g, the maleic anhydride content is 1wt%-2wt%, and the melting point is 70℃-100℃. This can ensure that the material has excellent mechanical properties, thermal properties and processing performance, while improving its compatibility and adhesion performance with other materials, and is suitable for various high-performance application fields.

[0010] Further, the weight fraction of the maleic anhydride modified polypropylene resin can be 100 parts, etc.

[0011] The weight fraction of the styrene-maleic anhydride copolymer resin can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc.

[0012] The weight fraction of the flame-retardant filler can be 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts, etc.

[0013] The weight fraction of the curing agent can be 2 parts, 3 parts, 4 parts, 5 parts, etc.

[0014] The weight fraction of the solvent can be 150 parts, 155 parts, 160 parts, 165 parts, 170 parts, 175 parts, 180 parts, 185 parts, 190 parts, 195 parts, 200 parts, etc.

[0015] In one embodiment of the present application, the flame-retardant filler is selected from one or more of phosphorus-based flame retardants, nitrogen-based flame retardants, and metal hydroxide-based flame retardants.

[0016] Further, the phosphorus-based flame retardant is selected from aluminum diethylphosphinate and / or triethyl phosphate;

[0017] The nitrogen-based flame retardant is selected from melamine and / or melamine phosphate;

[0018] The metal hydroxide-based flame retardant is selected from aluminum hydroxide and / or magnesium hydroxide.

[0019] In one embodiment of the present application, the curing agent is selected from one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and dicyclopentadiene phenol type epoxy resin.

[0020] In one embodiment of the present application, the solvent is selected from one or more of xylene, dichloromethane, cyclohexane, butanone, and ethyl acetate.

[0021] A second object of the present application is to provide a preparation method of the polypropylene hot melt adhesive, comprising the following steps: uniformly dispersing styrene-maleic anhydride copolymer resin, curing agent, and solvent, then uniformly stirring after adding flame-retardant filler, and finally uniformly mixing after adding maleic anhydride modified polypropylene resin, to obtain the polypropylene hot melt adhesive.

[0022] Further, the rotation speed of the uniform dispersion, the uniform stirring and the uniform mixing is independently 800 r / min-1000 r / min, for example, can be 800 r / min, 810 r / min, 820 r / min, 830 r / min, 840 r / min, 850 r / min, 860 r / min, 870 r / min, 880 r / min, 890 r / min, 900 r / min, 910 r / min, 920 r / min, 930 r / min, 940 r / min, 950 r / min, 960 r / min, 970 r / min, 980 r / min, 990 r / min, 1000 r / min, etc.; the time of the uniform dispersion is 10 min-20 min, for example, can be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, etc.; the time of the uniform stirring is 40 min-60 min, for example, can be 40 min, 41 min, 42 min, 43 min, 44 min, 45 min, 46 min, 47 min, 48 min, 49 min, 50 min, 51 min, 52 min, 53 min, 54 min, 55 min, 56 min, 57 min, 58 min, 59 min, 60 min, etc.; the time of the uniform mixing is 20 min-30 min, for example, can be 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, etc.

[0023] A third object of the present application is to provide a multifunctional hot melt adhesive film, which comprises a substrate layer and an adhesive layer disposed on the substrate layer; the adhesive layer is prepared from the polypropylene hot melt adhesive.

[0024] In an embodiment of the present application, the substrate layer is selected from a polypropylene film layer, a polyethylene terephthalate film layer, a polyimide film layer, a polycarbonate film layer or a polyamide film layer.

[0025] In an embodiment of the present application, the thickness of the substrate layer is 25 μm-125 μm; the thickness of the adhesive layer is 20 μm-50 μm.

[0026] Further, the thickness of the substrate layer is 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm; or any thickness value between any two numerical values; the thickness of the adhesive layer is 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, 41 μm, 42 μm, 43 μm, 44 μm, 45 μm, 46 μm, 47 μm, 48 μm, 49 μm, 50 μm; or any thickness value between any two numerical values.

[0027] The technical scheme of the present application has the following advantages compared with the prior art:

[0028] (1) The polypropylene hot melt adhesive of the present application is compounded by maleic anhydride modified polypropylene resin and styrene-maleic anhydride copolymer resin, so that the maleic anhydride functional groups in the styrene-maleic anhydride copolymer resin can react with or form hydrogen bonds with the maleic anhydride in the maleic anhydride modified polypropylene resin, thereby enhancing the compatibility of the two, reducing phase separation, and forming a more uniform composite material. At the same time, the styrene-maleic anhydride copolymer resin, as an elastomer, can improve the toughness of polypropylene to some extent and reduce the risk of brittle fracture; especially in low temperature environment, the styrene-maleic anhydride copolymer resin can help improve the impact resistance of the material.

[0029] (2) The multifunctional hot melt adhesive film has excellent bonding strength, temperature resistance, and weather resistance, and is suitable for bonding polar materials (such as metal, glass, rubber, ceramic, etc.). BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the drawings, in which:

[0031] Figure 1 Structure diagram of the insulating adhesive film for busbar of the present application;

[0032] Explanation of reference signs: 1 - substrate layer, 2 - adhesive layer. DETAILED DESCRIPTION

[0033] The present application will be further described below in conjunction with the drawings and specific embodiments so that those skilled in the art can better understand the present application and implement it. Obviously, the described embodiments are only a part of the embodiments of the present application and not all the embodiments. It should be understood that the specific embodiments are only used to explain the present application but not as a limitation of the present application.

[0034] In the present application, unless otherwise specified, the technical and scientific terms used in the present application have the same meanings as those commonly understood by the person skilled in the art to which the present application belongs.

[0035] In the present application, unless otherwise specified, the term "and / or" used in the embodiments of the present application includes any and all combinations of one or more of the related listed items.

[0036] In the present application, unless otherwise specified, the experimental methods used in the embodiments of the present application are conventional methods, and the materials, reagents, etc. used are commercially available, unless otherwise specified.

[0037] In the present application, unless otherwise specified, when the terms "comprising" and / or "including" are used in the present application, it means that the mentioned features, whole, steps, operations, raw materials or components exist, but it does not exclude the existence or addition of one or more other features, whole, steps, operations, raw materials, components or their combinations.

[0038] In the present application, unless otherwise specified,

[0039] In the present application, unless otherwise specified,

[0040] Example 1

[0041] Referring to Figure 1 The insulating adhesive film of the mother line of the present embodiment includes a base material layer 1 and an adhesive layer 2 arranged on the base material layer 1; wherein the base material layer 1 is a polyimide film layer with a thickness of 50 μm; the thickness of the adhesive layer 2 is 30 μm; the adhesive layer 2 is filled into a coating machine by polypropylene hot melt adhesive, and is coated on the base material layer 1 with a thickness of 50 μm respectively, and is dried by baking to obtain;

[0042] The raw material components and their weight parts of the polypropylene hot melt adhesive are as follows: maleic anhydride modified polypropylene resin 100 parts, styrene-maleic anhydride copolymer resin 10 parts, flame retardant filler 30 parts, curing agent 2 parts, solvent 200 parts;

[0043] Among them, the maleic anhydride modified polypropylene resin is purchased from Japan Toyo Spinning, the model is PMA-KE, the melting point is 95℃, the molecular weight is 60000, the acid value is 21 mgKOH / g, and the maleic anhydride content is 1.8wt%;

[0044] Styrene-maleic anhydride copolymer resin was purchased from Polyscope in the Netherlands, model EF60, molar ratio of styrene to maleic anhydride 6:1, molecular weight Mn 5500, acid value 155 mgKOH / g, maleic anhydride content 13wt%, glass transition temperature Tg 105℃;

[0045] The flame-retardant filler is a phosphorus-based flame retardant, purchased from Clariant Chemicals, model OP935;

[0046] The curing agent is a bisphenol A type epoxy resin, purchased from Nanya Plastic Industry, model NPEL-134;

[0047] The solvent is toluene and ethyl acetate (volume ratio 1:1);

[0048] The preparation of polypropylene hot melt adhesive specifically includes the following steps: mixing styrene-maleic anhydride copolymer resin, curing agent and solvent, using a high-speed disperser at a speed of 900r / min for high-speed dispersion for 15min, then slowly adding the flame-retardant filler, continuing to disperse for 50min after the addition is completed, and finally slowly adding the maleic anhydride modified polypropylene resin, continuing to disperse for 25min, to obtain the polypropylene hot melt adhesive.

[0049] Example 2

[0050] Referring to Figure 1 As shown in the figure, the busbar of the embodiment uses an insulating adhesive film, which includes a substrate layer 1 and an adhesive layer 2 arranged on the substrate layer 1; wherein the substrate layer 1 is a polyimide film layer with a thickness of 50μm; the thickness of the adhesive layer 2 is 30μm; the adhesive layer 2 is loaded into a coating machine by polypropylene hot melt adhesive, and is coated on the substrate layer 1 with a thickness of 50μm respectively, and is dried by baking to obtain;

[0051] The raw material components and their weight parts of the polypropylene hot melt adhesive are as follows: maleic anhydride modified polypropylene resin 100 parts, styrene-maleic anhydride copolymer resin 15 parts, flame-retardant filler 30 parts, curing agent 2 parts, solvent 200 parts;

[0052] The maleic anhydride modified polypropylene resin is purchased from Japan Toyo Spinning, model PMA-KE, melting point 95℃, molecular weight 60000, acid value 21mgKOH / g, maleic anhydride content 1.8wt%;

[0053] Styrene-maleic anhydride copolymer resin was purchased from Polyscope in the Netherlands, model EF60, molar ratio of styrene to maleic anhydride 6:1, molecular weight Mn 5500, acid value 155 mgKOH / g, maleic anhydride content 13wt%, glass transition temperature Tg 105℃;

[0054] The flame-retardant filler is a phosphorus-based flame retardant, purchased from Clariant Chemicals, model OP935;

[0055] The curing agent is bisphenol A type epoxy resin, which is purchased from Nanya Plastic Industry, and the model is NPEL-134;

[0056] The solvent is toluene and ethyl acetate (volume ratio 1:1);

[0057] The preparation of the polypropylene hot melt adhesive specifically includes the following steps: mixing styrene-maleic anhydride copolymer resin, curing agent and solvent, using a high-speed disperser to disperse at a speed of 900 r / min for 15 min, then slowly adding the flame-retardant filler, continuing to disperse for 50 min after the addition is completed, finally slowly adding the maleic anhydride modified polypropylene resin, and continuing to disperse for 25 min to obtain the polypropylene hot melt adhesive.

[0058] Example 3

[0059] Referring to Figure 1 As shown in the figure, the busbar of the embodiment includes a substrate layer 1 and an adhesive layer 2 arranged on the substrate layer 1; wherein the substrate layer 1 is a polyimide film layer with a thickness of 50 μm; the thickness of the adhesive layer 2 is 30 μm; the adhesive layer 2 is loaded into a coating machine by polypropylene hot melt adhesive, and is coated on the substrate layer 1 with a thickness of 50 μm respectively, and is dried by baking to obtain;

[0060] The raw material components and their weight parts of the polypropylene hot melt adhesive are as follows: maleic anhydride modified polypropylene resin 100 parts, styrene-maleic anhydride copolymer resin 20 parts, flame-retardant filler 30 parts, curing agent 2 parts, and solvent 200 parts;

[0061] The maleic anhydride modified polypropylene resin is purchased from Japan Toyo Spinning, and the model is PMA-KE, the melting point is 95℃, the molecular weight is 60000, the acid value is 21 mgKOH / g, and the maleic anhydride content is 1.8wt%;

[0062] The styrene-maleic anhydride copolymer resin is purchased from the Netherlands Polyscope, and the model is EF60, the molar ratio of styrene to maleic anhydride is 6:1, the molecular weight Mn is 5500, the acid value is 155 mgKOH / g, the maleic anhydride content is 13wt%, and the glass transition temperature Tg is 105℃;

[0063] The flame-retardant filler is a phosphorus-based flame retardant, which is purchased from Clariant Chemicals, and the model is OP935;

[0064] The curing agent is bisphenol A type epoxy resin, which is purchased from Nanya Plastic Industry, and the model is NPEL-134;

[0065] The solvent is toluene and ethyl acetate (volume ratio 1:1);

[0066] The preparation of the polypropylene hot melt adhesive specifically includes the following steps: mixing styrene-maleic anhydride copolymer resin, curing agent and solvent, using a high-speed disperser to disperse at a speed of 900 r / min for 15 min, then slowly adding the flame-retardant filler, continuing to disperse for 50 min after the addition is completed, finally slowly adding the maleic anhydride modified polypropylene resin, and continuing to disperse for 25 min to obtain the polypropylene hot melt adhesive.

[0067] Example 4

[0068] Referring to Figure 1 The insulating adhesive film for the busbar of the embodiment includes a substrate layer 1 and an adhesive layer 2 arranged on the substrate layer 1; the substrate layer 1 is a polyimide film layer with a thickness of 50 μm; the adhesive layer 2 has a thickness of 30 μm; the adhesive layer 2 is loaded into a coating machine by polypropylene hot melt adhesive, and is coated on the substrate layer 1 with a thickness of 50 μm, respectively, and is dried by baking to obtain;

[0069] The raw material components of the polypropylene hot melt adhesive and the weight parts thereof are as follows: maleic anhydride modified polypropylene resin 100 parts, styrene-maleic anhydride copolymer resin 10 parts, flame-retardant filler 30 parts, curing agent 5 parts, and solvent 200 parts.

[0070] The maleic anhydride modified polypropylene resin is purchased from Japan Toyo Spinning, with a model number of PMA-KE, a melting point of 95℃, a molecular weight of 60000, an acid value of 21 mgKOH / g, and a maleic anhydride content of 1.8 wt%;

[0071] The styrene-maleic anhydride copolymer resin is purchased from Polyscope in the Netherlands, with a model number of EF60, a molar ratio of styrene to maleic anhydride of 6:1, a molecular weight Mn of 5500, an acid value of 155 mgKOH / g, a maleic anhydride content of 13 wt%, and a glass transition temperature Tg of 105℃;

[0072] The flame-retardant filler is a phosphorus-based flame retardant, purchased from Clariant Chemicals, with a model number of OP935;

[0073] The curing agent is a bisphenol A type epoxy resin, purchased from Nanya Plastic Industry, with a model number of NPEL-134;

[0074] The solvent is toluene and ethyl acetate (volume ratio 1:1);

[0075] The preparation of the polypropylene hot melt adhesive specifically includes the following steps: mixing styrene-maleic anhydride copolymer resin, curing agent and solvent, using a high-speed disperser to disperse at a speed of 900 r / min for 15 min, then slowly adding the flame-retardant filler, continuing to disperse for 50 min after the addition is completed, finally slowly adding the maleic anhydride modified polypropylene resin, and continuing to disperse for 25 min to obtain the polypropylene hot melt adhesive.

[0076] Example 5

[0077] Referring to Figure 1 As shown in the drawing, the busbar insulating adhesive film of the present embodiment comprises a substrate layer 1 and an adhesive layer 2 arranged on the substrate layer 1; wherein the substrate layer 1 is a polyimide film layer with a thickness of 50 μm; the thickness of the adhesive layer 2 is 30 μm; the adhesive layer 2 is prepared by coating polypropylene hot melt adhesive on the substrate layer 1 with a thickness of 50 μm in a coating machine and then drying to obtain a surface dryness.

[0078] The raw material components of the polypropylene hot melt adhesive and their weight parts are as follows: maleic anhydride modified polypropylene resin 100 parts, styrene-maleic anhydride copolymer resin 10 parts, flame retardant filler 30 parts, curing agent 5 parts, solvent 200 parts.

[0079] The maleic anhydride modified polypropylene resin is purchased from Japan Toyo Spinning, with a model number of PMA-KE, a melting point of 95℃, a molecular weight of 60000, an acid value of 21 mgKOH / g, and a maleic anhydride content of 1.8 wt%.

[0080] The styrene-maleic anhydride copolymer resin is purchased from Polyscope in the Netherlands, with a model number of EF60, a molar ratio of styrene to maleic anhydride of 6:1, a molecular weight Mn of 5500, an acid value of 155 mgKOH / g, a maleic anhydride content of 13 wt%, and a glass transition temperature Tg of 105℃;

[0081] The flame retardant filler is a phosphorus-based flame retardant, purchased from Clariant Chemicals, with a model number of OP935;

[0082] The curing agent is a bisphenol A type epoxy resin, purchased from Nanya Plastic Industry, with a model number of NPEL-134;

[0083] The solvent is toluene and ethyl acetate (volume ratio 1:1);

[0084] The preparation of the polypropylene hot melt adhesive specifically comprises the following steps: mixing the styrene-maleic anhydride copolymer resin, the curing agent and the solvent, using a high-speed disperser to disperse at a speed of 900 r / min for 15 min, then slowly adding the flame retardant filler, continuing to disperse for 50 min after the addition is completed, and finally slowly adding the maleic anhydride modified polypropylene resin, continuing to disperse for 25 min to obtain the polypropylene hot melt adhesive.

[0085] Example 6

[0086] Referring to Figure 1As shown, the insulating adhesive film for busbar of the embodiment includes a base material layer 1 and an adhesive layer 2 arranged on the base material layer 1; wherein the base material layer 1 is a polyimide film layer with a thickness of 50 μm; the thickness of the adhesive layer 2 is 30 μm; the adhesive layer 2 is filled into a coating machine by polypropylene hot melt adhesive, and is coated on the base material layer 1 with a thickness of 50 μm respectively, and is dried by baking to obtain;

[0087] The raw material components of the polypropylene hot melt adhesive and the weight parts thereof are as follows: maleic anhydride modified polypropylene resin 100 parts, styrene-maleic anhydride copolymer resin 20 parts, flame retardant filler 30 parts, curing agent 5 parts, solvent 200 parts;

[0088] The maleic anhydride modified polypropylene resin is purchased from Japan Toyo Spinning, the model number is PMA-KE, the melting point is 95℃, the molecular weight is 60000, the acid value is 21 mgKOH / g, and the maleic anhydride content is 1.8wt%;

[0089] The styrene-maleic anhydride copolymer resin is purchased from Polyscope in the Netherlands, the model number is EF60, the molar ratio of styrene to maleic anhydride is 6:1, the molecular weight Mn is 5500, the acid value is 155 mgKOH / g, the maleic anhydride content is 13wt%, and the glass transition temperature Tg is 105℃;

[0090] The flame retardant filler is a phosphorus-based flame retardant, which is purchased from Clariant Chemicals, and the model number is OP935;

[0091] The curing agent is a bisphenol A type epoxy resin, which is purchased from Nanya Plastic Industry, and the model number is NPEL-134;

[0092] The solvent is toluene and ethyl acetate (volume ratio 1:1);

[0093] The preparation of the polypropylene hot melt adhesive specifically includes the following steps: the styrene-maleic anhydride copolymer resin, the curing agent and the solvent are mixed, after high-speed dispersion for 15 min at a speed of 900 r / min by using a high-speed disperser, the flame retardant filler is slowly added, and after the addition is completed, the dispersion is continued for 50 min, and finally the maleic anhydride modified polypropylene resin is slowly added, and the dispersion is continued for 25 min to obtain the polypropylene hot melt adhesive.

[0094] Comparative Example 1

[0095] The same as Example 1, except that the styrene-maleic anhydride copolymer resin is not added.

[0096] Comparative Example 2

[0097] The same as Example 1, except that the amount of the styrene-maleic anhydride copolymer resin is replaced by 30 parts.

[0098] Comparative Example 3

[0099] The same as example 1, except that the styrene-maleic anhydride copolymer resin is replaced by styrene-maleic anhydride copolymer resin EF10 purchased from Polyscope, the Netherlands, the molar ratio of styrene to maleic anhydride in EF10 is 1:1, the molecular weight Mn is 5000, the acid value is 480 mgKOH / g, the maleic anhydride content is 42 wt%, and the glass transition temperature Tg is 155°C.

[0100] Comparative Example 4

[0101] The same as example 1, except that the styrene-maleic anhydride copolymer resin is replaced by styrene-maleic anhydride copolymer resin EF30 purchased from Polyscope, the Netherlands, the molar ratio of styrene to maleic anhydride in EF30 is 3:1, the molecular weight Mn is 9500, the acid value is 280 mgKOH / g, the maleic anhydride content is 23 wt%, and the glass transition temperature Tg is 125°C.

[0102] Comparative Example 5

[0103] The same as example 1, except that the amount of flame-retardant filler is replaced by 10 parts.

[0104] Performance test

[0105] The hot melt adhesive films of examples 1-6 and comparative examples 1-5 are tested, and the test methods of each test item are as follows:

[0106] Peeling strength (N / mm): the hot melt adhesive film is cut into 300 mm wide and 150 mm long, and the cut hot melt adhesive film is hot-pressed on an aluminum plate, the hot-pressing temperature is 120-140°C, the hot-pressing time is 40s-180s, the pressure is 0.7Mpa-2Mpa, and the cooling is tested to room temperature; the peeling direction is 180°, and the rate is 100mm / min;

[0107] Shear strength (Mpa): the product with hot-pressed aluminum plate is cut into 25mm x 100mm sample, the same size of blank aluminum plate is used to coat high-strength structural adhesive with a lap area of 25mm x 12.5mm, and the structural adhesive is cured and crosslinked by using 80°C baking for 8H, and after complete curing, the sample is cooled to room temperature and placed for 24H before testing; the tensile direction is 180°, the tensile rate is 4mm / min, and the shear strength = test maximum force / actual bonding area;

[0108] Flame retardant performance: tested according to UL94V-0 flame retardant test standard;

[0109] High temperature and high humidity aging test: the same as 1, 2, the sample is placed in a high temperature and high humidity environment box for 1000H, the test conditions are: 85°C / 85%RH / 1000H; take out and cool to room temperature, test the peeling strength and shear strength;

[0110] Cold and hot shock aging test: the sample preparation method is the same as 1 and 2, and the sample is placed in a cold and hot shock environment box for 1000H. The test conditions are: constant temperature at-40℃ for 0.5H, constant temperature at 85℃ for 0.5H, and cold and hot switching time within 2mins. After 1000 cycles, it is taken out and cooled to room temperature, and the peel strength and shear strength are tested;

[0111] High temperature aging test: the sample preparation method is the same as 1 and 2, and the sample is placed in a 125℃ high temperature oven for 1000H. After aging for 1000H, it is taken out and cooled to room temperature, and the peel strength and shear strength are tested.

[0112] Table 1

[0113]

[0114]

[0115] As can be seen from Table 1, the peel strength of the multifunctional hot melt adhesive film prepared from the polypropylene hot melt adhesive of Examples 1-6 is 2.1N / mm-2.3N / mm, the shear strength is 12Mpa-15Mpa, the flame retardant grade is V-0; and the high temperature and high humidity, cold and hot shock and high temperature aging performance are excellent.

[0116] Compared with Example 1, no styrene and maleic anhydride copolymer is added in Comparative Example 1, and the bonding performance of the hot melt adhesive is very poor, which does not meet the use.

[0117] Compared with Example 1, the amount of styrene and maleic anhydride copolymer EF60 used in Comparative Example 2 is 30 parts, which is a relatively large amount. Although the bonding performance is excellent, the addition of excessive amount of maleic anhydride groups leads to a decrease in the high temperature and high humidity resistance of the hot melt adhesive.

[0118] Compared with Example 1, the molar ratio of styrene to maleic anhydride in the styrene and maleic anhydride copolymer EF10 used in Comparative Example 3 is 1:1, the maleic anhydride content in the resin is higher, and the molecular weight is smaller. After addition, the high temperature and high humidity resistance and high temperature performance of the hot melt adhesive are decreased.

[0119] Compared with Example 1, the molar ratio of styrene to maleic anhydride in the styrene and maleic anhydride copolymer EF10 used in Comparative Example 4 is 3:1, and the molecular weight is not high. The resin acid value is relatively high, which easily leads to a decrease in the high temperature and high humidity resistance and high temperature performance of the hot melt adhesive. The hot melt adhesive is easily delaminated from the substrate, which cannot meet the use.

[0120] Compared with Example 1, the amount of flame retardant OP935 used in Comparative Example 5 is 10 parts, and the amount of flame retardant filler is less. When the combustion test is carried out, the hot melt adhesive is easy to drip and ignite the degreasing cotton, and the flame retardant effect of the hot melt adhesive film is poor.

[0121] Obviously, the above-mentioned embodiments are only examples for clearly illustrating the present application, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A polypropylene hot melt adhesive, characterized in that, The polypropylene hot melt adhesive comprises maleic anhydride modified polypropylene resin 100 parts, styrene-maleic anhydride copolymer resin 10-20 parts, flame retardant filler 20-40 parts, curing agent 2-5 parts, and solvent 150-200 parts by weight; the styrene-maleic anhydride copolymer resin has a molecular weight Mn of 4000-10000, an acid value of 110 mgKOH / g-220 mgKOH / g, a maleic anhydride content of 5wt%-20wt%, and a glass transition temperature Tg of 100°C-120°C.

2. The polypropylene hot melt adhesive according to claim 1, characterized in that, The styrene-maleic anhydride copolymer resin is composed of styrene and maleic anhydride in a molar ratio of (6-8):

1.

3. The polypropylene hot melt adhesive according to claim 1, characterized in that, The maleic anhydride modified polypropylene resin has a molecular weight Mw of 50000-70000, an acid value of 15 mgKOH / g-25 mgKOH / g, a maleic anhydride content of 1wt%-2wt%, and a melting point of 70°C-100°C.

4. The polypropylene hot melt adhesive of claim 1, wherein, The flame retardant filler is selected from one or more of phosphorus-based flame retardant, nitrogen-based flame retardant, silicon-based flame retardant, metal hydroxide-based flame retardant, metal oxide flame retardant, and metal boride flame retardant.

5. The polypropylene hot melt adhesive of claim 1, wherein The curing agent is selected from one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and dicyclopentadiene phenol type epoxy resin.

6. The polypropylene hot melt adhesive of claim 1, wherein, The solvent is selected from one or more of xylene, dichloromethane, cyclohexane, butanone, and ethyl acetate.

7. The process for the preparation of a polypropylene hot-melt adhesive according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: The styrene-maleic anhydride copolymer resin, the curing agent, and the solvent are uniformly dispersed, then the flame retardant filler is added and stirred uniformly, finally the maleic anhydride modified polypropylene resin is added and mixed uniformly to obtain the polypropylene hot melt adhesive.

8. A multi-functional hot melt adhesive film, characterized by, The multifunctional hot melt adhesive film comprises a substrate layer and an adhesive layer arranged on the substrate layer; the adhesive layer is prepared from the polypropylene hot melt adhesive according to any one of claims 1-6.

9. The multi-functional hot melt adhesive film according to claim 8, wherein The substrate layer is selected from polypropylene film layer, polyethylene terephthalate film layer, polyimide film layer, polycarbonate film layer, or polyamide film layer.

10. The multi-functional hot-melt adhesive film according to claim 8, wherein The thickness of the substrate layer is 25μm-125μm, and the thickness of the adhesive layer is 20μm-50μm.

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