Thermosetting foam-type adhesive composition, magnetic pad comprising same, and wireless charging device comprising same

Abstract

The present invention provides a thermosetting foam-type adhesive composition, which may include a main polymer resin and a blowing agent, the foaming temperature of the thermosetting foam-type adhesive composition being 70 DEG C to 110 DEG C, the foaming rate being 50% to 400%, and the viscosity being 3000 cP to 100000 cP. Magnetic mats may include such thermoset foam adhesive compositions. A wireless charging device may include such a magnetic pad.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0153507, filed with the Korean Intellectual Property Office on November 1, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to a thermosetting foam adhesive composition, a magnetic pad comprising the composition, and a wireless charging device comprising the magnetic pad. Background Technology

[0004] In recent years, due to the expanding supply of electric vehicles, there has been a growing interest in wireless charging technology, which allows batteries to be charged freely without wired chargers. Wireless charging technology essentially consists of a transmitter that transmits power and a receiver that receives the transmitted power, both constructed from coils and magnetic materials. The magnetic material used in this paper is one of the key components determining the efficiency of wireless charging and is placed in the form of a pad within the wireless charging device. These magnetic pads primarily utilize ferrite tiles; however, due to the impact-sensitive nature of ceramic tiles, ferrite tiles are very brittle and difficult to fabricate into three-dimensional shapes. Specifically, in the case of the receiver (vehicle) in a wireless charging system for electric vehicles, ferrite tiles are easily damaged by vibration and external impacts during operation. To overcome this drawback, efforts are being made to manufacture ferrite magnetic materials resistant to external impacts. Specifically, flexible materials that can replace brittle ferrite tiles are being researched, and adhesives optimized for these materials are also being actively studied. Summary of the Invention

[0005] This invention relates to a thermosetting foam adhesive composition, a magnetic pad comprising the composition, and a wireless charging device comprising the magnetic pad. More specifically, it relates to a thermosetting foam adhesive composition comprising a main polymer resin and a foaming agent, having thermosetting and foaming properties, a magnetic pad comprising the composition, and a wireless charging device comprising the magnetic pad.

[0006] The embodiments of the present invention can solve the above-mentioned problems existing in the related art, and the embodiments of the present invention can provide a thermosetting foam adhesive composition, a magnetic pad including the composition, and a wireless charging device including the magnetic pad. The composition includes a polymer resin and a foaming agent, which expand in volume and simultaneously cure when exposed to heat, thereby exhibiting excellent impact resistance and mechanical properties.

[0007] An embodiment of the present invention can provide a thermosetting foam adhesive composition comprising a main polymer resin and a foaming agent, wherein the foaming temperature of the thermosetting foam adhesive composition is 70°C to 110°C, the foaming rate is 50% to 400%, and the viscosity is 3000 cP to 100000 cP.

[0008] An embodiment of the present invention may provide a magnetic pad comprising 65 to 95 parts by weight of magnetic material particles, 10 to 25 parts by weight of magnetic material powder, and 1.5 to 7 parts by weight of a thermosetting foam composition according to different embodiments of the present invention.

[0009] An embodiment of the present invention can provide a wireless charging device, the wireless charging device including a magnetic pad according to an embodiment of the present invention.

[0010] According to embodiments of the present invention, volume expansion and curing reactions may occur in the magnetic pad containing the adhesive composition during molding by pressure or heat. Therefore, using embodiments of the present invention ensures excellent appearance, mechanical strength, and impact resistance.

[0011] The magnetic pad according to the embodiments of the present invention can have excellent electromagnetic properties and can resist external impacts.

[0012] The adhesive compositions according to embodiments of the present invention can exhibit excellent moldability when mixed with ferrite particles or powders, thereby improving processability. Therefore, magnetic pads comprising such adhesive compositions according to embodiments of the present invention can also offer a high degree of design freedom. Attached Figure Description

[0013] The above and other features and advantages of the exemplary embodiments of the present invention will become apparent from the detailed description of the exemplary embodiments in conjunction with the accompanying drawings, wherein:

[0014] Figure 1 Images of the appearance of the present invention as observed with the naked eye in Examples 5-2 and Comparative Examples 3-2, which are exemplary embodiments of the present invention;

[0015] Figure 2 Images of the appearance of the present invention as observed with the naked eye in Examples 1-2 and Comparative Examples 4-2, which are exemplary embodiments of the present invention.

[0016] Figure 3 A graph showing the density and permeability of an embodiment and a comparative example of an exemplary embodiment of the present invention is provided. Detailed Implementation

[0017] Unless otherwise defined, the terms used herein (including technical or scientific terms) may have the same meaning as commonly understood by those skilled in the art. Terms as defined in a general dictionary may be interpreted as having a meaning that matches their meaning in the relevant technical context.

[0018] As used herein, terms such as "first" and "second" can be used to describe various components, but components are not necessarily limited by these terms. These terms may be used only to distinguish one component from another. For example, without departing from the scope of the invention, a first component may be named a second component, and similarly, a second component may be named a first component.

[0019] The terminology used herein may be used only to describe particular embodiments and is not intended to necessarily limit the invention. Singular expressions may include plural expressions unless the context otherwise defines them. In this invention, it is understood that the terms "including," "having," or "comprising" indicate the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0020] The thermosetting foam adhesive composition of the present invention may include a main polymer resin and a foaming agent.

[0021] In one embodiment of the present invention, the main polymer resin may include at least one selected from the group consisting of silicone resin, polyurethane resin, epoxy resin, polyester resin and acrylic resin.

[0022] In various embodiments of the present invention, the main polymer resin may be a two-component polymer resin. In one example, the main polymer resin may be a two-component polymer resin comprising a first component (containing vinyl dimethyl polysiloxane) and a second component (containing organohydrogen polysiloxane).

[0023] The first component may also contain dimethylpolysiloxane.

[0024] The first component may contain 25 to 35 parts by weight of vinyl dimethyl polysiloxane and 1 to 10 parts by weight of dimethyl polysiloxane.

[0025] The second component may also contain vinyl dimethyl polysiloxane.

[0026] The second component may include 20 to 30 parts by weight of vinyl dimethyl polysiloxane and 5 to 15 parts by weight of organohydrogen polysiloxane.

[0027] In one embodiment of the invention, the first component and the second component can be mixed or stirred and molded under hot pressing conditions. During such mixing or stirring, the polysiloxane (polymer) contained in the first component and the polysiloxane (polymer) contained in the second component can react with each other and cure. Therefore, the two-component polymer resin containing the first component and the second component, as well as the adhesive containing the two-component polymer resin, can be thermosetting.

[0028] As described above, the thermosetting foam adhesive composition of the embodiments of the present invention may include a foaming agent. During the manufacture of the magnetic pad, even with a low adhesive content, the foaming agent can improve the appearance and mechanical properties by filling the pores of the ferrite magnetic particles and ferrite magnetic powder through foaming.

[0029] The content of the foaming agent can be from 1 part by weight to 10 parts by weight or from 3 parts by weight to 7 parts by weight.

[0030] If the content is below this range, it may not foam properly even when exposed to heat.

[0031] If the content is higher than this range, dimensional accuracy may be reduced during the molding process due to excessive foaming.

[0032] The foaming agent may include at least one selected from the group consisting of azo-based foaming agents, hydrazide-based foaming agents, inorganic-based foaming agents, and microencapsulated-based foaming agents.

[0033] In one example, the blowing agent may be a capsule-type blowing agent with a particle size of 10 μm to 30 μm. The thermosetting foam adhesive composition according to embodiments of the invention may include a blowing agent that can achieve volume expansion through foaming when exposed to heat. In this way, mechanical properties can be improved and moldability can become excellent.

[0034] The mixing weight ratio of the main polymer resin to the foaming agent can be from 80:1 to 10:1. Preferably, in one embodiment, the mixing weight ratio can be from 45:1 to 15:1. More preferably, in one embodiment, the mixing weight ratio can be from 35:1 to 15:1.

[0035] When the mixing weight ratio is less than 80:1, the foaming rate may be low, which will degrade the appearance and mechanical strength of the magnetic pad.

[0036] When the mixing weight ratio is higher than 10:1, the dimensional accuracy of the molded parts may deteriorate due to excessive foaming.

[0037] The foaming temperature of the thermosetting foam adhesive composition according to various embodiments of the present invention can be from 70°C to 110°C. The foaming temperature of the thermosetting foam adhesive composition can be determined by the foaming temperature of the foaming agent and is almost unaffected by other components contained in the adhesive.

[0038] When the foaming temperature is below the range of 70°C to 110°C, the formability and storage properties may deteriorate during the manufacture of the magnetic pad according to an embodiment of the present invention due to early foaming during the hot pressing process.

[0039] When the foaming temperature is above the range of 70°C to 110°C, the foaming effect may be minimal during the hot pressing process when manufacturing the magnetic pad according to an embodiment of the present invention.

[0040] The foaming rate of the thermosetting foam adhesive composition according to various embodiments of the present invention can be from 50% to 400%. In one embodiment of the present invention, the foaming rate can refer to the volume increase rate when 10g of adhesive is injected into an aluminum cup and exposed at 175°C for 10 minutes.

[0041] When manufacturing a magnetic pad according to an embodiment of the present invention, when the foaming rate is less than the range of 50% to 400%, the foaming effect may be reduced and the moldability and appearance may be deteriorated.

[0042] When manufacturing a magnetic pad according to an embodiment of the present invention, when the foaming rate is higher than the range of 50% to 400%, the density may decrease, and the dimensional stability may deteriorate due to over-foaming.

[0043] The viscosity of the thermosetting foam adhesive composition according to various embodiments of the present invention can be from 3000 cP to 100000 cP.

[0044] When manufacturing a magnetic pad according to an embodiment of the present invention, when the viscosity is below this range, the mixing stability of the adhesive, magnetic material particles and powder may deteriorate, resulting in adhesive deposition.

[0045] When manufacturing a magnetic pad according to an embodiment of the present invention, the uniformity of mixing of the adhesive, magnetic material particles and powder may deteriorate when the viscosity is higher than this range.

[0046] The thermosetting foam adhesive composition according to embodiments of the present invention may further include additives. Additives may include (curing) catalysts, curing retardants, silane coupling agents, inorganic fillers, lubricants, etc. However, additives are not limited to these; any additives available in the art that can be used to improve the performance of the thermosetting foam adhesive composition may be used.

[0047] In one embodiment of the invention, the (cured) catalyst may comprise platinum (Pt). In one example, the catalyst may be included in the first component. In one embodiment, the catalyst content may be from 0.001 parts by weight to 0.1 parts by weight.

[0048] In one embodiment of the invention, the curing inhibitor may be a compound containing aliphatic unsaturated bonds. For example, the compound containing aliphatic unsaturated bonds may include one or more substances selected from the group consisting of 1-ethynyl-1-cyclohexanol, 3-methyl-1-penten-3-ol, 2-methyl-3-butyn-2-ol, 3-phenyl-3-butyn-2-ol, 2-phenyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 1,5-hexadiyne, 1,6-heptadiyne, 3,5-dimethyl-1-hexyne, 2-ethyl-3-butyne, 2-phenyl-3-butyne, 1,3-divinyltetramethyldisiloxane, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane, and 1,3-divinyl-1,3-diphenyldimethyldisiloxane.

[0049] In one embodiment of the invention, the curing retardant may be 1-ethynylcyclohexanol (ECH). However, the curing retardant is not limited to this, and any curing retardant used in the art may be used. The curing retardant can improve storage stability or regulate the reactivity of the hydrosilylation reaction in the curing process.

[0050] In one example, a curing inhibitor may be included in the second component. The content of the curing inhibitor may be from 0.01 parts by weight to 1 part by weight.

[0051] In one embodiment of the invention, the silane coupling agent may be at least one selected from the group consisting of, for example, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, γ-epoxypropoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-epoxypropoxypropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, and methyltriacetoxysilane. However, the silane coupling agent is not limited thereto, and any silane coupling agent available in the art may be used. Preferably, in one embodiment, the silane coupling agent may be an epoxysilane or an amino-based silane.

[0052] Silane coupling agents can possess reactive groups in their molecules that can bind to organic functional groups and reactive groups that can bind to inorganic substances. Therefore, they can improve the adhesion between different materials. They can also improve associated mechanical strength, water resistance, weather resistance, heat resistance, etc. In one embodiment of the invention, the silane coupling agent can improve the interfacial adhesion between thermosetting foam adhesives and ferrite fillers (powder or granules).

[0053] In one embodiment of the present invention, the silane coupling agent may be included in the first component or the second component.

[0054] The inorganic filler according to one embodiment of the present invention may include at least one selected from the group consisting of talc, clay, calcium carbonate, mica, whiskers, silica fume, carbon fiber, barium sulfate, and wollastonite. The inorganic filler can impart excellent filling properties, elongation, heat resistance, cold resistance, and weather resistance. The inorganic filler can effectively repair cracks caused by various factors and improve refractory properties by increasing the flash point.

[0055] In one embodiment of the present invention, the inorganic filler may be silica fume (or fumed silica). However, the inorganic filler is not limited to this, and any inorganic filler that can be used in the art may be used.

[0056] In one example, the inorganic filler may be included in both the first and second components. In this case, the content of the inorganic filler in the first component may be from 5 parts by weight to 17 parts by weight. The content of the inorganic filler in the second component may be from 5 parts by weight to 15 parts by weight.

[0057] In one embodiment of the invention, the lubricant may include any one selected from, for example, the group consisting of: fatty acid-based lubricants (e.g., stearic acid, hydroxystearic acid, complex stearic acid, and oleic acid); fatty alcohol-based lubricants; fatty amide-based lubricants (e.g., stearamide, oxystearic amide, oleamide, elsyl amide, ricinol amide, behenamide, hydroxymethyl amide, methylene bis-stearbehenamide, methylene bis-stearbehenamide, bisamic acid of higher fatty acids, and complex amides); aliphatic ester-based lubricants (e.g., n-butyl stearate, methyl hydroxystearate, polyol fatty acid esters, saturated fatty acid esters, and ester waxes); fatty acid metal soap-based lubricants, and combinations thereof. Thermosetting foam adhesive compositions according to embodiments of the invention may include lubricants to reduce friction between particles, thereby improving density and preventing internal stress.

[0058] In one embodiment of the invention, the lubricant may be contained in a first component or a second component.

[0059] The magnetic pads of embodiments of the present invention may include magnetic material particles, magnetic material powders, and thermosetting foam compositions according to various embodiments of the present invention.

[0060] In one example, a magnetic pad can be manufactured by mixing magnetic material particles, magnetic material powder, and a thermosetting foam-type composition according to various embodiments of the invention to prepare a paste, and then hot-pressing the paste.

[0061] By hot pressing, the magnetic pad undergoes volume expansion and thermosetting, resulting in excellent impact resistance and formability.

[0062] The magnetic material particles can be MnZn ferrite particles. In one example, the magnetic material particles can be spherical MnZn ferrite particles with a diameter of 2 mm to 5 mm.

[0063] The magnetic pad of this invention may comprise 65 to 95 parts by weight of magnetic material particles. Preferably, in one embodiment, the content of magnetic material particles may be 70 to 80 parts by weight. When the content of magnetic material particles is less than 65 parts by weight, the magnetism of the magnetic pad may deteriorate. When the content of magnetic material particles is greater than 95 parts by weight, the formability of the magnetic pad may deteriorate. Therefore, the above ranges may be preferred for the embodiments.

[0064] The magnetic material powder can be MnZn ferrite powder. In one example, the magnetic material powder can be MnZn ferrite powder with a diameter of 75 μm to 85 μm.

[0065] The magnetic pad of this invention may comprise 10 to 25 parts by weight of magnetic material powder. Preferably, in one embodiment, the content of magnetic material powder may be 15 to 21 parts by weight. When the content of magnetic material powder is less than 10 parts by weight, the formability of the magnetic pad may deteriorate. When the content of magnetic material powder is greater than 25 parts by weight, the magnetism of the magnetic pad may deteriorate. Therefore, the above ranges may be preferred for the embodiments.

[0066] The magnetic pad of the present invention may comprise 1.5 to 7 parts by weight of the thermosetting foam composition described above according to various embodiments of the present invention. Preferably, in one embodiment, the content of the thermosetting foam composition may be 2 to 5 parts by weight. When the content of the thermosetting foam composition is less than 1.5 parts by weight, the moldability of the magnetic pad may deteriorate. When the content of the thermosetting foam composition is greater than 7 parts by weight, the magnetism of the magnetic pad may deteriorate. Therefore, the above ranges may be preferred for the embodiments.

[0067] Since the thermosetting foam composition can be the same as the thermosetting foam composition according to the above embodiments, its description will be omitted.

[0068] The wireless charging device according to embodiments of the present invention may include the magnetic pad described above according to various embodiments of the present invention. In one example, the wireless charging device may be a wireless charging device for electric vehicles.

[0069] The present invention will now be described in detail with reference to embodiments. However, the following embodiments and experimental examples are intended to describe the present invention in more detail, and the scope of the present invention is not limited to the following embodiments and experimental examples.

[0070] Example 1

[0071] Example 1-1

[0072] To manufacture a two-component thermosetting foam adhesive, a first component and a second component were prepared. The first component was prepared by mixing 31.3 parts by weight of vinyl dimethyl polysiloxane (viscosity 7000 cP), 4.9 parts by weight of dimethyl polysiloxane (viscosity 6000 cP), 12.2 parts by weight of fumed silica, and 0.039 parts by weight of platinum (Pt 1%) catalyst.

[0073] The second component was prepared by mixing 24.3 parts by weight of vinyl dimethyl polysiloxane (viscosity 7000 cP), 10.7 parts by weight of organohydrogen polysiloxane (viscosity 5000 cP), 10.3 parts by weight of fumed silica and 0.029 parts by weight of curing inhibitor (ECH, 1-ethynyl-1-cyclohexanol).

[0074] The first and second components were mixed, and then 3.0 parts by weight of a capsule-type foaming agent (foaming temperature of 90°C and particle size of 15 μm) was added. The mixture was stirred and degassed to prepare the adhesive.

[0075] Examples 1-2

[0076] A magnetic pad comprising a thermosetting foam adhesive was prepared.

[0077] First, 76.2 g (3 mm diameter) of MnZn ferrite particles, 19.0 g (80 μm diameter) of MnZn ferrite powder, and 4.8 g of binder according to Example 1-1 were mixed in a horizontal rotary mixer for 1 hour to form a paste. The prepared paste was filled into a mold measuring 100 mm wide × 100 mm long × 5 mm high, and then pressed using a press preheated to 120 °C at a speed of 0.35 tons / cm². 2 Compress under pressure for 10 minutes to prepare a magnetic pad.

[0078] Example 2

[0079] Example 2-1

[0080] The adhesive was prepared in the same manner as in Examples 1-1, except that vinyl dimethyl polysiloxane (viscosity 4000 cP) and dimethyl polysiloxane (viscosity 3000 cP) were used as the first components, and vinyl dimethyl polysiloxane (viscosity 4000 cP) and organohydrogen polysiloxane (viscosity 2,500 cP) were used as the second components.

[0081] Example 2-2

[0082] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Example 2-1 was used.

[0083] Example 3

[0084] Example 3-1

[0085] The adhesive was prepared in the same manner as in Examples 1-1, except that vinyl dimethyl polysiloxane (viscosity 30000 cP) and dimethyl polysiloxane (viscosity 25000 cP) were used as the first components, and vinyl dimethyl polysiloxane (viscosity 30000 cP) and organohydrogen polysiloxane (viscosity 20000 cP) were used as the second components.

[0086] Example 3-2

[0087] The magnetic pad was prepared in the same manner as in Examples 1-2, except that the adhesive according to Example 3-1 was used.

[0088] Example 4

[0089] Example 4-1

[0090] Except for mixing 1.5 parts by weight of the capsule-type foaming agent, the adhesive was prepared in the same manner as in Examples 1-1.

[0091] Example 4-2

[0092] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Example 4-1 was used.

[0093] Example 5

[0094] Example 5-1

[0095] Except for mixing 5.0 parts by weight of the capsule-type foaming agent, the adhesive was prepared in the same manner as in Examples 1-1.

[0096] Example 5-2

[0097] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Example 5-1 was used.

[0098] Example 6

[0099] Example 6-1

[0100] The adhesive was prepared in the same manner as in Examples 1-1, except that a capsule-type foaming agent with a foaming temperature of 75°C was used.

[0101] Example 6-2

[0102] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Example 6-1 was used.

[0103] Example 7

[0104] Example 7-1

[0105] The adhesive was prepared in the same manner as in Examples 1-1, except that a capsule-type foaming agent with a foaming temperature of 105°C was used.

[0106] Example 7-2

[0107] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Example 7-1 was used.

[0108] Comparative Example 1

[0109] Comparative Example 1-1

[0110] The adhesive was prepared in the same manner as in Examples 1-1, except that vinyl dimethyl polysiloxane (viscosity 1000 cP) and dimethyl polysiloxane (viscosity 800 cP) were used as the first components, and vinyl dimethyl polysiloxane (viscosity 1000 cP) and organohydrogen polysiloxane (viscosity 800 cP) were used as the second components.

[0111] Comparative Examples 1-2

[0112] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Comparative Example 1-1 was used.

[0113] Comparative Example 2

[0114] Comparative Example 2-1

[0115] The adhesive was prepared in the same manner as in Examples 1-1, except that vinyl dimethyl polysiloxane (viscosity 90000 cP) and dimethyl polysiloxane (viscosity 80000 cP) were used as the first components, and vinyl dimethyl polysiloxane (viscosity 90000 cP) and organohydrogen polysiloxane (viscosity 85000 cP) were used as the second components.

[0116] Comparative Example 2-2

[0117] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Comparative Example 2-1 was used.

[0118] Comparative Example 3

[0119] Comparative Example 3-1

[0120] The adhesive was prepared in the same manner as in Examples 1-1, except that no foaming agent was mixed in.

[0121] Comparative Example 3-2

[0122] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Comparative Example 3-1 was used.

[0123] Comparative Example 4

[0124] Comparative Example 4-1

[0125] Except for mixing 0.5 parts by weight of the capsule-type foaming agent, the adhesive was prepared in the same manner as in Examples 1-1.

[0126] Comparative Example 4-2

[0127] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Comparative Example 4-1 was used.

[0128] Comparative Example 5

[0129] Comparative Example 5-1

[0130] Except for mixing 10.0 parts by weight of the capsule-type foaming agent, the adhesive was prepared in the same manner as in Examples 1-1.

[0131] Comparative Example 5-2

[0132] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Comparative Example 5-1 was used.

[0133] Comparative Example 6

[0134] Comparative Example 6-1

[0135] The adhesive was prepared in the same manner as in Examples 1-1, except that a capsule-type foaming agent with a foaming temperature of 60°C was used.

[0136] Comparative Example 6-2

[0137] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Comparative Example 6-1 was used.

[0138] Comparative Example 7

[0139] Comparative Example 7-1

[0140] The adhesive was prepared in the same manner as in Examples 1-1, except that a capsule-type foaming agent with a foaming temperature of 125°C was used.

[0141] Comparative Example 7-2

[0142] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Comparative Example 7-1 was used.

[0143] Comparative Example 8

[0144] Comparative Example 8-1

[0145] Prepare standard product QS119F two-component type silicone foam with a foaming temperature of room temperature as the adhesive.

[0146] Comparative Example 8-2

[0147] The magnetic pads were prepared in the same manner as in Examples 1-2, except that the adhesive according to Comparative Example 8-1 was used.

[0148] The adhesive compositions of the above embodiments and comparative examples are summarized in Table 1 below.

[0149] [Table 1]

[0150]

[0151] Experimental Example 1

[0152] Measurement of adhesive properties

[0153] In Experiment 1, the properties (viscosity, foaming rate, foaming temperature, and working time) of the adhesives according to the Examples and Comparative Examples were measured and summarized in Table 2 below. Viscosity was measured using a Brookfield viscometer, and foaming rate was measured by measuring the volume increase rate by exposing 10g of adhesive to an aluminum cup at 175°C for 10 minutes. Working time refers to the point in time when processability deteriorates due to viscosity increase caused by the curing reaction at room temperature.

[0154] [Table 2]

[0155]

[0156] N / A indicates that no foaming agent was added / no foaming temperature was applied.

[0157] Referring to Table 2, it can be seen that the foaming temperatures of the adhesives in the examples are all between 70°C and 110°C, the foaming rates are all between 50% and 400%, and the viscosities are all between 3000 cP and 100000 cP. On the other hand, it can be seen that in the cases of Comparative Examples 1 and 2, the viscosity is outside the range; in the cases of Comparative Examples 3, 6 to 8, the foaming temperature is outside the range; and in the cases of Comparative Examples 3 to 7, the foaming rate is outside the range. Therefore, it can be inferred that, in the manufacture of magnetic pads, the adhesives of the examples are superior to the adhesives of the comparative examples in terms of moldability and magnetism.

[0158] Experiment Example 2

[0159] Mixability evaluation

[0160] In Experiment 2, the following experiments were conducted to measure and evaluate the mixability of the magnetic pads according to the Examples and Comparative Examples.

[0161] During the manufacture of the magnetic pads according to the examples and comparative examples, the mixing state of the paste prepared as an intermediate was visually observed. When observed, the miscibility was rated as 5 because the MnZn ferrite particles, powder, and binder were uniformly mixed; the miscibility was rated as 1 because the binder was not applied evenly, resulting in severe agglomeration between the MnZn ferrite particles and powder, or because the binder had poor stability. The results are shown in Table 3 below.

[0162] [Table 3]

[0163]

[0164] Referring to Table 3, in the case of the embodiments, it was observed that the MnZn ferrite particles, powder, and binder were uniformly mixed, and therefore the evaluation value was 4 or higher; while in the case of the comparative examples, the evaluation value was 1 to 4, and the uniformity was lower than that of the embodiments. Therefore, it can be inferred that the magnetic pads of the embodiments are superior in terms of mechanical properties.

[0165] Experimental Example 3

[0166] Measurement of mechanical strength and impact resistance

[0167] In Experiment 3, the mechanical strength, such as impact resistance, of the magnetic pads according to the Examples and Comparative Examples was evaluated. Magnetic pads of the Examples and Comparative Examples were prepared and then dropped three times from a height of 1.5 m to observe whether the magnetic pads broke or whether particles detached. When the magnetic pads broke or cracked, or when some particles detached from the corners, the appearance of the pads was evaluated as "poor"; when the appearance did not deform after the drops, the appearance of the pads was evaluated as "good". The results are shown in Table 4 below.

[0168] [Table 4]

[0169]

[0170] Referring to Table 4, after the drop test, due to reasons such as pad breakage, the appearance of all comparative example magnetic pads was rated as "poor," and particle detachment was observed in Comparative Examples 1-2 to 4-2 and Comparative Examples 7-2 to 8-2. On the other hand, it can be seen that no particle detachment, pad breakage, or cracks were observed in any of the magnetic pads of the embodiments; therefore, the appearance of all pads was rated as "good." It can be seen that the magnetic pads of the embodiments have superior impact resistance and better mechanical properties than the magnetic pads of the comparative examples.

[0171] Meanwhile, the molding state and detachment of the magnetic pads according to the embodiments and comparative examples were observed visually. The appearance of the magnetic pads of Example 5-2 and Comparative Example 3-2 were observed visually, and the results are shown below. Figure 1 The appearance of the magnetic pads of Examples 1-2 and Comparative Examples 4-2 was observed by the naked eye, and the results are shown below. Figure 2 .

[0172] refer to Figure 1 It can be confirmed that the surface of the magnetic pad in Comparative Example 3-2 is uneven. This may be because the magnetic pad in Comparative Example 3-2 does not contain a foaming agent, resulting in lower dimensional stability and poorer moldability.

[0173] refer to Figure 2As can be seen, the magnetic pad of Comparative Example 4-2 has a poorer appearance and the particles are falling off. This may be because Comparative Example 4-2 has a lower content of foaming agent, resulting in insufficient foaming performance.

[0174] Experiment Example 4

[0175] Density measurement

[0176] In Experiment 4, the density of the magnetic pads according to the Examples and Comparative Examples was measured. The density was calculated using the following Formula 1.

[0177] Formula 1: Density (%) = Magnetic pad weight / Magnetic pad volume × 100

[0178] The results are shown in Table 5 below.

[0179] [Table 5]

[0180]

[0181]

[0182] Referring to Table 5, it can be seen that the density of the magnetic pads in the comparative examples ranges from 3.45 to 3.82 g / cm³. 3 The density of the magnetic pad according to the embodiment is 3.78 to 3.90 g / cm³. 3 Therefore, it can be inferred that the magnetic pad of the embodiment has a high density, and thus has an advantage in terms of dimensional stability.

[0183] Experimental Example 5

[0184] Dimensional accuracy measurement

[0185] In Experiment 5, the dimensional accuracy of the magnetic pads according to the Examples and Comparative Examples was measured. Dimensional accuracy was evaluated by setting (actual sample volume / mold volume × 100 (%)). The actual volume of the sample was measured using a hydrometer to obtain the actual volume of the manufactured magnetic pad. The results are shown in Table 6 below.

[0186] [Table 6]

[0187]

[0188]

[0189] Referring to Table 6, it can be seen that the dimensional accuracy of the magnetic pads in the embodiments is all between 98% and 100%. On the other hand, the dimensional accuracy of the magnetic pads in the comparative examples is mostly between 91% and 95%, specifically confirming that the magnetic pads of Comparative Examples 8-2 have poor moldability. This further confirms that the magnetic pads in the embodiments have better moldability.

[0190] Experimental Example 6

[0191] Magnetic measurement

[0192] In Experiment 6, the permeability of the magnetic pads according to the Examples and Comparative Examples was measured. The magnetic pads of the Examples and Comparative Examples were processed into a toroidal shape with an outer diameter of 39 mm × an inner diameter of 17 mm × a height of 5 mm, and then 10 turns of Φ0.5 copper wire were wound around them to measure the inductance using an LCR meter, and the permeability was converted according to the following formula 2.

[0193] Formula 2:

[0194] (L: Inductance (μH), l: Mean free path (cm), N: Number of turns, A: Cross-sectional area (cm²) 2 ))

[0195] The results are shown in Table 7 below.

[0196] [Table 7]

[0197]

[0198]

[0199] Referring to Table 7, it can be seen that the magnetic permeability of the magnetic pads in the embodiments ranges from 53.9 to 58.3 μH / cm, while the magnetic permeability of the magnetic pads in the comparative examples ranges from 35.6 to 51.9 μH / cm. This demonstrates that the magnetic pads in the embodiments are superior to those in the comparative examples in terms of magnetic properties. Furthermore, a graph was plotted to observe the relationship between the densities of the embodiments and comparative examples measured in Experimental Example 4 and the magnetic permeability measured in Experimental Example 6, as shown below. Figure 3 As shown. From Figure 3 As can be seen, the embodiment has higher values ​​in terms of both density and magnetic permeability than the comparative example.

[0200] The present invention has been described above with reference to preferred embodiments. Those skilled in the art will understand that the invention can be practiced in modified forms without departing from its scope. Therefore, the disclosed embodiments should be considered illustratively rather than necessarily limitingly. The scope of the invention is described by the appended claims, and differences within their equivalents may be interpreted as included within the invention.

Claims

1. A thermosetting foam adhesive composition comprising: Main polymer resin; and foaming agent, The thermosetting foam adhesive composition has a foaming temperature of 70°C to 110°C, a foaming rate of 50% to 400%, and a viscosity of 3000 cP to 100000 cP.

2. The composition according to claim 1, wherein the main polymer resin and the foaming agent are mixed in a weight ratio ranging from 80:1 to 10:

1.

3. The composition according to claim 1, wherein the main polymer resin is a two-component polymer resin comprising: The first component contains vinyl dimethyl polysiloxane; The second component contains organohydrogen polysiloxane.

4. The composition of claim 3, wherein the first component further comprises dimethylpolysiloxane, and wherein the second component further comprises vinyldimethylpolysiloxane.

5. The composition according to claim 4, wherein the first component comprises: 25 to 35 parts by weight of vinyl dimethyl polysiloxane, and 1 to 10 parts by weight of dimethyl polysiloxane; and The second component comprises: 20 to 30 parts by weight of vinyl dimethyl polysiloxane and 5 to 15 parts by weight of organohydrogen polysiloxane.

6. The composition according to claim 1, wherein the foaming agent comprises at least one selected from the group consisting of azo-based foaming agents, hydrazide-based foaming agents, inorganic-based foaming agents, and microencapsulation-based foaming agents.

7. The composition according to claim 1, wherein the foaming agent is a capsule-type foaming agent with a particle size of 10 μm to 30 μm.

8. A magnetic pad comprising: 1.5 to 7 parts by weight of a thermosetting foam adhesive composition, said thermosetting foam adhesive composition comprising: Main polymer resin, and foaming agent, The thermosetting foam adhesive composition has a foaming temperature of 70°C to 110°C, a foaming rate of 50% to 400%, and a viscosity of 3000 cP to 100000 cP.

9. The magnetic pad according to claim 8, wherein the main polymer resin is a two-component polymer resin comprising: A first component comprising vinyl dimethyl polysiloxane, wherein the first component further comprises dimethyl polysiloxane, wherein the first component comprises: 25 to 35 parts by weight of vinyl dimethyl polysiloxane, and 1 to 10 parts by weight of dimethyl polysiloxane; and The second component comprises an organohydrogen polysiloxane, wherein the second component further comprises vinyl dimethyl polysiloxane, wherein the second component comprises: 20 to 30 parts by weight of vinyl dimethyl polysiloxane and 5 to 15 parts by weight of organohydrogen polysiloxane.

10. The magnetic pad according to claim 9, wherein the foaming agent comprises at least one selected from the group consisting of azo-based foaming agents, hydrazide-based foaming agents, inorganic-based foaming agents, and microencapsulation-based foaming agents. The foaming agent mentioned above is a capsule-type foaming agent with a particle size of 10 μm to 30 μm. The main polymer resin and the foaming agent are mixed in a weight ratio ranging from 80:1 to 10:

1.

11. A wireless charging device comprising the magnetic pad according to claim 8.

12. The wireless charging device according to claim 11, wherein the main polymer resin is a two-component polymer resin, comprising: A first component comprising vinyl dimethyl polysiloxane, wherein the first component further comprises dimethyl polysiloxane, wherein the first component comprises: 25 to 35 parts by weight of vinyl dimethyl polysiloxane, and 1 to 10 parts by weight of dimethyl polysiloxane; and The second component comprises an organohydrogen polysiloxane, wherein the second component further comprises vinyl dimethyl polysiloxane, wherein the second component comprises: 20 to 30 parts by weight of vinyl dimethyl polysiloxane and 5 to 15 parts by weight of organohydrogen polysiloxane.

13. The wireless charging device according to claim 12, wherein the foaming agent comprises at least one selected from the group consisting of azo-based foaming agents, hydrazide-based foaming agents, inorganic-based foaming agents, and microencapsulation-based foaming agents. The foaming agent mentioned above is a capsule-type foaming agent with a particle size of 10 μm to 30 μm. The main polymer resin and the foaming agent are mixed in a weight ratio of 80:1 to 10:1.

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