Soft magnetic material-containing photocurable resin and method for forming the soft magnetic material-containing photocurable resin on a substrate.

Abstract

The ratio of soft magnetic material to be mixed into the adhesive (resin) and the amount to be dispensed onto the substrate are not clearly defined. If the amount is too low, the magnetic attraction will be weak; if the amount is too high, the viscosity of the adhesive after mixing will increase, worsening the dispenseability onto the substrate and reducing the elasticity after curing. [Solution] The range of the ratio of soft magnetic material powder (e.g., iron) to be mixed into the adhesive is defined. By defining the ratio, sufficient attraction to a magnet can be achieved, and a decrease in the elasticity of the adhesive after curing can be prevented. Furthermore, when dispensing the adhesive, which is made of a photocurable resin mixed with soft magnetic material, onto a substrate, the dispensing window is moved away from the substrate after a portion of the adhesive attached to the substrate has been cured, thereby preventing the dispensing shape of the adhesive from collapsing. This provides a method for forming a photocurable resin containing soft magnetic material onto a substrate, which allows for appropriate control of the dispensing amount based on an inspection of the distance between the dispensed resins.

Description

[Technical Field]

[0001] The present invention relates to a photocurable resin containing a soft magnetic material and a method for forming the photocurable resin containing a soft magnetic material onto a substrate. [Background technology]

[0002] Automotive seat cushions are generally manufactured by mold molding, where polyurethane raw materials are injected into a mold and foamed within the mold. A surface covering is then attached to the surface that comes into contact with the human body. During the mold molding process, a fabric-like base material is placed in the mold beforehand so that it faces the underside of the foam pad. The resulting foam pad has polyurethane formed on this base material, with the polyurethane being reinforced by the base material. In subsequent seat assembly processes, the seat cushion, formed by attaching the surface covering to the foam pad, becomes easier to handle as it is less prone to damage.

[0003] During the aforementioned mold molding process, a mold shaped to mimic the shape of the seat cushion on the side where the base material will be placed, and a mold shaped to correspond to the surface side of the finished seat cushion are used in combination. The base material is attached to the mold so as to cover it. Soft magnetic materials that have been pre-attached to several locations on the base material are attracted by magnets embedded in the mold, and the base material is fixed to the mold during the foam pad formation process in which polyurethane or the like is foamed.

[0004] Patent Document 1 discloses a technique for integrating a foamed synthetic resin pad body (foam pad in the present invention) and an insert member (base material in the present invention) such as reinforcing fabric, used in seats and furniture such as those installed in vehicles, ships, and aircraft, by attaching a magnetic layer to the surface of a pre-molded insert member and having it attracted to a magnet placed in the molding die, which is a molding die, thereby fixing the insert member to the molding die. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-036463 [Overview of the project] [Problems that the invention aims to solve]

[0006] Patent Document 1 describes a method for forming a magnetic layer by applying an adhesive mixed with powders such as iron and nickel to a stamp surface, transferring it to an insert member, and then curing it. Various synthetic polymer compounds such as synthetic rubber and other resins, as well as photocurable resins, can be used as the adhesive. However, the mixing ratio of iron and nickel and the amount applied to the insert member are not disclosed, and there are no specifications for the characteristics of the magnet attached to the mold (magnetic flux density, etc.). If the mixing ratio of metal powders such as iron is low, the attraction force to the magnet is weak, and the insert member cannot be fixed to the mold unless the number of magnets and magnetic layers on the mold is increased. If the mixing ratio of metal powders is increased too much, the viscosity of the adhesive becomes high, resulting in poor discharge and transfer properties, and a decrease in elasticity after curing. Therefore, it was necessary to find an appropriate range for the mixing ratio of metal powders and to apply an appropriate amount to the reinforcing cloth.

[0007] Therefore, the present invention aims to provide a range of ratios for the soft magnetic powder (e.g., iron) mixed into the resin of the adhesive that ensures elasticity and provides a magnetic layer (magnetic layer in Patent Document 1; obtained by mixing the resin and the soft magnetic powder (hereinafter sometimes simply referred to as soft magnetic material) and curing it; the same applies hereinafter), and that provides a range of ratios that allows the substrate on which the magnetic layer is formed to be sufficiently attracted to a magnet. Furthermore, the present invention aims to provide a method for forming a soft magnetic material-containing photocurable resin on a substrate that prevents the discharge shape of the resin from collapsing when discharging an adhesive made of a photocurable resin mixed with a soft magnetic material (hereinafter referred to as a soft magnetic material-containing photocurable resin) onto a reinforcing cloth (hereinafter referred to as a substrate) by curing a portion of the adhesive attached to the substrate before separating the discharge window from the substrate, and that allows the discharge amount to be appropriately controlled based on an inspection of the distance between the discharged resins. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides the following. As a first invention, There is provided a photocurable resin containing a soft magnetic material, which includes a raw material for polymerization containing at least a urethane oligomer having an acrylic group or / and an epoxy group, a crosslinking agent, a photoinitiator, and soft magnetic powder, and the soft magnetic powder is 50% or more and 75% or less in weight ratio.

[0009] As a second invention, based on the first invention, there is provided a photocurable resin containing a soft magnetic material, wherein the crosslinking agent is 2-hydroxypropyl methacrylate.

[0010] As a third invention, based on any one of the first or second inventions, there is provided a photocurable resin containing a soft magnetic material, which further contains a reaction acceleration additive.

[0011] As a fourth invention, based on any one of the first to third inventions, there is provided a photocurable resin containing a soft magnetic material, wherein the viscosity of the raw material for polymerization contained in the resin before photocuring is 1000 to 500000 millipascal seconds at a rotational speed of 0.6 rpm or less of a B-type viscometer.

[0012] As a fifth invention, based on any one of the first to fourth inventions, there is provided a photocurable resin containing a soft magnetic material, wherein the viscosity of the raw material for polymerization contained in the resin before photocuring is 40000 millipascal seconds or more and 44000 millipascal seconds or less at 6 rpm and 30000 millipascal seconds or more and 34000 millipascal seconds or less at 12 rpm with a B-type rotational viscometer.

[0013] As a sixth invention, a filling step of filling a cylinder with a photocurable resin containing a soft magnetic material according to any one of the first to fifth inventions; a discharging step of discharging the filled photocurable resin containing a soft magnetic material from a plurality of discharge windows provided at the tip of the cylinder onto a base material to such an extent that it penetrates the back surface of the base material; a spacing inspection step of inspecting the spacing between the discharged photocurable resins containing a soft magnetic material; A pass / fail determination step for determining the quality of ejection by an interval inspection step, A method for forming a soft magnetic material-containing photocurable resin on a base material having the same is provided.

[0014] As a seventh invention, based on the sixth invention, The base material is a non-woven fabric made of fibers containing polyester, having a thickness in the range of 0.5 mm or more and 50 mm or less, and a basis weight in the range of 50 g / m , , , , , , , ,

[0016] , , , ,

[0017] ,

[0015] , , , or more and 200 g / m 2 or less, and a method for forming a soft magnetic material-containing photocurable resin on the base material is provided.

[0015] As an eighth invention, based on any one of the sixth or seventh inventions, After the ejection step, further An irradiation step of irradiating a curing light from the back side of the soft magnetic material-containing photocurable resin ejected onto the base material, A retraction step of retracting the ejection window above the soft magnetic material-containing photocurable resin after the irradiation step, and having A curing step of irradiating the soft magnetic material-containing photocurable resin ejected onto the base material with a curing light from above or / and below after the retraction step, ​​​​​​​​​​​​​With the above configuration, the present invention provides a method for forming a soft magnetic material-containing photocurable resin on a substrate. This method allows for obtaining a magnetic layer by curing the resin after mixing in a soft magnetic material powder (e.g., iron) that also maintains elasticity, and provides a range of ratios in which the substrate on which the magnetic layer is formed and a magnet can be sufficiently attracted. Furthermore, when dispensing the soft magnetic material-containing photocurable resin onto a substrate, curing a portion of the adhesive attached to the substrate before separating the dispensing window from the substrate prevents the dispensing shape of the resin from collapsing, and allows for appropriate control of the dispensing amount based on an inspection of the distance between the dispensed resins. [Brief explanation of the drawing]

[0018] [Figure 1] Diagram illustrating the structure of an automobile seat. [Figure 2] Graph of the weight ratio (%) of iron powder and viscosity in the soft magnetic material-containing photocurable resin of the present invention. [Figure 3] Diagram illustrating the manufacturing process of seat inserts and seat cushions for automobile seats. [Figure 4] Flow diagram of the magnetic material mounting process according to Embodiment 6 of the present invention. [Figure 5] Examples of multiple discharge windows at the tip of the cylinder of the present invention [Figure 6] Schematic cross-sectional view 1 of the soft magnetic material-containing photocurable resin of the present invention after it has been extruded onto a substrate surface. [Figure 7] Schematic cross-sectional view 2 of the soft magnetic material-containing photocurable resin of the present invention after it has been extruded onto a substrate surface. [Figure 8] Photographs and schematic diagrams of examples of resin patterns after the soft magnetic material-containing photocurable resin of the present invention is dispensed onto a substrate surface. [Figure 9] A schematic diagram showing an example of a void inspection area in a soft magnetic material-containing photocurable resin pattern of the present invention, extruded onto the substrate surface. [Figure 10] Flow diagram of the magnetic material mounting process according to Embodiment 7 of the present invention [Figure 11] Diagram illustrating the magnetic material mounting process according to Embodiment 8 of the present invention. [Figure 12] Flow diagram of the magnetic material mounting process according to Embodiment 9 of the present invention [Figure 13] Flow diagram of the magnetic material mounting process according to Embodiment 9 of the present invention [Figure 14] Graph of the weight ratio (%) of iron powder and adsorption force (N) in the soft magnetic material-containing photocurable resin of the present invention. [Figure 15] Graph of the weight ratio (%) of iron powder and relative permeability in the soft magnetic material-containing photocurable resin of the present invention [Figure 16] Graph of the weight ratio (%) of iron powder and aperture ratio in the soft magnetic material-containing photocurable resin of the present invention [Modes for carrying out the invention]

[0019] The following describes embodiments of the present invention. However, the present invention is not limited in any way to these embodiments, and can be implemented in various forms without departing from its essence. Reference numerals in the description of the invention's structure and in the diagrams thereof are denoted by four-digit numbers, where the first two digits represent the drawing number and the last two digits represent the number uniquely assigned to each part.

[0020] This specification describes, as an example, a case in which a substrate made of a nonwoven fabric to which a magnetic layer obtained by curing the soft magnetic material-containing photocurable resin and the method for forming the soft magnetic material-containing photocurable resin on a substrate of the present invention is attached is used as a substrate for a foam pad that serves as a seat cushion for an automobile.

[0021] Furthermore, the use of this invention is not limited to automobile seats. It can be applied to seats in vehicles other than automobiles, such as motorcycles, transport equipment such as forklifts, construction machinery such as power shovels, agricultural machinery such as combine harvesters, passenger transport vehicles such as trains and buses, ships, aircraft, and spacecraft, as well as chairs such as sofas, game chairs, and office chairs, and wheelchair seats. In addition to seats, it can also be applied to cushioning materials for helmets, soundproofing materials, and heat insulating materials. Alternatively, the resin of the present invention and the nonwoven fabric on which a magnetic layer has been attached using the method of forming the resin on the base material of the present invention can be applied as a base material alone without forming a foam pad to automobile soundproofing and vibration damping insulators (dash insulators, floor insulators, door insulators, etc.).

[0022] Furthermore, the magnetic material can be used not only to attach a magnetic layer to a nonwoven fabric, woven fabric, or film-like sheet as a base material for magnet attraction, but also as an ink or coating. Information (e.g., identification information of the object, attribute information of the object (material, place of production, manufacturer, date of manufacture, manufacturing lot, product name, model number, owner, warranty period, expiration date, etc.), information of the sender and recipient, etc.) can be included in a predetermined pattern formed with the ink or coating using the soft magnetic material-containing photocurable resin of the present invention on the surface of an object such as a sheet, card, or box. For example, a barcode or two-dimensional code can be formed on the surface of a product or packaging box using an ink using the resin of the present invention. Furthermore, if the barcode or two-dimensional code is covered with an ink of the same color as the formed barcode, etc., it becomes unreadable by visual inspection or optical readers. By concealing the location where the barcode or two-dimensional code is formed visually and using a magnetic reader for reading, the possibility of others reading the contents of the code can be reduced.

[0023] Alternatively, by applying a paint using the resin of the present invention to the walls of buildings, posters can be attached with magnets, magnetic hooks can be attached, and various objects can be attached using magnets. When attaching an iron plate to a wall, it is necessary to reinforce the wall to withstand the weight of the iron plate, but the soft magnetic material-containing photocurable resin layer formed by applying a paint using the resin of the present invention is not as heavy as an iron plate, eliminating the need to reinforce the wall. Furthermore, the present invention, such as a paint containing a powder of a magnetized soft magnetic material, such as ferrite, which has high coercivity even though it is a soft magnetic material, can be used as a coating material for structures made of soft magnetic materials, such as automobile bodies (stainless steel with some soft magnetism remaining), bridges, and steel structural parts such as storage tanks. In this case, the paint is less likely to peel off from the surface of the structure, resulting in a highly durable coating.

[0024] <Seating: Structure> The structure of a car seat will be explained using Figure 1. Although car seats are divided into front and rear seats in terms of shape, their structure is almost the same and is composed of three main parts. As shown in Figure 1, these three parts are the seat surface (0101) (also called the seat cushion) on which a person sits, the backrest (0102) (also called the seat back) on which a person leans their back, and the headrest (0103) attached to the top of the backrest.

[0025] As shown in Figure 1, the seat consists of a pipe frame (0104) made of metal pipes and springs, to which a foam pad (0106) formed directly on a base material (0105) using foamed urethane resin or the like is attached. The foam pad (0106) is then covered with a surface material (0107) by adhesive or other means.

[0026] On the left of Figure 1, a cross-section of a part of the backrest of Figure 1 is shown within a circle. A base material (0105) made of nonwoven fabric, woven fabric, or film-like sheet is placed between the seat's pipe frame (0104) and the foam pad (0106) made of foamed urethane resin or the like, to prevent the foam pad (0106) from rubbing against the pipe frame (0104) and wearing down due to the shaking of the car while driving and the movement of the passenger's body. A surface covering (0107) is attached to the surface of the foam pad (0106) that comes into contact with the passenger, contributing to improved durability and appearance of the foam pad (0106).

[0027] <Embodiment 1 Summary> Mainly Claim 1 The photocurable resin containing a soft magnetic material, used to form a magnetic layer on a substrate such as a nonwoven fabric, comprises a polymerization raw material containing a urethane oligomer having at least an acrylic group and / or epoxy group, a crosslinking agent, a photoreaction initiator, and a soft magnetic material powder, wherein the soft magnetic material powder accounts for 50% or more and 75% or less by weight.

[0028] <Embodiment 1: Photocurable Resin> "Photocurable resins" require "polymerization raw materials" and "photoreaction initiators," and may also contain "crosslinking agents," "reaction-accelerating additives," "fillers," and "stabilizers."

[0029] <Embodiment 1: Photocurable resin: Curing mechanism> When a "photocurable resin" is exposed to light of a predetermined wavelength, radicals or cations are generated from the "photoinitiator" corresponding to the "polymerization raw material." The generated radicals or cations react with acrylic groups or epoxy groups in the molecules of the polymerization raw material, respectively, cleaving the C=C double bond of the acrylic group and polymerizing it with similar sites in other polymerization raw material molecules, or opening the ring of the epoxy group and polymerizing it with similar sites. The "crosslinking agent" has acrylic groups or epoxy groups similar to the polymerization raw material, and the polymerization reaction is made possible by the radicals or cations generated from the photoinitiator. It bonds with the cleaved or ring-opened sites in the polymerization raw material molecules, linking the polymerization raw materials together and forming a three-dimensional network polymer structure. "Reaction-accelerating additives" increase the efficiency of the photoinitiator, allowing the curing reaction to proceed faster and more efficiently. "Fillers" can be mixed with the resin to reduce the amount of resin used. In addition, the addition of fillers can reduce the shrinkage and expansion of the resin. "Stabilizers" are added for purposes such as thermal stabilization and preventing yellowing and cracking caused by light.

[0030] <Embodiment 1: Photocurable resin: Polymerization raw material> "Polymerization raw materials" form the main backbone of the photocurable resin after curing. Polymerization raw materials are monomers and / or oligomers. Known materials that can be used for polymerization raw materials include UV-curable acrylate resins having acrylic groups (e.g., urethane acrylate, polyester acrylate, methyl acrylate, ethyl acrylate, butyl acrylate, etc.), methacrylic resins having methacrylic groups in which the H in the acrylic group is replaced with CH3 (e.g., polymethacrylate, polymethacrylic acid ester, etc.), photocurable epoxy resins, vinyl ester resins, epoxy acrylates, etc.

[0031] <Embodiment 1: Photocurable resin: Photoreaction initiator> A "photoinitiator" generates and releases radicals or cations from its molecules upon receiving curing light (e.g., ultraviolet or visible light in a specific wavelength range) to react with the polymerization raw materials. If the polymerization raw materials used are acrylate-based, a photoinitiator for acrylate-based resins should be used. If the polymerization raw materials used are epoxy-based, a photoinitiator for epoxy-based resins should be used.

[0032] Photoinitiators for acrylate resins (e.g., benzophenone-based, acetophenone-based, benzoin ether-based, thioxanthone-based) generate radicals when exposed to ultraviolet light, which react with the C=C bonds of the acrylate to polymerize. Photoinitiators for epoxy resins (e.g., sulfonium salt-based, such as diphenylsulfonium salt, iodonium salt-based, such as triphenyliodonium salt) generate cations (acids) when exposed to ultraviolet light, which react with the epoxy groups to polymerize.

[0033] <Embodiment 1: Photocurable resin: Crosslinking agent> A "crosslinking agent" is added to polymerize raw materials to connect the molecules and create a three-dimensional network structure, thereby improving the degree of hardening, robustness, or durability of the resin. When polymerizing raw materials containing acrylic groups are used as crosslinking agents, 2-hydroxypropyl methacrylate is used, and when polymerizing raw materials containing epoxy groups are used, polyisocyanates are used. The specific names of substances used as crosslinking agents will be explained in Embodiment 2 below.

[0034] <Embodiment 1: Photocurable resin: Reaction-accelerating additive> A "reaction-promoting additive" accelerates the reaction in which a photoinitiator generates and releases radicals or cations. For example, it can directly transfer energy by absorbing light at wavelengths other than those absorbed by the photoinitiator and transferring energy to the photoinitiator at a distance of 10 nm or less (Förster mechanism), or by exchanging excited electrons in the reaction-promoting additive with electrons in the photoinitiator (Dexter mechanism). The photoinitiator molecule that receives the transferred energy generates and releases an active species (radical or cation). Alternatively, the reaction-promoting additive receives light of the same and / or different wavelengths as the photoinitiator and generates and releases the same type of active species (radical or cation) as the photoinitiator. In this way, the polymerization of the polymerization raw materials is accelerated by increasing the amount of active species generated and released.

[0035] When monomers and / or oligomers having an acrylic group are used as polymerization raw materials, triphenylamine (TPA) or dimethylamine (DMA) can be used as reaction-accelerating additives. Furthermore, when monomers and / or oligomers having an epoxy group are used as polymerization raw materials, methyldiethanolamine (MDEA) or dimethylamine (DMA) can be used as reaction-accelerating additives. Specific names of substances used as reaction-accelerating additives will be explained in Embodiment 3 below.

[0036] <Embodiment 1: Photocurable resin: Curing conditions> When curing a photocurable resin, use curing light suitable for the selected resin (e.g., ultraviolet light, UVA (wavelength 315 to 400 nm), visible light exceeding 400 nm and 420 nm or less, etc.) and apply the required integrated light amount (mJ / cm²). 2 ) Irradiate. This accumulated light quantity is the sum of the light quantities calculated as "light quantity" × "time". The unit of the accumulated light quantity required to cure the resin per unit area is mJ / cm as described above. 2Therefore, among acrylate resins that react quickly to light, it is preferable to use urethane acrylate oligomers, which are particularly elastic after curing, as the polymerization raw material. For photocurable resins using the urethane acrylate oligomer as the polymerization raw material, UVA (or visible light exceeding 400 nm and less than or equal to 420 nm) is generally used as the curing light, with an integrated light intensity of 1000 to 3000 mJ / cm². 2 When irradiated, curing progresses within a few seconds. If a light source with low light intensity is used, the required cumulative light intensity will not be reached in a short time, thus extending the irradiation time required for curing.

[0037] In this specification, ultraviolet-curable resins are described as an example of photocurable resins, but similar effects can be obtained using resins that cure with other wavelengths of light, such as visible light (the same applies to other embodiments). To adjust the wavelength of light for curing, a photoinitiator is prepared, and a photoinitiator that generates radicals and / or cations at the desired wavelength is selected.

[0038] The photocurable resin preferably has a glass transition temperature and / or a melting point of 150°C or higher. The magnetic layer formed on the substrate using the resin of this embodiment of the present invention is placed near where the foaming reaction of a resin, such as foamed urethane, occurs during the formation of a foam pad for a seat cushion, or when forming a foamed material for heat insulation or soundproofing. For example, the foaming of foamed urethane can reach temperatures of 60°C to 150°C. If the magnetic layer is exposed to such temperatures and melts, the photocurable resin may adhere to the mold and contaminate the substrate that is set next. Therefore, a resin that does not melt at the temperatures during the foaming reaction of such resins is preferable.

[0039] <Embodiment 1: Soft Magnetic Powder> In this invention, a magnetic layer is formed on a substrate made of a nonwoven fabric or the like. As the soft magnetic powder added to the photocurable resin as described above, powders of iron, nickel, cobalt, etc., can be used. Iron powder is the most preferred soft magnetic powder because it is readily available and inexpensive. In the embodiments described herein, iron powder is used as an example of the soft magnetic powder, but similar effects can be obtained by using other known soft magnetic materials such as nickel or cobalt.

[0040] <Embodiment 1: Weight ratio of soft magnetic powder> In the soft magnetic material-containing photocurable resin of the present invention, the weight ratio of the soft magnetic material powder to the photocurable resin is 50 wt% or more and 75 wt% or less in weight percent (hereinafter referred to as wt%). The range of the weight ratio of the soft magnetic material powder was determined by evaluating and studying the viscosity of the mixture of the photocurable resin and iron powder, the appearance after curing, the magnetic attraction force, BH characteristics, relative permeability, and the aperture ratio in the mixture (definition will be described later), using readily available iron powder as an example of soft magnetic material powder.

[0041] <Embodiment 1: Iron powder weight ratio: viscosity> First, we will explain the upper limit of the iron powder weight ratio for photocurable resins containing soft magnetic materials, based on the viscosity evaluation results of photocurable resins mixed with iron powder. Figure 2 shows the viscosity of the resin (Type B viscometer, 0.6 rpm) on the vertical axis (logarithmic scale), with the iron powder weight ratio (%) in the photocurable resin containing soft magnetic materials on the horizontal axis (linear scale). In Figure 2, the viscosity for each iron powder weight ratio (%) is indicated by black circles. The measured viscosity values ​​were 86670 mPa·s at 55 wt% iron powder weight ratio, 93330 mPa·s at 60 wt%, 100000 mPa·s at 65 wt%, 206700 mPa·s at 70 wt%, and 273300 mPa·s at 75 wt%. Furthermore, the exponential approximation line of the viscosity data for iron powder weight ratios from 55 to 75 wt%, indicated by black circles, is shown as a dotted line. The viscosity at 50 wt%, extrapolated based on the approximation line, was 53483 mPa·s.

[0042] Next, we will explain the lower limit of the iron powder weight ratio. When a photocurable resin containing soft magnetic material is dispensed onto a vertical surface, or when the resin is held in a droplet form at the tip of a syringe pointed downwards, the viscosity of the resin generally needs to be 5000 mPa·s or higher to prevent it from dripping downwards. The tendency to drip also depends on the thickness (or height) of the resin after dispensing. In this invention, the lower limit of the viscosity of the photocurable resin containing soft magnetic material before curing was set to 5000 mPa·s or higher. The upper limit was set to 1,000,000 mPa·s, which is the upper limit for mixing. Preferably, it should be 10,000 mPa·s or higher for less dripping, and 700,000 mPa·s or lower for mass production. Since it was not possible to specify the range of the mixing weight ratio of iron powder (soft magnetic material powder) from the viewpoint of viscosity, the range will be determined by other evaluations.

[0043] <Embodiment 1: Iron powder weight ratio: Appearance after curing> Explanation of iron powder weight ratio limit of 75 wt% or less When a photocurable resin mixed with iron powder is cured, if the weight ratio of iron powder exceeds 75 wt%, it loses its elasticity after curing and becomes prone to cracking when bent. For use as a base material for foam pads in automobile seats, it is unsuitable for magnetic layers where bending forces may be applied when attaching to the mold for forming the foam pad. Similarly, it is unsuitable for applications where bending forces are applied to the magnetic layer after curing (such as heat insulating materials and soundproofing materials with bendable sections, or covers formed on soft sheet-like base materials that are folded and stored when not in use). Therefore, the weight ratio of iron powder was kept below 75 wt%.

[0044] <Embodiment 1: Iron powder weight ratio: Adsorption with magnet> Explanation of the lower limit of the iron powder weight ratio of 50 wt% or more The lower limit of the iron powder weight ratio will be explained based on the evaluation results of adsorption with magnets. The adsorption of the resin cured from the soft magnetic material-containing photocurable resin of the present invention to a magnet is performed to fix and hold a sheet-like substrate from which the resin of the present invention has been extruded with a magnet. Therefore, if the iron powder weight ratio in the resin is too low, the adsorption force with the magnet will be insufficient. The lower limit of the iron powder weight ratio required to hold the substrate was investigated. As a specific example of evaluation, the adsorption force for holding a nonwoven fabric substrate was evaluated using a magnet (surface magnetic flux density 0.30 to 0.44 T) installed in a mold for forming foam pads. An adsorption force of at least 1.5 N is required. This is because the largest substrate used for automobile seats, the seat surface of a rear two-seater seat, has an area of ​​approximately 1.4 m × 0.5 m = 0.7 m². As the base material for the rear seat cushion, if a nonwoven fabric with a basis weight of 200 g / m2 within the range of 50 g / m2 to 200 g / m2 as described in Embodiment 7 below is used, an adsorption force of 1.5 N is sufficient to hold 0.75 m2 (weighing 150 g) of nonwoven fabric, and thus to hold the nonwoven fabric for the rear seat cushion. Ten samples were prepared for each condition with different iron powder weight ratios, and the adsorption force was measured. Due to variations in adsorption force measurement and the possibility of force being applied to shift the nonwoven fabric during foam expansion of urethane, etc., when forming the foam pad, a margin of safety was ensured, and 2.4 N or higher was used as the criterion for determining the quality of the conditions during evaluation, rather than 1.5 N or higher. Reducing the number of magnetic layers attached to the base material as much as possible reduces the man-hours and material costs required for attachment.

[0045] In evaluating the adsorption with magnets, three samples with iron powder weight ratios of 55 wt%, 60 wt%, and 65 wt% were evaluated (see Figure 9). For evaluation, samples were prepared by extruding 0.125 g of soft magnetic material-containing photocurable resin of each iron powder weight ratio into a 16 mm diameter circle on the surface of a nonwoven fabric substrate and curing it. From the evaluation results for the three iron powder weight ratio conditions, a linear approximation was used as the approximation line based on the three results. When the iron powder weight ratio is increased above 65 wt%, the amount of soft magnetic material powder contributing to adsorption to the magnet increases, so it is thought that the adsorption force becomes stronger than that of the 65 wt% sample, as shown by the approximation line, or that the adsorption force saturates with respect to the increase in iron powder weight ratio. For 65 wt% and above, this was confirmed by extrapolation using the aforementioned approximation line. For less than 55 wt%, it is thought that the adsorption force decreases in proportion to the decrease in iron powder weight ratio, so this was also confirmed by extrapolation using the aforementioned approximation line. At 50 wt% or more, the adsorption capacity was calculated to be approximately 2.4 N, and since it was expected that a margin of safety could be obtained over the standard of 1.5 N, the lower limit of the iron powder weight ratio was set at 50 wt%. Preferably, it is 55 wt% or more.

[0046] <Embodiment 1: Iron powder weight ratio: BH characteristics, relative permeability> Explanation of iron powder weight ratio limit of 75 wt% or less This section explains the upper limit of the iron powder weight ratio, based on the evaluation results of relative permeability obtained from measuring the BH characteristics of samples with varying iron powder weight ratios. Samples were prepared by mixing iron powder with a photocurable resin at different weight ratios (50 wt%, 60 wt%, 70 wt%) as a soft magnetic material, and their BH characteristics were measured. This was done to determine the appropriate iron powder weight ratio from the magnetic properties of the photocurable resin containing the soft magnetic material. The relative permeability was determined from the slope of the BH characteristic graph for each sample. A graph (Figure 10) was created with the iron powder weight ratio (wt%) on the horizontal axis and relative permeability on the vertical axis, and an approximation line was added as a dotted line. When preparing the sample for measurement, it was not possible to create a sample shape suitable for BH characteristic measurement at 75 wt%, so the 75 wt% value was obtained by extrapolation using the approximation line. The relative permeability for each iron powder weight ratio, based on the measured values, was 2.65 for 50 wt%, 3.68 for 60 wt%, and 4.06 for 70 wt%. The relative permeability at 75 wt% (for reference), extrapolated from the approximation line, was 4.16. The variation in these relative permeabilities was ±10%, with ±5% being preferable.

[0047] When iron powder is mixed into a resin, the magnetic permeability of the resin changes depending on the weight ratio of the iron powder. Generally, the relative permeability of a resin alone, without soft magnetic materials, is close to 1. When iron powder is mixed into a resin, the high responsiveness (magnetization) of the iron powder to a magnetic field is reflected in the properties of the entire material, so the magnetic resistance of the mixture (photocurable resin containing soft magnetic materials) decreases and the relative permeability increases. Magnetic permeability is an indicator of how easily a magnetic field passes through a material. When the weight ratio of iron powder increases to 50 to 60 wt%, the distance between the iron powder particles dispersed in the resin becomes closer than when the weight ratio is low, and magnetic coupling between the iron powder particles becomes easier. As a result, a path (magnetic path) is formed through which the magnetic field continuously passes between the iron powder particles, and the magnetic permeability increases. Furthermore, when the weight ratio of iron powder is increased to a very high level, such as 75 wt% or more, the distance between the iron powder particles becomes smaller, so the magnetic interaction between the iron powder particles strengthens, and sometimes contact may occur. Thus, at high weight ratios, the interaction between iron powder particles becomes dominant, the magnetization of individual iron powder particles tends to saturate, and the dense arrangement of iron powder makes it difficult for the magnetic field to pass through, slowing down the increase in relative permeability. Therefore, as the weight ratio of iron powder increases, the relative permeability of the mixed resin increases, resulting in the outcome shown in Figure 10.

[0048] As mentioned above, the relative permeability increases up to about 70 wt%, and beyond 75 wt%, the increase in relative permeability slows down even if the weight ratio of iron powder, which is a soft magnetic material, is increased. Therefore, the upper limit of the iron powder weight ratio is 75 wt% or less, and preferably 70 wt% or less.

[0049] <Embodiment 1: Iron Powder Weight Ratio: Aperture Ratio> Explanation of Iron Powder Weight Ratio Upper Limit of 75 wt% or Less The upper limit of the iron powder weight ratio will be described based on the result of irradiating a resin mixed with iron powder with a curing light and simply calculating the rate at which the light is irradiated to the opposite side from the irradiated surface. When irradiating a soft magnetic material-containing photocurable resin with a curing light, the rate at which the curing light passes through the iron powder mixed as a soft magnetic material powder in the photocurable resin without being blocked and reaches the resin surface on the side opposite to the light incident surface was roughly estimated as an area ratio. Generally, magnetite (Fe3O4) is formed on the surface of iron powder, which is easily available as a soft magnetic material powder. Magnetite has a low reflectance of UVA, which is a common curing light for photocurable resins. As a means of verifying the validity of the iron powder weight ratio, the area ratio was estimated as the ratio (hereinafter referred to as the aperture ratio) of the area where no iron powder particles are arranged in the thickness direction of the resin through which the light passes in the cured resin to the projected area of the cured resin.

[0050] <Embodiment 1 Iron powder weight ratio: Aperture ratio: Prerequisites> For the model studied, the specific gravity of the photocurable resin was 1.07, the average particle size of the iron powder was 58 μm, and the density of iron was 7.87 g / cm 3 , the resin discharge amounts of 0.125 g and 0.25 g onto the non-woven fabric surface, and the numerical values of a circle (2.011 cm 2 ) with a discharge area diameter of 16 mm were used.

[0051] <Embodiment 1 Iron powder weight ratio: Aperture ratio: Estimation procedure> As the estimation procedure, for each of the iron powder weight ratios of 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, and 75 wt%, the volume of 1 g of the soft magnetic material-containing photocurable resin was determined, and the density of the resin and the number density (number / cm 3 ) of the iron powder in the resin were calculated respectively. The thickness of the disk when the resin with each iron powder weight ratio was discharged in a disk shape with a bottom diameter of 16 mm was obtained from the formula: disk thickness = discharge amount (0.1 g, 0.125 g, or 0.25 g) / resin density / disk bottom area. The integer part of the quotient obtained by dividing the obtained thickness by the diameter of the iron powder of 58 μm was taken as the number of layers in which the iron powder is arranged in the thickness direction. For ease of calculation, the estimation was performed by limiting it to an area of 1 cm square (area 1 cm 2 ) in the disk of the discharged resin.

[0052] <Embodiment 1: Iron powder weight ratio: Aperture ratio: Method for calculating the aperture ratio> Within a 1cm square, 172 x 172 frames can be arranged, each divided into a grid pattern with a side length equal to the diameter of 58μm of iron powder. These 172 x 172 frames overlap in the thickness direction, corresponding to the number of layers calculated above. The number density calculated for each weight ratio is calculated using this total number of frames (the product of the number of frames per layer and the number of layers) × (1cm 2 Divide the number of iron powders obtained by (x × thickness of the extruded disk) by the probability of an iron powder being placed in each frame. Use a random number for each frame, and if the result is greater than or equal to the aforementioned probability, an iron powder is placed. For example, if the frames within one layer are represented by x, y coordinates and the layers are represented by z coordinates, and there are 3 layers (z=1,2,3) in thickness, (x n , y m , 1) from (x n , y m If iron powder is not placed in all three layers of 3), then (x n , y m Leave the box marked with ) blank, (x n , y m , 1) from (x n , y m ,3) If iron powder is placed in even one layer, then (x n , y m Frames marked with ) are counted as containing iron powder. Taking the thickness direction into account in this way, the number of empty frames in a 172 x 172 frame where no iron powder is placed was divided by the number of frames per layer (= 172 x 172) to determine the aperture ratio. Frames in the aforementioned thickness direction where no iron powder is placed are frames that can transmit the curing light.

[0053] <Embodiment 1: Iron powder weight ratio: Opening ratio: Results> Figure 11 shows the estimated opening ratio for each iron powder weight ratio. The graph shows three lines: 0.25g (thin solid line), 0.125g (thick solid line), and 0.1g (thin dotted line). Since the number of layers in the thickness direction is 0.25g < 0.125g < 0.1g, the opening ratio is highest in the above order, with 0.25g having the lowest opening ratio. For discharge volumes of 0.125g and 0.1g, the opening ratio is high, at 11% or more in the range of iron powder weight ratio from 50wt% to 65wt%. Even at an iron powder weight ratio of 75wt%, the opening ratio is 4% or more. On the other hand, for a discharge volume of 0.25g, the opening ratio is 1.2% or more in the range of iron powder weight ratio from 50wt% to 65wt%. At an iron powder weight ratio of 75wt% with a discharge volume of 0.25g, the opening ratio is low at approximately 0.3%, but not so low that it can be considered 0. Calculations show that at 80 wt%, the aperture ratio drops another order of magnitude from 0.02%. Therefore, from the viewpoint of aperture ratio, the upper limit of the iron powder weight ratio is 75 wt%. When the aperture ratio is low as described above, it is preferable to irradiate the extruded resin with curing light from both the back surface (nonwoven fabric side) and the front surface, as in the embodiment described later. Alternatively, the cumulative light intensity of the curing light irradiation can be increased.

[0054] The estimated aperture ratio indicates that the lower the iron powder weight ratio, the higher the aperture ratio, allowing the curing light to reach the opposite side of the irradiation surface more easily. The upper limit for the iron powder weight ratio is 75 wt% or less, with 70 wt% or less being preferable. Although the estimate was made by assuming that the iron powder is arranged in a grid pattern, in reality, a hexagonal close-pack arrangement is also possible, so the aperture ratio may be higher than the above estimate.

[0055] <Embodiment 1: Iron powder weight ratio: results of study> Based on the evaluations described above, and after examining the upper and lower limits of the iron powder weight ratio, the range of soft magnetic material powder to be included in the soft magnetic material-containing photocurable resin is 50 wt% or more and 75 wt% or less. Preferably, it is 55 wt% or more and 70 wt% or less, and most preferably 65 wt%. Although iron powder was used as an example in the weight ratio study, similar effects can be obtained using soft magnetic materials other than iron (e.g., nickel, cobalt, etc.).

[0056] <Effect of Embodiment 1> In Embodiment 1, by using a soft magnetic material-containing photocurable resin with an iron powder content of 50 wt% or more and 75 wt% or less by weight, a magnetic layer with excellent magnetic attraction and elasticity after curing can be obtained.

[0057] <Embodiment 2 Overview> Mainly Claim 2 The soft magnetic material-containing photocurable resin of Embodiment 2 is based on Embodiment 1, and uses 2-hydroxypropyl methacrylate as the crosslinking agent for the soft magnetic material-containing photocurable resin.

[0058] <Embodiment 2: Crosslinking Agent> A "crosslinking agent" is used to bond the monomers and / or oligomers of the polymerization raw materials to form a three-dimensional network structure, thereby improving the curing degree and durability of the resin. By adding functional monomers or oligomers as crosslinking agents, the polymerized molecules of the polymerization raw materials are further linked together to form a three-dimensional network structure. 2-hydroxypropyl methacrylate has a methacrylic group, and within that methacrylic group, it has a C=C bond similar to that of an acrylic group. In the polymerization reaction, radicals react with the C=C of the methacrylic group of 2-hydroxypropyl methacrylate, crosslinking with the molecules of the urethane oligomer. In the soft magnetic material-containing photocurable resin of Embodiment 1, using 2-hydroxypropyl methacrylate as a crosslinking agent for a resin having an acrylic group-containing urethane acrylate oligomer as a polymerization raw material is preferable because it has the effects described below.

[0059] Using 2-hydroxypropyl methacrylate (hereinafter referred to as MHP) has the following effects. (1) High crosslinking efficiency: MHP has high crosslinking efficiency and can form a porous structure. It can function as a lightweight insulating material and support the insulating effect of urethane. (2) Durability: Crosslinked polymers have high durability and improved mechanical strength. (3) Transparency: Polymers using MHP have high transparency and are suitable for optical applications. Therefore, they also have high ultraviolet light transmittance, and as crosslinking gradually progresses when curing light including ultraviolet light is irradiated, the polymer that has already cured does not interfere with ultraviolet light transmission. (4) Chemical stability: MHP is chemically stable and has excellent weather resistance and chemical resistance. These characteristics make it an excellent crosslinking agent for use in the present invention.

[0060] As for the "crosslinking agent," if the polymerization raw material has an acrylic group, methacrylic acid-based agents (e.g., 2-hydroxypropyl methacrylate, ethylenediamine dimethacrylate (DMAEMA), diglycidyl methacrylate (GDMA), etc.) are preferred.

[0061] When the polymerization raw material has an epoxy group, the crosslinking agent is preferably a polyisocyanate (e.g., diisocyanate trimellitic acid) or an amine (e.g., diethylaminoethanol (DEAE), triethanolamine).

[0062] <Effects of Embodiment 2> By using 2-hydroxypropyl methacrylate as a crosslinking agent in the soft magnetic material-containing photocurable resin of Embodiment 2, polymerized molecules can be further linked together to form a three-dimensional network structure.

[0063] <Embodiment 3 Overview> Mainly Claim 3 The soft magnetic material-containing photocurable resin of Embodiment 3 is configured to be based on either Embodiment 1 or Embodiment 2, and further to contain a reaction-promoting additive.

[0064] <Embodiment 3: Reaction-accelerating additive> "Reaction-accelerating additives" have the function of further accelerating the action of photoinitiators when exposed to light such as ultraviolet light. When the polymerization raw material for soft magnetic material-containing photocurable resin contains acrylic groups, the photoinitiator helps generate radicals for polymerization, thereby promoting polymerization. When the polymerization raw material for soft magnetic material-containing photocurable resin contains epoxy groups, the photoinitiator helps generate cations that open the epoxy groups and polymerize the epoxy groups together, thereby promoting polymerization.

[0065] <Embodiment 3: Reaction-promoting additive: Specific example> When monomers and / or oligomers having acrylic groups are used as polymerization raw materials, the following can be used as reaction-accelerating additives. (1) Amines Triphenylamine (TPA) and dimethylamine (DMA) are reaction-accelerating additives that promote the photopolymerization of acrylate resins. These amines efficiently facilitate the polymerization reaction of acrylic groups. (2) Phosphines Triphenylphosphine (TPP) and trimethylphosphine can sometimes accelerate reactions more efficiently than amines in UV curing. These are used in conjunction with photoinitiators to improve reaction rates. (3) Suburea (Urethane) compounds Polyurethane acrylate (PUA) is used to enhance the curing reaction of acrylate resins and improve their durability after curing. (4) Redox reagents Peroxides (e.g., benzoyl peroxide) enhance the effect of photoinitiators through redox reactions in acrylate resins, thereby accelerating the curing reaction.

[0066] <Embodiment 3: Reaction-promoting additive: Specific example> When monomers and / or oligomers having epoxy groups are used as raw materials for polymerization, the following can be used as reaction-accelerating additives. (1) Amines Methyldiethanolamine (MDEA) and dimethylamine (DMA) accelerate the reaction with epoxy groups, thereby promoting the curing reaction. These amines react directly with epoxy groups to drive the curing process. (2) Peroxides Benzoyl peroxide (BPO) and methyl ethyl ketone peroxide (MEK Peroxide) are used to accelerate the photocuring of epoxy resins. These peroxides decompose under ultraviolet light, generating free radicals that accelerate the reaction with epoxy groups. (3) Redox reagents Ascorbic acid (vitamin C) and naphthalene are used when oxidation-reduction reactions are utilized to accelerate the curing of epoxy resins. These agents help the curing reaction proceed more quickly by reducing oxides. (4) Metal complexes Titanate esters and chromium complexes are used to accelerate the UV curing reaction of epoxy resins. These metal complexes are activated by ultraviolet light and play a role in accelerating the reaction of epoxy groups.

[0067] <Embodiment 3 Effects> The soft magnetic material-containing photocurable resin of Embodiment 3 contains a reaction-accelerating additive, which allows the curing reaction to proceed rapidly when exposed to curing light.

[0068] <Embodiment 4 Overview> Mainly Claim 4 The soft magnetic material-containing photocurable resin of Embodiment 4 is based on any one of Embodiments 1 to 3, and is configured such that the viscosity of the polymerization raw material contained in the resin before photocuring is 1,000 to 500,000 millipascal seconds at a rotation speed of 0.6 rpm or less of a Type B viscometer.

[0069] <Embodiment 4: Viscosity of Polymerization Raw Materials> When soft magnetic materials such as iron powder are mixed in, the viscosity increases, so the viscosity of the polymerization raw materials contained in the soft magnetic material-containing photocurable resin before photocuring is also specified. The viscosity of the photocurable resin before mixing in the soft magnetic material is almost synonymous with the viscosity of the polymerization raw materials. This is because, while other additives such as crosslinking agents, photoinitiators, and reaction-accelerating additives are generally liquids, the monomers and oligomers that make up the polymerization raw materials have long molecular chains and large molecular weights, resulting in high viscosity. Consequently, the influence of the polymerization raw materials is dominant on the viscosity of the soft magnetic material-containing photocurable resin before photocuring. If the viscosity of the resin before mixing in the soft magnetic material is high, the viscosity after mixing in the soft magnetic material will also be high, and if you try to mix in soft magnetic material powder at a high weight ratio, the viscosity will become even higher, making mixing difficult. If the viscosity of the polymerization raw material is in the range of 1,000 to 500,000 mPa·s at a rotation speed of 0.6 rpm or less on a Type B viscometer, then by mixing it with the soft magnetic powder in the weight ratio shown in Embodiment 1, a soft magnetic material-containing photocurable resin can be obtained in which the viscosity after mixing with the soft magnetic powder as described in Embodiment 1 is 5,000 to 1,000,000 mPa·s or higher. Furthermore, having such a high viscosity prevents dripping from the tip of the dispensing device when dispensing onto a substrate surface, for example, and allows movement to the next dispensing location without taking measures to prevent dripping after dispensing. Dripping after dispensing can also be prevented when dispensing onto a vertical wall surface.

[0070] <Embodiment 4 Effects> By mixing a photocurable resin containing the polymerization raw materials of Embodiment 4 with a soft magnetic material, the soft magnetic material-containing photocurable resin shown in Embodiment 1 can be obtained.

[0071] <Embodiment 5 Summary> Mainly Claim 5 The soft magnetic material-containing photocurable resin of Embodiment 5 is based on any one of Embodiments 1 to 4, and is configured such that the viscosity of the polymerization raw material contained in the resin before photocuring is 40,000 millipascal seconds or more and 44,000 millipascal seconds or less at 6 rpm and 30,000 millipascal seconds or more and 34,000 millipascal seconds or less at 12 rpm, as measured by a B-type rotational viscometer.

[0072] For adhesives dispensed onto walls, there are applications where the viscosity must decrease when dispensed from the cylinder (when shear force is applied), and then increase after it has settled on the wall (after the shear force is released), making it less likely to drip. This change in viscosity is called thixotropy. Thixotropy is generally measured and compared using a ratio of viscosities measured with a B-type viscometer, for example (e.g., 6rpm viscosity / 12rpm viscosity).

[0073] <Embodiment 5: Thixotropic> "Thixotropy" is defined as "a type of abnormal viscosity. Simply stirring or shaking it causes a gel to turn into a fluid sol, and if left standing, it returns to a gel. Hysteresis occurs in the viscosity-shear stress curve. It was named by Freundlich (HMF) and Peterfi (T.)." (Quoted from Iwanami Dictionary of Physics and Chemistry, 5th edition, Iwanami Shoten, p. 833). In other words, if subjected to continuous shear stress, the viscosity gradually decreases and it becomes liquid, but when left at rest, the viscosity gradually increases and it eventually becomes solid.

[0074] When the resin of the present invention is extruded onto a nonwoven fabric substrate, if the thixotropy is low, the shape of the extruded resin tends to collapse and spread out between the time of extrusion and the time of curing by light irradiation. Furthermore, as in Embodiment 9 described later, if the soft magnetic material-containing photocurable resin is allowed to overflow from the extrusion window before the extrusion window is lowered toward the substrate surface, if the thixotropy is low, the resin extruded from the extrusion window may drip toward the substrate surface and adhere to places other than the desired location before the extrusion window itself approaches the substrate surface. Due to these problems, it is preferable to have a predetermined thixotropy. The polymerization raw material contained in the photocurable resin before mixing with the soft magnetic material powder is a polymerization raw material (i.e., photocurable resin) in which the viscosity of the polymerization raw material is measured on a B-type rotational viscometer at 6 rpm to 40,000 mPa·s or more and 44,000 mPa·s or less, and the viscosity at 12 rpm to 30,000 mPa·s or more and 34,000 mPa·s or less. Thus, by using a photocurable resin containing polymerization raw materials with a thixotropy greater than 40,000 mPa·s / 34,000 mPa·s = 1.176, it is possible to obtain a soft magnetic material-containing photocurable resin that is less likely to cause the aforementioned problems.

[0075] <Embodiment 5: Effects> By mixing a thixotropic photocurable resin containing the polymerization raw materials of Embodiment 5 with a soft magnetic material, a soft magnetic material-containing photocurable resin as shown in Embodiment 1 can be obtained, and when dispensing the soft magnetic material-containing photocurable resin onto a substrate, it is possible to prevent the resin from dripping onto the substrate surface before dispensing.

[0076] <Embodiment 6 Summary> Mainly Claim 6 A magnetic layer is formed on the substrate surface using a soft magnetic material-containing photocurable resin according to any one of Embodiments 1 to 5.

[0077] <Embodiment 6 Configuration> The method for forming the soft magnetic material-containing photocurable resin onto a substrate according to Embodiment 6 consists of a filling step, a dispensing step, a spacing inspection step, and a quality determination step. Before describing the formation method in detail, the manufacturing process of an automobile seat will be described first as an example of using the substrate.

[0078] <Embodiment 6: Seat Manufacturing Process> Figure 3 shows an example of an automobile seat. Figure 3 mainly illustrates the manufacturing process of the base material and the manufacturing process of the seat cushion, which are related to the present invention. In the seat assembly process for assembling an automobile seat, the seat cushion, including the backrest, seat surface, and headrest, is attached to a pipe frame manufactured in a separate process not shown in Figure 3, and the seat is assembled. In this specification, the "base material" is the same material that was called an insert member in Patent Document 1, and is also called a seat insert. Nonwoven fabrics, woven fabrics, film-like sheets, etc., can be used as the base material. In the following description, the case in which nonwoven fabric is used as the base material will be explained, but similar effects can be obtained by using other sheet-like materials such as woven fabrics or film-like sheets other than nonwoven fabrics.

[0079] <Embodiment 6: Seat Manufacturing Process: Substrate Manufacturing Process: Role of the Substrate> A base material made of nonwoven fabric or similar material is attached to the underside of the foam pad, which forms the seat cushion of an automobile seat and is made of materials such as polyurethane foam. The base material reinforces the foam pad, making it easier to handle during the seat assembly process. The base material remains useful even after the automobile is completed. The underside of the foam pad is in contact with the pipes and springs that make up the pipe frame, which is the skeleton of the seat. Because it rubs against these support members such as pipes and springs due to the shaking of the car while driving and the movement of the occupants' bodies, a soft, sponge-like polyurethane foam resin alone would be easily damaged. The base material on the underside of the foam pad is attached as a reinforcing material to prevent the foam pad from being damaged by rubbing against the support members such as the pipe frame.

[0080] <Embodiment 6: Seat Manufacturing Process: Nonwoven Fabric Preparation Process> The first step in the substrate manufacturing process shown in Figure 3 is the nonwoven fabric preparation step. The nonwoven fabric to be used as the material is prepared. It may be manufactured in the next step, or the nonwoven fabric may be purchased from another company.

[0081] <Embodiment 6: Seat manufacturing process: Nonwoven fabric preparation process: Nonwoven fabric manufacturing method> As an example of raw materials for a base material, a method for manufacturing nonwoven fabrics will be described. Nonwoven fabrics can be manufactured using known manufacturing methods and materials. The fibers used as raw materials for nonwoven fabrics must not be altered by the exothermic temperature during the foaming reaction when a foam pad is formed on the nonwoven fabric in a later process. For example, during the foaming reaction of polyurethane foam, the temperature near the center reaches about 60 to 150°C. Therefore, it is preferable that the melting point or softening point of the fibers constituting the nonwoven fabric be 150°C to a sufficiently high 160°C or 180°C or higher. For example, known fibers such as polyester, polypropylene, acrylic, and nylon can be used. When nonwoven fabrics are used for automobile seats, it is more preferable to use flame-retardant materials or fibers that have been given flame retardancy. Nonwoven fabrics are first formed by creating a fleece layer, which is an aggregate layer of fibers, and then interfiber bonding is performed to bond the fibers together. The fleece layer is formed by one of the known methods, such as the dry method, wet method, or spunbond method. The formed fleece is bonded together by one of the known methods, such as needle punching, water entanglement, chemical bonding, or thermal bonding.

[0082] <Embodiment 6: Seat manufacturing process: Nonwoven fabric preparation process: Nonwoven fabric specifications> The thickness of the nonwoven fabric is 1 mm to 5 mm. 1 mm to 3 mm is preferable, and 1.5 mm to 2.5 mm is more preferable. A certain thickness is necessary to ensure sufficient strength against friction with pipes and springs. If it becomes too thick, it will have difficulty conforming to the shape of the mold, so the above range is appropriate. The basis weight of the nonwoven fabric is 100 g / m² when the thickness is 2 mm. 2 From 200g / m 2 It is 120 to 160 g / m². 2 This is preferable. If the basis weight is too small, the nonwoven fabric will have a coarse weave, resulting in weaker strength. When the soft magnetic material-containing photocurable resin described later is dispensed onto the nonwoven fabric surface, it may soak into the fabric too much and spread out, potentially weakening the magnetic attraction. If the basis weight is too large, the rigidity of the nonwoven fabric will be too high, making it difficult to conform to the shape of the mold. Therefore, the above range is appropriate.

[0083] Furthermore, the nonwoven fabric may be made by forming a single nonwoven fabric by bonding the fibers together using methods such as needle punching or water entanglement. For example, the nonwoven fabric layer with densely packed fibers and a high basis weight can be placed on the side that comes into contact with the pipe frame, and the nonwoven fabric layer with a low basis weight can be placed on the side that forms the foam pad. As a result, the nonwoven fabric layer with densely packed fibers is resistant to friction with the pipe frame, and the nonwoven fabric layer with a low basis weight allows the foam pad's raw material resin, such as foamed urethane resin, to easily permeate, resulting in a nonwoven fabric with a strong bond between the nonwoven fabric and the foam pad.

[0084] <Embodiment 6: Seat manufacturing process: Substrate manufacturing process: Nonwoven fabric molding process> In the second step of the base material manufacturing process shown in Figure 3, the "nonwoven fabric molding process," the nonwoven fabric is processed to conform to the shape of the mold used to form the foam pad in a later step. The base material can be manufactured in two ways: a sewn type, where the nonwoven fabric is cut and shaped to fit the mold and sewn as needed; or a molded type, where it is formed by vacuum forming or press molding. In the latter molded type, thermoplastic fibers, for example, are used to maintain the shape of the mold. The nonwoven fabric molding process, which is a manufacturing method for the molded type, has the following steps:

[0085] <Embodiment 6: Seat manufacturing process: Substrate manufacturing process: Nonwoven fabric molding process: Mounting step> The "mounting step" is the step of attaching the nonwoven fabric, which has been cut to a predetermined shape, to a mold. The mold used in this step has the same shape as the mold used to form the foam pad in a later process. In the example in Figure 3, the mold (0312) has many holes (0313), and in the next molding step, the nonwoven fabric is molded by vacuum suction.

[0086] <Embodiment 6: Seat manufacturing process: Substrate manufacturing process: Nonwoven fabric molding process: Molding step> The "molding step" is the step of molding the nonwoven fabric. In the example in Figure 3, molding is performed by vacuum suction as described above. Although not shown, for example, an airtight sheet or bag is placed over the nonwoven fabric and the mold. By exhausting the space enclosed by the sheet or bag, the nonwoven fabric is sandwiched between the sheet or bag and the mold and molded into the shape of the mold. If thermoplastic fibers are used, the nonwoven fabric is heated before molding.

[0087] <Embodiment 6 Seat manufacturing process: Substrate manufacturing process: Nonwoven fabric molding process: Removal step> The "removal step" is the step of removing the molded nonwoven fabric (0323) formed from the mold (0312). After removal, any excess material is trimmed off as appropriate. The appearance of the molded nonwoven fabric may also be inspected during the removal step. This prevents defective products from being sent to the next magnetic material attachment process and starting work on that process.

[0088] <Embodiment 6: Seat Manufacturing Process: Substrate Manufacturing Process: Magnetic Material Attachment Process> Process relating to the present invention The "magnetic material attachment process" is a process of attaching a magnetic material to the molded nonwoven fabric so that it can be attracted to a magnet installed in the mold when it is attached to the mold used in the foam pad forming process of the next seat cushion manufacturing process. The method of forming a soft magnetic material-containing photocurable resin on a substrate of the present invention relates to this magnetic material attachment process, and will be described in detail after the seat manufacturing process is explained.

[0089] <Embodiment 6: Seat manufacturing process: Seat cushion manufacturing process: Foam pad forming process> The "foam pad forming process" is the process of forming a foam pad made of foamed urethane or the like on a nonwoven fabric after it has been molded as a seat cushion. The foam pad forming process consists of the following steps.

[0090] <Embodiment 6: Seat manufacturing process: Seat cushion manufacturing process: Foam pad forming process: Substrate attachment step> The "substrate mounting step" is the process of attaching a substrate (0305), which has a magnetic layer attached to a molded nonwoven fabric, to a mold 1 (0326). During mounting, the magnetic layer (0308), which is attached to a position corresponding to a magnet installed in the mold 1 (0326), is attracted to the substrate and fixed to the mold 1 (0326). Molded substrates are molded using a mold that corresponds to the shape of the mold 1, and can be attached along the shape of the mold 1. In the case of sewn substrates, the ability to conform to uneven areas when fixing to the mold 1 is inferior to that of molded substrates.

[0091] <Embodiment 6: Seat manufacturing process: Seat cushion manufacturing process: Foam pad forming process: Mold fitting step> The "mold matching step" is the process of combining one or more other molds with mold 1 (0326) to which the base material (0305) is attached. In the example described here, mold 1 and mold 2 are used in combination. Mold 1 and mold 2 are combined to form a closed space containing the base material.

[0092] <Embodiment 6: Seat manufacturing process: Seat cushion manufacturing process: Foam pad forming process: Resin injection foaming step> The "resin injection foaming step" is a step in which the raw material for the foam pad is injected into the closed space surrounded by mold 1 (0326) and mold 2 (0327), and a foaming reaction is carried out to form a foam pad (0306) integrally with the base material (0305). Known materials such as urethane resin are used as the raw material for the foam pad. The raw material for the foam pad may be injected into either mold 1 or mold 2 immediately before combining mold 1 and mold 2 in the mold joining step.

[0093] <Embodiment 6: Seat manufacturing process: Seat cushion manufacturing process: Foam pad forming process: Removal step> The "removal step" involves removing mold 2 (0327) from mold 1 (0326) and removing the formed foam pad (including the base material) from mold 1 (0326). The foam pad removed from the mold undergoes finishing, such as trimming off any excess material like burrs, and is then subjected to visual inspection.

[0094] <Embodiment 6: Seat manufacturing process: Seat cushion manufacturing process: Upholstery attachment process> The "skin attachment process" is the process of attaching the skin that will actually come into contact with the passenger's body to the foam pad formed on the base material. Adhesive is applied to the surface of the foam pad, and the skin is attached.

[0095] <Embodiment 6: Seat Manufacturing Process: Seat Assembly Process> The "seat assembly process" is the process of assembling a seat by attaching the seat backrest, seat cushion, and headrest, which were formed as described above, to a pipe frame manufactured in the pipe frame manufacturing process (not shown in Figure 3). The seat assembled in the seat assembly process is then attached to the automobile body in the automobile assembly process, completing the automobile.

[0096] <Embodiment 6: Description of the Magnetic Material Mounting Process> Of the automobile seat manufacturing processes described above, the magnetic material mounting process using the present invention will be explained in detail below. Figure 4 shows the steps of the magnetic material mounting process. The magnetic material mounting process consists of a filling step, a dispensing step, a spacing inspection step, and a quality determination step.

[0097] <Embodiment 6 Magnetic material mounting process: Filling step> The "filling step" is the step of filling a cylinder with a soft magnetic material-containing photocurable resin according to any one of Embodiments 1 to 5.

[0098] Dispensing equipment having a cylinder for supplying resin can also be a cylinder with multiple discharge windows, or known methods such as screen printing or roller transfer can be used. This specification will describe an example using a cylinder with multiple discharge windows.

[0099] The mixing of soft magnetic material into the photocurable resin may be performed by the manufacturer of the photocurable resin, or the person performing the magnetic material attachment may purchase the resin and soft magnetic material and mix them. When mixing, sufficient stirring should be performed so that the soft magnetic material is uniformly dispersed in the resin, and care should be taken to ensure that no air bubbles remain in the resin. Furthermore, in the area where the resin is removed from the container purchased from the resin manufacturer and mixed or filled, and in the production line near the magnetic material attachment process, it is advisable to use an illumination source that excludes or attenuates wavelengths of light that contribute to curing for at least 8 or 12 hours, equivalent to one shift of the production line, until the curing reaction of the photocurable resin does not occur, and the increase in viscosity due to the curing reaction is acceptable. For example, yellow fluorescent lamps or yellow LEDs that cut wavelengths below 500 nm may be used. Note that the filling of the cylinder may be performed by the resin manufacturer or the manufacturer of the equipment that dispenses the soft magnetic material-containing photocurable resin, and the cylinder may be delivered to the person who dispenses the resin onto the substrate.

[0100] By using photocurable resins, the need for heating to cure soft magnetic material-containing resins, which was previously required using thermosetting resins, is eliminated. Since both heating and cooling processes are unnecessary, energy efficiency is improved. Furthermore, while thermosetting resins required curing times ranging from tens of minutes to several hours, photocurable resins cure in just a few seconds after light irradiation, thus shortening working time. Additionally, with conventional thermosetting resins, there is a risk of burns to workers, and workers may inhale solvents volatilized during heating or products released into the air due to the reaction. With photocurable resins, the resin itself does not contain solvents, eliminating the risk of inhaling solvents or reaction products during curing. Moreover, by covering the light source for curing and requiring workers to wear protective equipment, worker exposure can be easily prevented even if the light source is ultraviolet. These are the advantages obtained by using photocurable resins.

[0101] <Embodiment 6 Magnetic material mounting process: Discharge step> The "discharge step" is a step in which the filled soft magnetic material-containing photocurable resin is discharged from multiple discharge windows provided at the tip of the cylinder to the substrate until it penetrates to the back surface of the substrate. Figure 5 shows an example of multiple discharge windows provided at the tip of the cylinder. In the example in Figure 5, there is one hole in the center and multiple holes (φ1 mm) surrounding it in a double circular shape.

[0102] The reason for dispensing from multiple discharge windows is to easily form a magnetic layer over a desired large area on the substrate surface. When a large amount of resin is dispensed from a single discharge window, it has thickness, but it does not spread as easily on the substrate as when dispensed from multiple discharge windows, resulting in a smaller area being formed.

[0103] A cylinder filled with a soft magnetic material-containing photocurable resin is brought close to the surface of the substrate, and the soft magnetic material-containing photocurable resin is discharged from the discharge window on the surface of the cylinder facing the substrate surface (cylinder tip). The discharge amount is determined by the magnitude of the pressure applied to the soft magnetic material-containing photocurable resin inside the cylinder and the duration of pressure application. It is most preferable to discharge the resin to the extent that it penetrates the back surface of the substrate, but penetration to more than half the thickness of the substrate is also acceptable. Preferably, penetration to more than two-thirds the thickness of the substrate is preferred.

[0104] The surface of the substrate from which the soft magnetic material-containing photocurable resin is extruded may be the surface facing the mold when attached to the mold in the foam pad forming process, or it may be the surface further away from the mold. If the resin is extruded onto the surface facing the mold to form the magnetic layer, it can be placed closer to the magnet installed in the mold. Forming the magnetic layer on the surface facing the mold allows for a stronger attraction force between the magnet and the magnetic layer than forming it on the surface further away from the mold. If the magnetic layer is attached to the side far from the mold, the substrate may be sandwiched between the magnetic layer and the magnet during attraction, potentially causing distortion of the substrate surface near the magnetic layer. When the foam pad is removed from the mold after formation, the thickness of the substrate near the magnetic layer may return to its original state and bulge slightly, potentially causing a deviation from the desired shape.

[0105] <Embodiment 6 Magnetic material mounting process: Spacing inspection step> The "spacing inspection step" is a step of inspecting the spacing between adjacent soft magnetic material-containing photocurable resin patterns that have been discharged from adjacent discharge windows and adhered to the surface of the substrate.

[0106] After the dispensing step, the cylinder is moved away from the substrate. As the resin is dispensed from multiple dispensing windows of the cylinder shown in Figure 5, the soft magnetic material-containing photocurable resin adhering to the substrate surface has a pattern shape that reflects the arrangement of the dispensing windows. The spacing between adjacent resin patterns is measured. The spacing between the resins is determined by the distance between the dispensing window at the tip of the cylinder and the substrate surface, and the amount of resin dispensed. The schematic cross-sectional diagram in Figure 6 and the photograph and schematic diagram of the resin pattern after dispensing in Figure 8 are examples where the amount of resin dispensed is appropriate. There are mounds of dispensed resin in the areas corresponding to the dispensing windows, and the areas corresponding to the base of these mounds have seeped into and spread across the substrate surface. The schematic cross-sectional diagram in Figure 7 shows an example where the amount of resin dispensed was too much, causing the resin patterns dispensed from adjacent dispensing windows to connect.

[0107] An example of "spacing" will be explained using the schematic cross-sectional diagram of the resin pattern on the substrate surface after extrusion shown in Figure 9. It may be the distance d1 between adjacent resin patterns on the substrate surface where the resin does not adhere or penetrate (or whether such a substrate surface is visible between the resins), or it may be the horizontal distances d2 and d3 at predetermined percentages of the resin height (e.g., 90%, 10%). Alternatively, the spacing may be determined by measuring the half-width d4 of the extruded resin pattern. This is because the apex position of the extruded resin corresponds to the position of the extrusion window and is almost fixed regardless of the extrusion conditions. Therefore, instead of measuring the distance between resin patterns, the half-width of the extruded resin pattern (the width of the resin pattern at a height half the height from the substrate surface to the apex) can be measured and subtracted from the spacing of the extrusion windows to determine the distance between resin patterns. Distances like this example can be measured and inspected using a measuring instrument.

[0108] As an example of spacing, as shown in the schematic diagram on the right of Figure 8, the distance between adjacent soft magnetic material-containing photocurable resin patterns (which may also be the substrate surface between adjacent resin patterns where the resin does not adhere or penetrate) d1 or d1' may be measured, or the presence or absence of the gap may be visually inspected. In the case of a simple visual inspection, for example, when both d1 and d1', which are the gaps between adjacent resins as shown in the schematic diagram on the right of Figure 8, disappear, it is judged that the discharge amount is excessive and exceeds the upper limit, and when the gap d'' (which may also be the substrate surface where the resin does not adhere or penetrate) between the resin patterns discharged from the central discharge window and the discharge window immediately outside it is visible, it is judged that the discharge amount is insufficient and falls below the lower limit. If it is determined that the discharge amount exceeds the upper limit or falls below the lower limit, the system is operated to judge it as NG in the quality judgment step described later, for example.

[0109] The interval inspection step may be performed either before or after curing the extruded soft magnetic material-containing photocurable resin.

[0110] <Embodiment 6 Magnetic material mounting process: Quality determination step> The "quality determination step" is a step in which the quality of the discharge is determined by the interval inspection step.

[0111] In the spacing inspection step, if the distance between the soft magnetic material-containing photocurable resins extruded and adhering to the substrate surface is greater than a predetermined value, the extrusion amount will fall below the lower limit, resulting in insufficient magnetic force on the mold's magnet and potentially preventing the resin from being fixed to the mold. This is considered a defect and the extrusion was not performed properly. Conversely, if the extrusion amount is so large that there are no gaps and exceeds the upper limit, while sufficient for adhesion to the mold, the amount of light irradiation for curing (cumulative light dose) may be insufficient, potentially leaving uncured areas. Furthermore, extruding more than necessary increases manufacturing costs. For this reason, it is also considered a defect. The pass / fail judgment may be based on the numerical result of the spacing measurement, or it may be performed by visual inspection to check for gaps between adjacent extruded resin patterns as described above. When measuring the spacing in the former case, the measuring instrument may be configured to incorporate a judgment function and perform the measurement simultaneously. Alternatively, the presence or absence of gaps between resin patterns extruded onto the substrate surface can be determined by pattern recognition using artificial intelligence.

[0112] If the discharge volume falls below the lower limit, additional soft magnetic material-containing photocurable resin may be manually dispensed. If the discharge volume exceeds the upper limit, additional curing light may be applied, or a portion may be removed if it has not yet cured.

[0113] When performing a quality determination step after curing of the extruded soft magnetic material-containing photocurable resin, it is preferable to configure the process to include not only the determination based on the results of the interval inspection step, but also the external shape of the magnetic layer formed on the surface of the substrate after extrusion (shape, thickness distribution, presence or absence of cracks and chips, presence or absence of foreign matter, etc.).

[0114] <Embodiment 6 Effects> The method for forming a soft magnetic material-containing photocurable resin on a substrate according to Embodiment 6 allows for inspection of the spacing between the resin particles adhering to the extruded substrate, enabling the determination of an appropriate extrusion amount and management of the extrusion step.

[0115] <Embodiment 7 Summary> Mainly Claim 7 Embodiment 7 forms a good magnetic layer by a soft magnetic material-containing photocurable resin extruded onto the surface of a substrate, by defining the specifications of the substrate (material, thickness, basis weight).

[0116] <Embodiment 7 Configuration> The base material of Embodiment 7, which is based on Embodiment 6, is a nonwoven fabric made of polyester fibers, and its material, thickness, and basis weight are configured as follows.

[0117] <Embodiment 7 Substrate> The "base material" of Embodiment 7, which is based on Embodiment 6, is a nonwoven fabric made of polyester fibers, with a thickness in the range of 0.5 mm to 50 mm, and a basis weight of 50 g / m². 2 More than 200g / m 2 The nonwoven fabric falls within the following range.

[0118] <Embodiment 7 Substrate: Nonwoven fabric material> When using an ultraviolet-curing resin that hardens with ultraviolet light as the photocurable resin contained in a soft magnetic material-containing photocurable resin, a nonwoven fabric made of polyester fibers is preferable as the base material. Polyester fibers are composed of polymers having aromatic rings, have a high molecular extinction coefficient for ultraviolet light, and have excellent ultraviolet shielding properties. Although it depends on the specifications of the fabric using polyester fibers, the transmittance of polyester fibers to UVA (wavelength 315 to 400 nm) is generally about 10 to 20%. Therefore, when light irradiation is performed from the back surface of the base material as in Embodiment 8 described later, light does not reach the soft magnetic material-containing photocurable resin near or on the surface of the base material more than necessary, thus preventing the resin on the surface side of the base material from starting to harden.

[0119] <Embodiment 7: Substrate: Thickness of nonwoven fabric> The nonwoven fabric used as a base material has a thickness in the range of 0.5 mm to 50 mm. When used in automobile seats, the thickness is 1 to 5 mm, preferably 1 mm to 3 mm, and more preferably 1.5 mm to 2.5 mm. For automobile seats, a certain thickness is necessary to ensure sufficient strength. If it becomes too thick, it becomes difficult to conform to the shape of the mold used to form the foam pad, so the above range is appropriate. The thickness of the nonwoven fabric used as a base material for cushions with complex shapes such as automobile seats is within the above range, but if it is used for other purposes (e.g., soundproofing material, heat insulating material, or doormats using nonwoven fabric alone with a magnetic layer), a thickness of 10 to 50 mm is appropriate.

[0120] <Embodiment 7: Base material: Nonwoven fabric basis weight> The basis weight of the nonwoven fabric is 50 g / m² when it is 2 mm thick. 2 From 200g / m 2 It is 100g / m 2 From 200g / m 2 Preferably, 120 to 160 g / m² 2 This is preferable. If the basis weight is small while maintaining the same thickness, it becomes a coarse nonwoven fabric, resulting in weaker strength. If the basis weight is small, when a soft magnetic material-containing photocurable resin is dispensed onto the substrate surface, it may soak into the nonwoven fabric too much, reach the back surface of the substrate, and adhere to and contaminate the stage of the dispensing device on which the substrate is placed. Conversely, if the basis weight is too large, the rigidity of the nonwoven fabric becomes too high, making it difficult to conform to the shape of the mold, so the above range is appropriate. When used as a base material for foam pads for automobile seats, if the basis weight is too large, the gas permeability during foaming of urethane resin and other materials may be further reduced.

[0121] <Embodiment 7 Effects> By using the nonwoven fabric of Embodiment 7 as a base material, the soft magnetic material-containing photocurable resin can be effectively extruded onto the base material surface, forming a magnetic layer.

[0122] <Embodiment 8 Summary> Mainly Claim 8 The method for forming a soft magnetic material-containing photocurable resin on a substrate according to Embodiment 8, which is based on either Embodiment 6 or Embodiment 7, is configured such that, after the dispensing step, a curing light is irradiated from the back side of the dispensed resin, the dispensing window is retracted above the resin, and the curing light is irradiated onto the resin.

[0123] <Embodiment 8 Configuration> A method for forming a soft magnetic material-containing photocurable resin on a substrate according to Embodiment 8, which is based on either Embodiment 6 or Embodiment 7, will be described with reference to Figures 10 and 11. The forming method of Embodiment 8, as indicated by the asterisk in Figure 10, is configured to include an irradiation step, a retraction step, and a curing step after the dispensing step, in addition to the forming method of Embodiment 6. Therefore, only the irradiation step, retraction step, and curing step will be described below. In the following description, the additional irradiation step, retraction step, and curing step are performed between the dispensing step and the interval inspection step, but the curing step may be performed after the interval inspection step or the pass / fail judgment step. The same effect can be obtained in that case as well.

[0124] <Embodiment 8: Irradiation Step> The "irradiation step" is a step performed after the discharge step in which a curing light beam is irradiated from the back side of the soft magnetic material-containing photocurable resin that has been discharged onto the substrate.

[0125] The leftmost figure in Figure 11 shows an example of the discharge step. A soft magnetic material-containing photocurable resin (1132) is discharged from the cylinder (1131) through the discharge window onto the surface of the substrate (1105). The center figure in Figure 11 shows an example of the irradiation step. UV light is irradiated from a UV-LED light source (1134) onto the back surface of the discharged resin through the substrate. In Figure 11, the stage (1133) where the cylinder (1131) and the substrate (1105) are in contact is missing, and the UV-LED light source (1134) is positioned there. A plate-shaped member that allows the curing light of the soft magnetic material-containing photocurable resin to pass through may be placed in the missing part of the stage. By positioning it at the same height as the stage surface in contact with the substrate, it is possible to prevent the substrate from bending significantly downward when the resin comes into contact with the substrate from the discharge window at the tip of the cylinder and a downward force is applied. When using UVA as the curing ray, and the resin is cured mainly with light of wavelengths around 365 nm to 385 nm, the plate-like member can be made of quartz glass or glass for flat panel displays such as liquid crystal panels, which have high transmittance from the aforementioned wavelengths to the visible light region. The same applies to the explanation using Figure 13 in Embodiment 9 described later.

[0126] When a soft magnetic material-containing photocurable resin is extruded onto a substrate and curing light is not irradiated from the back side, and the extrusion window is retracted vertically above the resin after the resin has been extruded onto the substrate surface, there was a problem in that the wettability or adhesion between the resin and the substrate surface was poor, and most of the extruded resin remained attached to the extrusion window and separated from the substrate surface. Therefore, conventionally, instead of retracting vertically, the window was moved slightly diagonally upward or horizontally before being retracted vertically upward to increase the contact area between the extruded resin and the substrate surface, preventing the resin from sticking to the extrusion window. This retraction method is like rubbing the resin extruded through multiple extrusion windows onto the substrate surface, and the gaps between the extruded resin particles are also filled with the rubbed resin. Therefore, it was not possible to inspect the extruded resin pattern to determine if the extruded amount was within the normal range. Instead, the only way to determine the extruded amount was to measure the cured resin after it had been cured using a ruler and a stylus step meter, which was not a simple procedure.

[0127] The curing light (e.g., ultraviolet light) irradiated from the back side of the resin discharged onto the substrate after the discharge step and before the discharge window is retracted is not for completely curing the resin, but rather to cure at least a portion of the resin that has penetrated the substrate or the resin near the substrate surface, thereby keeping the discharged resin on the substrate surface. By curing at least a portion of the resin that has penetrated or is in contact with the substrate, the resin can be kept attached to the discharge window and not separated from the substrate surface even when the discharge window is retracted vertically. In order to avoid distorting the shape of the discharged resin even when the discharge window is retracted vertically upward, the spacing of the resin corresponding to each discharge window can be measured in a later spacing inspection step.

[0128] The amount of curing light irradiated from the back during the irradiation step should be 10-20% of the total light amount required to completely cure the resin. Too much light will cause curing to begin on the surface side of the substrate. Too much light will cause the resin near the discharge window to begin curing, narrowing or blocking the opening of the discharge window. The above range is appropriate considering the transmittance of the nonwoven fabric and other materials that make up the substrate.

[0129] <Embodiment 8: Evacuation Step> The "retraction step" is a step in which the discharge window is retracted above the soft magnetic material-containing photocurable resin after the irradiation step.

[0130] As described above, when the irradiation step was not performed conventionally, instead of retracting vertically, the discharge window was moved slightly diagonally upward or horizontally before being retracted vertically upward to increase the contact area between the discharged resin and the substrate surface, preventing it from sticking to the discharge window. By using a photocurable resin as the polymerization raw material and further including an irradiation step, the discharge window can be retracted upward without distorting the shape of the resin discharged onto the substrate surface (without changing the spacing of the resin in contact with the substrate). The most preferable direction of retraction is vertically upward from the location where the resin was discharged, which is close to the substrate surface.

[0131] <Embodiment 8: Curing Step> The "curing step" is a step in which curing light is irradiated from above and / or below onto the soft magnetic material-containing photocurable resin that has been extruded onto the substrate after the retraction step. The far right figure in Figure 11 is an example of the curing step.

[0132] In the curing step, curing light is irradiated onto the substrate surface to completely cure the resin extruded onto it. The curing light varies depending on the type of photocurable resin used, but a typical example is the combination of a UV lamp or UV-LED for ultraviolet curable resins. In the example shown in the right-hand diagram of Figure 11, UV light is irradiated as curing light only from the surface side of the resin, but it is also possible to use only the UV-LED light source, which is the light source for the curing light on the back side used in the irradiation step, or to irradiate from both sides to cure the resin.

[0133] Using both upper and lower curing light sources increases the amount of curing light irradiated per unit time, thus shortening the curing time. The curing time for light-curing resins is only a few seconds, which is significantly shorter than the processing time for thermosetting resins, which can range from several minutes to tens of minutes (or even several hours depending on the type of resin).

[0134] <Embodiment 8: Effects> The method for forming a soft magnetic material-containing photocurable resin on a substrate according to Embodiment 8 allows the discharge window to be moved away from (retracted) from the substrate without having to apply the discharged soft magnetic material-containing photocurable resin. Furthermore, after being retracted in this manner, the distance between the resins can be measured, and the discharge amount can be controlled.

[0135] <Embodiment 9 Overview> Mainly Claim 9 The method for forming a soft magnetic material-containing photocurable resin on a substrate according to Embodiment 9 further includes an overflow pressing step in which, before curing the discharge window on the substrate, the tip of the cylinder is pressed against the substrate while the resin is overflowing from the discharge window.

[0136] <Embodiment 9 Configuration> Figures 12 and 13 show the forming method of Embodiment 9, which is based on the method for forming a soft magnetic material-containing photocurable resin on a substrate according to any one of Embodiments 6 to 8. The forming method of Embodiment 9 has an additional overflow pressing substep in the discharge step compared to the forming method of Embodiment 8. Since the steps other than the overflow pressing step have already been explained, only the overflow pressing step will be explained below. Similar effects can be obtained by basing the method on any one of Embodiments 6 and 7.

[0137] <Embodiment 9: Overflow Pressing Substep> The "overflow pressing substep" is a substep in the dispensing step in which, before lowering the dispensing window onto the substrate, the soft magnetic material-containing photocurable resin is allowed to overflow from the dispensing window, and then the tip of the cylinder is pressed against the substrate in that state.

[0138] Figure 12 shows a flow diagram of the magnetic material attachment process of Embodiment 9, which is based on Embodiment 8 (the method for forming a soft magnetic material-containing photocurable resin on a substrate according to the present application). In the discharge step, an overflow pressing step is performed.

[0139] Figure 13 is a schematic diagram illustrating each step. Five diagrams are arranged in a row. The leftmost diagram shows the state after the filling step is completed, the cylinder is set in the dispensing device, and the substrate (1305) is set on the stage of the dispensing device. Unlike Figure 11, the cylinder (1331) of the dispensing device has the UV-LED light source (1334) on the upper side of the substrate located in the opening and closing lid at the tip of the case (1336) that encloses the cylinder (1331). Similar to Figure 11, Figure 13 also lacks the stage portion corresponding to the substrate that the dispensed resin comes into contact with. As mentioned above, a plate-like member that transmits curing light, such as quartz glass, can be installed in this portion to prevent the substrate from bending downwards when the resin comes into contact with it.

[0140] The second figure from the left in Figure 13 shows the state after the dispensing step and the overflow pressing substep, in which the photocurable resin containing soft magnetic material is overflowed from the dispensing window. A predetermined amount is dispensed from the dispensing window and maintained with the photocurable resin containing soft magnetic material attached to the tip of the cylinder. If the viscosity and / or thixotropy is low, the dispensed resin will simply drip onto the substrate surface. With the lid at the tip of the cylinder (1331) case (1336) open, the tip of the cylinder is lowered below the lid and pressed against the substrate surface (see the figure in the center of Figure 13). By allowing a predetermined amount to overflow in advance, it is possible to prevent the dispensing amount from changing depending on the substrate, as the distance to the cylinder tip changes due to the unevenness of the substrate surface.

[0141] The fourth figure from the left in Figure 13 shows the irradiation step. While the tip of the cylinder is pressed down, a curing ray (UV light (1335) in the example of Figure 13) is irradiated from the back surface of the discharged soft magnetic material-containing photocurable resin to cure at least a portion of the resin that has penetrated the nonwoven fabric substrate or is near the surface of the substrate.

[0142] The rightmost diagram in Figure 13 shows the curing step. The cylinder is retracted vertically above the resin, the lid at the tip of the cylinder is closed, and UV light for curing the resin is irradiated from the UV-LED installed on the lid. After the resin has cured, the spacing between the resin pieces is inspected to determine if it is satisfactory, and the process is complete. In the curing step, it is also possible to configure the system to irradiate curing light from a lower UV-LED light source as well.

[0143] The cylinder for dispensing a soft magnetic material-containing photocurable resin shown in Figure 13 can be configured to open the lid at the front of the case by moving the cylinder to the dispensing position relative to the case. Conversely, it can be configured to close the lid at the front of the case by moving the cylinder upward relative to the case (away from the substrate surface). For example, a gear (pinion) can be installed on the rotation axis of the lid relative to the case so as to rotate in sync with the lid, and a rack (a flat plate with teeth of the same shape engraved at equal intervals) installed next to the cylinder can be engaged with it. With this configuration, the lid can be opened and closed by the vertical movement of the cylinder.

[0144] <Embodiment 9 Effects> The method for forming the soft magnetic material-containing photocurable resin onto a substrate according to Embodiment 9 makes it possible to keep the amount of resin discharged onto the substrate constant.

[0145] <Overview of Embodiment 10> In the dispensing step of the method for forming a soft magnetic material-containing photocurable resin onto a substrate according to Embodiment 10, the weight of the soft magnetic material-containing photocurable resin dispensed onto the substrate is in the range of 0.10 grams to 0.25 grams.

[0146] <Embodiment 10 Configuration> In the discharge step of the method for forming a soft magnetic material-containing photocurable resin onto a substrate according to Embodiment 10, which is based on any one of Embodiments 6 to 9, the weight of the soft magnetic material-containing photocurable resin discharged onto the substrate is in the range of 0.10 grams to 0.25 grams.

[0147] The weight of the resin dispensed onto the substrate in the dispensing step is between 0.1 grams and 0.25 grams. More preferably between 0.10 grams and 0.15 grams, and most preferably between 0.125 grams. If the dispensing amount is too small, the magnetic attraction force will be insufficient. If the dispensing amount is too large, when dispensed onto the substrate, adjacent resin patterns attached to the substrate surface may come into contact and merge, making it impossible to measure the distance between the resin patterns. With a dispensing amount of 0.25 grams or more, as estimated in Embodiment 1 regarding the aperture ratio, the transmission of curing light rays may be obstructed by the soft magnetic powder mixed with the resin, resulting in insufficient cumulative light required for curing inside the resin, and potentially insufficient curing. Therefore, the upper limit is 0.25 grams.

[0148] By setting the range as described above, the resin, after one dispensing step on the substrate surface, contains 0.05 grams to 0.1875 grams of soft magnetic material, forming a magnetic layer sufficient to be attracted to a magnet installed in the mold.

[0149] <Embodiment 10 Effects> In the method for forming a soft magnetic material-containing photocurable resin on a substrate according to Embodiment 10, by specifying the amount of resin to be discharged, it is possible to prevent the formed magnetic material layer from cracking or chipping when the substrate is bent, and furthermore, it can be successfully carried out when performing the overflow pressing substep.

[0150] <Effects> The present invention relates to a soft magnetic material powder (e.g., iron) to be mixed into an adhesive, and can provide a range of ratios in which a magnetic material layer with elasticity can be obtained, and in which a magnet can be sufficiently attracted to the substrate on which the magnetic material layer is formed. Furthermore, when dispensing the soft magnetic material-containing photocurable resin onto the substrate, a portion of the adhesive attached to the substrate can be cured before the dispensing window is removed from the substrate, thereby preventing the dispensing shape of the resin from collapsing, and the dispensing amount can be appropriately controlled based on an inspection of the distance between the dispensed resins. The present invention provides a method for forming a soft magnetic material-containing photocurable resin onto a substrate. [Explanation of Symbols]

[0151] Substrate ···1105 シリンダー···1131 Soft magnetic materials contain photocurable resins...1132 ステージ···1133 UV-LED light source... 1134 UV light...1135

Claims

1. A photocurable soft magnetic material-containing mixture for curing by irradiation with light, comprising polymerization raw materials including an ultraviolet-curable urethane oligomer having at least an acrylic group, a crosslinking agent, a photoreaction initiator, and iron powder, wherein the iron powder is present in a weight ratio of 50% or more to ensure magnetic force and 75% or less to ensure ultraviolet transmittance relative to the entire mixture before curing.

2. The soft magnetic material-containing photocurable mixture according to claim 1, wherein the crosslinking agent is 2-hydroxypropyl methacrylate.

3. The soft magnetic material-containing photocurable mixture according to claim 1 or claim 2, further containing a reaction-promoting additive.

4. The soft magnetic material-containing photocurable mixture according to claim 1 or claim 2, wherein the viscosity of the polymerization raw material contained in the mixture before photocuring is 1,000 to 500,000 millipascal seconds at a rotation speed of 0.6 rpm or less of a B-type viscometer.

5. The soft magnetic material-containing photocurable mixture according to claim 4, wherein the viscosity of the polymerization raw material contained in the mixture before photocuring is, as measured by a B-type rotational viscometer, 40,000 millipascal seconds or more and 44,000 millipascal seconds or less at 6 rpm and 30,000 millipascal seconds or more and 34,000 millipascal seconds or less at 12 rpm.

6. A filling step of filling a cylinder with the soft magnetic material-containing photocurable mixture described in claim 1, A dispensing step involves dispensing a filled soft magnetic material-containing photocurable mixture from multiple dispensing windows provided at the tip of the cylinder to the substrate until it penetrates to the back surface of the substrate, An irradiation step in which a curing light beam is irradiated from the back side of the soft magnetic material-containing photocurable mixture discharged onto the substrate, The process includes a retraction step in which, after the irradiation step, the discharge window is retracted upward in the direction normal to the surface of the substrate containing the soft magnetic material photocurable mixture. A spacing inspection step for inspecting the spacing between adjacent soft magnetic material-containing photocurable mixture patterns that have been discharged from adjacent discharge windows and adhered to the substrate surface, A quality determination step in which the quality of dispensing is determined by interval inspection steps, A method for forming a photocurable mixture containing a soft magnetic material onto a substrate.

7. The method for forming a soft magnetic material-containing photocurable mixture onto a substrate according to claim 6, wherein the substrate is a nonwoven fabric made of polyester fibers, having a thickness in the range of 0.5 mm to 50 mm and a basis weight in the range of 50 g / m² to 200 g / m².

8. After the aforementioned discharge step, A curing step in which a curing ray is irradiated from above and / or below onto the soft magnetic material-containing photocurable mixture discharged onto the substrate after the retraction step, A method for forming a soft magnetic material-containing photocurable mixture onto a substrate according to claim 6 or claim 7, further comprising the above.

9. The method for forming a soft magnetic material-containing photocurable mixture onto a substrate according to claim 6 or claim 7, wherein the discharge step further comprises a sub-step in which the soft magnetic material-containing photocurable mixture is allowed to overflow from the discharge window before the discharge window is lowered onto the substrate, and then the tip of the cylinder is pressed against the substrate in that state.

10. A method for forming a soft magnetic material-containing photocurable mixture onto a substrate according to claim 6 or claim 7, wherein the weight of the soft magnetic material-containing photocurable mixture discharged onto the substrate in the discharge step is in the range of 0.10 grams to 0.25 grams.

Images