Method for manufacturing a safety guard panel, transfer sheet, safety guard panel, and safety guard

Abstract

This invention provides a method for efficiently manufacturing safety guard panels that have good scratch resistance and good chemical resistance. [Solution] A method for manufacturing a safety guard panel is provided, comprising: a preparation step of preparing a transfer sheet having a release film and a transfer layer; and a lamination step of laminating the polycarbonate substrate and the transfer sheet so that the polycarbonate substrate and the transfer layer face each other while the polycarbonate substrate is heated to 100°C or higher, wherein the transfer layer has a hard coat layer and a heat seal layer in that order from the release film side, and when an acetone rubbing test is performed on the side of the hard coat layer opposite to the heat seal layer, the difference in the haze value of the safety guard panel before and after the acetone rubbing test is 1% or less.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a safety guard panel, a transfer sheet, a safety guard panel, and a safety guard.

Background Art

[0002] Polycarbonate is a type of thermoplastic resin and has characteristics of high transparency, impact resistance, and heat resistance. Therefore, polycarbonate is used, for example, as a panel of a safety guard that protects an operator from machinery such as industrial machines. For example, Patent Document 1 discloses a safety guard using polycarbonate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a coating is applied to the surface of a polycarbonate substrate to form a hard coat layer, a safety guard panel having good scratch resistance can be obtained. However, when applying a coating, generally, it is necessary to perform it on a manufacturing line different from the molding of the polycarbonate substrate, and the process becomes complicated. Furthermore, since the coating requires a coating process, a drying process, and a curing process, the manufacturing efficiency is low. Therefore, a method for manufacturing a safety guard panel with high manufacturing efficiency is required. In addition, the hard coat layer may be required to have not only scratch resistance but also chemical resistance.

[0005] The present disclosure has been made in view of the above circumstances, and the main object thereof is to provide a method for manufacturing a safety guard panel capable of efficiently manufacturing a safety guard panel having good scratch resistance and good chemical resistance. [Means for solving the problem]

[0006] This disclosure provides a method for manufacturing a safety guard panel, comprising: a preparation step of preparing a transfer sheet having a release film and a transfer layer; and a lamination step of laminating the polycarbonate substrate and the transfer sheet so that the polycarbonate substrate and the transfer layer face each other while the polycarbonate substrate is heated to 100°C or higher, wherein the transfer layer has a hard coat layer and a heat seal layer in that order from the release film side, and when an acetone rubbing test is performed on the side of the hard coat layer opposite to the heat seal layer, the difference in the haze value of the safety guard panel before and after the acetone rubbing test is 1% or less.

[0007] This disclosure provides a transfer sheet used in the manufacture of a safety guard panel having a polycarbonate substrate, wherein the transfer sheet comprises a release film and a transfer layer, the transfer layer comprising a hard coat layer and a heat seal layer in order from the release film side, and when an acetone rubbing test is performed on the side of the hard coat layer opposite to the heat seal layer, the difference in the haze value of the transfer sheet before and after the acetone rubbing test is 1% or less.

[0008] This disclosure provides a safety guard panel comprising a polycarbonate substrate and a transfer layer, wherein the transfer layer has, in order from the polycarbonate substrate side, a heat seal layer and a hard coat layer, and when an acetone rubbing test is performed on the side of the hard coat layer opposite to the heat seal layer, the difference in the haze value of the safety guard panel before and after the acetone rubbing test is 1% or less.

[0009] This disclosure provides a safety guard comprising the safety guard panel described above and a frame disposed around the periphery of the safety guard panel. [Effects of the Invention]

[0010] This disclosure offers the advantage of efficiently manufacturing safety guard panels that have good scratch resistance and good chemical resistance. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view illustrating a method for manufacturing the safety guard panel described in this disclosure. [Figure 2] This is a schematic cross-sectional view illustrating a transfer sheet in this disclosure. [Figure 3] This is a schematic cross-sectional view illustrating the method for manufacturing the transfer sheet in this disclosure. [Figure 4] This is a schematic perspective illustrating the safety guards in this disclosure. [Modes for carrying out the invention]

[0012] The embodiments will be described below with reference to the drawings, etc. However, this disclosure can be implemented in many different ways and is not limited to the embodiments described below. In addition, the drawings may schematically represent the width, thickness, and shape of each part compared to the actual form in order to make the explanation clearer, but this is merely an example and should not be interpreted as limiting.

[0013] In this specification, when describing a manner in which one member is placed on another member, the term "above" or "below" includes, unless otherwise specified, both cases: when the other member is placed directly above or directly below the member so as to be in contact with it, and when the other member is placed above or below the member via yet another member. Similarly, in this specification, when describing a manner in which one member is placed on the surface of a member, the term "on the surface" includes, unless otherwise specified, both cases: when the other member is placed directly above or directly below the member so as to be in contact with it, and when the other member is placed above or below the member via yet another member.

[0014] A. Manufacturing method of safety guard panel Figure 1 is a schematic cross-sectional view illustrating a method for manufacturing a safety guard panel according to this disclosure. First, as shown in Figure 1(a), a transfer sheet 10 having a release film 1 and a transfer layer X is prepared (preparation step). The transfer layer X has a hard coat layer 2 and a heat seal layer 3 in order from the release film 1 side. Next, as shown in Figures 1(b) and (c), the polycarbonate substrate 20 and the transfer sheet 10 are laminated together with the polycarbonate substrate 20 and the transfer layer X facing each other while the polycarbonate substrate 20 is heated to 100°C or higher (lamination step). Next, as shown in Figures 1(c) and (d), the release film 1 is peeled off from the laminate of the polycarbonate substrate 20 and the transfer sheet 10 to obtain a safety guard panel 100. As shown in Figure 1(d), when an acetone rubbing test is performed on the surface S1 of the hard coat layer 2 opposite to the heat seal layer 3, the difference in the haze value of the safety guard panel 100 before and after the acetone rubbing test is 1% or less.

[0015] According to this disclosure, a hard coat layer having good scratch resistance and good chemical resistance is provided on a polycarbonate substrate by a transfer method. Therefore, a safety guard panel with good scratch resistance and good chemical resistance can be efficiently manufactured. As described above, if a hard coat layer is formed on the surface of the polycarbonate substrate after molding, for example, a coating is applied to the surface of the polycarbonate substrate to obtain a safety guard panel with good scratch resistance. However, when applying a coating, it is generally necessary to do so on a separate manufacturing line from the molding of the polycarbonate substrate, making the process complicated. Furthermore, since coating requires a coating process, a drying process and a curing process, the manufacturing efficiency is low. In addition, with general coatings, a primer layer must be applied and dried before the hard coat layer is applied, dried and cured, so the manufacturing efficiency is further reduced.

[0016] In contrast, this disclosure provides a hard coat layer to a polycarbonate substrate using a transfer method with a transfer sheet. Therefore, it is possible to provide the hard coat layer on the same production line as the molding of the polycarbonate substrate, simplifying the process. Furthermore, when using the transfer method, a transfer sheet with a hard coat layer already applied is used, significantly improving manufacturing efficiency compared to when using the coating method. Moreover, when using the coating method, it is necessary to heat the polycarbonate substrate to a high temperature in order to form the hard coat layer. In contrast, by using the transfer method, it is not necessary to heat the polycarbonate substrate to a high temperature compared to when using the coating method, thereby reducing thermal damage to the polycarbonate substrate and improving energy efficiency during manufacturing.

[0017] In addition, when adopting the coating method, after forming the hard coat layer, it is necessary to attach a protective film (masking film). On the other hand, when adopting the transfer method, the release film of the transfer sheet can be utilized as a protective film (masking film), and the manufacturing efficiency is improved. Further, the hard coat layer in the present disclosure has good chemical resistance in addition to good scratch resistance, so that deterioration of the polycarbonate base material due to chemicals can be suppressed, and a safety guard panel having good durability can be obtained.

[0018] 1. Preparation process The preparation process in the present disclosure is a process of preparing a transfer sheet having a release film and a transfer layer. As shown in FIG. 1(a), the transfer sheet 10 has a release film 1 and a transfer layer X. Further, the transfer layer X has a hard coat layer 2 and a heat seal layer 3 in order from the release film 1 side. As shown in FIG. 2, the transfer layer X may have a primer layer 4 between the hard coat layer 2 and the heat seal layer 3. By providing the primer layer 4, the adhesion between the hard coat layer 2 and the heat seal layer 3 is improved.

[0019] (1) Hard coat layer The hard coat layer in the present disclosure is a layer that imparts hard coat properties to a polycarbonate base material described later. In particular, the hard coat layer in the present disclosure has good scratch resistance and good chemical resistance.

[0020] As shown in FIG. 1(a), the hard coat layer 2 in the transfer layer X has a surface S1 on the side opposite to the heat seal layer 3. When an acetone rubbing test is performed on the surface S1, the difference in the haze value of the transfer layer X before and after the acetone rubbing test is usually 1% or less. Specifically, before performing the acetone rubbing test, the haze value of the transfer layer X is measured using a haze meter based on JIS K 7136. Then, a gauze impregnated with acetone is brought into contact with the surface S1, and a load of 300 g / cm 2Perform five back-and-forth passes (acetone rubbing test). Then, measure the haze value of the transfer layer X in the same manner as above. The difference in haze value before and after the acetone rubbing test (haze value after the test - haze value before the test) is usually 1% or less. To reduce the difference in haze value before and after the acetone rubbing test, it is preferable, for example, to reduce the molecular weight of the resin component and increase the crosslinking density.

[0021] As shown in Figure 1(a), the hard coat layer 2 in the transfer layer X has a surface S1. When a steel wool test is performed on surface S1, it is preferable that almost no change in appearance is observed. Specifically, steel wool (bonstar, #0000) is brought into contact with surface S1 and a load of 300 g / cm² is applied. 2 The steel wool test is performed by passing the material back and forth five times. When 10 observers visually inspect surface S1 after the steel wool test, it is preferable that at least 8 people judge that there was almost no change in appearance. Methods to minimize the change in appearance before and after the steel wool test include, for example, adjusting the amount of additives such as scratch-resistant particles, and increasing the crosslinking density of the resin components.

[0022] The hard coat layer contains a resin. Preferably, the resin is a cured product of a composition containing a curable resin. Examples of curable resins include ionizing radiation curable resins and thermosetting resins. The curable resin may also be a polymerizable oligomer (prepolymer) or a polymer. The composition containing the curable resin may use the curable resin alone or in combination with other resins. In this disclosure, it is particularly preferable to use an ionizing radiation curable resin. By using an ionizing radiation curable resin, energy consumption during transfer film production can be further reduced. Furthermore, by using an ionizing radiation curable resin, a high crosslinking density can be designed, making it particularly suitable for applications such as safety guard panels where scratch resistance and chemical resistance are required.

[0023] Ionizing radiation-curable resins are resins that harden when irradiated with ionizing radiation. Ionizing radiation includes electromagnetic waves and charged particle beams that have energy quanta capable of polymerizing or crosslinking molecules. Examples of ionizing radiation include ultraviolet (UV) rays, electron beams (EB), electromagnetic waves (e.g., X-rays, gamma rays), and charged particles (e.g., alpha rays, ion beams).

[0024] The ionizing radiation-curable resin may be a polymerizable oligomer (prepolymer) or a polymer. Examples of polymerizable oligomers include those having radical polymerizable unsaturated groups in the molecule. Examples of oligomers having radical polymerizable unsaturated groups in the molecule include epoxy (meth)acrylate, urethane (meth)acrylate, polyether-based urethane (meth)acrylate, caprolactone-based urethane (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate. The above oligomer is preferably a polyfunctional polymerizable oligomer. The number of functional groups in the polyfunctional polymerizable oligomer may be, for example, 2 to 15, 2 to 8, or 2 to 6. In this disclosure, (meth)acrylate means acrylate or methacrylate.

[0025] On the other hand, an example of a monofunctional polymerizable oligomer is caprolactone-based urethane (meth)acrylate obtained by the reaction of a caprolactone-based polyol with an organic isocyanate and a hydroxy(meth)acrylate. Another example of a monofunctional polymerizable oligomer is polybutadiene (meth)acrylate having a (meth)acrylate group in the side chain of a polybutadiene oligomer.

[0026] The molecular weight of the polymerizable oligomer may be, for example, 8,000 or less, or 5,000 or less.

[0027] Polymerizable polymers are polymers that have radically polymerizable unsaturated groups in their molecules. Examples of polymerizable polymers include epoxy (meth)acrylate, urethane (meth)acrylate, polyether-based urethane (meth)acrylate, polycaprolactone-based urethane (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate.

[0028] The hard coat layer may contain scratch-resistant particles. Examples of scratch-resistant particles include inorganic particles. Examples of materials for the inorganic particles include silica, alumina, kaolinite, iron oxide, diamond, and silicon carbide. The shape of the scratch-resistant particles is not particularly limited. The average particle size of the scratch-resistant particles is not particularly limited, but for example, it may be 4 μm or less, 2 μm or less, or less than 1 μm. On the other hand, the average particle size of the scratch-resistant particles is, for example, 0.05 μm or more. The average particle size in this disclosure is measured by a laser diffraction particle size distribution analyzer. 50 This refers to the proportion of scratch-resistant particles in the hard coat layer, which is, for example, 1 part by mass or more and 5 parts by mass or less per 100 parts by mass of resin component in the hard coat layer.

[0029] The hard coat layer may contain weather-resistant agents such as UV absorbers and light stabilizers. Adding weather-resistant agents improves the weather resistance of the safety guard panel. Examples of UV absorbers include hydroxyphenyltriazine-based UV absorbers. Examples of light stabilizers include hindered amine-based light stabilizers. The proportion of UV absorber in the hard coat layer is, for example, 1 to 5 parts by mass per 100 parts by mass of resin components in the hard coat layer. The proportion of light stabilizer in the hard coat layer is, for example, 1 to 5 parts by mass per 100 parts by mass of resin components in the hard coat layer.

[0030] The thickness of the hard coat layer is not particularly limited, but for example, it may be 1 μm or more, 1.5 μm or more, or 2 μm or more. If the hard coat layer is too thin, good scratch resistance and good chemical resistance may not be obtained. On the other hand, the thickness of the hard coat layer may be 20 μm or less, 10 μm or less, or 5 μm or less. If the hard coat layer is too thick, the effect of curing shrinkage during manufacturing will be large, which may reduce manufacturing efficiency.

[0031] (2) Heat seal layer The heat-seal layer in this disclosure is a layer for adhering the transfer layer to the polycarbonate substrate described later.

[0032] The heat seal layer contains a heat-sealing resin. Examples of heat-sealing resins include acrylic resins, modified polyolefin resins, vinyl chloride-vinyl acetate copolymers, polyamide resins, polyester resins, chlorinated polypropylene, chlorinated rubber, urethane resins, epoxy resins, and styrene resins.

[0033] The heat seal layer may contain weather-resistant agents such as UV absorbers and light stabilizers. The type and proportion of weather-resistant agents are the same as those described in "(1) Hard coat layer" above. The thickness of the heat seal layer is not particularly limited, but for example, it may be 1 μm to 7 μm, or 1 μm to 6 μm.

[0034] (3) Primer layer As shown in Figure 2, the transfer layer X may have a primer layer 4 between the hard coat layer 2 and the heat seal layer 3. Providing the primer layer 4 improves the adhesion between the hard coat layer 2 and the heat seal layer 3.

[0035] The primer layer contains a resin. Examples of the resin include the cured product of a two-component curable resin composition containing a main resin and a curing agent.

[0036] Examples of the main resin include polyurethane resin, (meth)acrylic resin, vinyl chloride / vinyl acetate copolymer, polyester resin, butyral resin, chlorinated polypropylene, and chlorinated polyethylene. The main resin may be used alone or in combination of two or more types. Among these resins, polyurethane resin is preferred from the viewpoint of adhesion and weather resistance.

[0037] The polyurethane resin is preferably a polyurethane resin having an acrylic skeleton in its polymer chain. This is because it has high weather resistance and durability. Examples of polyurethane resins having an acrylic skeleton in its polymer chain include urethane-acrylic copolymers, which are copolymers of a urethane component and an acrylic component. One example of a method for forming a urethane-acrylic copolymer is to react an acrylic resin having at least two hydroxyl groups in one molecule with a polyol compound and an isocyanate compound (see Japanese Patent Publication No. 6-100653, etc.). Another example of a method for forming a urethane-acrylic copolymer is to react an acrylic monomer with a urethane prepolymer having unsaturated double bonds at both ends (see Japanese Patent Publication No. 10-1524, etc.).

[0038] Among polyurethane resins having an acrylic skeleton in the polymer chain, polyurethane resins further having a polycarbonate skeleton or a polyester skeleton in the polymer chain are preferred. This is because they have high adhesion to the hard coat layer. Examples of polyurethane resins having an acrylic skeleton in the polymer chain and further having a polycarbonate skeleton include polycarbonate-based urethane-acrylic copolymers, which are copolymers of a polycarbonate-based urethane component and an acrylic component. On the other hand, examples of polyurethane resins having an acrylic skeleton in the polymer chain and further having a polyester skeleton include polyester-based urethane-acrylic copolymers, which are copolymers of a polyester-based urethane component and an acrylic component.

[0039] Examples of curing agents in a two-component curing resin composition include isocyanate curing agents such as tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, cyclohexanephenylene diisocyanate, and naphthalene-1,5-diisocyanate. The amount of isocyanate curing agent used is, for example, 1 to 40 parts by mass per 100 parts by mass of the main resin component, and may be 10 to 30 parts by mass, or 20 to 30 parts by mass.

[0040] The primer layer may contain additives. Examples of additives include fillers, UV absorbers, light stabilizers, abrasion resistance enhancers, infrared absorbers, antistatic agents, adhesion enhancers, leveling agents, thixotropic agents, coupling agents, plasticizers, defoamers, fillers, solvents, and colorants. In particular, it is preferable that the primer layer contains at least one of UV absorbers and light stabilizers. The types and proportions of UV absorbers and light stabilizers are the same as those described in "(1) Hard Coat Layer" above. The thickness of the primer layer is not particularly limited, but for example, it may be 0.1 μm to 10 μm, 0.1 μm to 5 μm, or 1 μm to 4 μm.

[0041] (4) Release film The release film in this disclosure is a film that supports the transfer layer. The release film contains a resin. Examples of the resin include polyester resins such as polybutylene terephthalate, polyethylene naphthalate, polyarylate, polycarbonate, and ethylene terephthalate-isophthalate copolymer; and polyolefin resins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer, and olefin thermoplastic elastomer.

[0042] The release film is preferably a stretched film because it has high shrinkage resistance and allows for stable production of transfer sheets. The release film may be uniaxially stretched or biaxially stretched, but the latter is preferred because it has higher shrinkage resistance.

[0043] To improve the release properties of the release film from the hard coat layer, the surface facing the hard coat layer may be treated with a release agent, or a release layer containing a release agent such as silicone resin or fatty acid ester may be provided. Conversely, to improve the adhesion of the release film to the hard coat layer, a surface treatment may be applied. Examples of surface treatments include corona discharge treatment, plasma treatment, chromium oxidation treatment, flame treatment, hot air treatment, and ozone / ultraviolet treatment.

[0044] The release film preferably has a high visible light transmittance. This is because it allows the worker to easily visually confirm the adhesion between the transfer layer and the polycarbonate substrate through the release film. The visible light transmittance of the release film is, for example, 75% or higher, may be 80% or higher, or 85% or higher. The visible light transmittance is the average transmittance in the visible light region (wavelengths from 380 nm to 780 nm) and is measured by a spectrophotometer.

[0045] The thickness of the release film is not particularly limited, but for example, it is between 4 μm and 200 μm. If the release film is too thin, curling or wrinkling may occur easily, and if the release film is too thick, it may be disadvantageous in terms of cost.

[0046] (5) Transfer sheet The transfer sheet in this disclosure comprises a release film and a transfer layer. As described above, the transfer layer comprises at least a hard coat layer and a heat seal layer, in that order from the release film side. The transfer layer may have other layers, such as a primer layer, between the hard coat layer and the heat seal layer.

[0047] The transfer sheet preferably has a high visible light transmittance. This is because it allows the worker to easily visually inspect the condition of the polycarbonate substrate through the transfer sheet. The visible light transmittance of the transfer sheet is, for example, 75% or higher, may be 80% or higher, or 85% or higher. The method for measuring the visible light transmittance is as described above.

[0048] The method for producing the transfer sheet is not particularly limited. For example, as shown in Figure 3(a), a release film 1 is prepared. Next, as shown in Figure 3(b), a hard coat layer forming composition is applied to one side of the release film 1 to form a hard coat layer 2. Examples of coating methods include gravure coating, gravure reverse coating, gravure offset coating, spinner coating, roll coating, reverse roll coating, kiss coating, wheeler coating, and dip coating. For example, consider a case where the hard coat layer forming composition contains an ionizing radiation-curable resin, and the hard coat layer forming composition is cured using an electron beam as the ionizing radiation. In this case, the acceleration voltage of the electron beam is, for example, 70kV to 300kV, and the irradiation dose of the electron beam is, for example, 5Mrad to 10Mrad.

[0049] Next, as shown in Figure 3(c), a primer layer-forming composition is applied to the side of the hard coat layer 2 opposite to the release film 1 to form a primer layer 4. The application method is as described above. Next, as shown in Figure 3(d), a heat seal layer-forming composition is applied to the side of the primer layer 4 opposite to the hard coat layer 2 to form a heat seal layer 3. The application method is as described above. In this way, a transfer sheet 10 is obtained.

[0050] 2.Lamination process The lamination process in this disclosure is a process of laminating the polycarbonate substrate and the transfer sheet so that the polycarbonate substrate and the transfer layer face each other while the polycarbonate substrate is heated to 100°C or higher.

[0051] The polycarbonate substrate contains a polycarbonate resin. The type of polycarbonate resin is not particularly limited. The polycarbonate substrate may also contain additives as needed. Examples of such additives include release agents (e.g., fatty acid ester-based release agents), heat stabilizers (e.g., phosphate ester-based heat stabilizers, phenol-based heat stabilizers), ultraviolet absorbers (e.g., benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, acetophenone-based ultraviolet absorbers, salicylate-based ultraviolet absorbers), antistatic agents (polyhydric alcohol-based antistatic agents, anionic antistatic agents such as ammonium salts), whitening agents, colorants, and flame retardants.

[0052] A polycarbonate substrate with high visible light transmittance is preferable, as it allows operators to easily visually inspect the machine's condition through the release film. The visible light transmittance of the polycarbonate substrate is, for example, 80% or higher, may be 85% or higher, or 90% or higher. The method for measuring visible light transmittance is as described above.

[0053] The polycarbonate substrate is preferably flat. The thickness of the polycarbonate substrate is, for example, 1 mm or more, may be 1.5 mm or more, or 2 mm or more. On the other hand, the thickness of the polycarbonate substrate is, for example, 20 mm or less, or 15 mm or less.

[0054] One example of a method for producing a polycarbonate substrate is the extrusion molding method. In the extrusion molding method, for example, a polycarbonate resin is heated and melted, extruded from the die of an extruder, rolled with a cooling roll, passed through a guide roll, and cooled and solidified while being moved with a moving roll. In this disclosure, the production of the polycarbonate substrate and the lamination process may be carried out continuously on the same line.

[0055] The lamination process is carried out with the polycarbonate substrate heated to 100°C or higher. By heating the polycarbonate substrate, residual stress in the polycarbonate substrate is released, and the polycarbonate substrate can be bonded to the heat seal layer in the transfer sheet. The heating temperature of the polycarbonate substrate may be 120°C or higher, or 150°C or higher. On the other hand, the heating temperature of the polycarbonate substrate may be, for example, 250°C or lower.

[0056] The method for heating the polycarbonate substrate is not particularly limited, but one example is the use of a heater. It is preferable that at least the side of the polycarbonate substrate on which the transfer sheet is laminated is heated. On the other hand, both sides of the polycarbonate substrate may be heated. Furthermore, it is preferable to heat the polycarbonate substrate so that its surface temperature falls within the above temperature range.

[0057] In the lamination process, the polycarbonate substrate and the transfer sheet are laminated so that the polycarbonate substrate and the transfer layer face each other. The method of laminating the polycarbonate substrate and the transfer sheet is not particularly limited, but for example, the transfer sheet is unwound from a winding body, the unwound transfer sheet is positioned to face the polycarbonate substrate, and the facing polycarbonate substrate and transfer sheet are heated and pressurized by a pair of rolls. The pressure of the rolls is, for example, 1.0 MPa or more. The heating temperature of the rolls is, for example, 90°C to 150°C.

[0058] 3. Peeling process The manufacturing method for the safety guard panel in this disclosure may include a peeling step after the lamination step in which a release film is peeled off from the laminate formed by laminating the polycarbonate substrate and the transfer sheet. By peeling off the release film from the laminate, the hard coat layer is usually exposed. Alternatively, the release film may not be peeled off from the laminate, and the release film may be used as a protective film (masking film) for the safety guard panel. The protective film is peeled off from the laminate, for example, after the frame is installed on the safety guard panel and the safety guard is manufactured.

[0059] 4. Safety Guard Panel As shown in Figure 1(d), the hard coat layer 2 of the safety guard panel 100 has a surface S1 opposite to the heat seal layer 3. When an acetone rubbing test is performed on surface S1, the difference in the haze value of the safety guard panel 100 before and after the acetone rubbing test is usually 1% or less. The acetone rubbing test is the same as described above. The haze value of the safety guard panel before the acetone rubbing test is not particularly limited, but may be, for example, 15% or less, 12.5% ​​or less, or 10% or less.

[0060] As shown in Figure 1(d), the hard coat layer 2 of the safety guard panel 100 has a surface S1. When a steel wool test is performed on surface S1, it is preferable that almost no change in appearance is observed. The steel wool test is the same as described above. When 10 observers visually inspect surface S1 after the steel wool test, it is preferable that 8 or more people judge that almost no change in appearance was observed.

[0061] Safety guard panels should preferably have a high visible light transmittance. This is because it allows workers to easily see the condition of the machine through the safety guard panel. The visible light transmittance of the safety guard panel should be, for example, 75% or higher, but may also be 80% or higher, or 85% or higher. The method for measuring visible light transmittance is as described above.

[0062] The shape of the safety guard panel is preferably flat. That is, it is preferable not to perform heat bending on the laminate formed by laminating the polycarbonate substrate and the transfer sheet after the lamination process. This is because a flat shape for the safety guard panel makes it easier to install the frame on the safety guard panel.

[0063] B. Transfer sheet As shown in Figure 1(a), the transfer sheet 10 in this disclosure has a release film 1 and a transfer layer X. The transfer layer X has a hard coat layer 2 and a heat seal layer 3 in that order from the release film 1 side. Furthermore, when an acetone rubbing test is performed on the surface S1 of the hard coat layer 2 opposite to the heat seal layer 3, the difference in the haze value of the transfer layer X before and after the acetone rubbing test is 1% or less.

[0064] According to this disclosure, the transfer sheet has a hard coat layer with good scratch resistance and good chemical resistance, resulting in a transfer sheet with good durability. Furthermore, the transfer sheet in this disclosure is the same as that described in "A. Method for Manufacturing Safety Guard Panels" above.

[0065] C. Safety Guard Panel As shown in Figure 1(d), the safety guard panel 100 in this disclosure comprises a polycarbonate substrate 20 and a transfer layer X. The transfer layer X is a layer transferred from a transfer sheet and is not a layer formed by coating. The transfer layer X also has a heat seal layer 3 and a hard coat layer 2 in that order from the polycarbonate substrate 20 side. Furthermore, when an acetone rubbing test is performed on the surface S1 of the hard coat layer 2 opposite to the heat seal layer 3, the difference in the haze value of the safety guard panel 100 before and after the acetone rubbing test is 1% or less.

[0066] According to this disclosure, a safety guard panel has good durability because it has a hard coat layer with good scratch resistance and good chemical resistance.

[0067] The safety guard panel in this disclosure is the same as that described in "A. Method for Manufacturing a Safety Guard Panel" above. In addition, this disclosure also provides a safety guard 200 having a safety guard panel 100 and a frame 150 arranged around the periphery of the safety guard panel 100, as shown in Figure 4.

[0068] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of this disclosure and achieves similar effects is included within the technical scope of this disclosure. [Examples]

[0069] [Example 1] (Preparation of transfer sheet) A biaxially oriented PET film (50 μm thick), which serves as a release film, is coated with the following hard coat layer formation composition at a rate of 5 g / m² using the gravure reverse coating method. 2 A hard coat layer with a thickness of 4 μm was formed by coating with the specified amount and curing with electron beam irradiation at 5 Mrad. (Composition for forming a hard coat layer) Polyfunctional urethane acrylate (molecular weight: approximately 1,000): 60 parts by mass 2-polyfunctional caprolactone-modified urethane acrylate (molecular weight: several thousand): 40 parts by mass Nanosilica (average particle size: less than 1 μm): 3 parts by mass Hydroxyphenyltriazine-based UV absorber: 3 parts by mass Hindered amine-based light stabilizer: 3 parts by mass

[0070] Next, the following primer layer-forming composition is applied to the hard coat layer by gravure reverse application at a rate of 5 g / m². 2The coating was applied using the specified amount to form a 4 μm thick primer layer. (Composition for forming primer layer) Urethane-acrylic copolymer (urethane component / acrylic component = 1 / 1): 100 parts by mass Silica particles (average particle size: 5 μm): 5 parts by mass Hydroxyphenyltriazine-based UV absorber: 10 parts by mass Hindered amine-based light stabilizer: 5 parts by mass Curing agent (hexanemethylene diisocyanate): 10 parts by mass

[0071] Next, a heat seal layer forming composition (100 parts by mass of acrylic resin) is applied to the primer layer by gravure reverse application at a rate of 5 g / m². 2 The coating was applied with the specified amount to form a heat-seal layer with a thickness of 4 μm. This resulted in obtaining a transfer sheet having a release film and a transfer layer (hard coat layer, primer layer, and heat-seal layer).

[0072] (Manufacturing of safety guard panels) Polycarbonate resin (Teijin Panlite L-1250Y) was kneaded and molded into a 3mm thick sheet to obtain a polycarbonate substrate. Both sides of the obtained polycarbonate substrate were heated with a heater until the surface temperature reached 100°C, and then the polycarbonate substrate and the heat seal layer of the transfer sheet were bonded together. The surface temperature of the polycarbonate substrate was recorded by connecting a non-contact temperature sensor (GT-P710, Optex FA Co., Ltd.) to a data logger (GL240, Graphtec Corporation). The release film was peeled off from the laminate of the polycarbonate substrate and the transfer sheet to obtain a safety guard panel.

[0073] [Example 2] A safety guard panel was obtained in the same manner as in Example 1, except that the heating temperature of the polycarbonate substrate was changed to 130°C.

[0074] [Example 3] A safety guard panel was obtained in the same manner as in Example 1, except that the heat seal layer forming composition was changed to a modified polyolefin resin.

[0075] [Comparative Example 1] A safety guard panel was obtained in the same manner as in Example 1, except that the heating temperature of the polycarbonate substrate was changed to 90°C.

[0076] [Comparative Example 2] A safety guard panel was obtained in the same manner as in Example 1, except that the composition for forming the hard coat layer was modified as described below. (Composition for forming a hard coat layer) Bifunctional polycarbonate diol-based urethane acrylate (molecular weight: approximately 30,000): 60 parts by mass Bifunctional polycarbonate diol-based urethane acrylate (molecular weight: approximately 50,000): 40 parts by mass Nanosilica (average particle size less than 1 μm): 3 parts by mass Hydroxyphenyltriazine-based UV absorber: 3 parts by mass Hindered amine-based light stabilizer: 3 parts by mass

[0077] [evaluation] (Scratch resistance) The scratch resistance of the safety guard panels obtained in Examples 1-3 and Comparative Examples 1 and 2 was evaluated. Specifically, steel wool (Bonstar, #0000) was brought into contact with the surface of the hard coat layer of the safety guard panel, and a load of 300 g / cm² was applied. 2 The test involved five passes (steel wool test). Afterward, the surface condition of the hard coat layer was visually inspected and evaluated according to the following criteria. The results are shown in Table 1. ○: Of the 10 observers, 8 or more judged that little to no change in appearance was observed. △: Of the 10 observers, 4 or more and 7 or fewer judged that little to no change in appearance was observed. ×: Of the 10 observers, 3 or fewer judged that little to no change in appearance was observed.

[0078] (Chemical resistance) The chemical resistance of the safety guard panels obtained in Examples 1-3 and Comparative Examples 1 and 2 was evaluated. Specifically, the haze value of the safety guard panels was measured using a haze meter (HM-150L2N type, Murakami Color Technology Research Institute Co., Ltd.) in accordance with JIS K 7136. Subsequently, gauze impregnated with acetone was brought into contact with the surface of the hard coat layer of the safety guard panel, and a load of 300 g / cm² was applied. 2 The panel was rubbed back and forth five times (acetone rubbing test). Afterward, the haze value of the safety guard panel was measured in the same manner as described above. The difference in haze value before and after the acetone rubbing test (haze value after the test - haze value before the test) was calculated. The results are shown in Table 1.

[0079] (Adhesion) The adhesion of the transfer layer was evaluated using the safety guard panels obtained in Examples 1-3 and Comparative Examples 1 and 2. Specifically, the adhesion of the transfer layer was evaluated on a 6-point scale from class 0 to class 5 based on JIS K 5600-5-6 (cross-cut method). The results are shown in Table 1.

[0080] [Table 1]

[0081] As shown in Table 1, the safety guard panels obtained in Examples 1 to 3 were confirmed to have good scratch resistance and good chemical resistance. Furthermore, the safety guard panels obtained in Examples 1 to 3 also had good adhesion. In contrast, the safety guard panel obtained in Comparative Example 1 had good scratch resistance and chemical resistance, but the heating temperature was low and the adhesion was poor. Also, the safety guard panel obtained in Comparative Example 2 had poor scratch resistance and chemical resistance. This is presumed to be because the molecular weight of the resin component in the hard coat layer forming composition was high and the crosslinking density was low.

[0082] Thus, the present disclosure provides, for example, the following inventions.

[0083] [1] A method for manufacturing a safety guard panel, Preparation steps include preparing a transfer sheet having a release film and a transfer layer, The process includes a lamination step in which the polycarbonate substrate and the transfer sheet are laminated so that the polycarbonate substrate and the transfer layer face each other while the polycarbonate substrate is heated to 100°C or higher. The above transfer layer has, in order from the release film side, a hard coat layer and a heat seal layer. A method for manufacturing a safety guard panel, wherein when an acetone rubbing test is performed on the side of the hard coat layer opposite to the heat seal layer, the difference in the haze value of the safety guard panel before and after the acetone rubbing test is 1% or less.

[0084] [2] The method for manufacturing a safety guard panel according to [1], wherein the hard coat layer contains a cured product of an ionizing radiation-curable resin.

[0085] [3] A method for manufacturing a safety guard panel according to [1] or [2], wherein the transfer layer has a primer layer between the hard coat layer and the heat seal layer.

[0086] [4] A method for manufacturing a safety guard panel according to any one of [1] to [3], wherein at least one layer constituting the above transfer layer contains an ultraviolet absorber.

[0087] [5] The manufacturing method for the safety guard member according to any one of [1] to [4], wherein the haze value of the above safety guard panel is 15% or less.

[0088] [6] The visible light transmittance of the above-mentioned safety guard panel is 75% or more, a method for manufacturing a safety guard member according to any one of [1] to [5].

[0089] [7] The method for manufacturing a safety guard panel according to any one of [1] to [6], wherein the thickness of the hard coat layer is 1 μm or more.

[0090] [8] The method for manufacturing a safety guard panel according to any one of [1] to [7], wherein the thickness of the polycarbonate substrate is 1 mm or more.

[0091] [9] The shape of the safety guard panel is a flat plate, and the method for manufacturing a safety guard panel as described in any of [1] to [8].

[0092]

[10] The method for manufacturing a safety guard panel according to any one of [1] to [9], wherein the visible light transmittance of the above release film is 75% or more.

[0093]

[11] A transfer sheet used in the manufacture of a safety guard panel having a polycarbonate substrate, The above transfer sheet has a release film and a transfer layer. The above transfer layer has, in order from the release film side, a hard coat layer and a heat seal layer. A transfer sheet in which, when an acetone rubbing test is performed on the side of the hard coat layer opposite to the heat seal layer, the difference in the haze value of the transfer layer before and after the acetone rubbing test is 1% or less.

[0094]

[12] It is a safety guard panel, The above safety guard panel comprises a polycarbonate substrate and a transfer layer. The above transfer layer has, in order from the polycarbonate substrate side, a heat seal layer and a hard coat layer. A safety guard panel in which, when an acetone rubbing test is performed on the side of the hard coat layer opposite to the heat seal layer, the difference in the haze value of the safety guard panel before and after the acetone rubbing test is 1% or less.

[0095]

[13]

[12] The safety guard panel described therein, A frame positioned around the periphery of the above safety guard panel, A safety guard that has [a certain feature]. [Explanation of Symbols]

[0096] 1…Release film 2…Hard court layer 3… Heat seal layer 4…Primer layer 10…Transfer sheet 20…Polycarbonate base material 100…Safety Guard Panel 150...Frame 200... Safety Guard

Claims

1. A method for manufacturing a safety guard panel, Preparation steps include preparing a transfer sheet having a release film and a transfer layer, The process includes a lamination step of heating the polycarbonate substrate to 100°C or higher, and then laminating the polycarbonate substrate and the transfer sheet so that the polycarbonate substrate and the transfer layer face each other. The transfer layer has, in order from the release film side, a hard coat layer and a heat seal layer. A method for manufacturing a safety guard panel, wherein when an acetone rubbing test is performed on the side of the hard coat layer opposite to the heat seal layer, the difference in the haze value of the safety guard panel before and after the acetone rubbing test is 1% or less.

2. The method for manufacturing a safety guard panel according to claim 1, wherein the hard coat layer contains a cured product of an ionizing radiation-curable resin.

3. The method for manufacturing a safety guard panel according to claim 1, wherein the transfer layer has a primer layer between the hard coat layer and the heat seal layer.

4. The method for manufacturing a safety guard panel according to claim 1, wherein at least one layer constituting the transfer layer contains an ultraviolet absorber.

5. The method for manufacturing a safety guard member according to claim 1, wherein the haze value of the safety guard panel is 15% or less.

6. The method for manufacturing a safety guard member according to claim 1, wherein the visible light transmittance of the safety guard panel is 75% or more.

7. The method for manufacturing a safety guard panel according to claim 1, wherein the thickness of the hard coat layer is 1 μm or more.

8. The method for manufacturing a safety guard panel according to claim 1, wherein the thickness of the polycarbonate substrate is 1 mm or more.

9. The method for manufacturing a safety guard panel according to claim 1, wherein the shape of the safety guard panel is a flat plate.

10. The method for manufacturing a safety guard panel according to claim 1, wherein the visible light transmittance of the release film is 75% or more.

11. A transfer sheet used in the manufacture of a safety guard panel having a polycarbonate substrate, The transfer sheet comprises a release film and a transfer layer. The transfer layer has, in order from the release film side, a hard coat layer and a heat seal layer. A transfer sheet in which, when an acetone rubbing test is performed on the side of the hard coat layer opposite to the heat seal layer, the difference in the haze value of the transfer layer before and after the acetone rubbing test is 1% or less.

12. It is a safety guard panel, The aforementioned safety guard panel comprises a polycarbonate substrate and a transfer layer. The transfer layer has, in order from the polycarbonate substrate side, a heat seal layer and a hard coat layer. A safety guard panel in which, when an acetone rubbing test is performed on the side of the hard coat layer opposite to the heat seal layer, the difference in the haze value of the safety guard panel before and after the acetone rubbing test is 1% or less.

13. The safety guard panel according to claim 12, A frame positioned around the periphery of the aforementioned safety guard panel, A safety guard that has [a certain feature].

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