Surface modification method and method for producing three-dimensional decorative body

Abstract

To provide a method for effectively and rapidly modifying surfaces of various poorly adhesive substrates while reducing carbon dioxide emissions by applying a directional hydrogen flame treatment derived from a hydrogen-air mixture so as to control the surface tension to a specified value.SOLUTION: A surface modification method using hydrogen flame treatment, the method comprises the following steps (1) and (2): (1) a step of preparing a predetermined poorly adhesive substrate; and (2) a step of applying a hydrogen flame treatment derived from a mixture of hydrogen and air as a fuel gas to a surface of the predetermined poorly adhesive substrate so as to control the surface tension to a value of 40 mN / m or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a surface modification method using hydrogen flame treatment and a method for producing a three-dimensional decorative object. In particular, the present invention relates to a surface modification method and a method for producing a three-dimensional decorative object that utilizes hydrogen flame treatment to suppress the generation of carbon dioxide. [Background technology]

[0002] BACKGROUND ART Olefin resins, silicone resins, fluororesins, and other poorly adhesive materials such as aluminum and ceramic materials are widely used in vehicle parts and the like. However, the surfaces of poorly adhesive substrates and the like made of these poorly adhesive materials are often hydrophobic or water-repellent, and it is generally difficult to adhere other components to them, or to perform surface treatments such as printing or ultraviolet coating. In particular, when these poorly adhesive materials are three-dimensionally processed or foamed, the surface structure of the poorly adhesive substrate becomes complex and uneven, making it difficult to adhere to other components.

[0003] Therefore, methods for improving the surface properties of such poorly adhesive substrates include applying a primer treatment or coating the surface with a silane coupling agent, titanium coupling agent, or the like. However, in order to achieve the desired modification effect, relatively large amounts of primers, silane coupling agents, etc. are required, and in addition, problems have been observed in the manufacturing process, such as the need for specific processing equipment and the long processing time.

[0004] Therefore, the applicant of the present invention has proposed a surface modification method using a silicate flame treatment derived from a silicon-containing compound as a surface modification method for poorly adhesive substrates as an alternative to primer treatment or coupling agent treatment (e.g., Patent Document 1). More specifically, as shown in FIG. 8, a surface modification device 110 has been proposed, which includes a storage chamber 121 for storing a silicon-containing compound as a modifier compound 123, a vaporization section 111 (111a, 111b) to which the modifier compound 123 is supplied from the storage chamber 121 and evaporated at a predetermined temperature to generate a gaseous modifier compound 23′, a transfer section 130 for introducing a carrier gas 141 into the vaporization section 111 (111a, 111b) and transferring the gaseous modifier compound 123′ to an injection section 150 as part of a fuel gas, and an injection section 150 for spraying a flame 151 derived from the fuel gas containing the modifier compound 123′. In the surface modification device 110, the vaporization section 111 is characterized by having a plurality of vaporization chambers including at least a first vaporization chamber 111a and a second vaporization chamber 111b, and also having a switching device 160 (160a, 160b, 160c, 160d, 160e, 160f) for alternately using the first vaporization chamber 111a and the second vaporization chamber 111b. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5436118 (Claims, etc.) Summary of the Invention [Problem to be solved by the invention]

[0006] However, the surface modification device described in Patent Document 1 is characterized by blending a silicon-containing compound as a modifier compound into a portion of the fuel gas, and although it stably exerts an extremely outstanding surface modification effect, it is insufficient in terms of solving environmental problems. In other words, such surface modification devices use a considerable amount of propane or natural gas as fuel gas, which results in the emission of a certain amount of carbon dioxide, and the flame used for surface treatment tends to spread along the direction of travel, making selective surface modification difficult. Therefore, in view of the need to solve environmental problems such as global warming in recent years, there has been a demand for a surface modification method that uses highly directional flame treatment to effectively achieve a surface modification effect while suppressing carbon dioxide emissions.

[0007] Therefore, as a result of extensive efforts, the inventors discovered that by using a mixture of hydrogen and air as a fuel gas on the surface of a poorly adhesive substrate, the directionality of the flame can be increased, carbon dioxide emissions can be suppressed, and the surface of various poorly adhesive substrates can be modified effectively in a short time, thereby completing the present invention. In other words, the present invention aims to provide a surface modification method for a poorly adhesive substrate and a method for producing a three-dimensional decorative body, which uses a hydrogen flame derived from a mixture of hydrogen and air as a fuel gas, which has high directionality and small flame spread, and which suppresses the generation of carbon dioxide. [Means for solving the problem]

[0008] That is, according to the present invention, there is provided a surface modification method using a predetermined hydrogen flame treatment, characterized by including the following steps (1) to (2), which can solve the above-mentioned problems. (1) A step of preparing a predetermined poorly adhesive substrate (2) A process of subjecting the surface of a predetermined poorly adhesive substrate to a hydrogen flame treatment using a mixture of hydrogen and air as fuel gas, thereby increasing the surface tension to 40 mN / m or more. That is, by carrying out the process in this manner, a mixture of hydrogen and air is used as the fuel gas, and the resulting hydrogen flame has a small flame spread and is highly directional. By using this, and by setting the surface tension to a predetermined value, it is possible to significantly suppress the generation of carbon dioxide, and to effectively and quickly achieve a good surface modification effect on various poorly adhesive substrates.

[0009] When carrying out the surface modification method of the present invention, it is preferable that the hydrogen content in the fuel gas is set to a value within the range of 5 to 70 mol % relative to the total amount. By limiting the hydrogen content in the fuel gas in this way, it is possible to burn the hydrogen-containing fuel gas quantitatively, and to achieve a better surface modification effect with a hydrogen flame that has a small flame spread and does not substantially emit carbon dioxide.

[0010] When carrying out the surface modification method of the present invention, it is preferable to set the air content in the fuel gas to a value within the range of 30 to 95 mol % relative to the total amount. By limiting the air content in the fuel gas in this way, it is possible to quantitatively burn the fuel gas containing hydrogen, and to achieve a better surface modification effect with a hydrogen flame that has a small flame spread in the direction of travel and does not substantially emit carbon dioxide.

[0011] When carrying out the surface modification method of the present invention, it is preferable to premix hydrogen and air to prepare a fuel gas, and then carry out the hydrogen flame treatment. In this way, by generating a mixture of hydrogen and air as the fuel gas in advance and using the hydrogen flame treatment derived from it, the flame spread in the direction of travel is small, and a better surface modification effect can be achieved with a hydrogen flame that does not substantially emit carbon dioxide.

[0012] When carrying out the surface modification method of the present invention, it is preferable to set the surface temperature of the predetermined poorly adhesive substrate to a value within the range of 30 to 80°C before carrying out the hydrogen flame treatment. By limiting the surface temperature of a predetermined poorly adhesive substrate to a predetermined temperature range in this way, a favorable surface modification effect can be more effectively achieved by the hydrogen flame.

[0013] When carrying out the surface modification method of the present invention, the surface of a given poorly adhesive substrate is modified by hydrogen flame treatment. 2 It is preferable to set the surface treatment time per 1000 μm to a value within the range of 0.01 to 10 seconds. By limiting the surface treatment time of a predetermined poorly adhesive substrate to a predetermined range in this manner, it is possible to burn the fuel gas containing hydrogen reliably and safely, thereby achieving a better surface modification effect.

[0014] When carrying out the surface modification method of the present invention, the predetermined poorly adhesive substrate is preferably at least one of polyolefin resin, aluminum material, and ceramic material. By using a specific poorly adhesive substrate in this manner, it is possible to reliably and safely burn a fuel gas containing hydrogen, thereby achieving a favorable surface modification effect on various poorly adhesive substrates.

[0015] Another aspect of the present invention is a method for producing a three-dimensional decorative object, which includes a surface modification method using hydrogen flame treatment, and is characterized by including the following steps (1) to (3). (1) A process for preparing a three-dimensionally processed, poorly adhesive substrate (2) A process of subjecting the surface of the three-dimensionally processed, poorly adhesive substrate to a hydrogen flame treatment using air containing hydrogen compounds as fuel gas, thereby increasing the surface tension to 40 mN / m or more. (3) A process of sequentially laminating an intermediate layer and a decorative member on the treated surface of the three-dimensionally processed, poorly adhesive substrate that has been subjected to hydrogen flame treatment to create a three-dimensional decorative body. By carrying out this method of manufacturing a three-dimensional decorative body, a mixture of hydrogen and air is used as fuel gas, and the resulting hydrogen flame, which has a small flame spread, is used to set the surface tension to a predetermined value, thereby significantly suppressing the generation of carbon dioxide, and the hydrogen-containing fuel gas can be burned reliably and in a short time, resulting in a three-dimensional decorative body with excellent adhesion between each layer. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram of a surface modification apparatus for carrying out the surface modification method of the present invention. [Figure 2] FIG. 2 is a block diagram provided for explaining the surface modification method of the present invention. [Figure 3] FIG. 3(a) is a perspective view of a burner used in the surface modification method of the present invention, and FIG. 3(b) is a diagram provided for explaining an example of the arrangement of nozzle holes of a burner used in the surface modification method of the present invention. [Figure 4] FIG. 4(a) is a diagram provided for explaining the workpiece to which the surface modification method of the present invention is applied, and FIG. 4(b) is a diagram provided for explaining the state in which the surface modification method of the present invention is applied to the workpiece. [Figure 5] FIG. 5(a) is a diagram provided to explain the surface treatment state of a polypropylene resin plate to which the surface modification method of the present invention has been applied, and FIG. 5(b) is a diagram provided to explain the surface treatment state of an aluminum plate after the surface modification method of the present invention has been applied. [Figure 6] FIG. 6 is a diagram provided for explaining the effect on the surface tension when the hydrogen / air ratio of the fuel gas is changed. [Figure 7] FIG. 7 is a diagram used to explain the flames that are generated when the fuel gas is changed to Type 1 (natural gas / oxygen / air), Type 2 (natural gas / hydrogen / air), and Type 3 (hydrogen / air). [Figure 8] FIG. 8 is a diagram provided for explaining a conventional silicate flame treatment method. DETAILED DESCRIPTION OF THE INVENTION

[0017] [First embodiment] As shown in FIGS. 1 and 2, the first embodiment is a surface modification method using a hydrogen flame treatment, and is characterized by including the following steps (1) and (2). (1) A step of preparing a predetermined poorly adhesive substrate (2) A process of subjecting the surface of a predetermined poorly adhesive substrate to a hydrogen flame treatment using air containing hydrogen as a fuel gas, thereby increasing the surface tension to a value of 40 mN / m or more. Hereinafter, the surface modification method of the first embodiment will be specifically described with reference to the drawings as appropriate.

[0018] 1. Certain poorly adhesive substrates (1) Type The type of the predetermined poorly adhesive substrate is not particularly limited, and examples of resin-based substrates include at least one selected from the group consisting of urethane resin, fluororesin, silicone resin, polyester resin, polyethylene resin, polypropylene resin, modified polypropylene resin, polymethylpentene resin, polyester resin, polycarbonate resin, polyethersulfone resin, polyacrylic resin, polyetheretherketone resin, polyimide resin, polysulfone resin, polystyrene resin, polyamide resin, polyphenylene sulfide resin, ethylene-tetrafluoroethylene copolymer, polyvinyl fluoride resin, tetrafluoroethylene-perfluoroether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polytetrafluoroethylene resin, polyvinylidene fluoride resin, polytrifluorochloroethylene resin, ethylene-trifluorochloroethylene copolymer olefin rubber, urethane rubber, fluororubber, silicone rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, styrene-based thermoplastic elastomer, and urethane-based thermoplastic elastomer.

[0019] Among these resins, by performing hydrogen flame treatment on polyethylene resin, polypropylene resin, polyester resin (polyethylene terephthalate resin or polybutylene terephthalate resin), polycarbonate resin, polytetrafluoroethylene resin, etc., it is possible to achieve an excellent modification effect on poorly adhesive substrates made of versatile resins.

[0020] When the poorly adhesive substrate is a metal substrate, at least one of aluminum, stainless steel, nickel, zinc oxide, chromium oxide, steel plate, etc. may be used. Furthermore, when the poorly adhesive substrate is a ceramic substrate, at least one of soda glass, quartz glass, colored glass, and the like can be used.

[0021] (2) Filling material It is also preferable to add a filler such as a metal material, an inorganic filler, or a fiber to the poorly adhesive substrate. Such metal materials are preferably aluminum, magnesium, stainless steel, nickel, chromium, tungsten, gold, copper, iron, silver, zinc, tin, lead, and the like, either singly or in combination.

[0022] Furthermore, preferred inorganic fillers include titanium oxide, zirconium oxide, zinc oxide, indium oxide, tin oxide, silica, talc, calcium carbonate, lime, zeolite, gold, silver, copper, zinc, nickel, tin, lead, solder, glass, ceramics, and the like, which may be used alone or in combination. Furthermore, the fibers are preferably carbon fibers, aramid fibers, glass fibers, polyester fibers, polyamide fibers, metal fibers, ceramic fibers, etc., either singly or in combination. When a metal material, inorganic filler, or fiber is added to a poorly adhesive substrate, the amount added is preferably within a range of 0.01 to 80% by weight, more preferably within a range of 0.1 to 50% by weight, and even more preferably within a range of 1 to 30% by weight, based on the total amount.

[0023] (3) Form Furthermore, the shape of the poorly adhesive substrate is not particularly limited as long as it is three-dimensional, but for example, cylindrical, columnar, spherical, block-like, tubular, pipe-like, uneven, film-like, fibrous, woven, bundle-like, etc. are preferred. The poorly adhesive substrate may also be one that partially has a planar structure such as a plate, sheet, film, tape, strip, panel, or string shape. Furthermore, as a modified example of the form of such a poorly adhesive substrate, a composite structure formed by combining a three-dimensional structure made of a poorly adhesive substrate with metal parts, ceramic parts, glass parts, paper parts, wooden parts, or the like is also preferred. Therefore, the poorly adhesive substrate is preferably at least one of typical examples of interior components for vehicles, namely, an in-front panel, a door, a chair, a console box, a bumper, and an ornament.

[0024] (4)Surface temperature The surface temperature of the poorly adhesive substrate before the hydrogen flame treatment may be room temperature, but is usually preferably set to a value within the range of 30 to 80°C. The reason for this is that by limiting the surface temperature of the poorly adhesive substrate to a predetermined temperature range in this manner, the hydrogen flame derived from the hydrogen-containing fuel gas can more effectively and reliably exert a good surface modification effect. Therefore, it is more preferable to set the surface temperature of the poorly adhesive substrate to a value within the range of 35 to 75°C, and even more preferable to set it to a value within the range of 40 to 70°C. In order to control the surface temperature of the poorly adhesive substrate to a predetermined temperature, it is preferable to spray a flame containing no hydrogen in the fuel gas for a predetermined period of time.

[0025] (5) Surface treatment time In addition, the unit area (100cm) of a specific poorly adhesive substrate by hydrogen flame treatment 2 It is preferable to set the surface treatment time per 1000 μm to a value within the range of 0.01 to 10 seconds. The reason for this is that if the surface treatment time is less than 0.01, the surface modification effect may be poor. On the other hand, if the surface treatment time is 10 seconds or longer, the poorly adhesive substrate may be damaged. Therefore, the unit area (100 cm) of a given poorly adhesive substrate by hydrogen flame treatment 2 The surface treatment time per 1000 μm layer is more preferably set to a value within the range of 0.1 to 8 seconds, and even more preferably set to a value within the range of 0.5 to 5 seconds.

[0026] 2. Fuel gas (1) Hydrogen A burner or the like shown in FIGS. 3(a) to 3(b) is used to irradiate a hydrogen flame derived from a predetermined fuel gas, and hydrogen is used as the main component in the fuel gas. The reason for this is that by using hydrogen, even if it is burned, the amount of carbon dioxide generated can be made virtually zero, which is extremely preferable from the viewpoint of environmental characteristics. Furthermore, although the combustion energy per unit volume of hydrogen is smaller than that of propane gas or natural gas, hydrogen has an extremely fast flow velocity and a fast combustion rate compared to these gases, resulting in a high flame temperature. Therefore, by adjusting the hydrogen / oxygen mixture ratio, it is possible to carry out surface modification in an extremely short time while suppressing deformation of the appearance, even on substrates that are difficult to adhere to, such as olefin resins, which have relatively low heat resistance. The flame temperature can be measured directly or indirectly using a thermocouple made of tungsten or the like, or a thermoviewer using infrared rays.

[0027] (2) Air A burner or the like shown in Figs. 3(a) to (b) is used to irradiate a hydrogen flame derived from a predetermined fuel gas, and air is used as a combustion-supporting component in the fuel gas. The reason for this is that by using air, the oxygen contained in the air can be used as a combustion improver. Furthermore, in the case of air, the combustion energy per unit volume is smaller than that of propane gas or natural gas, so even when it is applied to a substrate that is difficult to adhere to, such as an olefin resin, which has relatively low heat resistance, deformation of the appearance, etc., can be more easily suppressed. However, if the outside air is used as it is, it may contain moisture, dust, etc., so it is preferable to use it as fuel gas after removing moisture, dust, etc. through an air filter.

[0028] (3)Content The content (blending amount) of hydrogen in the fuel gas is preferably set to a value within the range of 10 to 70 mol % relative to the total amount (100 mol %) of the fuel gas. The reason for this is that by limiting the hydrogen content in the fuel gas in this way, it is possible to perform hydrogen flame treatment by burning hydrogen reliably and safely. Therefore, it is more preferable to set the hydrogen content in the fuel gas to a value within the range of 20 to 60 mol % relative to the total amount of fuel gas (100 mol %), and it is even more preferable to set the hydrogen content in the fuel gas to a value within the range of 30 to 55 mol % relative to the total amount of fuel gas (100 mol %).

[0029] On the other hand, the content of air in the fuel gas (for example, the amount mixed with hydrogen) is preferably set to a value within the range of 30 to 95 mol % relative to the total amount of the fuel gas (100 mol %). The reason for this is that by limiting the air content in the fuel gas in this way, it is possible to perform hydrogen flame treatment by burning hydrogen reliably and safely. Therefore, it is more preferable to set the air content in the fuel gas to a value within the range of 40 to 90 mol % relative to the total amount of fuel gas (100 mol %), and it is even more preferable to set the hydrogen content in the fuel gas to a value within the range of 20 to 80 mol % relative to the total amount of fuel gas (100 mol %).

[0030] Here, with reference to FIG. 6, the effect on the surface tension when the ratio of hydrogen to air in the fuel gas is changed will be described. The horizontal axis of FIG. 6 shows the hydrogen / air ratio (-), and the vertical axis shows the surface tension on the surface of the polypropylene resin. In addition, characteristic curve A in FIG. 6 corresponds to the surface tension before the surface modification, and characteristic curve B corresponds to the surface tension after the surface modification. Comparing characteristic curves A and B, when the hydrogen / air ratio in the fuel gas is 50 / 50 (molar ratio), the degree of increase in surface tension due to surface modification is lower than before and after, but a certain increase in surface tension is still observed. On the other hand, when the hydrogen / air ratio is lower than 50 / 50 or conversely, when it is higher, the degree of increase in surface tension due to surface modification tends to be higher, but the flame state tends to become slightly more unstable. Therefore, to obtain the effect of surface modification, it is preferable that the hydrogen / air ratio be a molar ratio of 30 / 70 to 70 / 70 with 50 / 50 as the center, and more preferably a molar ratio of 35 / 65 to 65 / 35.

[0031] (4) Flammable gases, etc. It is also preferable to add a relatively small amount of a combustible gas to the fuel gas, since this makes it easy to control the flame temperature, changes the color of the hydrogen flame, and allows the state of the hydrogen flame to be visually observed. Such flammable gases include hydrocarbon gases such as propane gas and natural gas, and flammable gases such as oxygen. When a flammable gas is used in an aerosol can, it is preferable to use propane gas, compressed air, or the like as such a flammable gas.

[0032] Furthermore, it is preferable that the content of such combustible gases and the like be set to a value within the range of 0.01 to 40 mol % when the total amount of fuel gas is taken as 100 mol %. The reason for this is that if the content of such a flammable gas is less than 0.01 mol%, the effect of blending the flammable gas etc. will not be exerted, and the improvement in the recognizability of the hydrogen flame may be insufficient, or the modifying effect on poorly adhesive substrates may not be exerted. On the other hand, if the content of such flammable gas exceeds 40 mol %, the amount of carbon dioxide generated may increase sharply. Therefore, when a flammable gas or the like is blended, the content is preferably set to a value within the range of 0.5 to 30 mol %, and even more preferably to a value within the range of 1 to 10 mol %, when the total amount of fuel gas is taken as 100 mol %.

[0033] Here, with reference to FIGS. 7(a) to (c), the influence of different types of fuel gas on the spread and directionality of the generated flame will be described. FIG. 7(a) is a conceptual diagram showing a flame when the type of fuel gas is changed to natural gas / oxygen / air=50 / 30 / 20 (molar ratio). FIG. 7(b) is a conceptual diagram showing a flame when the types of fuel gas are changed to natural gas / hydrogen / air=50 / 30 / 20 (molar ratio). Furthermore, FIG. 7(c) is a conceptual diagram showing a flame when the types of fuel gas are changed to hydrogen / air=50 / 50 (molar ratio). Comparing the spread and directionality of these flames, as shown in Figure 7(c), it can be said that using a certain amount of hydrogen or more in the fuel gas reduces the spread of the flame and improves the directionality, making it preferable to selectively modify the surface of only the desired areas.

[0034] (4) Additives It is also preferable to add to the fuel gas at least one compound selected from the group consisting of alkylaluminum-containing compounds, alkoxyaluminum-containing compounds, alkyltitanium-containing compounds, alkoxytitanium-containing compounds, alkylsilicon-containing compounds, alkoxysilicon-containing compounds, and modified compounds thereof, as a modifying aid. The reason for this is that the addition of these compounds changes the color of the hydrogen flame, making it possible to visually observe the state of the hydrogen flame. Furthermore, by adding such a modification aid, it is possible to improve the difficulty in handling fuel gases due to the low boiling point of silicon-containing compounds, and it is also possible to further enhance the surface modification effect on poorly adhesive substrates.

[0035] Furthermore, when the total amount of fuel gas is taken as 100 mol %, it is also preferable to set the amount of the reforming aid added to a value within the range of 0.0001 to 1 mol %. The reason for this is that if the amount of the modification aid added is less than 0.0001 mol %, the effect of adding the modification aid may not be achieved. On the other hand, if the amount of the reforming aid added exceeds 1 mol %, incomplete combustion of the fuel gas may occur.

[0036] 3.Surface modification (1) Surface tension after surface modification Furthermore, it is preferable that the surface-modified poorly adhesive substrate has a surface tension (sometimes called the wetting index, measured at 25° C.) of 40 mN / m or more. The reason for this is that if the surface tension of such a poorly adhesive substrate is less than 40 mN / m, it may become difficult to easily perform adhesion, printing, painting, etc. On the other hand, if the surface tension of such a poorly adhesive substrate exceeds 100 mN / m, the surface treatment will be carried out excessively, which may cause thermal deterioration of the poorly adhesive substrate. Therefore, in the surface-modified poorly adhesive substrate, the surface tension is more preferably set to a value within the range of 45 to 75 dyn / cm, and even more preferably to a value within the range of 50 to 70 mN / m.

[0037] (2) Surface tension before surface modification Furthermore, it is preferable that the surface tension (measurement temperature: 25° C.) of the poorly adhesive substrate before surface modification (before surface treatment) is set to a value within the range of 20 to 45 mN / m. The reason for this is that if the surface tension of such a poorly adhesive substrate is less than 20 mN / m, the surface treatment will be carried out over a long period of time, which may result in thermal deterioration of the poorly adhesive substrate. Therefore, the surface tension of the poorly adhesive substrate before surface modification (before surface treatment) is more preferably set to a value within the range of 25 to 40 mN / m, and even more preferably to a value within the range of 30 to 38 mN / m. In particular, it is also preferable to repeatedly subject the same poorly adhesive substrate to hydrogen flame surface treatment multiple times to achieve the desired surface tension.

[0038] (3) Contact angle Furthermore, it is preferable that the contact angle measured using water (measurement temperature: 25° C.) of the surface-modified poorly adhesive substrate is set to a value within the range of 0.1 to 30°. The reason for this is that if the contact angle of such a poorly adhesive substrate is less than 0.1°, excessive surface treatment may be performed, which may cause thermal degradation of the poorly adhesive substrate, whereas if the contact angle of such a poorly adhesive substrate is more than 30°, it may become difficult to easily perform adhesion, printing, painting, etc. Therefore, in the surface-modified poorly adhesive substrate, the contact angle measured using water (measurement temperature: 25°C) is more preferably set to a value within the range of 0.5 to 20°, and even more preferably to a value within the range of 1 to 10°.

[0039] Furthermore, it is preferable that the contact angle measured using water (measurement temperature: 25° C.) of the poorly adhesive substrate before surface modification (before surface treatment) is set to a value within the range of 50 to 120°. The reason for this is that if the contact angle of such a poorly adhesive substrate is less than 50°, it may be difficult to efficiently treat the surface with a flame. On the other hand, if the contact angle of such a poorly adhesive substrate exceeds 120°, the surface treatment will be carried out over a long period of time, which may cause thermal deterioration of the poorly adhesive substrate. Therefore, the contact angle measured using water on the poorly adhesive substrate before surface modification (before surface treatment) is more preferably set to a value within the range of 60 to 110°, and even more preferably to a value within the range of 80 to 100°.

[0040] [Second embodiment] The second embodiment is a method for producing a three-dimensional decorative object, which includes a surface modification method using a specified hydrogen flame treatment, and is characterized by including the following steps (1) to (3). (1) A process for preparing a three-dimensionally processed, poorly adhesive substrate (2) A process of subjecting the surface of the three-dimensionally processed, poorly adhesive substrate to a hydrogen flame treatment using air containing hydrogen as the fuel gas, to bring the surface tension to 40 mN / m or more. (3) A process of sequentially laminating an intermediate layer and a decorative member on the flame-treated, three-dimensionally processed, poorly adhesive substrate to form a three-dimensional decorative body.

[0041] 1. Step (1) (Preparation of a three-dimensionally processed, poorly adhesive substrate) Step (1), a step of preparing a three-dimensionally processed poorly adhesive substrate, can be prepared by various methods, but it is preferable to prepare the poorly adhesive substrate by at least one manufacturing method such as a pressing method, a mold injection method, an injection molding method, a cutting method, or a polishing method. The thickness of such a poorly adhesive substrate depends on its intended use, but is generally preferably in the range of 1 to 20 mm, more preferably in the range of 3 to 15 mm, and even more preferably in the range of 5 to 10 mm.

[0042] 2. Step (2) (hydrogen flame treatment step) Step (2) is a step in which the three-dimensionally processed, poorly adhesive substrate prepared in step (1) is quickly and effectively surface-treated using a hydrogen flame, which has little flame spread. In other words, when propane or natural gas is used as the fuel gas, the resulting flame tends to spread widely, but a hydrogen flame, which is primarily composed of hydrogen, has the advantage of being small in spread, highly directional, and capable of selectively modifying the surface of only desired areas. The hydrogen flame treatment step will be described below to the extent that it does not overlap with the contents described in the first embodiment.

[0043] (1) Fuel gas In step (2) (hydrogen flame treatment step), hydrogen and air can be used in the same manner as described in the first embodiment, and therefore a description thereof will be omitted here.

[0044] (2) Hydrogen flame treatment conditions It is also preferable that the flame temperature in the hydrogen flame treatment be set to a value within the range of 200 to 1000°C. The reason for this is that if the flame temperature is less than 200°C, it may become difficult to effectively prevent incomplete combustion of hydrogen. On the other hand, if the temperature of the flame exceeds 1000°C, the poorly adhesive substrate to be surface-modified may be thermally deformed or deteriorated, which may excessively limit the types of poorly adhesive substrates that can be used. Therefore, the flame temperature is preferably set to a value within the range of 250 to 800°C, and more preferably within the range of 300 to less than 600°C. The flame temperature is the temperature measured at the tip of the flame, and can be adjusted appropriately depending on the type of fuel gas used, the flow rate of the fuel gas, or the type and amount of hydrogen added to the fuel gas. As described above, the flame temperature can be measured using a thermocouple, a thermoviewer utilizing infrared rays, or the like, and can be controlled within a predetermined range.

[0045] In addition, the unit area (approximately 100 cm) in hydrogen flame treatment 2 It is preferable to set the hydrogen flame treatment time (injection time) per 1000 kJ / kcal to a value within the range of 0.01 seconds to 10 seconds. The reason for this is that if the treatment time with the hydrogen flame is less than 0.01 seconds, the reforming effect of hydrogen may not be uniformly manifested. On the other hand, if the flame treatment time exceeds 10 seconds, the poorly adhesive substrate to be surface-modified may be thermally deformed or deteriorated, which may excessively limit the types of poorly adhesive substrates that can be used. Therefore, the flame treatment time is preferably set to a value within a range of 0.3 to 3 seconds, and more preferably to a value within a range of 0.5 to 1 second.

[0046] (3) Surface tension 1 It is also preferable to measure and confirm that the surface tension (temperature: 25° C.) of the three-dimensionally processed poorly adhesive substrate is 40 mN / m or more by hydrogen flame treatment. The reason for this is that when the surface tension reaches a value of 40 mN / m or more, the adhesion resistance drops sharply, and a desired coating film can be formed by applying a normal paint or the like. Therefore, it is more preferable to adjust the surface tension of the three-dimensionally processed, poorly adhesive substrate to a value within the range of 45 to 80 mN / m, and even more preferable to adjust it to a value within the range of 50 to 70 mN / m, by hydrogen flame treatment.

[0047] (4) Surface tension 2 It is also preferable to measure the surface tension of the three-dimensionally processed poorly adhesive substrate before the hydrogen flame treatment. That is, it is relatively difficult to distinguish the degree of surface modification from the appearance of the poorly adhesive substrate. Therefore, it is preferable to measure the surface tension (γ1) of the three-dimensionally processed poorly adhesive substrate before the hydrogen flame treatment, and then measure the surface tension (γ2) after the hydrogen flame treatment, and confirm that the ratio (γ2 / γ1) is at least 1.3. The reason for this is that the surface tension of a poorly adhesive substrate changes depending on factors such as the environmental temperature, and therefore, by considering the ratio of the surface tension before and after the hydrogen flame treatment, it is possible to confirm that the surface treatment has been carried out reliably and stably. Therefore, the surface tension ratio (γ2 / γ1) is preferably set to a value within the range of 1.4 to 2.5, and more preferably to a value within the range of 1.5 to 2.

[0048] 3. Process (3) (Lamination process) Step (3) is a step of sequentially laminating an intermediate layer and a decorative member on the treated surface of the three-dimensionally processed, poorly adhesive substrate that has been subjected to hydrogen flame treatment in step (2) to form a three-dimensional decorative body.

[0049] (1) Decorative materials The decorative member is preferably made of at least one resin selected from the group consisting of epoxy resin, vinyl chloride resin, acrylic resin, olefin resin, urethane resin, polycarbonate resin, and polyester resin. The reason for this is that this configuration allows for the use of decorative members that are highly versatile, inexpensive, and have excellent decorative properties, i.e., it is possible to provide a three-dimensional decorative object that is inexpensive and has excellent decorative properties. However, it is more preferable to use B-stage (semi-cured) epoxy resin, as it is suitable for powder slush molding, which will be described later.

[0050] It is also preferable that the thickness (average thickness) of the decorative member be within the range of 10 to 2,000 μm. The reason for this is that if the thickness of the decorative member is less than 10 μm, the mechanical strength and durability of the decorative member may be significantly reduced. On the other hand, if the thickness of the decorative member exceeds 2,000 μm, handling and adhesion may become difficult. Therefore, it is more preferable that the thickness of the decorative member be set to a value within the range of 50 to 1,000 μm, and even more preferable that it be set to a value within the range of 200 to 800 μm.

[0051] The decorative member is preferably in the form of a flat film for ease of adhesion and handling, but is also preferably embossed or has openings (including slits) on the surface for better decorative effect.Furthermore, it is also preferable that the surface or interior of the decorative member is printed or colored as desired.

[0052] Moreover, it is preferable that the decorative member is formed by a powder slush method. The reason for this is that decorative components made using powder slush molding have excellent three-dimensionality, maintain a special shape, and can be provided in any size, from large dimensions (e.g., widths of 1 m or more) to small dimensions (e.g., widths of 10 cm or less).

[0053] Although not shown, when performing powder slush molding, it is preferable to first carry out a step of heating a metal slush mold having a molding surface using a heating device that uses gas or electricity as a heat source. In other words, it is preferable to heat the slush mold to a temperature at which the powdered resin melts.

[0054] Next, it is preferable to carry out a step of integrally connecting the heated slush mold and the reservoir tank containing the flowable powdered resin from top to bottom with the molding surface of the mold facing downward and the opening surface of the reservoir tank facing upward. It is then preferable to rotate the slush mold while it is connected to the reservoir tank, and carry out a step of forming a resin film of a predetermined thickness on the molding surface of the molding die of the slush mold. Therefore, the powdered resin in the reservoir tank falls onto the molding surface of the mold due to its own weight, and the heat of the mold is transferred to the resin, causing it to melt, which forms a resin film of a predetermined thickness on the molding surface.

[0055] Next, with a resin film of a predetermined thickness formed on the mold, the reservoir tank is removed from the slush mold, and then the entire slush mold or a portion of the mold is cooled by cooling means such as water cooling or air cooling to solidify the resin film. Finally, after cooling to a predetermined temperature, a step of demolding is carried out while peeling the resin film from the molding die, thereby obtaining a three-dimensionally processed hard-to-adhere substrate.

[0056] (2) Middle class The intermediate layer is preferably, for example, a foam layer, a cushion layer, or an adhesive layer. The reason for this is that by providing a foam layer or a cushion layer, it is possible to provide a three-dimensional decorative article that has a more excellent three-dimensional appearance and also has a moderate cushioning property. Also, by providing an adhesive layer, the adhesive strength between the poorly adhesive substrate and the decorative member can be significantly improved.

[0057] The material constituting the intermediate layer is not particularly limited, but examples thereof include urethane resin, epoxy resin, acrylic resin, and polyester resin. The thickness of such an intermediate layer depends on its function, but in the case of a foam layer or cushion layer, for example, it is usually preferably set to a value within the range of 0.1 to 20 mm, more preferably a value within the range of 0.5 to 10 mm.

[0058] (3)Lamination process Furthermore, when a decorative member formed by powder slush molding or the like is laminated on a poorly adhesive substrate, it is preferable to form an intermediate layer first. Here, a primer treatment or an adhesion adjustment layer is usually applied to a poorly adhesive substrate, but according to the present invention, the primer treatment and the adhesion adjustment layer can be omitted or simplified.

[0059] Furthermore, since this makes it possible to simplify and speed up the entire manufacturing process, it is preferable to apply the raw material for the intermediate layer (e.g., urethane foam raw material) to a poorly adhesive substrate, and then laminate and fix the decorative member on top of it. In other words, it is preferable to position at least the poorly adhesive substrate, the intermediate layer, and the decorative member in predetermined locations, stack them, and then firmly bond the poorly adhesive substrate and the decorative member via the intermediate layer. More specifically, by heating to a predetermined temperature, for example the foaming temperature of the urethane resin, in a predetermined mold or in the pressure section of a press, pressurizing, and then irradiating with ultraviolet light to harden it, the decorative member is adhered and fixed and an intermediate layer is formed at the same time, resulting in a three-dimensional decorative object.

[0060] [Third embodiment] The third embodiment is a surface modification device used when carrying out the surface modification method of the first embodiment and the method for manufacturing a three-dimensional decorative body of the second embodiment, and is preferably a surface modification device 10 for hard-to-adhere substrates, as shown in Figure 1, etc., which is equipped with a first storage tank 24 for storing hydrogen, an air pipe 22c for transporting air from the second storage tank 22, a mixing section 18 for mixing hydrogen and air to produce fuel gas, and an injection section including a burner 12 for blowing a hydrogen flame 14 derived from the fuel gas onto the hard-to-adhere substrate. A more specific description will be given below with reference to the schematic diagram of FIG. 1 and the block diagram of FIG.

[0061] (1) Storage tank As shown in FIGS. 1 and 2, a first storage tank (P1) 24 for storing hydrogen to generate fuel gas is provided with a flow meter 24a and an on-off valve 24b in the middle of a hydrogen pipe 24c. On the other hand, the second storage tank (P2) 22 is provided with a compressor 22b equipped with an air filter in the middle of the air piping 22c, in order to adjust the moisture content, take in air that has been removed from contaminants, and introduce it as compressed air.

[0062] As shown in Figures 1 and 2, when surface treating a poorly adhesive substrate, first, hydrogen stored in a first storage tank (P1) 24 is transferred to a mixing section 18 through a hydrogen piping 24c via an on-off valve 24b while being monitored with a flow meter 24a and a pressure gauge (not shown). At the same time, the compressor 22a is operated to take in air from the second storage tank (P2) 22 or directly from the outside, and the air is passed through an air filter to adjust the moisture content and remove contaminants, turning it into compressed air, which is then transported to the mixing section 18 through the air pipe 22c. An air regulating valve 22d equipped with a pressure gauge 22e is provided in the air pipe 22c immediately before the mixing section 18. That is, the flow rates of hydrogen and air are adjusted to achieve a predetermined mixture ratio, and then the mixture is transported to the roughly T-shaped mixing section 18, where the two are uniformly mixed to produce fuel gas.

[0063] Since the content of hydrogen in the fuel gas (mixed amount relative to air) is extremely important, a pressure gauge (or a liquid level gauge) is provided in the first storage tank to monitor the flow rate of hydrogen and the pressure of the pump. It is preferable to monitor the internal pressure of each. In addition, since the transfer speed of hydrogen is particularly fast compared to that of air, it is also preferable to provide baffles or the like inside or on the inner walls of the hydrogen piping or mixing chamber to increase the residence time so that the flow rate can be strictly controlled.

[0064] (2) Transfer section As shown in Figures 1 and 2, the transfer section is usually a tubular structure having a mixing section 18 for uniformly mixing hydrogen transferred from the first storage tank 24 through the hydrogen piping 24c and air transferred from the second storage tank 22 through the air piping 22c to produce fuel gas. It is preferable that the generated fuel gas is then transferred to the inlet 12c of the burner 12 through the fuel gas pipe 26c, thereby generating a stable hydrogen flame. Therefore, due to the high speed of hydrogen movement and its high flammability, it is preferable to provide a check valve 26 in the fuel gas piping 26c between the mixing section 18 and the inlet 12c of the burner 12 in order to prevent flashback. However, in order to adjust the combustibility of hydrogen, it is also preferable to provide a mixing section with air inside the burner, introduce hydrogen and air just before combustion, and burn them simultaneously with mixing.

[0065] (3) Hydrogen flame treatment unit As shown in Figures 1 and 2, the hydrogen flame treatment unit preferably includes a burner for burning fuel gas sent through the inlet 12c of the burner 12 and spraying the resulting hydrogen flame onto the poorly adhesive substrate, which is the workpiece. The type of such burner is not particularly limited, and may be, for example, any of a premix burner, a diffusion burner, a partial premix burner, a spray burner, an evaporation burner, a pulverized coal burner, and the like. The shape of the burner is not particularly limited either, and although an example is shown in FIGS. 3(a) and 3(b), any known burner can be used. Therefore, the burner may be fan-shaped overall, expanding toward the tip, or may be roughly rectangular with multiple nozzles arranged in a single or multiple rows horizontally, as shown in Figures 3(a) to 3(b).

[0066] It is also preferable to provide a flame detector 28 in the hydrogen flame treatment section to monitor the combustion state of the hydrogen flame. That is, it is preferable to provide a scale plate for detecting the height of the hydrogen flame, a temperature measuring device for detecting the temperature of the hydrogen flame, and an image combustion device for determining whether the hydrogen flame is burning uniformly. If the height, temperature, or combustion state of the hydrogen flame exceeds the expected range, it is preferable to adjust the hydrogen flow rate, air flow rate, their mixed state, as well as the ambient temperature, burner state, etc., as appropriate to bring them within the desired range.

[0067] Furthermore, the location of the hydrogen flame treatment section, that is, the location of the burner, is preferably determined taking into consideration the ease of surface modification of the hard-to-adhere substrate to be treated, etc. For example, it is preferable to arrange them along a circle or an ellipse, or to arrange them close to both sides of the poorly adhesive substrate to be treated. It is also preferable to place them on one side of the poorly adhesive substrate to be treated at a predetermined distance, or to place them on both sides of the poorly adhesive substrate to be treated at a predetermined distance.

[0068] (4) Form of surface modification device 1 and 2, the surface modification apparatus preferably has a housing 30, which is equipped with a predetermined hydrogen storage tank, an air storage tank, etc., a fuel gas mixing section, a transfer section for transferring the fuel gas, and a hydrogen flame treatment section for spraying a hydrogen flame derived from the fuel gas. Although not shown, it is also preferable to spray a flame from the spray section while the position of the hard-to-adhere substrate, which is the treatment object, is appropriately changed in a state where it is placed on a fixture on a rotary table and rotated by the fixture. Such a stationary surface modification device can efficiently modify the surface of a large number of poorly adhesive substrates to be treated.

[0069] It is also preferable to make the surface modification device for poorly adhesive substrates portable. That is, it is preferable to prepare a cartridge-type hydrogen storage tank, a piping pipe, a box equipped with a flow meter and a pressure gauge, and further to provide a burner at the tip of the piping. With this configuration, by moving the box as needed, it becomes possible to easily perform surface treatment on objects placed outdoors or objects with a large surface area and large volume. To make the box easy to carry, it is preferable to attach a handle or a string to the top of the box, or to limit the total weight of the box to 20 kg or less. [Example]

[0070] [Example 1] 1. Manufacturing of three-dimensional decorative objects A three-dimensionally processed, poorly adhesive substrate was prepared. That is, a polypropylene front panel substrate for a vehicle (thickness: 8 mm) was prepared as a poorly adhesive substrate. Next, the surface of this poorly adhesive substrate was subjected to a hydrogen flame treatment, that is, treatment was performed using a hydrogen flame derived from a predetermined fuel gas so that the intermediate layer and decorative member could be firmly bonded to the substrate. More specifically, the flow rate of hydrogen is set to 1.8 × 10 6 cm 3 / Hr, and air flow rate is 1.8 x 10 6 cm 3 The flow rates of the fuel gases were adjusted to 100 mol % and 50 mol % of hydrogen and 50 mol % of air, respectively, and mixed to prepare a fuel gas (denoted as 1.0 in Figure 1). Next, a urethane foaming agent was applied, and a 2 mm thick vinyl chloride resin decorative member molded by the powder slush method was laminated on top. The panel was then heated in a specified mold at 30 to 60°C for 1 to 5 minutes, foaming a 10 mm thick urethane foam agent to form an intermediate layer, and a specified decorative member was attached to form a front panel for a vehicle.

[0071] 2. Evaluation of three-dimensional decorative objects (1) Evaluation of surface tension (wetting index) As shown in Figures 4(a) to (b), a hydrogen flame treatment (distance L: 1 to 3 cm) was performed on the surface tension measurement material 13a using a specified jig 13b, and the surface tension (wetting index) of the vehicle front panel substrate at that stage was measured using a standard liquid and evaluated according to the following criteria. That is, a hydrogen flame 14 was ejected upward from a hydrogen burner 12 along the extension direction, and a location a predetermined distance L away was moved horizontally (arrow D) at a predetermined speed to perform surface modification.

[0072] Figure 5(a) shows the surface conditions of a hydrogen flame treated area (A) and a non-hydrogen flame treated area (B), which is covered with a specified jig and not treated, at the stage when the surface tension of the vehicle front panel substrate was measured. It can be seen that the surface tension measurement materials 13a and 13d, which have a surface tension of approximately 45 mN / m to 50 mN / m, remain neatly linear in the hydrogen flame treated area (A), but are repelled and appear patchy in the non-hydrogen flame treated area (B). In addition, the surface tension (wetting index) of the vehicle front panel substrate before the hydrogen flame treatment was similarly evaluated using a surface tension measurement material, and it was confirmed that the surface tension was approximately 30 mN / m.

[0073] (2) Evaluation of adhesion The adhesion of the vehicle front panel obtained by forming a urethane foam layer and a decorative member on the vehicle front panel substrate was measured by measuring the peel force of the decorative member using a cross-cut test (in accordance with JIS K5600:1999) using a specified adhesive tape, and was evaluated according to the following criteria. ◎: No peeling at all in a cross-cut test of 100 pieces. ○: In a cross-cut test of 100 pieces, the number of peeled pieces was 1 to 2. △: In a cross-cut test of 100 pieces, the number of peeled pieces is 3 to 10. ×: In the cross-cut test of 100 pieces, the number of peeled pieces is 11 or more.

[0074] [Examples 2 to 6] In Examples 2 to 6, as shown in Table 1, the hydrogen / air mixture ratio constituting the fuel gas and the hydrogen flame treatment time for the type of flame-retardant substrate were changed, and the vehicle front panel substrate and the three-dimensional decorative body were evaluated in the same manner as in Example 1.

[0075] [Examples 7 to 8] In Examples 7 and 8, as shown in Table 1, the type of flame-retardant substrate was a PET film (thickness 25 μm), and the fuel gas was hydrogen / propane / air = 45 mol% / 5 mol% / 50 mol%, and hydrogen / propane / air = 30 mol% / 5 mol% / 50 mol%, respectively, and the hydrogen / air mixing ratios were 0.9 and 0.6, respectively. Except for this, the surface treatment time per unit time (1 second) was the same as in Example 1. In Examples 7 and 8, a small amount of propane was used as the fuel gas together with hydrogen, but the amount of carbon dioxide emitted was significantly low, less than 1 / 10, compared with the amount of each conventional fuel gas.

[0076] [Comparative Examples 1 to 2] In Comparative Examples 1 and 2, as shown in Table 1, hydrogen was not used as the fuel gas, but a propane / air mixture was used, and the flame treatment time was changed, and the vehicle front panel substrate and three-dimensional decorative body were evaluated in the same manner as in Example 1. That is, in Comparative Examples 1 and 2, the type of flame-retardant substrate was a polypropylene film (thickness 25 μm), the fuel gas was propane / air = 50 mol% / 50 mol%, and the mixture ratio of hydrogen / air was 0, but other than that, the surface treatment time per unit time was the same as in Example 1 and Example 2 (0.1 and 0.5 seconds).

[0077] [Table 1] [Industrial Applicability]

[0078] As explained above, according to the surface modification method of the present invention, by performing surface treatment on the surface of a poorly adhesive substrate using a hydrogen flame derived from a fuel gas containing hydrogen, which has a small flame spread and is highly directional, it is possible to perform effective surface modification in a short time, for example, within one second, even when a special primer treatment or the like is omitted. Therefore, by using a hydrogen flame, the problem of the generation of carbon dioxide and the like can be almost completely suppressed, and effective surface modification of the surface of a poorly adhesive substrate can be achieved in an extremely short time. Furthermore, by blending extremely small amounts of conventional hydrocarbon gas (propane or natural gas) or modifiers into the fuel gas together with hydrogen, and then modifying the surface to form a hydrogen flame, it has become possible to effectively suppress the generation of carbon dioxide and other gases, thereby improving environmental practicality. Therefore, the surface modification method using a hydrogen flame according to the present invention is believed to have wide market potential as a hydrogen burner that suppresses the generation of carbon dioxide and enables rapid surface modification.

[0079] Furthermore, according to the method for manufacturing a three-dimensional decorative body of the present invention, by applying a surface treatment using a hydrogen flame with a small spread derived from a fuel gas containing hydrogen to the surface of the three-dimensionally processed, poorly adhesive substrate and the surface of the intermediate layer, or to either one of the surfaces, it is possible to efficiently and quickly provide a three-dimensional decorative body that has strong adhesive strength between the three-dimensionally processed, poorly adhesive substrate and the decorative member via the intermediate layer, while taking environmental issues into consideration, and without carrying out special primer treatments, etc. [Explanation of symbols]

[0080] 10: Hydrogen flame treatment equipment 12: Hydrogen burner 12b: spout 12c: Connection 14: Hydrogen flame 18: Mixing section 22: Raw material tank (air) 22a:Flowmeter 22b:Air filter 22c: Air piping 22d: Air regulating valve 22e: Pressure gauge 24: Raw material tank (hydrogen) 24a:Flow meter 24b: Opening and closing valve 24c: Hydrogen piping 26: Check valve 26c: Fuel gas piping 28: Flame detection unit 30: Cabinet

Claims

1. A surface modification method using hydrogen flame treatment, comprising the following steps (1) and (2): (1) A step of preparing a predetermined poorly adhesive substrate (2) A step of subjecting the surface of the predetermined poorly adhesive substrate to a hydrogen flame treatment using a mixture of hydrogen and air as a fuel gas, thereby increasing the surface tension to a value of 40 mN / m or more.

2. 2. The surface modification method according to claim 1, wherein the content of hydrogen in the fuel gas is set to a value within a range of 5 to 70 mol % of the total amount.

3. 3. The surface modification method according to claim 1, wherein the content of air in the fuel gas is set to a value within a range of 30 to 95 mol % with respect to the total amount.

4. 3. The surface modification method according to claim 1, wherein the hydrogen compound and the air are mixed in advance to prepare the fuel gas, and then the hydrogen flame treatment is carried out.

5. The surface modification method according to claim 1 or 2, characterized in that the surface temperature of the predetermined poorly adhesive substrate before the hydrogen flame treatment is set to a value within a range of 30 to 80 ° C.

6. The unit area (100 cm ) of the predetermined poorly adhesive substrate by the hydrogen flame treatment 2 3. The surface modification method according to claim 1, wherein the surface treatment time per one of the two particles is set to a value within a range of 0.01 to 10 seconds.

7. 3. The surface modification method according to claim 1, wherein the poorly adhesive substrate is at least one of a polyolefin resin, an aluminum material, and a ceramic material.

8. A method for producing a three-dimensional decorative body, including a surface modification method using hydrogen flame treatment, characterized by comprising the following steps (1) to (3): (1) A step of preparing a three-dimensionally processed poorly adhesive substrate (2) A process of subjecting the surface of the three-dimensionally processed poorly adhesive substrate to a hydrogen flame treatment using air containing a hydrogen compound as a fuel gas, thereby increasing the surface tension to a value of 40 mN / m or more. (3) A step of sequentially laminating an intermediate layer and a decorative member on the treated surface of the three-dimensionally processed, poorly adhesive substrate that has been subjected to the hydrogen flame treatment, to form the three-dimensional decorative body.

Images