JP5039573B2 - White marked resin structure and manufacturing method thereof - Google Patents

Description

  The present invention provides a white marking having a protective film for preventing fouling and abrasion on a white marking portion of a resin molded body on which a white marking is applied by irradiating a laser beam to form a foam structure on the surface of the resin The present invention relates to a resin structure and a method for producing the same.

  Laser beam irradiation (laser marking) is widely used as an alternative to printing and painting with ink, but recently, in order to improve visibility and quality, a high contrast of the printed part with respect to the background color is recently required. Often done. However, even if the contrast is excellent immediately after marking, the contrast and visibility are reduced due to contamination, damage and wear of the marking part during the subsequent processing process and transportation, and also in the process of use. It has been regarded as a problem that the feeling and the like are impaired.

  For example, if a button printed with foam marking is used continuously, the printed portion may become dark and the printed image may be difficult to visually recognize. This is mainly due to the following two reasons. The first reason is that since the surface of the foamed marking is uneven, dirt or dust on the hand adheres during use, and is recognized as fouling in comparison with a marking portion that is not soiled. And since this adhering dirt has penetrated into the uneven part, it cannot be completely removed. The second reason is that the foamed structure of the marking portion is crushed by the pressure when the button is pressed, and is recognized as a decrease in contrast.

  As described above, in the case of foamed marking, since the surface of the printed part has an uneven foamed structure, light is scattered there and recognized as white print, so the influence over time Countermeasures are demanded because it is easy to be affected and the deterioration of the texture due to the influence over time is remarkable.

  As a means for solving this problem, it is conceivable to provide a protective layer so as not to directly touch the marking portion. For example, it has been proposed to coat the marking portion after marking (see Patent Document 1). However, the coating after marking is not necessarily preferable because the resin in the marking portion is eroded by the solvent in the paint, and the foamed structure is changed to lower the visibility of the characters. In addition, since the normal marking process is often carried out after assembling the parts, there is a concern that the subsequent coating may affect the parts. Further, depending on the type of paint, there is a thing that requires a coating film drying and curing step by heating, and the heat treatment may further collapse the foamed structure and further reduce the contrast of the marking portion.

  In addition, although a method of providing a transparent protective film after marking and multi-layering has been proposed, it is necessary to heat and pressure-bond when providing the protective film, the foam structure is damaged by the heat and pressure, or Due to insufficient adhesion to the marking material, there is a problem that the visibility of the marking portion is reduced. For this problem, a method of marking after multi-layering has also been proposed, but a gap with the protective film is generated at the time of marking, resulting in poor character contrast or sufficient adhesion of the protective film. There is a problem that coloring may be insufficient. Considering this cause as the effect of gas generated during marking, an attempt has been made to solve the problem by using a material having good gas permeability for the protective film (see Patent Document 2). However, considering the balance between the gas generation rate during marking and the gas permeation rate of the protective film, the effectiveness of this proposed method remains questionable.

  From the above, when white marking is performed by forming a foamed structure, the method of providing a protective layer for the purpose of preventing the white marking part from being soiled and worn is maintained while maintaining excellent visibility. At present, no method has been found.

JP 2002-127599 A Japanese Patent Laid-Open No. 2001-1642

Accordingly, an object of the present invention is to provide a resin structure with white marking that has high contrast of the printed portion with respect to the background color and does not deteriorate the design of the printed portion due to contamination, wear, etc., and can maintain high visibility. To provide a body.
Another object of the present invention is to provide a resin structure with white marking, which has high contrast of the printed part with respect to the background color, and does not deteriorate the design of the printed part due to contamination, wear, etc., and can maintain high visibility. It is in providing the manufacturing method of a body.

  As a result of intensive studies in order to achieve the above object, the present inventor has included a crystalline resin in a white color-forming thermoplastic resin for laser marking. We found that it became hard to be influenced by such. In addition to the crystalline resin, a resin that melts or softens at a temperature lower than the melting point of the crystalline resin is added to the white-colorable thermoplastic resin, and the resin that forms the protective film also includes the above-described resin Using a resin that melts or softens at a temperature lower than the melting point of the crystalline resin, and heats the resin at a temperature lower than the melting point of the crystalline resin to adhere a protective film, thereby forming a foam structure formed by the crystalline resin. It has been found that a protective film can be provided without damage, the marking does not become fouled or worn over time, and the visibility is not lowered. The present invention has been completed based on these findings and further research.

That is, in the present invention, the resin molded body composed of the resin (A) and the resin (B) is subjected to white marking by laser beam irradiation, and on the white marking portion on which the white marking is applied, the resin ( When B) is resin (B1), the melting point (T _2-1 ) or higher, and when the resin (B) is resin (B2), the glass transition temperature (T _2-2 ) or higher, and the resin (B A white-marked resin structure provided with a protective film made of resin (C) is provided by heating at a temperature lower than the melting point (T ₁ ) of A).
Resin (A): Crystalline resin [melting point (T ₁ )]
Resin (B): Crystalline resin (B1) having a melting point (T _2-1 ) lower than the melting point (T ₁ ) of resin (A), or glass lower than the melting point (T ₁ ) of resin (A) Amorphous resin (B2) having a transition temperature (T _2-2 )
Resin (C): Melting point (T _2-1 ) of crystalline resin (B1) or glass transition temperature (T _2-2 ) of amorphous resin (B2), which is lower than melting point (T ₁ ) of resin (A) ) The crystalline resin (C1) having the above melting point (T _3-1 ) or lower than the melting point (T ₁ ) of the resin (A), and the melting point (T _2-1 ) of the crystalline resin (B1) or Amorphous resin (C2) having a glass transition temperature (T _3-2 ) higher than the glass transition temperature (T _2-2 ) of the amorphous resin (B2)

  The resin (B) is preferably an amorphous resin (B2), and the blending ratio of the resin (A) and the resin (B) [the former: the latter (weight ratio)] is 20:80 to 80: 20 is preferable.

  The resin (C) is preferably a resin having compatibility with the resin (B).

In the present invention, the resin molded body comprising the resin (A) and the resin (B) is irradiated with a laser beam to give white marking on the surface of the resin molded body, and then the resin is formed on the surface of the white marking portion. When (B) is resin (B1), the melting point (T _2-1 ) or higher, and when the resin (B) is resin (B2), the glass transition temperature (T _2-2 ) or higher, and the resin Provided is a method for producing a white-marked resin structure, characterized in that a protective film made of a resin (C) is melt-bonded by heating at a temperature lower than the melting point (T ₁ ) of (A).

  According to the present invention, since the protective film can be provided in close contact with the white marking portion without damaging the foam structure that forms the white marking on the surface of the resin molded body, the contrast of the marking portion by providing the protective film can be increased. There is no decline. In addition, since the protective film is provided on the white marking portion, the foamed structure can be prevented from being crushed by the pressure of a finger or the like. In addition, since dirt and dust from the hands do not enter the uneven part of the foam structure, the contrast of the marking part does not decrease over time, and good visibility can be maintained and the texture can be impaired. Absent.

[Resin forming body]
The resin-formed body in the present invention can be recognized as white when the irradiated resin foams by laser beam irradiation to form an uneven foam structure, and light scatters into the foam structure. The resin formed body includes a crystalline resin (A), a crystalline resin (B1) having a melting point (T _2-1 ) lower than the melting point (T ₁ ) of the crystalline resin (A), or a resin ( It is obtained by curing a white-colored thermoplastic resin which is a mixture with an amorphous resin (B2) having a glass transition temperature (T _2-2 ) lower than the melting point (T ₁ ) of A).

  Examples of the crystalline resin (A) include polyolefin resins such as polyethylene resins and polypropylene resins; polyamide resins; polyethylene resins such as polyethylene terephthalate resins, polybutylene terephthalate resins, and polytrimethylene terephthalate resins. Trees, polyoxymethylene resins; polyphenylene sulfide resins; polyether ether ketone resins; liquid crystal polymers; fluorine resins and the like. In the present invention, among them, polyolefin resins such as polyethylene resins and polypropylene resins; polyamide resins; polyethylene resins such as polyethylene terephthalate resins, polybutylene terephthalate resins and polytrimethylene terephthalate resins are molded. From the standpoints of performance and cost balance. In this invention, the said crystalline resin can be used individually or in mixture of 2 or more types.

The melting point (T ₁ ) of the crystalline resin (A) may be higher than the melting point (T _2-1 ) when the resin (B) is the crystalline resin (B1), and the resin (B) is amorphous. In the case of the functional resin (B2), it may be higher than its glass transition temperature (T _2-2 ). The melting point of the crystalline resin (A) (T _1), for example, about 80 to 400 ° C., preferably about 100 to 350 ° C.. When the melting point of the crystalline resin is lower than 80 ° C., the crystalline resin (B1) having a melting point (T _2-1 ) lower than the melting point (T ₁ ) of the crystalline resin (A), or the crystalline resin (A) There is a tendency that the range of selection of a resin that can be used as the amorphous resin (B2) having a glass transition temperature (T _2-2 ) lower than the melting point (T ₁ ) is remarkably narrowed.

When the resin (B) is a crystalline resin (B1), the resin (B) in the present invention may have a melting point (T _2-1 ) lower than the melting point (T ₁ ) of the crystalline resin (A). When (B) is an amorphous resin (B2), the glass transition temperature (T _2-2 ) should be lower than the melting point (T ₁ ) of the crystalline resin (A). The resin (B) in the invention has a temperature equal to or higher than the melting point (T _2-1 ) of the crystalline resin (A) when the resin (B) is the crystalline resin (B1), and the melting point (T ₁ ) of the crystalline resin (A). ), And when the resin (B) is an amorphous resin (B2), the glass transition temperature (T _2-2 ) or higher and the crystalline resin (A) By heating at a temperature lower than the melting point (T ₁ ), the resin (C) constituting the protective film can be melt-bonded. Furthermore, the resin (B) in the invention is preferably compatible with the resin (C) that forms the protective film.

  Examples of the crystalline resin (B1) include polyolefin resins such as polyethylene resins and polypropylene resins; polyoxymethylene resins; polyphenylene sulfide resins; polyether ether ketone resins; liquid crystal polymers; fluorine resins; Polyester resins such as polyethylene terephthalate resins, polybutylene terephthalate resins, and polytrimethylene terephthalate resins.

  Examples of the amorphous resin (B2) include polystyrene, styrene-acrylonitrile copolymer (AS), styrene-acrylonitrile-butadiene copolymer (ABS), and maleic anhydride-modified styrene-ethylene / butylene-styrene block. Styrene copolymer such as copolymer (SEBS), styrene-N-phenylmaleimide-maleic anhydride copolymer (MIP), methyl methacrylate-acrylonitrile-styrene-butadiene copolymer (MMA-AN-ST-Bd) Polycarbonate; polyphenylene ether; polyacrylate; polysulfone; polymethyl methacrylate and the like.

The melting point (T _2-1 ) of the crystalline resin (B1) and the glass transition temperature (T _2-1 ) of the amorphous resin (B2) should be lower than the melting point (T ₁ ) of the crystalline resin (A). Good. As the difference between the melting point (T ₁ ) of the crystalline resin (A), the melting point (T _2-1 ) of the crystalline resin (B 1), and the glass transition temperature (T _2-1 ) of the amorphous resin (B 2), For example, it is about 5-300 degreeC, Preferably it is about 10-200 degreeC. The temperature difference between the melting point (T ₁ ) of the crystalline resin (A) and the melting point (T _2-1 ) of the crystalline resin (B1) or the glass transition temperature (T _2-1 ) of the amorphous resin (B2) is small. If too large, the foamed structure formed of the crystalline resin (A) may be damaged when the protective film is melt-bonded, and the contrast of the marking portion may be lowered. On the other hand, the temperature difference between the melting point (T ₁ ) of the crystalline resin (A), the melting point (T _2-1 ) of the crystalline resin (B 1), and the glass transition temperature (T _2-1 ) of the amorphous resin (B 2). If is too large, the adhesion of the protective film may be reduced.

  In the present invention, the resin (B) is preferably an amorphous resin (B2) in that it has excellent dimensional stability.

  The blending ratio of the resin (A) and the resin (B) [the former: the latter (weight ratio)] is, for example, about 20:80 to 80:20, and more preferably 25:75 to 75:25. 30:70 to 70:30 are particularly preferred. If the blending ratio of the resin (A) to the resin (B) is less than 20% by weight, the strength of the foam structure is insufficient, so the foam structure is crushed by heating and pressurization when a protective film is provided on the marking portion. As a result, the contrast of the marking portion tends to be reduced by providing the protective film. On the other hand, if the blending ratio of the resin (A) with respect to the resin (B) exceeds 80% by weight, the amount of the resin that melts and exhibits adhesiveness when the protective film is melt-bonded is insufficient. There is a tendency to be sufficient.

  In addition to the resin (A) and the resin (B), the white coloring thermoplastic resin constituting the resin molded body in the present invention preferably contains a coloring material, a higher fatty acid or a derivative thereof.

  The colorant preferably includes at least an organic or inorganic dark dye or pigment. The dark dye / pigment absorbs a laser beam (for example, a wavelength of 354 to 1064 nm), converts it into thermal energy, and foams or crazes the resin to develop a white marking.

  Examples of the dark dyes include carbon black (acetylene black, lamp black, thermal black, furnace black, channel black, ketjen black, etc.), graphite, titanium black, black iron oxide, and the like. Among these, carbon black is preferable from the viewpoints of dispersibility, color developability, cost, and the like. The dark dyes and pigments can be used alone or in combination of two or more.

  The average particle diameter of the dark dye / pigment can be appropriately selected from a wide range of, for example, 10 nm to 3 μm, preferably 10 nm to 1 μm. When the dark dye / pigment is carbon black, the average particle size is, for example, about 10 to 90 nm, preferably 12 to 70 nm, and more preferably about 14 to 50 nm (particularly 16 to 40 nm). If the particle size of the dark dye / pigment is too small, dispersion becomes difficult, and if it is too large, the marking tends to be unclear.

  The amount of the dark dye / pigment used is, for example, 0.0001 to 5 parts by weight, preferably 0.005 to 3 parts by weight, and more preferably 0.033 to 2 parts by weight with respect to 100 parts by weight of the white coloring thermoplastic resin. About a part. If the amount of the dark-colored dye / pigment is too small, the conversion efficiency of the laser beam into heat is lowered and color development tends to be insufficient. Conversely, if the amount is too large, the marking becomes excessive and yellowing tends to occur.

  In the present invention, dyes other than dark dyes can be used as the colorant. Such a non-dark color dye / pigment may be either inorganic or organic. Examples of non-dark dyes include white pigments (eg, calcium carbonate, titanium oxide, zinc oxide, zinc sulfide, lithopone), yellow pigments (eg, cadmium yellow, yellow lead, titanium yellow, zinc chromate, ocher, yellow) Iron oxide, etc.), red pigment (eg, red mouth pigment, amber, red iron oxide, cadmium red, red lead, etc.), blue pigment (eg, bitumen, ultramarine blue, cobalt blue, etc.), green pigment (eg, chrome green, etc.) Etc. The non-dark color dyes can be used alone or in combination of two or more.

  Among these, white dyes and pigments (for example, titanium oxide) that are inexpensive, have excellent hiding power and dispersibility, and enable extremely clear white marking are preferable. The white dye / pigment is a combination of a dark dye and a white dye / pigment in order to increase the efficiency of conversion to heat by improving the absorption efficiency of the laser beam by the dark dye / pigment by scattering the laser beam. Marking with extremely high whiteness can be obtained. In addition, by including a white dye / pigment, marking is possible even when the irradiation energy of the laser beam is lowered.

  The amount of the non-dark color dye / pigment used is, for example, 2 parts by weight or less (for example, 0.0001 to 2 parts by weight), preferably 1.5 parts by weight or less (for example, 0, for example) with respect to 100 parts by weight of the white coloring thermoplastic resin. 0.01 to 1.5 parts by weight). If the amount of the non-dark color dye / pigment is too small, the effect of scattering the laser beam becomes poor. Conversely, if the amount is too large, the marking color becomes tinged with the hue of the dye / pigment.

  The total amount of the coloring material to be used is generally 0.0001 to 5 parts by weight, preferably 0.01 to 4 parts by weight, more preferably 0.1 to 3 parts by weight with respect to 100 parts by weight of the white coloring thermoplastic resin. Degree.

  The higher fatty acid or derivative thereof is preferable in that it can improve the dispersibility of the color material such as carbon black and improve the color developability by blending. When a higher fatty acid metal salt is blended as a higher fatty acid derivative, the laser beam absorption efficiency is improved, and white marking with high whiteness can be obtained.

  Examples of the higher fatty acid include saturated or unsaturated higher fatty acids having about 12 to 30 carbon atoms such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. Derivatives of higher fatty acids include salts, esters, amides and the like. Examples of salts of higher fatty acids include zinc laurate, magnesium stearate, calcium stearate, barium stearate, zinc stearate, copper stearate, lead stearate, aluminum stearate, sodium stearate, lithium stearate, oleic acid Examples include alkali metal salts, alkaline earth metal salts, transition metal salts of higher fatty acids such as sodium. Examples of higher fatty acid amides include ethylene bisstearylamide and lauric acid amide. As the higher fatty acid or derivative thereof, stearic acid or a stearic acid derivative (salt, ester, amide, etc.) is particularly preferably used.

  The amount of the higher fatty acid or derivative thereof used is, for example, about 0.01 to 5 parts by weight, preferably about 0.02 to 3 parts by weight, with respect to 100 parts by weight of the white coloring thermoplastic resin. If the amount used is less than 0.01 parts by weight, the effect of improving the dispersibility of the coloring material is small, and if it exceeds 5 parts by weight, there is a high possibility of mold contamination due to evaporation and volatilization during molding.

  In the white color forming thermoplastic resin constituting the resin-formed body in the present invention, if necessary, a compatibilizer, a flame retardant, an antistatic agent, a filler, a stabilizer, a lubricant, a dispersant, an additive, a foaming agent, An additive such as an antibacterial agent may be included.

[Protective film]
The protective film in the present invention prevents the foamed structure from being crushed by the pressure of a finger or the like by adhering it onto the white marking part of the resin molded body that has been subjected to white marking by forming a foamed structure by laser beam irradiation. Further, it has an effect of preventing the white marking portion from becoming dark due to the dirt, dust, etc. of the hand entering the concavo-convex portion of the foam structure.

  The protective film in the present invention is formed in close contact with the white marking portion on the surface of the resin molded body. The protective film may be either a single layer composed of a transparent to translucent resin, or a multilayer structure in which one or more resin layers are laminated, and may have an adhesive layer. The resin (C) constituting the protective film may be a crystalline resin (C1) or an amorphous resin (C2).

The melting point (T _3-1 ) of the crystalline resin (C1) forming the protective film is lower than the melting point (T ₁ ) of the crystalline resin (A), and the resin (B) is the crystalline resin (B1). In the case, the melting point (T _2-1 ) or higher, and when the resin (B) is an amorphous resin (B2), the glass transition temperature (T _2-2 ) or higher may be used. Further, the glass transition temperature (T _3-2 ) of the amorphous resin (C2) forming the protective film is lower than the melting point (T ₁ ) of the crystalline resin (A), and the resin (B) is crystalline. In the case of the resin (B1), the melting point (T _2-1 ) or higher, and when the resin (B) is the amorphous resin (B2), the glass transition temperature (T _2-2 ) or higher may be used.

The resin melting point of (A) the temperature difference of the melting point (T _3-1) of (T ₁₎ and the crystalline resin (C1), or melting point of the resin of (A) (T ₁₎ and the amorphous resin (C2) The temperature difference of the glass transition temperature (T _3-2 ) is, for example, about 5 to 300 ° C. (preferably about 10 to 200 ° C.). If the temperature difference between the melting point (T _3-1 ) or glass transition temperature (T _3-2 ) of the resin (C) and the melting point (T ₁ ) of the resin (A) is too small, the protective film is melt bonded. The foamed structure formed by the resin (A) may be damaged, and the contrast of the marking portion may be lowered.

  Further, as the resin (C) constituting the protective film, it is preferable to use a resin having compatibility with the resin (B). When the protective film has a multilayer structure, there is a resin layer that does not directly adhere to the resin molded body, but the resin constituting this layer is not particularly limited, and a resin having physical properties suitable for the application should be selected. Can do.

  As the resin (C) constituting the protective film, in the case of a single layer, heat such as urethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, etc. Plastic elastomers; further, olefin resins such as polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer, polyethylene terephthalate, polybutylene terephthalate, ethylene terephthalate- Polyester resins such as isophthalate copolymer, polyamide resins such as 6 nylon, 6-66 copolymer nylon, 66 nylon, 6-12 copolymer nylon, 12 nylon, polymer (Meth) acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, acrylic resin such as methyl (meth) acrylate-styrene copolymer, polystyrene, acrylonitrile-styrene Examples thereof include a composition in which a resin such as a styrene resin such as a copolymer, an acrylonitrile-styrene-butadiene copolymer, a methyl (meth) acrylate-acrylonitrile-styrene-butadiene copolymer, or a polycarbonate resin is mixed.

  When the protective film is multi-layered, the resin laminated on the adhesive resin layer includes urethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, etc. Thermoplastic elastomer, polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer and other olefin resins, polyethylene terephthalate, polybutylene terephthalate, ethylene terephthalate-isophthalate copolymer Polyester resins such as 6 nylon, 6-66 copolymer nylon, 66 nylon, 6-12 copolymer nylon, polyamide resin such as 12 nylon, polymethyl (meth) acrylate Acrylic resins such as polybutyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, methyl (meth) acrylate-styrene copolymer, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile- One type or a mixture of two or more types of resins such as styrene resins such as styrene-butadiene copolymer and methyl (meth) acrylate-acrylonitrile-styrene-butadiene copolymer, and polycarbonate resins can be used.

  As the adhesive layer that the protective film may have, a known resin such as a thermoplastic resin, a thermosetting resin, or an ionomer resin can be used. For example, ethyl cellulose, cellulose nitrate, cellulose acetate, ethyl hydroxyethyl cellulose , Cellulose derivatives such as cellulose acetate propionate, styrene resins or styrene copolymers such as polystyrene and poly-α-methylstyrene, acrylic resins such as poly (meth) acrylate, polyvinyl acetate, and vinyl chloride -Vinyl acetate copolymer, ethylene-vinyl acetate copolymer, vinyl copolymer resins such as polyvinyl butyral, rosin, rosin acid ester resins such as rosin-modified maleic acid resin, polyisoprene, polyisobutylene, styrene-butadiene, etc. Rubber resin, petroleum resin, tellurium Down resins, polyamide resins, chlorinated polyolefin resins, ionomer resins. These can be used alone or in admixture of two or more.

  In the adhesive layer, an α-methylstyrene resin, a silicone elastomer, or the like may be blended in order to adjust the adhesive force.

  Regarding the multilayering method, the above resin types are laminated and integrated by T-die method or inflation method, etc., multilayer coextrusion method, extrusion laminating method by laminating by extrusion, thermal laminating method, etc., and the resin is diluted with solvent The obtained resin liquid can be multilayered by a known printing or coating means. Furthermore, it is also possible to make a multilayer by using an adhesive layer between the layers.

  The protective film only needs to have transparency to the extent that marking can be visually recognized. For example, the total light transmittance of the protective film (in the thickness during use) is about 35 to 100%, preferably 45. -100%, more preferably 50-100%. When the total light transmittance of the protective film is less than 35%, it is difficult to visually recognize the print through the protective film.

  As thickness of a protective film, it is 5-5000 micrometers normally, More preferably, it is 10-3000 micrometers, More preferably, it is 20-2000 micrometers. When the thickness of the protective film is less than 5 μm, the protection of the printed foam layer structure tends to be insufficient, and when it exceeds 5000 μm, it tends to be difficult to visually recognize the print, and a protective film should be provided. May cause the product to deform.

  As long as the protective film does not impair the visibility of the print and the protection of the foam structure, as necessary, a colorant, a compatibilizer, a flame retardant, an antistatic agent, a filler, a stabilizer, a lubricant, a dispersant, an additive, Additives such as foaming agents and antibacterial agents may be included.

[Method for producing white-marked resin structure]
As a method for producing a white-marked resin structure according to the present invention, a resin molded body composed of a resin (A) and a resin (B) is irradiated with a laser beam to give a white marking to the surface of the resin molded body, and thereafter When the resin (B) is a resin (B1), the melting point (T _2-1 ) or higher is applied to the surface of the white marking portion, and when the resin (B) is a resin (B2), the glass transition temperature ( The protective film made of the resin (C) is melt-bonded by heating at a temperature _{equal to} or higher than T _2-2 ) and lower than the melting point (T ₁ ) of the resin (A).

  The resin molded body can be produced by subjecting a white-colorable thermoplastic resin to a conventional molding method such as extrusion molding, injection molding, or compression molding. The shape of the resin molded body can be appropriately selected according to the purpose, the type of the final product, and the like, and may be any of a prismatic shape, a cylindrical shape, a flat plate shape (plate shape), a sheet shape, and the like.

  By irradiating the resin molded body thus obtained with a laser beam, a foamed structure is formed on the surface of the resin molded body, and a resin molded body having a white marking is obtained. In the white marking, characters and the like are recognized when light is scattered on the foamed structure and is visually recognized as white. The type of laser used for marking is not particularly limited and may be any of a gas laser, a semiconductor laser, an excimer laser, a YAG laser, and the like, but a YAG laser is most preferably used. The type of marking is not particularly limited, and may be any of characters, symbols, designs, pictures, photographs, and the like.

  The existing method can be used as a method for adhering and laminating the protective film to the surface of the marking part of the resin molded body with white marking. Two-color molding, insert molding, in-mold molding, co-extrusion, hot press Methods such as vacuum hot pressing, pressure forming, laser welding, vibration welding and hot plate welding can be employed.

The manufacturing method of the resin structure marked with white according to the present invention includes a melting point (T _2-1 ) or a glass transition temperature (T _2-2 ) of the resin (B), a melting point (T) of the crystalline resin (A). ₁ ) It is characterized in that the protective film is melt-bonded by heating at a temperature of less than ₁ . When heated at a temperature equal to or higher than the melting point (T ₁ ) of the crystalline resin (A), the crystalline resin (A) is melted, so that the foamed structure formed by laser beam irradiation is damaged, and the contrast of the marking portion is lowered. . On the other hand, if the heating temperature is lower than the melting point (T _2-1 ) or glass transition temperature (T _2-2 ) of the resin (B), the resin (B) does not melt or soften, so that the adhesiveness is insufficient and a protective film is formed. It becomes difficult to adhere to the surface of the foam structure. Specifically, when the resin (B) is a crystalline resin (B1), even if it is heated at a temperature higher than the glass transition temperature of the crystalline resin (B1) and lower than the melting point (T _2-1 ), the shape depends on the crystal structure. This is because the protective film is not melted for the first time by heating at a melting point (T _2-1 ) or higher, so that the protective film can be bonded. In addition, when the resin (B) is an amorphous resin (B2), it can be softened and melted by heating at a glass transition temperature (T _2-2 ) or higher so that the protective film can be adhered. is there.

Further, the protective film is formed at a heating temperature lower than the melting point (T ₁ ) of the resin (A) and higher than the melting point (T _2-1 ) or the glass transition temperature (T _2-2 ) of the resin (B). A temperature lower than the melting point (T _3-1 ) or glass transition temperature (T _3-2 ) of the resin (C) in terms of maintaining the adhesion of the protective film and the foam structure that forms the white marking. More preferred.

  The white marked resin structure thus obtained has a strong foamed structure of the crystalline resin (A) and contains a resin that melts or softens at a temperature lower than the melting point of the crystalline resin (A). Therefore, by heating at a temperature lower than the melting point of the crystalline resin (A), the protective film can be adhered and laminated on the foam structure without crushing the foam structure. Since the protective film can be adhered and laminated on the foamed structure by laser beam irradiation without damaging the foamed structure, the white marking contrast caused by the foamed structure being crushed by the lamination of the protective film. There is no decline. In addition, the visibility is not lowered due to insufficient adhesion between the protective film and the white marking. Furthermore, since the foam structure is protected by a protective film, it is not crushed by the pressure of a finger or the like, and dirt and dust from the hand does not enter the uneven portion of the foam structure. Contrast does not decrease and good visibility such as printing can be maintained. Further, by preventing a decrease in the contrast of the marking portion, it is possible to prevent loss of texture due to the decrease in contrast.

  The white-marked resin structure according to the present invention can be widely used for, for example, OA equipment such as a computer keyboard, automobile parts (button parts, etc.), household goods, and building materials.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.

(Creation of resin film for protective film)
The protective film resin shown in Table 1 was extruded by a T-die method to prepare protective film resin films having thicknesses of 20 μm, 200 μm, and 1000 μm. The processing temperature was 200 ° C for elastomers 2, 3, 4, and 5 and 230 ° C for elastomers 1, 6, AS, and MMA-AN-ST-Bd. The film thickness was measured using a standard outer micrometer, trade name “MDC-25SB” (manufactured by Mitutoyo Corporation).

Examples 1-17, Comparative Examples 1-3
(Creation of resin moldings made of white-colored thermoplastic resin)
Each component shown in Tables 2 to 4 was blended and extruded to produce pellets, and the pellets were injection molded to produce a 2 mm thick resin molded body (marking colored resin flat plate; 120 mm × 120 mm). .

(Marking method)
The obtained resin molding was irradiated with a laser beam, and white marking [describes a 10 mm square BOX (line distance: 75 μm)] was applied to the surface of the resin molding. An Nd: YAG laser (wavelength: 1064 nm) was used as the laser. As the irradiation conditions, the aperture is fixed to 2 mm in diameter, the light source current value (LC), the frequency (QS), and the printing speed (SP) are changed within the following ranges, and marking is performed under the condition that the most clear white print is obtained. Carried out.
Light source current value (LC): 8-20A
Frequency (QS): 1-10kHz
Printing speed (SP): 100-1500mm / sec

(Lamination method of resin molding and protective film)
The protective film resin film obtained above was melt-bonded to the surface of the marking portion of a resin molded body (120 mm × 120 mm) having a thickness of 2 mm to obtain a test body.

  The following evaluation tests were performed on each resin molded body and each test body obtained in the examples and comparative examples.

(1) Light transmittance of protective film (%)
About the obtained resin film for protective films, using a haze meter (trade name “Fully Automatic Haze Meter TC-HIIIDPK”, manufactured by Tokyo Denshoku Co., Ltd.), the total light transmittance (T%) was determined according to JIS K7105. It was measured.

(2) Marking property of white-colored thermoplastic resin For resin molded bodies made of white-colored thermoplastic resins obtained in the examples and comparative examples, printing was performed by irradiating a laser beam, and the shape of the applied print was correct. Whether it was printed or not was visually observed and evaluated according to the following criteria.
Evaluation criteria Printed as designed: ○
Insufficient printing: ×

(3) Adhesiveness of protective film The test specimens obtained in Examples and Comparative Examples were twisted to visually check whether voids were generated between the protective film and the molded resin (marking layer). Evaluated according to.
Evaluation criteria No voids were generated: ○
A void was generated: ×

(4) Visibility of printing In the examples and comparative examples, changes in visibility caused by changes in the contrast of printing before and after the protective film lamination step were visually observed and evaluated according to the following criteria.
Evaluation criteria No reduction in contrast and no change in visibility: ○
Contrast decreased and visibility decreased: ×

(Ingredients used in Examples and Comparative Examples)
Crystalline resin PP: Polypropylene, trade name “Sun Allomer PM870L”, Sun Allomer Co., Ltd. PET: Polyethylene terephthalate, trade name “Belpet EFG6C”, Kanebo Gosei Co., Ltd. PBT: Polybutylene terephthalate, trade name “TRE-” DM2 ”, Wintech Polymer Co., Ltd. PA: Polyamide (PA6): Trade name“ A1030BRL ”, Unitika Ltd.

Amorphous resin AS: Copolymer composed of 76% by weight of styrene (St) and 24% by weight of acrylonitrile (AN), MI under the condition of 220 ° C./10 kg = 32 g / 10 minutes ABS-1: St 45% by weight, 15% by weight of AN %, Butadiene (Bd) 40 wt% copolymer, MEK (methyl ethyl ketone) 30 ° C. η viscosity 0.47
ABS-2: a copolymer comprising St 40% by weight, AN 15% by weight, Bd 40% by weight, methacrylic acid (MA) 5% by weight, η viscosity 0.67 at MEK 30 ° C.
SEBS: maleic anhydride modified styrene / ethylene / butylene / styrene block copolymer, trade name “Tuftec M1943”, manufactured by Asahi Kasei Chemicals MIP: Styrene-N-phenylmaleimide-maleic anhydride copolymer, trade name “ Marekka MS-NC ", manufactured by Denki Kagaku Kogyo Co., Ltd. MMA-AN-ST-Bd: a quaternary copolymer comprising St22 wt%, AN11 wt%, MMA58 wt% and Bd9 wt% (under 220 ° C / 10 kg conditions) MI = 18 g / 10 min), rubber average particle size 250 μm)

Color material CB: Carbon black, commercial product, average particle size 17 nm
TiO ₂ : Titanium dioxide, commercial product, average particle size 0.18 μm

Other additives Antioxidant 1: Phenol antioxidant, trade name “Irganox 1010”, manufactured by Ciba Specialty Chemicals Co., Ltd. Antioxidant 2: Sulfur antioxidant, trade name “Sumilyzer TPS”, Sumitomo Made by Chemical Industry Co., Ltd.

Elastomer Elastomer 1: Polyetheresteramide elastomer (PEEA), trade name “Pelestat NC6321”, manufactured by Sanyo Chemical Industries, Ltd. Elastomer 2: Polyetheresteramide elastomer (PEEA), trade name “Pelestat 300”, Sanyo Chemical Industries ( Elastomer 3: Polyester thermoplastic elastomer (Polyester EL), trade name “Primalloy A1606C”, Mitsubishi Chemical Corporation Elastomer 4: Polyurethane thermoplastic elastomer (TPU EL), trade name “Elastolan S95A”, Elastomer 5 manufactured by BASF Japan Ltd .: Olefin thermoplastic elastomer (Olefin EL), trade name “ZELLAS MC717”, manufactured by Mitsubishi Chemical Corporation Elastomer 6: Polyester thermoplastic elastomer Polyester EL), the trade name of "ECDEL9966", Eastman Chemical Japan Ltd.

Claims (5)

The resin molded body composed of the resin (A) and the resin (B) is subjected to white marking by laser beam irradiation, and the resin (B) is a resin (B1) on the white marking portion on which the white marking is applied. ) Above the melting point (T _2-1 ), when the resin (B) is the resin (B2) above the glass transition temperature (T _2-2 ), and the melting point (T) of the resin (A) ₁ ) A white marked resin structure provided with a protective film made of resin (C) by heating at a temperature lower than ₁ .
Resin (A): Crystalline resin [melting point (T ₁ )]
Resin (B): Crystalline resin (B1) having a melting point (T _2-1 ) lower than the melting point (T ₁ ) of resin (A), or glass lower than the melting point (T ₁ ) of resin (A) Amorphous resin (B2) having a transition temperature (T _2-2 )
Resin (C): Melting point (T _2-1 ) of crystalline resin (B1) or glass transition temperature (T _2-2 ) of amorphous resin (B2), which is lower than melting point (T ₁ ) of resin (A) ) The crystalline resin (C1) having the above melting point (T _3-1 ) or lower than the melting point (T ₁ ) of the resin (A), and the melting point (T _2-1 ) of the crystalline resin (B1) or Amorphous resin (C2) having a glass transition temperature (T _3-2 ) higher than the glass transition temperature (T _2-2 ) of the amorphous resin (B2)   The resin structure with white marking according to claim 1, wherein the resin (B) is an amorphous resin (B2).   3. The white marked resin structure according to claim 1, wherein a blending ratio of the resin (A) and the resin (B) [the former: the latter (weight ratio)] is 20:80 to 80:20.   The resin structure with white marking according to any one of claims 1 to 3, wherein the resin (C) is a resin having compatibility with the resin (B). The resin molded body composed of the resin (A) and the resin (B) is irradiated with a laser beam to give white markings on the surface of the resin molded body, and then the resin (B) is a resin ( In the case of B1), the melting point (T _2-1 ) or higher, and when the resin (B) is the resin (B2), the glass transition temperature (T _2-2 ) or higher, and the melting point of the resin (A) ( A method for producing a white-marked resin structure, which comprises melting and bonding a protective film made of resin (C) by heating at a temperature lower than T ₁ ).
Resin (A): Crystalline resin [melting point (T ₁ )]
Resin (B): Crystalline resin (B1) having a melting point (T _2-1 ) lower than the melting point (T ₁ ) of resin (A), or glass lower than the melting point (T ₁ ) of resin (A) Amorphous resin (B2) having a transition temperature (T _2-2 )
Resin (C): Melting point (T _2-1 ) of crystalline resin (B1) or glass transition temperature (T _2-2 ) of amorphous resin (B2), which is lower than melting point (T ₁ ) of resin (A) ) The crystalline resin (C1) having the above melting point (T _3-1 ) or lower than the melting point (T ₁ ) of the resin (A), and the melting point (T _2-1 ) of the crystalline resin (B1) or Amorphous resin (C2) having a glass transition temperature (T _3-2 ) higher than the glass transition temperature (T _2-2 ) of the amorphous resin (B2)