JP2006305795A - Resin molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a flexible resin molded product having a surface protective layer excellent in abrasion resistance and weatherability by in-mold molding. <P>SOLUTION: The resin molded product 1 comprises a resin base material 3 having flexibility and the protective layer 2 at least on the surface of the resin base material 3, wherein the constituent element of the protective layer 2 comprises an urethane acrylate comprising an alicyclic isocyanate, an ester type polyol, an acrylate or methacrylate compound having a hydroxyl group as essential components, and a photopolymerization initiator, and wherein the protective layer 2 is laminated on the resin base material 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resin molded product in which a surface protective layer is provided on the surface of a flexible resin.

  Conventionally, there is a resin molded product having a surface protective layer for protecting a surface by applying a printed layer on a resinous substrate. In-mold molding is efficient in molding a resin molded product. For this reason, an ultraviolet curable resin is used as a surface protective layer for protecting the surface of the resin substrate, and there is an in-mold molded product (see, for example, Patent Document 1). Like the surface protective layer (hard coat layer) of the molded article, the surface protective layer composed of an ultraviolet curable resin is generally hard and has excellent wear resistance and weather resistance.

JP-A-11-32478

  Recently, a flexible resin has been used as the resinous substrate. In order to make use of the flexibility of the substrate, the surface protective layer that protects the substrate also needs flexibility. However, the surface protective layer of a molded product by conventional in-mold molding is made of a hard resin. For this reason, the flexibility of the base material could not be utilized. Also, if the substrate is forcibly bent, the conventional surface protective layer is a hard resin, so it is difficult to bend, the printed layer between the substrate and the surface protective layer is distorted, and the printed layer breaks. There was a fear.

  On the other hand, it is also conceivable that the substrate is bent by arranging a thin resin on the surface protective layer and printing under the resin. However, if the conventional resin is simply made thin, the surface strength becomes weak, so the wear resistance and weather resistance are lowered, and the substrate cannot be sufficiently protected. For this reason, there existed a problem that a molded article was not excellent in practicality.

  Therefore, an object of the present invention is to obtain a flexible resin molded product having a surface protective layer excellent in wear resistance and weather resistance by in-mold molding.

  The first configuration of the resin molded product of the present invention for achieving the above object is a resin molded product having a flexible resin base and a protective layer on at least the surface of the resin base, As a constituent element of the protective layer, an urethane acrylate containing an alicyclic isocyanate, an ester-based polyol, and an acrylate or methacrylate compound having a hydroxyl group as essential components, and a photopolymerization initiator, and the resin base material by in-mold molding The above-mentioned protective layer is laminated.

  Moreover, the 2nd structure of a resin molded product is a resin molded product of the 1st structure, Comprising: The said ester-type polyol is polycaprolactone more than trifunctional as a hydroxyl group, It is characterized by the above-mentioned.

  According to the first configuration, the protective layer has a flexible configuration. For this reason, even if it uses the thing of the material which has flexibility for the said resin base material, the said protective layer bends according to the bending of the said resin base material. For this reason, distortion does not arise between the said protective layer and the said resin base material, and even if there exists a printing layer between the said protective layer and the said resin base material, the said printed layer does not crack.

  In the resin molded product, the protective layer and the resin base material are injected integrally in a film shape and molded by in-mold molding. For this reason, compared with the structure which affixes a protective layer to a resin base material by secondary processing, it does not take time and productivity is good.

  Moreover, since the said protective layer is ultraviolet curable resin containing a photoinitiator, it has abrasion resistance and a weather resistance. For this reason, at least the surface of the flexible resin substrate can be sufficiently protected.

  According to the said 2nd structure, the said ester-type polyol becomes a structure which is excellent also in flexibility, maintaining abrasion resistance and a weather resistance by using polycaprolactone more than trifunctional as a hydroxyl group.

  Embodiments of the present invention will be described with reference to the drawings. In the description, the outline of the resin molded product, the detailed description of the protective layer, and the example of the resin molded product according to the present embodiment will be described in this order.

[Outline of resin molded product]
The resin molded product 1 will be described with reference to FIG. FIG. 1 is a cross-sectional view of a resin molded product 1 of this embodiment.

  As shown in FIG. 1A, the resin molded product 1 of the present embodiment has a protective layer 2 on the surface of a flexible resin base material 3. Since the protective layer 2 has a structure excellent in weather resistance and wear resistance, the surface of the resin base material 3 is protected by the protective layer 2. The protective layer may be provided not only on the surface of the resin base material 3 but also on the back surface. That is, as shown in FIG. 1B, the protective layer 2, the resin base material 3, and the protective layer 4 may be laminated in this order from the surface. The configuration of the protective layers 2 and 4 will be described in detail later.

  As the flexible resin base material 3, a TPE resin (Thermoplastic Elastomer) is suitable. TPE resin is soft like rubber and excellent in workability like plastic. Moreover, since it is easy to recycle, it has little environmental impact and is used for various products.

  As the TPE resin, polyester (TPEE), urethane (TPU), olefin (TPO), styrene (TPS), amide (TPEA), vinyl chloride (TPVC) and the like can be used. Moreover, the above-mentioned TPE resin and thermoplastics may be mixed, and the above-mentioned TPE resin and rubber such as EPDM may be mixed and used after resin modification. The TPE resin can be selected by changing the configuration according to the application of the product to be implemented.

  The resin base material is not limited to TPE resin. That is, any flexible resin material may be used, and a resin other than the TPE resin may be used.

  When the resin molded product 1 is molded, a resin that is a material of the resin base material 3 is poured into the protective layers 2 and 4 installed in the mold and formed by in-mold molding. Then, as shown in FIG. 1, the protective layers 2 and 4 are laminated on the resin base material 3. Here, in-mold molding is a method in which a printed film is inserted into an injection mold and the film and the container are integrally molded during molding. When in-mold molding is performed, the decorative property is excellent, the strength is high, and the functionality can be imparted by selecting a film. In addition, the labor can be greatly reduced as compared with the method of attaching the protective layers 2 and 4 to the molded resin base material 3 by secondary processing.

[Detailed description of protective layer]
The protective layer will be described in detail with reference to FIG. FIG. 2 is an enlarged cross-sectional view of the protective layer 2 of the resin molded product 1.

  As shown in FIG. 2, the protective layer 2 is formed in multiple layers, and is integrated with the resin base material 3 by in-mold molding to form a resin molded product 1. As shown in FIG. 2, the layers of the protective layer 2 are laminated from the surface like a special protective layer 13, an anchor coat 14, a printed layer 15, an anchor coat 16, and an adhesive layer 17. The adhesive layer 17 adheres to the surface of the resin base material 3 to form a film. A surface layer 11 and a release treatment layer 12 are formed on the special protective layer 13, and after the resin molded product is completed, the special protective layer 13 is peeled off from the protective layer 2. Next, each part will be described in detail.

(Surface layer 11 and mold release layer 12)
The surface layer 11 protects the resin base material 3 at the stage before molding of the resin molded product 1, and is peeled off together with the release treatment layer 12 after molding of the resin molded product 1. As the material for the surface layer 11, polyethylene terephthalate (PET) is usually used. The thickness is preferably 38 μm or 50 μm. The release treatment layer 12 is usually formed of a melamine paint.

(Special protective layer 13)
The special protective layer 13 is a characteristic part of the present embodiment, and is a layer that protects the surface of the resin substrate 3. The special protective layer 13 of the present embodiment includes, as its material, at least a urethane acrylate having an alicyclic isocyanate, an ester polyol, and an acrylate or methacrylate compound having a hydroxyl group as essential components, and a photopolymerization initiator. Features.

  The composition constituting the special protective layer 13 may include a reactive oligomer, a non-reactive polymer, and various additives in addition to the reactive oligomer mainly composed of the urethane acrylate and the photopolymerization initiator. Well, the composition ratio is 20-95% by weight of reactive oligomer, 1-15% of photoinitiator, 0-35% of reactive monomer, 0-15% of non-reactive polymer, various additives It is preferable to prepare in the range of 0 to 5%. By blending in this range, a highly flexible special protective layer 13 can be obtained.

  Examples of the reactive monomer include methoxypolyethylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and lactone-modified tetrahydrofurfuryl acrylate. , 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, poly ε-caprolactone mono ( Monofunctional monomers such as (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (me ) Acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, bifunctional monomers such as neopentyl glycol di (meth) acrylate, and trimethylolpropane tri (Meth) acrylate, caprolactone-modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) Polyfunctional monomers such as acrylates can be used.

  As the non-reactive polymer, acrylic resins, polyester resins, urethane resins, vinyl chloride, nitrified cotton, CAB, and other fiber-based resins can be used.

  Examples of the photopolymerization initiator include acetophenone compounds, benzoin ether compounds, benzophenone compounds, phosphine oxide compounds, and specific examples thereof include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and acetoin. , Butyroin, toluoin, benzyl, benzophenone, p-methoxybenzophenone, diethoxyacetophenone, α, α-dimethoxy-α-phenylacetophenone, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4'-bis (dimethylamino) Benzophenone), carbonyl compounds such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, tetramethyl Use sulfur compounds such as thiuram monosulfide and tetramethylthiuram disulfide, azo compounds such as azobisisobutyronitrile and azobis-2,4-dimethylvalero, peroxide compounds such as benzoyl peroxide and ditertiary butyl peroxide can do.

  As said various additives, a leveling agent, an antifoamer, antioxidant, a ultraviolet absorber, a sensitizer, a polymerization inhibitor, and a whitening agent can be used, for example.

  The reactive oligomer is mainly composed of polyurethane acrylate. The polyurethane acrylate is an acrylate having a polyurethane structure (—NHCOO—) in the main chain. The polyurethane acrylate is obtained by a reaction of an alicyclic isocyanate, an ester polyol, and an acrylate or methacrylate compound having a hydroxyl group.

  The weather resistance varies depending on the alicyclic isocyanate compound. As the alicyclic isocyanate compound, for example, isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate (H6XDI), or dicyclohexylmethane diisocyanate (H12MDI) is preferably used. In addition to alicyclic isocyanates, aliphatic isocyanate hexamethylene diisocyanate (HMDI) may be used. Since these compounds are non-yellowing or hard yellowing, the yellowing of the resin can be suppressed. As a result, the weather resistance can be increased.

  The ester-based polyol is preferably polycaprolactone (PCL) having at least three functional groups as a hydroxyl group. By being trifunctional or more, the wear resistance of the special protective layer 13 can be sufficiently obtained. Here, as a polycaprolactone having a trifunctional or higher functional group as a hydroxyl group, a ring-opening reaction product of ε-caprolactone and a modified product thereof and a trifunctional or higher functional polyol can be used.

  As the acrylate or methacrylate compound having a hydroxyl group, the following are preferable. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (Meth) acrylate, polypropylene glycol mono (meth) acrylate, pentaerythritol tri (meth) acrylate and the like can be used.

(Anchor coat 14)
The anchor coat 14 is an anchor coat for attaching prints such as colors, patterns, and logos. Basically, an acrylic paint may be used, and a plurality of layers may be formed as necessary. In some cases, urethane or the like is added and reaction curing is used with heat as a medium.

(Print layer 15)
The printing method in the printing layer 15 is preferably gravure printing or silk screen printing.

(Anchor coat 16)
The anchor coat 16 is provided to bring the adhesive layer 17 into close contact. The material of the anchor coat 16 needs to be selected depending on the composition of the adhesive layer 17, but is similar to the composition of the anchor coat 14, and basically uses an acrylic material.

(Adhesive layer 17)
The adhesive layer 17 is a layer for adhering to the resin base material 3. The material of the adhesive layer 17 needs to be selected depending on the composition of the resin base material 3, but an acrylic, ester or olefin adhesive can be used.

(Production method of resin molded product 1)
When the resin molded product 1 is manufactured, the surface layer 11, the release treatment layer 12, the special protective layer 13, the anchor coat 14, the printing layer 15, the anchor coat 16, and the adhesive layer 17 described above are laminated for in-mold molding. The in-mold resin molded product 1 is formed by forming a film and bonding the adhesive layer 17 and the resin base material 3 by injection molding. Thereafter, the surface layer 11 and the release treatment layer 12 are released from the special protective layer 13. As a result, the special protective layer 13 appears on the surface, and the resin base material 3 is protected.

  The protective layer 2 of the resin molded product 1 of the present embodiment is an ultraviolet curable resin. For this reason, it has the characteristic of being excellent in abrasion resistance and a weather resistance of ultraviolet curable resin. When the ultraviolet curable resin is cured, it may be cured by irradiating with ultraviolet rays before in-mold molding, or may be cured by irradiating with ultraviolet rays after in-mold molding. The timing of irradiating ultraviolet rays may be selected depending on the type of the ultraviolet curable resin and the situation of other materials of the resin molded product.

〔Example〕
An example in which the molded article having the above-described configuration is used as a part of a mobile phone will be described. FIG. 3 is a diagram showing a usage state of the mobile phone 50 to which the resin molded product 1 of the present embodiment is applied.

  As shown in FIG. 3A, the resin molded product 1 of the present embodiment can be used for the cover member 51 of the earphone jack of the mobile phone 50 and the cap member 52 of the memory or power supply insertion portion.

  Conventionally, flexible members such as rubber members have been used as cover members and cap members in mobile phones. However, since the cover member and the cap member are configured to be opened and closed by directly touching the hand, there is a problem that the cover member and the cap member are easily soiled by touching. Moreover, there was a risk of yellowing or swelling by absorbing surrounding moisture.

  On the other hand, when the resin molded product 1 of the present embodiment is used as the cover member 51 or the cap member 52, the protective layer 2 on the surface protects the flexible resin base material 3. The protective layer 2 is excellent in weather resistance and abrasion resistance due to the composition of the special protective layer 13. For this reason, even if it is the cover member 51 and the cap member 52 which a user touches directly, it can suppress that it becomes dirty. Moreover, yellowing and swelling can also be suppressed. As a result, the durability of the cover member 51 and the cap member 52 can be improved.

  Conventionally, in order to prevent the contamination, secondary processing such as acrylic coating on the surface of a flexible member has been performed. However, there is a problem that it takes time and cost. In addition, a dedicated paint for a flexible member must be selected, and the color may be limited. In this case, there is a problem that the color tone does not match the adjacent members and the design properties are impaired.

  On the other hand, the resin molded product 1 of this embodiment can form the protective layer 2 and the resin base material 3 at once by carrying out in-mold molding of the continuous film member. For this reason, the effort which performs a secondary process can be skipped and cost can also be reduced. As a result, it is also possible to expect an effect that productivity is good.

  In addition, since the conventional surface protective layer is difficult to bend, if it is disposed on the surface of a flexible resin substrate, the printed layer between the resin substrate and the surface protective layer is distorted, and the printed layer There was a risk of cracking.

  In contrast, the special protective layer 13 of this embodiment is flexible. For this reason, even if the special protective layer 13 is provided on the surface of the flexible resin base material 3, the special protective layer 13 is bent in the same manner as the resin base material 3 is bent. For this reason, the printed layer 15 between the resin base material 3 and the special protective layer 13 is not distorted. For this reason, it is possible to prevent the printing of the printing layer 15 from being broken.

  Further, since the printing layer 15 is sandwiched between the anchor coat 14 and the anchor coat 16 as in the present embodiment, the printing layer 15 does not directly contact the resin base material 3. For this reason, regardless of the material of the resin base material 3, it is possible to freely select a printing paint or method. As a result, it is possible to perform printing with excellent design properties.

  Conventionally, when a flexible member is used in a wide range such as a housing, there is a problem that the design property of the surface of the flexible member is restricted or the flexible member is conspicuous. For this reason, it has been difficult to use in a wide range such as a casing of a mobile phone. As a result, the conventional flexible member is supposed to be used only for members in a small range such as a cover member of an earphone jack, a memory or a cap member of a power supply insertion portion.

  However, since the flexible resin molded product 1 of this embodiment is excellent in weather resistance, wear resistance, and design, it is not limited to a small range of members such as the cover member 51 and the cap member 52, but in a wider range. It is also suitable to use. For example, as shown in FIG. 3B, the mobile phone 50 can be a part of the housing.

  As shown in FIG. 3B, when the resin molded product 1 of the present embodiment is used for the replacement member 53 on the surface of the casing of the mobile phone 50, even if the resin base material 3 is a flexible member, As described above, since the anchor coats 14 and 16 can be printed in any color, the surface of the casing of the mobile phone can be excellent in design.

  Moreover, since the resin base material 3 of this embodiment has flexibility, it can be utilized also as a buffer material. For this reason, if the resin molded product 1 of this embodiment is used as a part of the cushioning member 54 of the casing of the mobile phone, the impact transmitted to the inside of the location where the resin molded product 1 is present can be reduced.

  For example, as shown in FIG. 3C, when an IC chip 55 is built in a mobile phone 50 and the IC chip is recognized by a dedicated IC chip recognition device 60, the mobile phone is recognized by the recognition device 60. When approaching the unit 61, the mobile phone 50 and the recognition unit 61 may come into contact with each other. In this case, if the casing is hard, an impact at the time of contact may be directly transmitted to the IC chip 55, which may adversely affect the IC chip 55. In this case, if the resin molded product 1 of the present embodiment is used as a buffer member 54 in a part of the casing of the mobile phone 50, the impact at the time of contact can be absorbed by the flexible resin base material 3. The impact transmitted to the IC chip 55 can be reduced.

  Although the present embodiment is applied to the mobile phone 50, the present invention is not limited to this. For example, the present invention can be applied to similar electronic devices such as PDAs and notebook personal computers.

  The present invention can be used for all molded articles using a resin material. For example, it can be used for cosmetic containers and stationery goods.

Sectional drawing of the resin molded product 1 of this embodiment. The expanded sectional view of the protective layer 2 of the resin molded product 1 of this embodiment. The figure which shows the use condition of the mobile telephone 50 to which the resin molded product 1 of this embodiment is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Resin molded product 2 ... Protective layer 3 ... Resin base material 4 ... Protective layer
11… Surface
12… Releasing treatment layer
13… Special protective layer
14… Anchor coat
15… Printing layer
16… Anchor coat
17… Adhesive layer
50… Mobile phone
51… Cover member
52… Cap member
53… replacement parts
54… Cushioning member
55 IC chip
60 IC chip recognition device
61… Recognition part

Claims (2)

A resin molded product having a flexible resin substrate and a protective layer on at least the surface of the resin substrate,
As a constituent element of the protective layer, a urethane acrylate containing an alicyclic isocyanate, an ester polyol and an acrylate or methacrylate compound having a hydroxyl group as essential components, and a photopolymerization initiator,
A resin molded product, wherein the protective layer is laminated on the resin base material by in-mold molding. The resin molded product according to claim 1,
The ester-based polyol is a polycaprolactone having three or more functional hydroxyl groups.

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