JP4973365B2 - Mobile phone housing - Google Patents

Description

  The present invention relates to a cellular phone casing in which a fiber reinforced composite material and a frame portion are joined. More specifically, a thin, lightweight, and rigid fiber reinforced composite material is joined to a frame portion. The present invention relates to a cellular phone casing having features of thin wall, light weight, and high rigidity.

  A fiber reinforced composite material is a material excellent in mechanical properties and lightness, and is widely used for components such as aircraft and automobiles. In recent years, fiber reinforced composite materials have come to be used for relatively small and complex parts such as electrical / electronic equipment, office automation equipment, home appliances, and medical equipment that require thin, light, and rigid. . In particular, application to mobile phone housings, which have a large number of popularized devices, is considered to be able to make full use of the characteristics of thin, lightweight, and highly rigid fiber-reinforced composite materials.

  Patent Document 1 describes a mobile communication housing using vapor-grown carbon fiber and synthetic resin. Specifically, it is a casing made of 0.1 to 1 mm of vapor-grown carbon fiber and polyester, polyamide, or vinyl resin, and has excellent mechanical characteristics and EMI characteristics. However, since discontinuous fibers are used, the mechanical properties such as the rigidity of the housing are not sufficient, and further improvements have been expected.

  Patent Document 2 describes an electric / electronic device casing made of a carbon fiber reinforced thermosetting resin. This is a casing obtained by molding a resin composition containing discontinuous carbon fibers and unsaturated polyester or vinyl ester, and is excellent in rigidity, EMI characteristics and the like as compared with an unreinforced resin casing. However, since discontinuous fibers are also used in this document, it cannot be said that the mechanical properties such as rigidity of the fiber reinforced composite material are sufficient, and further improvement has been expected.

Patent Document 3 describes a composite molded product composed of a fiber reinforced composite material and a metal molded product, and specifically describes application to an electronic device casing utilizing the heat dissipation of the metal material. Yes. Since a metal molded product is used for this, the lightness is still limited, and further improvement has been expected.
JP-A-3-235398 JP-A-8-311242 JP-A-11-147286

  An object of the present invention is to provide a thin, lightweight, and highly rigid mobile phone casing in which a thin, lightweight, and highly rigid fiber-reinforced composite material and a frame member are integrated.

As a result of intensive studies to achieve the above object, the present inventors have found the following mobile phone casing that can achieve the above-described problems.

(1) including the continuous reinforcing fibers and a matrix resin, a fiber-reinforced composite material substantial thickness is in the range of 0.1 to 0.6 mm (I), as a frame portion (II) and the thermoplastic resin (A) Bonded via a polyester resin, the projected area of the bonded portion is in the range of 5 to 75% of the projected area of the fiber reinforced composite material (I), and in the fiber reinforced composite material (I), at least one of A design layer containing polyester or polycarbonate as a main component was joined to the surface via the thermoplastic resin (A), and the thermoplastic resin present in the layered form was also formed on the opposite surface of the fiber reinforced composite material. Mobile phone housing.

(2) The mobile phone housing according to (1), wherein the maximum projected area of the fiber-reinforced composite material (I) is 10,000 mm ² or less.

  (3) The mobile phone casing according to any one of (1) to (2), wherein the fiber-reinforced composite material (I) has a flexural modulus of 35 GPa or more.

  (4) The mobile phone casing according to any one of (1) to (3), wherein the specific gravity ρ1 of the fiber-reinforced composite material (I) is in the range of 1.4 to 1.6.

  (5) The mobile phone casing according to any one of (1) to (4), wherein the frame portion (II) is one or more resin compositions selected from polycarbonate resin, ABS resin, and thermoplastic elastomer resin.

( 6 ) The thermoplastic resin (A) is impregnated by forming a concavo-convex shape between the reinforcing fibers constituting the fiber reinforced composite material (I) and having a maximum impregnation thickness h of 10 to 200 μm. The mobile phone housing according to any one of (1) to (5) .

( 7 ) The mobile phone case according to any one of (1) to (6) , wherein a melting point Tm of the polyester resin is in a range of 120 ° C to 160 ° C.

( 8 ) The mobile phone casing according to any one of (1) to (7), wherein a glass transition temperature Tg of the polyester resin is in a range of 0 ° C to 80 ° C.

( 9 ) The mobile phone casing according to any one of (1) to (8) , wherein the number average molecular weight of the polyester resin is in a range of 10,000 to 30,000.

( 10 ) The mobile phone according to any one of (1) to (9) , wherein the polyester resin is a copolyester resin containing a polyethylene terephthalate component and / or a polybutylene terephthalate component in a range of 10 to 80% by weight. Enclosure.

(11) The mobile phone casing according to ( 10 ), wherein the polyester resin is a copolyester containing a polytetramethylene glycol component as a diol component.

(12) The mobile phone casing according to any one of (1) to (11) , wherein the thermoplastic resin has a tensile breaking strength of 25 MPa or more and / or a tensile breaking elongation of 200% or more.

( 13 ) One or two selected from the group consisting of a primary amino group, an epoxy group, a carboxyl group, and an acid anhydride group at one or both ends of at least one polyester resin among the polyester resins The mobile phone case according to any one of (1) to (12) , which has a functional group structure of:

( 14 ) The mobile phone casing according to ( 13 ), wherein the functional group content is 1000 to 100,000 equivalents.

( 15 ) The mobile phone casing according to any one of (1) to ( 14 ), wherein the reinforcing fibers constituting the fiber-reinforced composite material (I) are carbon fibers.

( 16 ) The mobile phone casing according to any one of (1) to ( 15 ), wherein the matrix resin constituting the fiber-reinforced composite material (I) is a thermosetting epoxy resin.

( 17 ) The mobile phone casing according to any one of (1) to ( 16 ), wherein at least part of the mobile phone casing has radio wave transparency.

( 18 ) The mobile phone casing according to ( 17 ), wherein the electromagnetic wave shielding property of the portion having radio wave permeability is 6 dB or less.

  The cellular phone case of the present invention has a structure in which a thin and lightweight fiber reinforced composite material is joined to a frame portion, and has the excellent strength, rigidity and impact resistance of the fiber reinforced composite material. It is a housing.

  Hereinafter, the heat bonding substrate of the present invention will be specifically described.

  The cellular phone casing of the present invention is formed by joining a continuous reinforcing fiber, a fiber reinforced composite material (I) containing a matrix resin, and a frame portion (II), and is thin as a cellular phone casing. This is important from the viewpoint of improving the light weight and eliminating the interference with the internal parts to widen the width of the housing design, and it is important that the substantial thickness is 0.1 to 0.6 mm. Preferably it is 0.2-0.5 mm. Here, the substantial thickness means that the thickness of the fiber reinforced composite material (I) used in the mobile phone casing is the thickness of the fiber reinforced composite material (I). The actual thickness is measured at any five points from the plane portion of the fiber reinforced composite material (I) portion of the mobile phone casing, and the average value is defined as the actual thickness of the fiber reinforced composite material (I).

  Since the fiber reinforced composite material (I) constituting the mobile phone casing of the present invention includes continuous reinforcing fibers, it is not easy to be molded into a complicated shape, and its application site is relatively flat such as a planar shape. It is preferable that it is a site | part of a simple shape. Specifically, it is preferable to form the top surface portion of the mobile phone casing as shown in FIGS. 3a and 3b.

  The frame portion is a portion other than a portion made of the fiber reinforced composite material (I) among members constituting the mobile phone casing. In general, there are many curved portions due to the structure and design of bosses, ribs, and the like for mounting and arrangement of internal parts, etc., and the members are relatively complicated shapes.

  Further, in order to reduce the weight of the housing, it is necessary to reduce the frame portion (II) as much as possible. However, it is premised that the fiber reinforced composite material (I) can be sufficiently bonded and supported as a frame, and considering the effect, the projected area of the joint portion between the fiber reinforced composite material (I) and the frame portion (II) is the fiber. It is important that it is 5 to 75% of the projected area of the reinforced composite material (I). Preferably it is 10 to 60% of the projected area, more preferably 20 to 50% of the projected area. By setting it as the said range, it is possible to fully adhere | attach and support the fiber reinforced composite material (I) to frame part (II), aiming at weight reduction.

The fiber reinforced composite material (I) is preferably small in size and lightweight from the viewpoint of use in a mobile phone casing, and its maximum projected area is preferably 10,000 mm ² or less. More preferably, it is 8000 mm < ² > or less, More preferably, it is 6000 mm < ² > or less.

  The fiber reinforced composite material (I) preferably has a flexural modulus of 35 GPa or more in order to ensure rigidity as a mobile phone casing. More preferably, it is 45 MPa or more, More preferably, it is 55 MPa or more. Although there is no restriction | limiting in particular about the upper limit of a bending elastic modulus, As a mobile telephone housing | casing of this invention, if it is about 100 Mpa, it will be enough practically. Here, the bending elastic modulus is evaluated. First, the fiber-reinforced composite material (I) is cut out from the mobile phone casing. In that case, the rib part, the hinge part, and the part provided with the uneven shape are avoided as much as possible, and when the above part is included, these are removed by cutting and used for the test. The test piece is cut out from at least two different angles. Preferably there are 3 directions, more preferably 4 directions. The angles of the test pieces are each 90 ° different in the case of two-way cutout, and preferably 60 ° different in the case of three-way cutout, and 45 ° different in the case of four-way cutout. The size of the test piece preferably conforms to ISO 178. However, when the size cannot be ensured or when the required number of test pieces cannot be secured, a large test piece is cut out as much as possible for evaluation. It is preferable if a test piece having a width of at least 5 mm and a length of about 20 mm can be secured. If a sample that conforms to the standard cannot be secured, a sample having a size in which the ratio of width and length is reduced to a certain value with respect to the standard sample is cut out, and the thickness remains substantially the same. In this case, the span (distance between fulcrums) at the time of measurement is determined by reducing in proportion to the length of the sample. Three to five test pieces shall be evaluated. Other evaluation methods conform to ISO178.

  Moreover, it is preferable that specific gravity (rho) 1 is the range of 1.4-1.6 from the viewpoint of the lightweight property of a mobile telephone housing | casing of the fiber reinforced composite material (I) of this invention. More preferably, it is the range of 1.45 to 1.55.

  Further, the specific gravity ρ2 of the frame portion (II) is preferably in the range of 1.1 to 1.5 from the viewpoint of light weight of the cellular phone casing. More preferably, it is the range of 1.2-1.4.

Here, based on the method described in ISO 1183, the specific gravity is determined by measuring the density of the reinforcing fiber composite material (I) and the frame portion (II) by an underwater substitution method at 25 ° C. In addition, when measurement by the underwater substitution method is difficult, such as when the sample contains voids, the volume and mass of the sample are directly measured and evaluated based on the method described in ISO845. From the viewpoint of improving impact resistance, the frame portion (II) is preferably a member having excellent impact resistance. Specific materials of the frame part (II) include, for example, polycarbonate, an alloy resin of polycarbonate and ABS, an alloy resin of polycarbonate and polyethylene terephthalate, an alloy resin of polycarbonate and polybutylene terephthalate, polycarbonate and polymethyl methacrylate. Alloy resin, polycarbonate resin and polylactic acid resin, or thermoplastic elastomer. Examples of the thermoplastic elastomer include styrene elastomers, olefin elastomers, polyvinyl chloride elastomers, urethane elastomers, polyester elastomers, polyamide elastomers and the like.

  From the viewpoint of impact resistance, polycarbonate, an alloy resin of polycarbonate and ABS, or a thermoplastic elastomer is preferable. In order to improve the impact resistance, other elastomers or rubber components may be added to these resin compositions, and other fillers or An additive may be contained. For example, inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping agents, antibacterial agents, insect repellents, deodorants, anti-coloring agents, heat stabilizers, release agents , Antistatic agents, plasticizers, lubricants, colorants, pigments, dyes, foaming agents, antifoaming agents, coupling agents and the like. Moreover, the reinforcing fiber may be included from a viewpoint of improving the intensity | strength of thermoplastic resin member (II). Examples of the reinforcing fiber include glass fiber, carbon fiber, metal fiber, aromatic polyamide fiber, polyaramid fiber, alumina fiber, silicon carbide fiber, boron fiber, and basalt fiber. These are used alone or in combination of two or more. When reinforcing fibers are included, the fiber content is preferably 5 to 60% by weight.

Fiber reinforced composite material (I) and frame portion and (II) conveniently joined, Ru are bonded to each other with heat welding from the viewpoint of enhancing the adhesion thermoplastic resin (A). From the viewpoint of improving adhesiveness, more preferably, the thermoplastic resin (A) is composed of a fiber-reinforced composite material (I) including continuous reinforcing fibers 2 and a thermosetting matrix resin 3, as shown in FIG. The frame portion (II) is joined to the fiber reinforced composite material (I) (1 in the drawing) via at least a part of the thermoplastic resin (A) (4 in the drawing). From the viewpoint of increasing the adhesive strength, the thermoplastic resin (A) includes at least a part of the reinforcing fibers 2 of the fiber-reinforced composite material (I) as shown in FIG. Yes. Thereby, the anchor effect via the reinforced fiber 2 can be produced. Similarly, from the viewpoint of the anchor effect, among the reinforcing fibers 2 in contact with the thermoplastic resin (A), the fiber (2-out) closest to the frame portion (II) and the fiber (2-in) closest to the frame portion (II) ) Is defined as the maximum impregnation thickness h (6 in the figure), it is important that h is 10 to 200 μm in order to develop a strong bond. The maximum impregnation thickness h is more preferably 20 to 150 μm, and further preferably 30 to 100 μm. The maximum impregnation thickness h can be obtained by cutting out the case telephone case and observing the cross section with an optical microscope, a scanning electron microscope (SEM), or a transmission electron microscope (TEM). When the thermoplastic resin (A) cannot be clearly observed, it may be dyed as necessary in order to enhance the contrast of observation.

  The thermoplastic resin (A) preferably has a minimum thickness t (7 in the figure) of 10 to 500 μm from the viewpoint of securing an adhesive layer for adhesion with other members. The definition of the minimum thickness t of the thermoplastic resin (A) is, as shown in FIG. 1, the thermoplastic resin (A) present in the part facing the boundary between the frame part (II) and the fiber reinforced composite material (I). Is the smallest of the thicknesses. This minimum thickness t is preferably 20 to 300 μm, more preferably 40 to 100 μm.

  Furthermore, the thermoplastic resin (A) is preferably strong as the adhesive itself, and specifically, the tensile strength at break is preferably 25 MPa or more. More preferably, it is 30 MPa or more, More preferably, it is 35 MPa or more. The tensile strength at break is basically evaluated based on ISO 527. If the evaluation is difficult due to insufficient sample amount, a small film with a width of 5 mm and a length of 20 mm is prepared from the thermoplastic resin (A). You may use for a tension test. The upper limit of the tensile strength at break is not particularly defined, but considering that the thermoplastic resin is the main component, if it is about 100 MPa, it can function sufficiently as an adhesive.

  The thermoplastic resin (A) preferably has a tensile elongation at break of 200% or more in order to absorb the load and effectively function as an adhesive. More preferably, it is 250% or more, More preferably, it is 300% or more. The tensile elongation at break is basically evaluated based on ISO 527. If the evaluation is difficult due to insufficient sample amount, a small film with a width of 5 mm and a length of 20 mm is prepared from the thermoplastic resin (A). May be subjected to a tensile test. The upper limit of the tensile elongation at break is not particularly defined, but if it is about 1000%, it can function sufficiently as an adhesive.

  In the cellular phone casing of the present invention, it is preferable that the fiber reinforced composite material (I) and the frame portion (II) are bonded with excellent adhesive strength from the viewpoint of enhancing the mechanical characteristics of the entire cellular phone casing. Specifically, the adhesive strength between the fiber reinforced composite material (I) and the frame portion (II) is preferably 12 MPa or more at 25 ° C. More preferably, it is 15 MPa or more, More preferably, it is 20 MPa or more. The upper limit of the adhesive strength is not particularly limited, but if it is about 40 MPa, it is sufficiently practical as a mobile phone casing of the present invention.

  The adhesive strength is evaluated by cutting out a part where the fiber reinforced composite material (I) and the frame part (II) are joined and integrated as shown in FIG. . The size of the test piece represented by L, M, W, and T shown in FIG. 2 is preferably based on ISO4587. However, if the size is insufficient, a portion where L, M, W, and T can be taken as large as possible is possible. A test piece is cut out, a lap shear tensile test is performed, and the measured adhesive breaking load is divided by the adhesive area to obtain the adhesive strength. If a sample that conforms to the standard cannot be secured, a sample having a size in which the ratio of width and length is reduced to a certain level is cut out, and the thickness remains substantially the same. When the sample becomes small, it may be difficult to attach the sample to the measuring apparatus. Therefore, a new attachment site may be created on the sample. Specifically, the holding part is joined to the fiber reinforced composite material (I) part and the frame part (II) so that the sample can be held in the testing machine. The gripping part is preferably made of a material that does not break in the test. For example, an aluminum plate is preferably bonded with an adhesive. The span (distance between the gripping portions) at the time of measurement is determined by reducing in proportion to the length of the sample.

  When one or more resin compositions selected from polycarbonate, an alloy resin of polycarbonate and ABS, and a thermoplastic elastomer are used for the frame part (II), in order to increase the adhesion to the fiber reinforced composite material (I) Moreover, it is preferable that the thermoplastic resin (A) is a polyester resin having a high affinity with the resin composition.

  The polyester resin preferably has a melting point Tm of 120 ° C. ≦ Tm ≦ 160 ° C. By setting the melting point Tm within this range, not only the adhesive strength near room temperature but also the excellent adhesive strength can be exhibited even at a high temperature exceeding 80 ° C. Furthermore, when the melting point Tm is within this range, the temperature at the time of welding does not become extremely high, there is no problem such as thermal decomposition or thermal deformation of the adherend during use, and in terms of process. There is no heavy load. Here, in the case where the polyester resin is a mixture of two or more types, and there are two or more melting points, the highest melting point is selected from the viewpoint of bonding the polyester resin after sufficiently melting it. It will be handled as Tm. The melting point is evaluated by a differential scanning calorimeter (DSC). A sealed sample container having a capacity of 50 μl is filled with 1 to 5 mg of sample, heated from a temperature of 30 ° C. to a temperature of 350 ° C. at a heating rate of 10 ° C./min, and evaluated. When a plurality of melting points are observed in a mixture or the like, the highest melting point is adopted as the melting point of the composition.

  In order to make the melting point within the above range, it is effective to control the crystallinity of the polyester resin. For that purpose, for example, as a copolyester using two or more kinds of dicarboxylic acids and two or more kinds of diols, the molecular chain regularity is controlled, and the melting point is controlled by increasing or decreasing the crystallinity. It is possible.

  The polyester resin preferably has a glass transition temperature Tg of 0 ° C. ≦ Tg ≦ 80 ° C. When the glass transition temperature Tg is in this range, it is possible to suppress the molecular mobility near room temperature and to exhibit high adhesive strength as a strong polyester resin. More preferably, 10 ° C. ≦ Tg ≦ 80 ° C., and further preferably 25 ° C. ≦ Tg ≦ 80 ° C. Here, when there are two or more glass transition temperatures, such as when the polyester resin is a mixture of two or more, the lowest glass transition temperature is selected from the viewpoint of evaluating the strength of the polyester resin near room temperature. It will be handled as the glass transition temperature Tg of the resin. Here, the glass transition temperature is measured using DSC in the same manner as the melting point measurement described above.

  In order to make the glass transition temperature within the above range, it is effective to control the skeleton structure of the polyester resin. For example, when a polyester resin is produced using a rigid component such as an aromatic dicarboxylic acid component or an alicyclic diol component as a raw material, the glass transition temperature can be increased.

  The polyester resin constituting the thermoplastic resin (A) preferably has a number average molecular weight of 10,000 to 30,000 in order to ensure the strength and fluidity of the resin itself. More preferably, it is 12,000-28,000, More preferably, it is 15,000-25,000. The number average molecular weight is measured by a general measuring means such as gel permeation chromatography (GPC). Here, when the polyester resin is a mixture of two or more, when the number average molecular weight is different, that is, when there are two distributions of the number average molecular weight, from the viewpoint of evaluating the strength of the polyester resin, the lowest number Those having an average molecular weight are handled as the number average molecular weight of the polyester resin.

  Moreover, as a structure of the polyester resin, it contains 10 to 80% by weight of a polyester component composed of an aromatic or alicyclic cyclic dicarboxylic acid as a hard segment and a diol represented by the structural formula 1, as a soft segment. Copolymer containing 20 to 95% by weight of a polyester component comprising an aromatic ring type or alkylene dicarboxylic acid having 2 to 10 carbon atoms and a diol represented by structural formula 1 wherein R is a linear alkylene oxide. Polyester is preferred. When the polyester resin is a mixture of two or more polyester resins, it is preferable that at least one polyester resin has the above structure. Preferably, the polyester resin having the above structure is contained in an amount of 30 to 95% by weight, more preferably 45 to 90% by weight, and still more preferably 55 to 85% by weight.

[Structural Formula 1] HO—R—OH
(Wherein R is a linear or branched alkylene group represented by C _n H _2n (n = 2 to 10), or C _2n H _4n O _n (n is an integer of 1 or more). Linear alkylene oxide represented)
Here, the aromatic ring type dicarboxylic acid constituting the hard segment is terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, paraphenylene dicarboxylic acid, sodium sulfoisophthalate. For example. Preferably, terephthalic acid and isophthalic acid are preferable in terms of increasing the polyester resin strength by making the polyester skeleton rigid. Among these, terephthalic acid is preferable from the viewpoint of increasing the crystallinity of the polyester resin and ensuring the resin strength.

  Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, and the like. Among them, 1,4-cyclohexanedicarboxylic acid is preferable from the viewpoint of symmetry and enhancing the rigidity and crystallinity of the polyester resin.

Examples of the diol represented by Structural Formula 1 include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, neo Examples include pentyl glycol, ethylene oxide adduct and propylene oxide adduct of bisphenol A, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, dimer diol and the like. As the diol, ethylene glycol and 1,4-butanediol used in polyethylene terephthalate and polybutylene terephthalate which are frequently used industrially as polyesters having excellent mechanical properties are preferable.
Examples of the aromatic ring type dicarboxylic acid constituting the soft segment include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, paraphenylene dicarboxylic acid and sodium sulfoisophthalate. Is given as an example. Examples thereof include fumaric acid, maleic acid, itaconic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid and dimer acid. Of these, sebacic acid, which is frequently used industrially, is preferable.
The diol used for the soft segment is preferably selected according to the same guidelines as those for the hard segment diol.

  The hard segment structure preferably contains one or both of a polyethylene terephthalate component and a polybutylene terephthalate component, which are resin components that are widely used industrially. As content, even when either one is included or both are included, the total is preferably in the range of 10 to 80% by weight, and more preferably in the range of 20 to 70% by weight.

  Moreover, it is preferable that polytetremethylene glycol is included as a diol component in order to give flexibility to the resin.

  Examples of such polyester resins include “Chemit” (registered trademark) manufactured by Toray Industries, Inc., “Hytrel” (registered trademark) manufactured by Toray DuPont, and “Byron” (registered trademark) manufactured by Toyobo Co., Ltd. Trademark) can be cited as an example.

  Furthermore, from the viewpoint of improving the adhesiveness, this polyester resin is one or two selected from the group consisting of a primary amino group, an epoxy group, a carboxyl group, and an acid anhydride group at one or both ends of the polyester resin. It is preferable to have a seed functional group structure. These reactive functional groups are preferable not only for the formation of covalent bonds by chemical reaction, but also for improving the adhesiveness with various materials by electrostatic force due to hydrogen bonds and high polarity. When the polyester resin is a mixture of two or more kinds of polyester resins, it is preferable that at least one kind of polyester resin has the above terminal structure.

  The content of the functional group can be evaluated using an existing method. For example, there is a method in which the structure of a resin is determined by techniques such as IR, proton NMR, carbon NMR, and mass spectrum, and the amount of functional groups is evaluated.

  As another method, measurement is performed by titrating a resin solution. If it is a carboxyl group equivalent, the resin is dissolved in an organic solvent such as chloroform and dimethylformamide (DMF), titrated with potassium hydroxide using phenolphthalein as an indicator, and the number of carboxyl groups per molecule of the resin is determined. Divide the number average molecular weight of the resin by the number of carboxyl groups to determine the carboxyl equivalent.

  When the amine equivalent has only a primary amino group in the resin, the amine equivalent is dissolved in an organic solvent such as chloroform or DMF, titrated with hydrochloric acid with a known concentration, and the number of amino groups per molecule of the resin is determined. Then, the amine equivalent is determined by dividing the number average molecular weight of the resin by the number of amino groups. When secondary amino groups and tertiary amino groups are mixed in the resin, the resin is dissolved in an organic solvent such as chloroform or DMF, and an aldehyde compound such as p-nitrobenzaldehyde is reacted with the primary amino group. After the purification of the resulting resin reaction product, the amount of imine introduced at the end is measured by proton NMR, the amount of primary amino groups is quantified, and the number average molecular weight of the resin is divided by the number of amino groups to give the amine equivalent It is also possible to use a method such as

The epoxy equivalent is determined by dissolving the resin in an organic solvent such as chloroform or DMF, titrating with hydrochloric acid to react the epoxy group with hydrochloric acid, and back-titration excess hydrochloric acid with potassium hydroxide to determine the number of epoxy groups per resin molecule. The number is quantified, and the epoxy equivalent is determined by dividing the number average molecular weight of the resin by the number of epoxy groups. When an amino group and an epoxy group are mixed in the resin, a method of specifying the resin structure is preferable to titration.
The acid anhydride equivalent is determined by measuring the strength of the absorption peak derived from carbon of the acid anhydride from carbon NMR evaluation of the resin to quantify the acid anhydride group amount, and dividing the number average molecular weight of the resin by the number of acid anhydride groups. Determine the anhydride equivalent.

  The polyester resin may be used alone, but may be a thermoplastic resin composition containing other additive components. Examples of additives include inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping agents, antibacterial agents, insect repellents, deodorants, anti-coloring agents, and heat stabilizers. , Mold release agents, antistatic agents, plasticizers, lubricants, colorants, pigments, dyes, foaming agents, antifoaming agents, and coupling agents.

The form of the continuous reinforcing fiber of the fiber reinforced composite material (I) constituting the mobile phone casing of the present invention is not particularly limited, and a reinforcing fiber bundle composed of a large number of reinforcing fibers, and a cloth formed from this fiber bundle. , A reinforcing fiber bundle (unidirectional fiber bundle) in which a large number of reinforcing fibers are arranged in one direction, a unidirectional cloth composed of this unidirectional fiber bundle, a combination of them, and a plurality of layers arranged The thing etc. can be illustrated.
Among these, from the viewpoint of substrate productivity, cloth and unidirectional fiber bundles are preferable. The reinforcing fiber bundle may be composed of a plurality of fibers having the same form or may be composed of a plurality of fibers having different forms. The number of reinforcing fibers constituting one reinforcing fiber bundle is usually 300 to 48,000, but considering the production of the base material, it is preferably 300 to 24,000, and more preferably 1,000. ~ 12,000.

  Here, the reinforcing fiber is composed of a large number of reinforcing fibers continuous in a length of 10 mm or more in at least one direction. The reinforcing fibers do not need to be continuous over the entire length in the length direction of the fiber reinforced composite material or over the entire width in the width direction of the fiber reinforced composite material, and may be divided in the middle.

  Examples of the fiber material of the reinforcing fiber bundle used include glass fiber, carbon fiber, metal fiber, aromatic polyamide fiber, polyaramid fiber, alumina fiber, silicon carbide fiber, boron fiber, and basalt fiber. These are used alone or in combination of two or more. These fiber materials may be subjected to surface treatment. Examples of the surface treatment include a metal deposition treatment, a treatment with a coupling agent, a treatment with a sizing agent, and an additive adhesion treatment. Among these fiber materials, conductive fiber materials are also included. As the fiber material, carbon fiber having a small specific gravity, high strength and high elastic modulus is preferably used.

Further, as the matrix resin constituting the fiber reinforced composite material (I) constituting the cellular phone casing of the present invention, it is common to use a thermosetting resin or a thermoplastic resin. It is preferable to use a thermosetting resin having excellent resistance. Examples of the thermosetting resin include unsaturated polyesters, vinyl esters, epoxies, phenols (resol type), urea melamines, polyimides, bismaleimides, cyanate esters, and the like, copolymers thereof, modified products, and There are resins that blend at least two of these. In order to improve impact properties, an elastomer or a rubber component may be added. In particular, an epoxy resin is preferable from the viewpoint of the mechanical properties of the molded product. Furthermore, the epoxy resin is preferably contained as a main component in order to express its excellent mechanical properties, and specifically, it is preferably contained in an amount of 60% by weight or more.
Mobile phone housing of the present invention, in consideration of use in design applications, it is important to impart a design layer on the surface. The material used as the design layer, such as a resin film can be cited for example surface smoothness of certain resin films and design pattern has been printed. In particular, as shown in FIG. 4, a design layer containing polyester or polycarbonate as a main component is bonded to at least one surface via the thermoplastic resin present in the layer shape, and the surface opposite to the fiber-reinforced composite material is also bonded. It is important that the cellular phone case uses a fiber-reinforced composite material in which the layered thermoplastic resin is formed. Via the thermoplastic resin of the formed layered fiber reinforced composite material, by bonding the decorative layer containing as a major component a polyester or polycarbonate, Ru can be strongly bonded to the fiber-reinforced composite material design layer. The joining is preferably performed by heat welding, and in that case, it is preferably performed in a temperature region in which the design layer is not deformed / deformed by heat. By forming the layered thermoplastic resin also on the opposite surface of the fiber reinforced composite material, a cellular phone case that is firmly joined to other members via the layered thermoplastic resin is obtained. it is Ru can.

  In the mobile phone casing of the present invention, it is preferable that at least a part of the mobile phone casing has radio wave permeability in order to enhance the communication function as a mobile phone. By having radio wave permeability, signals can be transmitted and received using the part as an antenna, which is preferable as a means for ensuring a communication function. However, from the viewpoint of preventing malfunction, it is necessary to ensure radio wave shielding at the same time, and it is preferable that the part having radio wave permeability is a part of the cellular phone casing.

  Here, radio wave permeability is measured by the Advantest method. A square flat plate is cut out from the mobile phone housing to obtain a test piece. The size of the test piece is preferably as large as possible. Even if the size of the test piece is small, 20 mm × 20 mm is preferable. If the size of the test piece cannot be ensured, the relevant material portion may be cut out and re-formed by hot press molding or the like so that the thickness is the same as that of the frame member, and then subjected to evaluation. If the material is denatured by heat or cannot be reshaped, the composition of the corresponding material may be analyzed, and a material having an equivalent composition may be formed into a test piece shape for evaluation. In evaluating the test piece, the test piece is in an absolutely dry state (moisture content of 0.1% or less), and a conductive paste (Dotite manufactured by Fujikura Kasei Co., Ltd.) is applied to the four sides, and the conductive paste is sufficiently dried. A test piece is sandwiched in a shield box, and a radio wave shielding property (unit: dB) at a frequency of 1 GHz is measured with a spectrum analyzer to obtain an electromagnetic wave shielding property. The lower the radio wave shielding property, the better the radio wave permeability.

  It is preferable that at least a part of the mobile phone casing has a radio wave transmission of 6 dB or less. More preferably, it is 4 dB or less, More preferably, it is 2 dB or less.

  In addition, the frame portion (II) can be designed relatively easily as compared with the fiber reinforced composite material (I) having a large number of planar shapes, so that radio wave permeability is provided in a part of the frame portion (II). It is preferable.

  In the cellular phone casing of the present invention, when the fiber reinforced composite material (I) and the frame part (II) are integrated via the thermoplastic resin (A), thermal welding, vibration welding, ultrasonic welding, Laser welding, insert injection molding, outsert injection molding and the like are preferably used, and outsert molding and insert molding can be preferably used because of a fast molding cycle and high productivity.

  Hereinafter, based on an Example, this invention is demonstrated further more concretely. The blending ratios (%) shown in the following Examples and Comparative Examples are all values based on% by weight, unless otherwise specified. First, the evaluation method performed in the present invention will be described.

(1) Evaluation of flexural modulus Test pieces having a width of 8 mm and a length of 30 mm from the fiber reinforced composite material (I) of the cellular phone case shown in FIG. Was cut out. The number of test pieces was 3 each. As the measuring device, “Instron” (registered trademark) 5565 type universal material testing machine (manufactured by Instron Japan Co., Ltd.) was used. The tensile test was performed at an ambient temperature of 25 ° C. in a test chamber in which the ambient temperature can be adjusted. Before starting the test, keep the test piece in the test chamber free from the tensile test load for at least 5 minutes, and place a thermocouple on the test piece to confirm that it is equivalent to the ambient temperature. After that, a bending test was performed. The bending test was performed at an indenter speed of 1.27 mm / min.

(2) Evaluation of specific gravity Based on the method described in ISO 1183, the density of the reinforced fiber composite material was measured by an underwater substitution method at 25 ° C.

(3) Melting point evaluation The melting point was evaluated by a differential scanning calorimeter (DSC). A sealed sample container having a capacity of 50 μl was filled with 1 to 5 mg of sample, and the temperature was raised from a temperature of 30 ° C. to a temperature of 350 ° C. at a heating rate of 10 ° C./min. As an evaluation apparatus, Pyris 1 DSC manufactured by PerkinElmer was used. When multiple melting points were observed in a mixture or the like, the highest melting point was adopted as the melting point of the composition.

(4) Melt viscosity evaluation Using a dynamic viscoelasticity measuring device, using a parallel plate with a diameter of 20 mm, under conditions of a distance between parallel plates of 1.0 mm, a measurement frequency of 0.5 Hz, and a generated torque of 3 to 200 gf · cm. The viscoelasticity was measured using 3 g of the polyester resin component at a predetermined temperature, and the complex viscosity η ^* was read. As a dynamic viscoelasticity measuring device, a dynamic viscoelasticity measuring device ARES manufactured by TA Instruments Inc. was used.

(5) Glass transition temperature (Tg) evaluation Based on the method of ISO11357-2, the glass transition temperature (Tg) was measured using Pyris 1 DSC (Perkin Elmer Instruments company make a differential scanning calorimeter). The heating rate was 10 ° C./min, and the midpoint of the portion where the DSC curve showed a step change was the glass transition temperature. When a plurality of Tg was observed in a mixture or the like, the lowest Tg was adopted as the Tg of the composition.

(6) Evaluation of Maximum Impregnation Thickness h Evaluation of the maximum impregnation thickness h was obtained from the image obtained by cutting out the mobile phone casing and photographing the cross section with an optical microscope.

(7) Evaluation of adhesive layer thickness t A fiber reinforced composite material was cut out, a cross-sectional image was taken with an optical microscope, and the adhesive layer thickness t was measured and determined from the image.

(8) Number average molecular weight evaluation It evaluated using the well-known technique by a gel permeation chromatography.

(9) Evaluation of Adhesive Strength A portion where the fiber reinforced composite material (I) and the frame portion (II) were joined and integrated as shown in FIG. The sizes of the test pieces represented by L, M, W, and T shown in FIG. 1 were L = 3 mm, M = 20 mm, W = 10 mm, and T = 2 mm. As the measuring device, “Instron” (registered trademark) 5565 type universal material testing machine (manufactured by Instron Japan Co., Ltd.) was used. The tensile test was performed at an ambient temperature of 25 ° C. in a test chamber in which the ambient temperature can be adjusted. Before starting the test, keep the test piece in the test chamber free from the tensile test load for at least 5 minutes, and place a thermocouple on the test piece to confirm that it is equivalent to the ambient temperature. After that, a tensile test was performed. The tensile test was performed by pulling at a pulling speed of 1.27 mm / min, and the value obtained by dividing the maximum load by the bonding area was defined as the bonding strength (unit: MPa). The number of samples was n = 3.

(10) Radio wave permeability evaluation Measured by the Advantest method. The part of the frame part (II) was cut out from the mobile phone casing, and re-formed by hot press molding at 270 ° C. into a square shape of 20 mm × 20 mm × thickness 1 mm, and used for evaluation. The test piece was kept in an absolutely dry state (moisture content of 0.1% or less), and a conductive paste (Dotite manufactured by Fujikura Kasei Co., Ltd.) was applied to all sides to sufficiently dry the conductive paste. The test piece was sandwiched in a shield box, and the radio wave shielding property (unit: dB) at a frequency of 1 GHz was measured with a spectrum analyzer to obtain an electromagnetic wave shielding property.

(11) Evaluation of Functional Group Equivalent The polyester resin used in the examples is a polyester resin having a carboxyl group, 1 g of resin is dissolved in 30 ml of DMF, and titrated with potassium hydroxide using phenolphthalein as an indicator. The number of carboxyl groups per molecule was quantified, and the carboxyl equivalent was determined by dividing the number average molecular weight of the resin by the number of carboxyl groups.

[Reference Example] Creation of unidirectional carbon fiber prepreg Raw material used <Epoxy resin>
“Epicoat (registered trademark)” 828, “Epicoat (registered trademark)” 834, “Epicoat (registered trademark)” 1001 (above, bisphenol A type epoxy resin, manufactured by Japan Epoxy Resins Co., Ltd.), “Epicoat (registered trademark)” "154 (Phenol novolac type epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd.)
<Curing agent>
DICY7 (Dicyandiamide, manufactured by Japan Epoxy Resin Co., Ltd.)
<Curing accelerator>
3- (3,4-dichlorophenyl) -1,1-dimethylurea <thermoplastic resin>
“Vinylec (registered trademark)” K (polyvinyl formal, manufactured by Chisso Corporation)
<Carbon fiber>
“Torayca (registered trademark)” T700SC-12K-50C (tensile strength 4900 MPa, tensile elastic modulus 235 GPa, fiber specific gravity 1.80) (manufactured by Toray Industries, Inc.).

2. Preparation method of uncured resin composition (Abbreviated as epoxy resin composition in this example) of matrix resin [A] containing epoxy resin Mixing with a kneader according to the procedure shown below with the following raw materials and composition ratios, An epoxy resin composition in which polyvinyl formal was uniformly dissolved was obtained.
Raw material and composition ratio of epoxy resin composition “Epicoat (registered trademark)” 828: 20
“Epicoat (registered trademark)” 834: 20
“Epicoat (registered trademark)” 1001: 25
“Epicoat (registered trademark)” 154: 35
DICY7: 4
3- (3,4-dichlorophenyl) -1,1-dimethylurea: 5
“Vinyleck®” K: 5.

  (1) Each epoxy resin raw material and polyvinyl formal are stirred for 1 to 3 hours while heating at 150 to 190 ° C. to uniformly dissolve the polyvinyl formal.

  (2) Lower the resin temperature to 55-65 ° C., add DICY7 and 3- (3,4-dichlorophenyl) -1,1-dimethylurea, knead at this temperature for 30-40 minutes, and then remove from the kneader To obtain an epoxy resin composition.

3. Production of Carbon Fiber Unidirectional Prepreg The epoxy resin composition was applied onto release paper using a reverse roll coater to produce a resin film. The coating amount per unit area of the resin film was 31 g / m ² .

Next, carbon fiber “Treka (registered trademark)” T700SC-12K-50C (manufactured by Toray Industries, Inc., tensile strength 4900 MPa) aligned in one direction in a sheet shape so that the fiber weight per unit area is 125 g / m ^2. The resin film was layered on both sides to a tensile modulus of 230 GPa) and heated and pressed to impregnate the epoxy resin composition to prepare a unidirectional prepreg.

( Reference Example 1)
(A) Preparation of thermoplastic resin (A) Copolyester resin (“Hytrel” (registered trademark) 2551, manufactured by Toray DuPont Co., Ltd., melting point 164 ° C.) and copolyester resin (“Chemit” manufactured by Toray Industries, Inc.) (Registered trademark) R248, melting point 113 ° C.) using a JSW TEX-30α type twin screw extruder (screw diameter 30 mm, die diameter 5 mm, barrel temperature 200 ° C., rotation speed 150 rpm), and these were kneaded sufficiently. Was continuously extruded, cooled, and then cut into 5 mm lengths with a cutter to obtain a polyester resin. This polyester resin was press-molded at a temperature of 200 ° C. and a pressure of 50 MPa to obtain a film.

(B) Preparation of fiber reinforced composite material (I) The unidirectional carbon fiber prepreg described in the reference example is cut into a predetermined size (300 × 300 mm), and the direction along the one side is defined as the 0 ° direction. Three prepregs were laminated such that 0 °, 90 °, and 0 from the top. From the top of the last laminated prepreg, one piece of the thermoplastic resin (A) produced in the above (a) cut to the same size as the prepreg laminate was laminated and laminated. Next, the prepreg laminate was set in a press mold, heated and cured at a temperature of 160 ° C. for 30 minutes while applying a pressure of 1 MPa, and press-molded to obtain a fiber-reinforced composite material (I).

(C) Production of mobile phone casing The fiber-reinforced composite material (I) obtained in (b) above was cut into a predetermined size and then set in an injection mold. At this time, it arrange | positioned so that the base-material surface for heat bonding of fiber reinforced composite material (I) may come to an adhesion surface. As a frame part (II), a polycarbonate resin (manufactured by Nippon GEP Co., Ltd., Lexan 141R) pellets was injection molded and integrated with the fiber reinforced composite material (I) to obtain a mobile phone case as shown in FIG. . The evaluation results are shown in Table 1.

( Reference Example 2)
(A) Preparation of thermoplastic resin (A)
A film was obtained in the same manner as in Reference Example 1 (a).

(B) Preparation of fiber reinforced composite material (I)
Fiber reinforced composite material (I) was obtained in the same manner as in Reference Example 1 (b).

(C) Preparation of mobile phone casing The figure is the same as in Reference Example 1 except that GF / polycarbonate resin (manufactured by Nippon GEP Co., Ltd., Lexan 3412R, GF 20% by weight) pellets was used as the frame part (II). A mobile phone casing as shown in FIG. The evaluation results are shown in Table 1.

(Example 1 )
(A) Preparation of thermoplastic resin (A) Copolyester resin (“Hytrel” (registered trademark) 2551, manufactured by Toray DuPont Co., Ltd., melting point 164 ° C.) and copolyester resin (“Chemit” manufactured by Toray Industries, Inc.) (Registered trademark) R248, melting point 113 ° C.) using a JSW TEX-30α type twin screw extruder (screw diameter 30 mm, die diameter 5 mm, barrel temperature 200 ° C., rotation speed 150 rpm), and these were kneaded sufficiently. Was continuously extruded, cooled, and then cut into 5 mm lengths with a cutter to obtain a polyester resin. This polyester resin was press-molded at a temperature of 200 ° C. and a pressure of 50 MPa to obtain a film.

(B) Creation of fiber reinforced composite material The unidirectional carbon fiber prepreg described in the reference example is cut into a predetermined size (300 × 300 mm), and the fiber direction is from the top with the direction along one side as the 0 ° direction. Three prepregs were laminated so as to be 0 °, 90 °, and 0. From the top of the last laminated unidirectional carbon fiber prepreg, one piece of the thermoplastic resin (A) prepared in (a) above cut to the same size as the prepreg laminate is laminated and laminated thereon. "XYLEX" (registered trademark) film D7010MC-112- manufactured by GE Plastics Co., Ltd. One piece of 007 (thickness: 175 μm) cut to the same size as the prepreg laminate was laminated and laminated. Furthermore, one sheet of the thermoplastic resin (A) produced in (a) cut to the same size as that of the prepreg laminate was laminated and laminated on the opposite surface of the prepreg laminate. Next, the prepreg laminate was set in a press mold, heated and cured at 120 ° C. for 60 minutes while applying a pressure of 1 MPa, and press-molded to obtain a fiber-reinforced composite material.

(C) Production of mobile phone casing The fiber-reinforced composite material (I) obtained in (b) above was cut into a predetermined size and then set in an injection mold. At this time, it arrange | positioned so that the base-material surface for heat bonding of fiber reinforced composite material (I) may come to an adhesion surface. As a frame part (II), pellets of GF / polycarbonate resin (manufactured by Nippon GEP Co., Ltd., Lexan 3412R, GF 20% by weight) are injection-molded and integrated with the fiber reinforced composite material (I). Got the phone casing. The evaluation results are shown in Table 1.

( Reference Example 3 )
(A) Preparation of fiber reinforced composite material (I) A fiber reinforced composite material (I) was obtained in the same manner as in Reference Example 1 (b) except that the thermoplastic resin (A) was not used.

(B) Preparation of mobile phone casing GF / polycarbonate resin (manufactured by Nippon GEP Co., Ltd., Lexan 3412R, GF 20% by weight) pellets is pre-injected into a frame shape as frame part (II), and (a) The obtained fiber reinforced composite material (I) and the frame part (II) are joined using a one-pack type epoxy adhesive (manufactured by Sumitomo 3M Co., Ltd., EW2070), and a cellular phone case as shown in FIG. Obtained. The evaluation results are shown in Table 1.

( Reference Example 4 )
(A) Preparation of thermoplastic resin (A) Copolyester resin (Toyobo Co., Ltd. “Byron” (registered trademark) GM480, melting point 163 ° C.) 50% by weight and copolyester resin (Toyobo Co., Ltd.) 50% by weight of “Byron” (registered trademark) GM925, melting point 166 ° C.) was used using a JSW TEX-30α type twin screw extruder (screw diameter 30 mm, die diameter 5 mm, barrel temperature 200 ° C., rotation speed 150 rpm). In a state of sufficiently kneading, the gut was continuously extruded, cooled, and then cut into 5 mm lengths with a cutter to obtain a polyester resin. This polyester resin was press-molded at a temperature of 200 ° C. and a pressure of 50 MPa to obtain a film.

(B) Preparation of fiber reinforced composite material (I) Fiber reinforced composite material (I) was obtained in the same manner as in Reference Example 1 (b) except that the thermoplastic resin (A) prepared in (a) above was used. It was.

(C) Preparation of mobile phone casing The figure is the same as in Reference Example 1 except that GF / polycarbonate resin (manufactured by Nippon GEP Co., Ltd., Lexan 3412R, GF 20% by weight) pellets was used as the frame part (II). A mobile phone casing as shown in FIG. The evaluation results are shown in Table 1.

(Comparative Example 1)
(A) Preparation of fiber reinforced composite material (I) The thermoplastic resin (A) was not used, and the unidirectional carbon fiber prepreg was cut into a predetermined size (300 × 300 mm), along one side. Reference was made except that 9 prepregs were laminated so that the fiber direction was 0 °, 90 °, 0, 90 °, 0 ° 90 °, 0 °, 90 °, 0 ° from the top with the measured direction as 0 ° direction. Fiber reinforced composite material (I) was obtained in the same manner as Example 1 (b).

(B) Preparation of mobile phone casing GF / polycarbonate resin (manufactured by Nippon GEP Co., Ltd., Lexan 3412R, GF 20% by weight) pellets is pre-injected into a frame shape as frame part (II), and (a) The obtained fiber reinforced composite material (I) and the frame part (II) are joined using a one-pack type epoxy adhesive (manufactured by Sumitomo 3M Co., Ltd., EW2070), and a cellular phone case as shown in FIG. Obtained. The evaluation results are shown in Table 1.

(Comparative Example 2)
(A) Preparation of fiber reinforced composite material (I) A fiber reinforced composite material (I) was obtained in the same manner as in Reference Example 1 (b) except that the thermoplastic resin (A) was not used.

(B) Preparation of mobile phone case GF / polycarbonate resin (manufactured by Nippon GEP Co., Ltd., Lexan 3412R, GF 20% by weight) pellets was previously injection molded into a frame shape as a frame part (II). At this time, it shape | molded using the metal mold | die whose joining part area with fiber reinforced composite material (I) will be 120 mm < ² >. The fiber reinforced composite material (I) obtained in (a) and the frame part (II) are joined together using a one-pack type epoxy adhesive (manufactured by Sumitomo 3M Co., Ltd., EW2070), and the portable as shown in FIG. Got the phone casing. The evaluation results are shown in Table 1.

As described above, in Example 1 and Reference Examples 1 to 4 , the mobile phone casing was thin and excellent in lightness, but in Comparative Example 1, the fiber-reinforced composite material (I) became thick and lightweight. Inferior and interference with internal parts has occurred. Furthermore, in Example 1 , since the design layer was present on the surface, the molded product was smooth and glossy and had a good appearance. Further, in Comparative Example 2, since the proportion of the joint portion was as small as 3%, the frame portion (II) of the mobile phone casing cannot sufficiently support the fiber reinforced composite material (I), and the casing is easily deformed. As a result, the bonding stability was insufficient.

  The mobile phone case of the present invention is a thin and lightweight mobile phone case having excellent rigidity.

It is sectional drawing which shows typically an example of the junction part of the fiber reinforced composite material (I) and frame part (II) which comprise the mobile telephone housing | casing of this invention. It is a schematic diagram of the test piece of adhesive strength. It is a perspective view of a mobile phone housing. It is A-A 'sectional drawing of the mobile telephone housing | casing of FIG. 3a. It is a schematic cross section for demonstrating the structure of the fiber reinforced composite material which provided the design layer.

Explanation of symbols

1 Fiber reinforced composite material (I)
2 Reinforcing fiber 3 Matrix resin 4 Thermoplastic resin (A)
5 Frame part (II)
6 Maximum impregnation thickness h
7 Adhesive layer thickness t
8 Fiber-reinforced composite materials (I)
9 Thermoplastic resin member (II)
10 Adhesive area 11 Mobile phone case 12 Design layer

Claims (18)

Successive containing reinforcing fibers and matrix resin, a fiber-reinforced composite material substantial thickness is in the range of 0.1 to 0.6 mm (I), the frame portion (II) and is a polyester resin as the thermoplastic resin (A) And the projected area of the bonded portion is in the range of 5 to 75% of the projected area of the fiber reinforced composite material (I), and the heat is applied to at least one surface of the fiber reinforced composite material (I). A cellular phone housing in which a design layer containing polyester or polycarbonate as a main component is bonded via a plastic resin (A), and a thermoplastic resin that is present in a layered manner is formed on the opposite surface of the fiber-reinforced composite material . The cellular phone housing according to claim 1, wherein the maximum projected area of the fiber-reinforced composite material (I) is 10,000 mm ² or less. The mobile phone case according to claim 1 or 2, wherein the fiber-reinforced composite material (I) has a flexural modulus of 35 GPa or more. The cellular phone case according to any one of claims 1 to 3, wherein a specific gravity ρ1 of the fiber-reinforced composite material (I) is in a range of 1.4 to 1.6. The mobile phone casing according to any one of claims 1 to 4, wherein the frame portion (II) is one or more resin compositions selected from polycarbonate resin, ABS resin, and thermoplastic elastomer resin. The thermoplastic resin (A) is in a form of impregnated by forming a concavo-convex shape in a range of a maximum impregnation thickness h of 10 to 200 μm between reinforcing fibers constituting the fiber reinforced composite material (I). Item 6. A mobile phone casing according to any one of Items 1 to 5 . The mobile phone case according to any one of claims 1 to 6, wherein the polyester resin has a melting point Tm in a range of 120C to 160C. The cell phone case according to any one of claims 1 to 7, wherein the polyester resin has a glass transition temperature Tg in a range of 0C to 80C. The cell phone case according to claim 1 , wherein the polyester resin has a number average molecular weight in the range of 10,000 to 30,000. Mobile phone housing according to any one of claims 1 to 9 wherein the polyester resin is a copolyester resin containing in the range of 10 to 80 wt% of polyethylene terephthalate component and / or polybutylene terephthalate component. The mobile phone case according to claim 10 , wherein the polyester resin is a copolyester containing a polytetramethylene glycol component as a diol component. The cellular phone case according to claim 1 , wherein the thermoplastic resin has a tensile breaking strength of 25 MPa or more and / or a tensile breaking elongation of 200% or more. One or two functional groups selected from the group consisting of a primary amino group, an epoxy group, a carboxyl group, and an acid anhydride group at one or both ends of at least one polyester resin among the polyester resins mobile phone housing according to any one of claims 1 to 12 having the structure. The mobile phone case according to claim 13 , wherein the functional group content is 1000 to 100,000 equivalents. The cellular phone housing according to any one of claims 1 to 14 , wherein the reinforcing fibers constituting the fiber-reinforced composite material (I) are carbon fibers. The mobile phone casing according to any one of claims 1 to 15 , wherein the matrix resin constituting the fiber-reinforced composite material (I) is an epoxy resin. The mobile phone casing according to any one of claims 1 to 16 , wherein at least a part thereof has radio wave permeability. The mobile phone case according to claim 17 , wherein the electromagnetic wave shielding property of the portion having radio wave permeability is 6 dB or less.

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