JP5571645B2 - Manufacturing method of electronic equipment exterior parts - Google Patents

Description

  The present invention relates to a method for manufacturing an electronic device exterior part comprising a polylactic acid resin composition with improved injection moldability. More specifically, an electronic equipment exterior excellent in heat resistance and mechanical properties obtained by stereocomplexing a specific combination of polylactic acid under specific heat treatment conditions and molding the polylactic acid under injection molding conditions The present invention relates to a part manufacturing method.

  In recent years, due to concerns about the depletion of petroleum resources and the problem of increased carbon dioxide in the air that causes global warming, biomass resources that do not depend on petroleum as a raw material and that do not increase carbon dioxide even when burned are formed. In the polymer field, biomass plastics produced from biomass resources are actively developed.

  A representative example of biomass plastic is polylactic acid, which has relatively high heat resistance and mechanical properties among biomass plastics, so its application is expanding to tableware, packaging materials, general merchandise, etc. Sexuality has also been considered.

  However, polylactic acid is insufficient in heat resistance when used as an industrial material, and when a molded product is obtained by injection molding with high productivity, the crystalline polymer has low crystallinity. There is a problem that moldability is inferior. Usually, in order to obtain a molded product crystallized by injection molding of polylactic acid, it is preferable for production to be molded at a mold temperature of about 80 to 130 ° C., but since polylactic acid is inferior in crystallization speed, Even if a crystal nucleating agent is used, solidification hardly progresses in this temperature range, and it is necessary to make a molded product in an amorphous state by lowering the mold temperature to 40 ° C. or lower. However, productivity is inferior because the number of steps increases.

  On the other hand, polylactic acid has optical isomers. When poly-L-lactic acid and poly-D-lactic acid, which are polymers of L-lactic acid and D-lactic acid, are mixed, a stereocomplex crystal is formed. Or it is known that it becomes a material which shows melting | fusing point higher than the crystal | crystallization of poly D-lactic acid alone (refer patent document 1 and nonpatent literature 1), and this stereocomplex polylactic acid is utilized for the exterior of electronic devices using the heat resistance. Attempts have been made to use them for industrial purposes such as parts and home appliance parts (see Patent Document 2).

  However, when this stereocomplex polylactic acid is to be produced by an industrially advantageous melt extrusion process, it is very difficult to sufficiently make the stereocomplex, and if the stereocomplexation is insufficient, The good heat resistance which is the characteristic is not exhibited.

  In addition, stereocomplex polylactic acid tends to have a higher crystallization speed than poly L-lactic acid or poly D-lactic acid, but is still insufficient for efficient production by injection molding. In order to increase the crystallization speed, a method for improving the moldability by adding a specific nucleating agent to stereocomplex polylactic acid has also been proposed (see Patent Document 3). At present, high mold temperature is required and improvement is not sufficient.

JP 63-24014 A Japanese Patent No. 3583097 JP 2003-192894 A

Macromolecules, 24,5651 (1991)

Therefore, a main object of the present invention is to provide a method for manufacturing an electronic device exterior component that takes advantage of the heat resistance of stereocomplex polylactic acid.
As a result of diligent research to achieve such an object, the present inventors have obtained heat resistance by molding polylactic acid obtained by melt-kneading a specific polylactic acid by a specific method by a specific injection molding method. The present inventors have found that a method for producing an electronic device exterior part having excellent mechanical properties can be obtained, and the present invention has been completed.

That is, the present invention
(I) Polylactic acid (component A) consists of the following combination 1,
Combination 1 comprises (A-2) a polylactic acid unit (component A-2) and (A-5) a polylactic acid unit (component A-5), and the weight ratio of the component A-2 to the component A-5 (A-2 component / A-5 component) is in the range of 40/60 to 60/40,
The polylactic acid unit (A-2) is composed of 90 to 99 mol% of L-lactic acid units and 1 to 10 mol% of D-lactic acid units and / or copolymer component units other than lactic acid (A- Two components)
The polylactic acid unit (A-5) is composed of 90 to 99 mol% of D-lactic acid units and 1 to 10 mol% of L-lactic acid units and / or copolymerization component units other than lactic acid (A- 5 components)
(Ii) Polylactic acid (component A) is heat-treated at 280 to 300 ° C., and in the differential scanning calorimeter (DSC) measurement, the proportion of the melting peak at 195 ° C. or higher is 80% or higher in the melting peak in the temperature rising process. Producing a stereocomplex polylactic acid,
(Iii) Stereocomplex polylactic acid resin composition by melt-kneading 100 parts by weight of stereocomplex polylactic acid (component A), 0.01 to 5 parts by weight of talc and 0.3 to 200 parts by weight of glass fiber Obtaining a step,
(IV) a step of injection-molding the stereocomplex polylactic acid resin composition in a mold range of 80 to 130 ° C .;
A method for manufacturing an electronic device exterior component comprising:
2. (D) The manufacturing method of the electronic equipment exterior component of the preceding clause 1 which contains 0.01-5 weight part of terminal blocker (D component) per 100 weight part of polylactic acid components (A component).

  The present invention is an electronic equipment exterior part obtained from polylactic acid forming a stereocomplex at a high ratio, and has good heat resistance, mechanical properties, chemical resistance, and hydrolysis resistance. Since it is a resin composition with a reduced environmental load, it is useful for electronic equipment exterior parts, and the industrial effects that it exhibits are exceptional.

It is the perspective view which showed the outline | summary of the jig which performs 3 point | piece bending in evaluation of chemical resistance which is one of the evaluation items of an Example. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic front perspective view of a molded product simulating a notebook personal computer housing used in Examples (length 178 mm × width 245 mm × edge height 10 mm, thickness 1.2 mm). It is the perspective view which showed the outline | summary of the jig which performs 3 point | piece bending in evaluation of chemical resistance which is one of the evaluation items of an Example. It is the surface side front schematic diagram of the molded article used in the Example, and shows the gate position and the cutout position of the sample for evaluation. It is the perspective view which showed the outline | summary of the jig which performs 3 point | piece bending in evaluation of chemical resistance which is one of the evaluation items of an Example. It is the back side front schematic diagram of the molded article used in the Example, and shows a mode that there is a boss with a rib (the part of a matte surface becomes a boss with a rib on both upper and lower sides).

  Hereinafter, each component which comprises the resin composition of this invention, those compounding ratios, a preparation method, etc. are demonstrated concretely one by one.

<About component A>
The polylactic acid of component A in the resin composition constituting the electronic device exterior part of the present invention has a melting peak of 195 ° C. or higher in the melting peak derived from polylactic acid in the temperature rising process of differential scanning calorimetry (DSC) measurement. The ratio is 80% or more. The larger the melting peak ratio at 195 ° C. or higher, the higher the injection moldability.
The weight average molecular weight of polylactic acid (component A) is preferably 80,000 to 500,000. More preferably, it is 100,000-300,000, More preferably, it is 100,000-150,000, and 100,000-130,000 are especially preferable. The weight average molecular weight is a weight average molecular weight value in terms of standard polystyrene as measured by gel permeation chromatography (GPC) using chloroform as an eluent.

主としてＬ−乳酸単位からなるポリ乳酸単位であるＡ−２成分および主としてＤ−乳酸単位からなるポリ乳酸単位であるＡ−５成分である。 The polylactic acid (A component) in the resin composition constituting the electronic device exterior part of the present invention is polylactic acid having an L-lactic acid unit and a D-lactic acid unit as basic components, represented by the following formula (i):

A component A-2 which is a polylactic acid unit mainly composed of L-lactic acid units and an A-5 component which is a polylactic acid unit mainly composed of D-lactic acid units.

The A-2 component is a polylactic acid unit composed of 90 to 99 mol% of L-lactic acid units and 1 to 10 mol% of copolymer component units other than D-lactic acid units and / or lactic acid.
The A-5 component is a polylactic acid unit composed of 90 to 99 mol% of D-lactic acid units and 1 to 10 mol% of L-lactic acid units and / or copolymerization component units other than lactic acid.

The polylactic acid (A component) in the resin composition constituting the electronic device exterior part of the present invention is composed of an A-2 component that is a polylactic acid unit mainly composed of L-lactic acid units and a polylactic acid unit mainly composed of D-lactic acid units. It consists of a specific combination with A-5 component which is.

That polylactic acid (A component), the component A-2 and consists of A-5 component, the weight ratio of component A-2 and A-5 Component (A-2 component / A-5 component) 40/60 Polylactic acid (combination 1) in the range of 60/40 .

[Table 1]
Polylactic acid unit component (mol%)
Combination 1: A-2 90 ≦ [L] ≦ 99
A-5 90 ≦ [D] ≦ 99
[L]: L-lactic acid unit
[D]: D-lactic acid unit

In polylactic acid (component A ), the weight ratio of polylactic acid units mainly composed of L-lactic acid units ( components A-2 and polylactic acid units mainly composed of D-lactic acid units ( component A-5 )) is 40/60 to If the weight ratio of one polymer is less than 40 or exceeds 60, homocrystallization is prioritized and it is difficult to form a stereocomplex, which is not preferable.

  The copolymer component unit other than lactic acid in the polylactic acid unit in the polylactic acid (component A) is derived from dicarboxylic acid, polyhydric alcohol, hydroxycarboxylic acid, lactone, etc. having a functional group capable of forming two or more ester bonds. Units and units derived from various polyesters, various polyethers, various polycarbonates and the like composed of these various components can be used alone or as a mixture.

  Examples of the dicarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, and isophthalic acid. Examples of polyhydric alcohols include aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, octanediol, glycerin, sorbitan, neopentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol, and polypropylene glycol. Or aromatic polyhydric alcohol etc., such as what added ethylene oxide to bisphenol, etc. are mentioned. Examples of the hydroxycarboxylic acid include glycolic acid and hydroxybutylcarboxylic acid. Examples of the lactone include glycolide, ε-caprolactone glycolide, ε-caprolactone, β-propiolactone, δ-butyrolactone, β- or γ-butyrolactone, pivalolactone, δ-valerolactone, and the like.

<About the production method of polylactic acid (component A)>
Each of the polylactic acid units ( A-2 and A-5 components ) constituting the polylactic acid (A component) in the resin composition constituting the electronic device exterior part of the present invention is produced by any known polylactic acid polymerization method. For example, it can be produced by ring-opening polymerization of lactide, dehydration condensation of lactic acid, and a method combining these with solid phase polymerization.
When each polylactic acid unit ( components A-2 and A-5 ) is produced by any known polymerization method, lactide, which is a cyclic dimer of lactic acid, may be produced as a by-product. Each polylactic acid unit may contain such a lactide as long as it does not impair the thermal stability of the resin.

  The lactide contained in each polylactic acid unit can be removed from the polylactic acid unit by a method of removing the polylactic acid unit after the polymerization of each polylactic acid unit under a melt pressure or a method of extracting and removing using a solvent. It is preferable for improving the thermal stability. The lactide contained in each polylactic acid unit is 2% or less, preferably 1% or less, more preferably 0.5% or less with respect to each polylactic acid unit.

The copolymer component unit other than lactic acid used for each polylactic acid unit ( components A-2 and A-5 ) constituting polylactic acid (component A) is a dicarboxylic acid having a functional group capable of forming two or more ester bonds. Examples thereof include acids, polyhydric alcohols, hydroxycarboxylic acids, lactones, and the like, and various polyesters, various polyethers, and various polycarbonates composed of these various components.

  Examples of the dicarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, and isophthalic acid. Examples of polyhydric alcohols include aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, octanediol, glycerin, sorbitan, neopentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol, and polypropylene glycol. Or aromatic polyhydric alcohol etc., such as what added ethylene oxide to bisphenol, etc. are mentioned. Examples of the hydroxycarboxylic acid include glycolic acid and hydroxybutylcarboxylic acid. Examples of the lactone include glycolide, ε-caprolactone glycolide, ε-caprolactone, β-propiolactone, δ-butyrolactone, β- or γ-butyrolactone, pivalolactone, δ-valerolactone, and the like.

Each polylactic acid unit ( components A-2 and A-5 ) constituting the polylactic acid (component A) may contain a catalyst involved in polymerization within a range not impairing the thermal stability of the resin. Examples of such catalysts include various tin compounds, aluminum compounds, titanium compounds, zirconium compounds, calcium compounds, organic acids, and inorganic acids. Such catalysts include tin, aluminum, zirconium and titanium fatty acid salts, carbonates, sulfates, phosphates, oxides, hydroxides, halides, alcoholates, or the metals themselves. Specific examples include tin octylate, aluminum acetylacetonate, aluminum alkoxide, titanium alkoxide, and zirconium alkoxide.

The catalyst involved in the polymerization contained in each polylactic acid unit ( components A-2 and A-5 ) is a method of extracting and removing using a solvent after the polymerization reaction of each polylactic acid unit, or inactivating the catalyst. In order to improve the thermal stability of the resin, it is preferable to remove or deactivate it by a method in which a known stabilizer to be coexisted.

A polylactic acid unit ( A-2 component ) mainly composed of L-lactic acid units and a polylactic acid unit ( A-5 component ) mainly composed of D-lactic acid units, which constitute polylactic acid ( A component ), are required (D ) Components and other components may be blended, but before mixing with these components, it is possible to efficiently produce a stereocomplex in the molded article by preliminarily coexisting them and heat-treating them together. Is preferable.

Specifically, a polylactic acid unit mainly composed of L-lactic acid units ( A-2 component ) and a polylactic acid unit mainly composed of D-lactic acid units ( A-5 component ) coexisting with 245 to 300 The method of heat-treating at 0 ° C. efficiently generates a stereocomplex in the molded article.

In the heat treatment, the polylactic acid unit mainly composed of L-lactic acid units ( component A-2 ) and the polylactic acid unit mainly composed of D-lactic acid units ( component A-5 ) can be mixed as uniformly as possible. preferable. The mixing can be any method as long as they are uniformly mixed when heat-treated.

As such a mixing method, a polylactic acid unit mainly composed of L-lactic acid units ( component A-2 ) and a polylactic acid unit mainly composed of D-lactic acid units ( component A-5 ) are mixed in the presence of a solvent. Then, a method of obtaining a mixture by reprecipitation and a method of obtaining a mixture by removing the solvent by heating can be exemplified. In this case, it is preferable to carry out by preparing a solution in which the A-2 component and the A-5 component are separately dissolved in a solvent and mixing them, or by dissolving both in a solvent together. .

The solvent is not particularly limited as long as polylactic acid units ( A-2 and A-5 components ) can be dissolved. For example, chloroform, methylene chloride, dichloroethane, tetrachloroethane, phenol, tetrahydrofuran, N -Methylpyrrolidone, N, N-dimethylformamide, butyrolactone, trioxane, hexafluoroisopropanol, etc., alone or in combination of two or more are preferred

  Even in the presence of a solvent, the solvent evaporates by heating and can be heat-treated in a solvent-free state. The rate of temperature increase after evaporation of the solvent (heat treatment) is preferably, but not limited to, a short time since there is a possibility of decomposition when heat treatment is performed for a long time.

In addition, mixing of a polylactic acid unit mainly composed of L-lactic acid units ( component A-2 ) and a polylactic acid unit mainly composed of D-lactic acid units ( component A-5 ) can also be carried out in the absence of a solvent. That is, a method in which A-2 component and A-5 component previously powdered or chipped are mixed in a predetermined amount and then melted, or after melting, kneaded and mixed, or A-2 component, or It is possible to employ a method in which one of the A-5 components is melted and then the remaining one is added and kneaded and mixed.

Therefore, the present invention relates to a polylactic acid unit mainly composed of L-lactic acid units ( component A-2 ) and a polylactic acid unit mainly composed of D-lactic acid units ( component A-5 ) in the presence of a solvent or non-solvent. It includes a molded article made of a resin composition produced by a method for producing polylactic acid that is mixed and heat-treated in the presence.

Here, the size of the powder or chip is not particularly limited as long as the powder or chip of each polylactic acid unit ( components A-2 and A-5 ) is uniformly mixed. The following is preferable, and the size is preferably 1 to 0.25 mm. When melting and mixing, a stereocomplex crystal is formed regardless of the size. However, when the powder or chip is simply melted after being uniformly mixed, if the diameter of the powder or chip becomes 3 mm or more, the Since crystals also precipitate, it is not preferable.

In a method of heat-treating a polylactic acid unit (component A), a polylactic acid unit mainly composed of L-lactic acid units ( component A-2 ) and a polylactic acid unit mainly composed of D-lactic acid units ( component A-5 ) are mixed. The mixing device used for the mixing is a reactor with a batch-type stirring blade when mixing by melting, a continuous reactor, a biaxial or uniaxial extruder, and when mixing with powder A tumbler type powder mixer, a continuous powder mixer, various milling devices, and the like can be suitably used.

The heat treatment in the present invention refers to a polylactic acid unit (component A-2) mainly composed of L-lactic acid units and a polylactic acid unit mainly composed of D-lactic acid units ( component A-5 ) in a weight ratio of 40/60. It means coexisting in a range of ˜60 / 40 and maintaining in a temperature range of 245 to 300 ° C. If it exceeds 300 ° C., it is difficult to suppress the decomposition reaction, which is not preferable. The heat treatment time is not particularly limited, but is 0.2 to 60 minutes, preferably 1 to 20 minutes. As an atmosphere during the heat treatment, either an inert atmosphere at normal pressure or a reduced pressure can be applied.

  The apparatus and method used for the heat treatment can be any apparatus and method that can be heated while adjusting the atmosphere. For example, a batch reactor, a continuous reactor, a biaxial or uniaxial extruder, etc. Alternatively, it is possible to adopt a method of processing while molding using a press machine or a flow tube type extruder.

<About B component>
The crystal nucleating agent, which is the component B used in the present invention, is mainly a known compound that is generally used as a crystal nucleating agent for crystalline resins such as polylactic acid and aromatic polyester.
For example, inorganic fine particles such as talc, silica, graphite, carbon powder, pyroferrite, gypsum, neutral clay, metal oxides such as magnesium oxide, aluminum oxide, titanium dioxide, sulfate, phosphate, phosphonate, Examples thereof include oxalate, oxalate, stearate, benzoate, salicylate, tartrate, sulfonate, montan wax salt, montan wax ester salt, terephthalate, benzoate, carboxylate and the like.

Among these compounds used as the crystal nucleating agent, talc is particularly effective, and those having an average particle size of 20 μm or less are preferably used, but those having an average particle size of 5 μm or less are more preferable. .
The blending amount of these crystal nucleating agents cannot be uniformly defined because the amount of the effect varies depending on the type and shape of the crystal nucleating agent. -5 parts by weight, preferably 0.05-3 parts by weight, more preferably 0.1-2 parts by weight. If the amount of the crystal nucleating agent is too small, the effect as a crystal nucleating agent will not be exhibited, and conversely, if it is too much, the effect as a crystal nucleating agent will not be increased. May give bad results.

  Although there is no restriction | limiting in particular in the compounding method of the crystal nucleating agent of B component used in this invention, It consists mainly of the polylactic acid unit (A-2 and A-3 component) which consists of L-lactic acid units, and D-lactic acid unit mainly. After mixing polylactic acid units (components A-5 and A-6), if there are other components to be blended if necessary, the method of adding them together with them has an adverse effect on the formation of the stereo complex. It is preferable because it is small.

<About component C>
In the resin composition constituting the electronic device exterior part of the present invention, when an inorganic filler (component C) is further blended, a molded product having excellent mechanical characteristics, dimensional characteristics, and the like can be obtained.
As inorganic fillers, various inorganic emphasis commonly known such as glass fiber, carbon fiber, glass flake, wollastonite, kaolin clay, mica, talc and various whiskers (potassium titanate whisker, aluminum borate whisker, etc.) Materials can be mentioned. The shape of the inorganic filler can be freely selected from fibrous, flaky, spherical and hollow shapes, and fibrous and flaky materials are suitable for improving the strength and impact resistance of the resin composition.
Among them, the inorganic filler is preferably an inorganic filler made of a pulverized product of natural mineral, more preferably an inorganic filler made of a pulverized product of a natural mineral of silicate, and from the point of its shape. Are preferably mica, talc, and wollastonite.

  On the other hand, since these inorganic fillers are non-petroleum resource materials compared to petroleum resource materials such as carbon fibers, raw materials with a lower environmental load are used. There exists an effect that the significance which uses C component is raised more. Furthermore, the above-mentioned more preferable inorganic filler has an advantageous effect that good flame retardancy is exhibited as compared with carbon fiber and the like.

  The average particle size of mica that can be used in the present invention is a number average particle size calculated by a number average of a total of 1000 particles observed with a scanning electron microscope and extracted those having a size of 1 μm or more. The number average particle diameter is preferably 10 to 500 μm, more preferably 30 to 400 μm, still more preferably 30 to 200 μm, and most preferably 35 to 80 μm. When the number average particle diameter is less than 10 μm, the impact strength may be lowered. On the other hand, if it exceeds 500 μm, the impact strength is improved, but the appearance tends to deteriorate.

  As the thickness of mica, one having a thickness measured by electron microscope observation of 0.01 to 10 μm can be used. Preferably 0.1-5 micrometers thing can be used. An aspect ratio of 5 to 200, preferably 10 to 100 can be used. The mica used is preferably mascobite mica, and its Mohs hardness is about 3. Muscovite mica can achieve higher rigidity and strength than other mica such as phlogopite, and more suitable automobile parts are provided.

  In addition, as a method for pulverizing mica, a dry pulverization method of pulverizing raw mica ore with a dry pulverizer, and coarsely pulverizing mica rough ore with a dry pulverizer, followed by adding a grinding aid such as water in a slurry state There is a wet pulverization method in which main pulverization is performed by a wet pulverizer, followed by dehydration and drying. The mica of the present invention can be produced by any pulverization method, but the dry pulverization method is generally lower in cost. On the other hand, the wet pulverization method is effective for pulverizing mica more thinly and finely, but is expensive. Mica may be surface-treated with various surface treatment agents such as silane coupling agents, higher fatty acid esters, and waxes, and further granulated with sizing agents such as various resins, higher fatty acid esters, and waxes to form granules. May be.

Talc that can be used in the present invention is a scaly particle having a layered structure, which is a hydrous magnesium silicate in terms of chemical composition, and is generally represented by the chemical formula 4SiO ₂ .3MgO.2H ₂ O. the SiO ₂ 56-65 wt%, the MgO 28 to 35 wt%, and a H ₂ O about 5 wt%. As other minor components, Fe ₂ O ₃ is 0.03 to 1.2% by weight, Al ₂ O ₃ is 0.05 to 1.5% by weight, CaO is 0.05 to 1.2% by weight, K ₂ O. Is 0.2 wt% or less, Na ₂ O is 0.2 wt% or less, the specific gravity is about 2.7, and the Mohs hardness is 1.

  The average particle diameter of the talc of the present invention is preferably 0.5 to 30 μm. The average particle size is a particle size at a 50% stacking rate obtained from the particle size distribution measured by the Andreazen pipette method measured according to JIS M8016. The particle diameter of talc is more preferably 2 to 30 μm, further preferably 5 to 20 μm, and most preferably 10 to 20 μm. Talc in the range of 0.5 to 30 μm imparts good surface appearance and flame retardancy to the molded product in addition to rigidity and low anisotropy.

  In addition, there is no particular restriction on the manufacturing method when talc is crushed from raw stone, and the axial flow mill method, the annular mill method, the roll mill method, the ball mill method, the jet mill method, the container rotary compression shearing mill method, etc. are used. can do. Further, the talc after pulverization is preferably classified by various classifiers and having a uniform particle size distribution. There are no particular restrictions on the classifier, impactor type inertial force classifier (variable impactor, etc.), Coanda effect type inertial force classifier (elbow jet, etc.), centrifugal field classifier (multistage cyclone, microplex, dispersion separator) , Accucut, Turbo Classifier, Turboplex, Micron Separator, and Super Separator).

  Further, talc is preferably in an agglomerated state in view of its handleability and the like, and as such a production method, there are a method by deaeration compression, a method of compression using a sizing agent, and the like. In particular, the method by deaeration and compression is preferred because it is simple and does not allow unnecessary sizing agent resin components to be mixed into the automobile parts of the present invention.

The wollastonite that can be used in the present invention is substantially represented by the chemical formula CaSiO ₃ , usually SiO ₂ is about 50 wt% or more, CaO is about 47 wt% or more, and other Fe ₂ O ₃ , Al ₂ O _3. Etc. Wollastonite is a white acicular powder obtained by crushing and classifying raw wollastonite, and has a Mohs hardness of about 4.5. The average fiber diameter of wollastonite used is preferably 0.5 to 20 μm, more preferably 0.5 to 10 μm, and most preferably 1 to 5 μm. The average fiber diameter is observed by a scanning electron microscope, and is calculated by a number average of a total of 1000 samples having a diameter of 0.1 μm or more extracted.

  Some of these inorganic fillers also function as a crystal nucleating agent which is a B component. However, when used as an inorganic filler for the purpose of improving mechanical properties, the amount of the inorganic filler is 100% by weight of polylactic acid (A component). 0.3-200 parts by weight per part is preferred, 1.0-100 parts by weight is more preferred, and 3-50 parts by weight is most preferred. When the blending amount is less than 0.3 parts by weight, the reinforcing effect on the mechanical properties of the molded product of the present invention is not sufficient, and when it exceeds 200 parts by weight, the molding processability and hue deteriorate, which is not preferable. .

  In addition, in the resin composition which comprises the electrical equipment exterior component of this invention, when using a fibrous inorganic filler and a flaky inorganic filler, the folding inhibitor for suppressing those folding can be included. The folding inhibitor inhibits adhesion between the matrix resin and the inorganic filler, reduces stress acting on the inorganic filler during melt kneading, and suppresses the folding of the inorganic filler. Examples of the effect of the folding inhibitor include (1) improvement of rigidity (increase in aspect ratio of inorganic filler), (2) improvement of toughness, and (3) improvement of conductivity (in the case of conductive inorganic filler). Can do. Specifically, the crease suppressor has (i) a compound having a low affinity with the resin, and (ii) a structure having a low affinity with the resin when the surface of the inorganic filler is directly coated with the compound. It is a compound having a functional group capable of reacting with the surface of the inorganic filler.

  Representative examples of the compound having a low affinity for the resin include various lubricants. Examples of the lubricant include mineral oil, synthetic oil, higher fatty acid ester, higher fatty acid amide, polyorganosiloxane (silicone oil, silicone rubber, etc.), olefinic wax (paraffin wax, polyolefin wax, etc.), polyalkylene glycol, fluorinated fatty acid. Fluorine oils such as esters, trifluorochloroethylene, and polyhexafluoropropylene glycol are listed.

  As a method of directly coating the surface of the inorganic filler with a compound having a low affinity for the resin, (1) a method of directly immersing the compound or a solution or emulsion of the compound in the inorganic filler; A method of passing an inorganic filler in the vapor or powder of a compound, (3) a method of irradiating the inorganic filler with the powder of the compound at high speed, and (4) a mechanochemical that rubs the inorganic filler and the compound. And the like.

  Examples of the compound having a structure having a low affinity with the resin and having a functional group capable of reacting with the surface of the inorganic filler include the above-described lubricants modified with various functional groups. Examples of such functional groups include a carboxyl group, a carboxylic acid anhydride group, an epoxy group, an oxazoline group, an isocyanate group, an ester group, an amino group, and an alkoxysilyl group.

  One suitable folding inhibitor is an alkoxysilane compound in which an alkyl group having 5 or more carbon atoms is bonded to a silicon atom. The number of carbon atoms of the alkyl group bonded to the silicon atom is preferably 5 to 60, more preferably 5 to 20, still more preferably 6 to 18, and particularly preferably 8 to 16. The alkyl group is preferably 1 or 2, particularly preferably 1. Further, preferred examples of the alkoxy group include a methoxy group and an ethoxy group. Such alkoxysilane compounds are preferred in that they have high reactivity with the inorganic filler surface and excellent coating efficiency. Therefore, it is suitable for a finer inorganic filler.

  One suitable folding inhibitor is a polyolefin wax having at least one functional group selected from a carboxyl group and a carboxylic anhydride group. The molecular weight is preferably 500 to 20,000, more preferably 1,000 to 15,000 in terms of weight average molecular weight. In such a polyolefin wax, the amount of carboxyl group and carboxylic anhydride group is in the range of 0.05 to 10 meq / g per gram of lubricant having at least one functional group selected from carboxyl group and carboxylic anhydride group. Is preferable, more preferably 0.1 to 6 meq / g, and still more preferably 0.5 to 4 meq / g. It is preferable that the ratio of the functional group in the folding inhibitor is the same as the ratio of the carboxyl group and the carboxylic anhydride group in the functional group other than the carboxyl group.

A particularly preferred example of the folding inhibitor is a copolymer of an α-olefin and maleic anhydride. Such a copolymer can be produced by melt polymerization or bulk polymerization in the presence of a radical catalyst according to a conventional method. Here, as the α-olefin, those having 10 to 60 carbon atoms as an average value can be preferably exemplified. More preferable examples of the α-olefin include those having an average carbon number of 16 to 60, and more preferably 25 to 55.
The folding inhibitor is preferably 0.01 to 2 parts by weight, more preferably 0.05 to 1.5 parts by weight, and more preferably 0.1 to 0.8 parts by weight per 100 parts by weight of the polylactic acid (component A) of the present invention. Is more preferable.

<About D component>
In the resin composition constituting the electronic device exterior part of the present invention, when a terminal blocking agent (D component) is further blended, a molded product having further improved hydrolysis resistance can be obtained.
The component D end-capping agent indicates the function of blocking by reacting with part or all of the carboxyl group ends of polylactic acid (component A) in the resin composition constituting the electronic device exterior part of the present invention. Examples include condensation reaction type compounds such as aliphatic alcohols and amide compounds, and addition reaction type compounds such as carbodiimide compounds, epoxy compounds, oxazoline compounds, oxazine compounds, and aziridine compounds. If the latter addition reaction type compound is used, there is no need to discharge an extra by-product out of the reaction system as in the case of end-capping by dehydration condensation reaction of alcohol and carboxyl group. Therefore, in producing the resin composition of the present invention, polylactic acid units (A-2 and A-3 components) mainly composed of L-lactic acid units and polylactic acid units (A-5) mainly composed of D-lactic acid units. A-6 component) is mixed in advance, and by adding, mixing, and reacting an addition-reaction type end-capping agent, the decomposition of the resin by the by-product is suppressed and sufficient carboxyl groups are obtained. The end capping effect can be obtained, and a molded product having practically sufficient hydrolysis resistance can be obtained.

  As the carbodiimide compounds (including polycarbodiimide compounds) among the end-capping agents that can be used in the present invention, those synthesized by a generally well-known method can be used. A compound that can be synthesized by subjecting various polyisocyanates to a decarboxylation condensation reaction in a solvent-free or inert solvent at a temperature of about 70 ° C. or higher is used. .

  Examples of the monocarbodiimide compound contained in the carbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide and the like. Of these, dicyclohexylcarbodiimide or diisopropylcarbodiimide is preferred from the viewpoint of easy industrial availability.

  In addition, as the polycarbodiimide compound contained in the carbodiimide compound, those produced by various methods can be used. Basically, conventional polycarbodiimide production methods (US Pat. No. 2,941,956, No. 47-33279, J.0rg.Chem.28, 2069-2075 (1963), Chemical Review 981, Vol.81 No.4, p619-621) can be used.

  Examples of the organic diisocyanate that is a synthetic raw material in the production of the polycarbodiimide compound include aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and mixtures thereof. Specifically, 1,5-naphthalene diisocyanate. 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2, , 4-tolylene diisocyanate and 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophor Diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, 2,6-diisopropylphenyl isocyanate, 1,3,5-triisopropylbenzene-2,4-diisocyanate, etc. be able to.

Moreover, in the case of the said polycarbodiimide compound, it can also control to a suitable polymerization degree using the compound which reacts with the terminal isocyanate of polycarbodiimide compound, such as monoisocyanate.
Examples of the monoisocyanate for sealing the end of such a polycarbodiimide compound and controlling the degree of polymerization thereof include phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, naphthyl isocyanate and the like. be able to.

  Examples of epoxy compounds among the end-capping agents that can be used in the present invention include, for example, N-glycidylphthalimide, N-glycidyl-4-methylphthalimide, N-glycidyl-4,5-dimethylphthalimide, N-glycidyl- 3-methylphthalimide, N-glycidyl-3,6-dimethylphthalimide, N-glycidyl-4-ethoxyphthalimide, N-glycidyl-4-chlorophthalimide, N-glycidyl-4,5-dichlorophthalimide, N-glycidyl- 3,4,5,6-tetrabromophthalimide, N-glycidyl-4-n-butyl-5-bromophthalimide, N-glycidylsuccinimide, N-glycidylhexahydrophthalimide, N-glycidyl-1,2,3 6-tetrahydrophthalimide, N-glycidyl male N-glycidyl-α, β-dimethylsuccinimide, N-glycidyl-α-ethylsuccinimide, N-glycidyl-α-propylsuccinimide, N-glycidylbenzamide, N-glycidyl-p-methylbenzamide, N- Glycidylnaphthamide, N-glycidylsteramide, N-methyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, N-ethyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, N- Phenyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, N-naphthyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, N-tolyl-3-methyl-4,5-epoxycyclohexane -1,2-dicarboxylic acid imide, orthophenyl phenylglycol Sidyl ether, 2-methyloctyl glycidyl ether, phenyl glycidyl ether, 3- (2-xenyloxy) -1,2-epoxypropane, allyl glycidyl ether, butyl glycidyl ether, lauryl glycidyl ether, benzyl glycidyl ether, cyclohexyl glycidyl ether, α -Cresyl glycidyl ether, pt-butylphenyl glycidyl ether, glycidyl methacrylate ether, ethylene oxide, propylene oxide, styrene oxide, octylene oxide, hydroquinone diglycidyl ether, resorcin diglycidyl ether, 1,6-hexanediol di Glycidyl ether, hydrogenated bisphenol A-diglycidyl ether, and the like. Diester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, phthalic acid dimethyl diglycidyl ester, phenylene diglycidyl ether, ethylene diglycidyl ether, trimethylene diglycidyl ether, tetramethylene diglycidyl ether, hexamethylene di Examples thereof include glycidyl ether. One or more compounds selected from these epoxy compounds may be arbitrarily selected to block the carboxyl terminal of the polylactic acid unit, but in terms of reactivity, ethylene oxide, propylene oxide, phenyl glycidyl ether, ortho Preferred are phenylphenyl glycidyl ether, pt-butylphenyl glycidyl ether, N-glycidyl phthalimide, hydroquinone diglycidyl ether, resorcin diglycidyl ether, 1,6-hexanediol diglycidyl ether, hydrogenated bisphenol A-diglycidyl ether, and the like. .

  Examples of oxazoline compounds among the end-capping agents that can be used in the present invention include, for example, 2-methoxy-2-oxazoline, 2-ethoxy-2-oxazoline, 2-propoxy-2-oxazoline, 2-butoxy-2 -Oxazoline, 2-pentyloxy-2-oxazoline, 2-hexyloxy-2-oxazoline, 2-heptyloxy-2-oxazoline, 2-octyloxy-2-oxazoline, 2-nonyloxy-2-oxazoline, 2-decyloxy -2-oxazoline, 2-cyclopentyloxy-2-oxazoline, 2-cyclohexyloxy-2-oxazoline, 2-allyloxy-2-oxazoline, 2-methallyloxy-2-oxazoline, 2-crotyloxy-2-oxazoline, 2 -Phenoxy-2-oxazo , 2-cresyl-2-oxazoline, 2-o-ethylphenoxy-2-oxazoline, 2-o-propylphenoxy-2-oxazoline, 2-o-phenylphenoxy-2-oxazoline, 2-m-ethylphenoxy- 2-oxazoline, 2-m-propylphenoxy-2-oxazoline, 2-p-phenylphenoxy-2-oxazoline, 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-propyl-2-oxazoline, 2-butyl-2-oxazoline, 2-pentyl-2-oxazoline, 2-hexyl-2-oxazoline, 2-heptyl-2-oxazoline, 2-octyl-2-oxazoline, 2-nonyl-2-oxazoline, 2- Decyl-2-oxazoline, 2-cyclopentyl-2-oxazoline, 2-cycl Hexyl-2-oxazoline, 2-allyl-2-oxazoline, 2-methallyl-2-oxazoline, 2-crotyl-2-oxazoline, 2-phenyl-2-oxazoline, 2-o-ethylphenyl-2-oxazoline, 2 -O-propylphenyl-2-oxazoline, 2-o-phenylphenyl-2-oxazoline, 2-m-ethylphenyl-2-oxazoline, 2-m-propylphenyl-2-oxazoline, 2-p-phenylphenyl- 2-oxazoline and the like, and further, 2,2'-bis (2-oxazoline), 2,2'-bis (4-methyl-2-oxazoline), 2,2'-bis (4,4 ' -Dimethyl-2-oxazoline), 2,2'-bis (4-ethyl-2-oxazoline), 2,2'-bis (4,4'-diethyl-2) -Oxazoline), 2,2'-bis (4-propyl-2-oxazoline), 2,2'-bis (4-butyl-2-oxazoline), 2,2'-bis (4-hexyl-2-oxazoline) ), 2,2'-bis (4-phenyl-2-oxazoline), 2,2'-bis (4-cyclohexyl-2-oxazoline), 2,2'-bis (4-benzyl-2-oxazoline), 2,2'-p-phenylenebis (2-oxazoline), 2,2'-m-phenylenebis (2-oxazoline), 2,2'-o-phenylenebis (2-oxazoline), 2,2'- p-phenylenebis (4-methyl-2-oxazoline), 2,2'-p-phenylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-m-phenylenebis (4-methyl- 2-oxazoline), , 2'-m-phenylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-ethylenebis (2-oxazoline), 2,2'-tetramethylenebis (2-oxazoline), 2, 2'-hexamethylenebis (2-oxazoline), 2,2'-octamethylenebis (2-oxazoline), 2,2'-decamethylenebis (2-oxazoline), 2,2'-ethylenebis (4- Methyl-2-oxazoline), 2,2′-tetramethylenebis (4,4′-dimethyl-2-oxazoline), 2,2′-9,9′-diphenoxyethanebis (2-oxazoline), 2, Examples thereof include 2'-cyclohexylenebis (2-oxazoline) and 2,2'-diphenylenebis (2-oxazoline). Furthermore, a polyoxazoline compound containing the above-described compound as a monomer unit, such as a styrene-2-isopropenyl-2-oxazoline copolymer, can be mentioned. One or more compounds may be arbitrarily selected from these oxazoline compounds to block the carboxyl terminal of the polylactic acid unit.

  Examples of the oxazine compound among the end-capping agents that can be used in the present invention include, for example, 2-methoxy-5,6-dihydro-4H-1,3-oxazine, 2-ethoxy-5,6-dihydro-4H. -1,3-oxazine, 2-propoxy-5,6-dihydro-4H-1,3-oxazine, 2-butoxy-5,6-dihydro-4H-1,3-oxazine, 2-pentyloxy-5 6-dihydro-4H-1,3-oxazine, 2-hexyloxy-5,6-dihydro-4H-1,3-oxazine, 2-heptyloxy-5,6-dihydro-4H-1,3-oxazine, 2-octyloxy-5,6-dihydro-4H-1,3-oxazine, 2-nonyloxy-5,6-dihydro-4H-1,3-oxazine, 2-decyloxy-5,6-dihydro 4H-1,3-oxazine, 2-cyclopentyloxy-5,6-dihydro-4H-1,3-oxazine, 2-cyclohexyloxy-5,6-dihydro-4H-1,3-oxazine, 2-allyloxy- 5,6-dihydro-4H-1,3-oxazine, 2-methallyloxy-5,6-dihydro-4H-1,3-oxazine, 2-crotyloxy-5,6-dihydro-4H-1,3- Oxazine and the like, and 2,2'-bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-methylenebis (5,6-dihydro-4H-1,3- Oxazine), 2,2'-ethylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-propylenebis (5,6-dihydro-4H-1,3-oxazine), 2 , 2 ' Butylene bis (5,6-dihydro-4H-1,3-oxazine), 2,2′-hexamethylene bis (5,6-dihydro-4H-1,3-oxazine), 2,2′-p-phenylene bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-m-phenylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-naphthylenebis (5 6-dihydro-4H-1,3-oxazine), 2,2'-P, P'-diphenylenebis (5,6-dihydro-4H-1,3-oxazine) and the like. Furthermore, the polyoxazine compound etc. which contain an above-described compound as a monomer unit are mentioned. One or two or more compounds may be arbitrarily selected from these oxazine compounds to block the carboxyl terminal of the polylactic acid unit.

  Further, one or more compounds selected from the oxazoline compounds exemplified above and the above-mentioned oxazine compounds may be arbitrarily selected and used together to block the carboxyl end of polylactic acid. 2,2′-m-phenylenebis (2-oxazoline) and 2,2′-p-phenylenebis (2-oxazoline) are preferable from the viewpoints of affinity and affinity with aliphatic polyester.

Examples of the aziridine compound among the end-capping agents that can be used in the present invention include, for example, an addition reaction product of a mono-, bis- or polyisocyanate compound and ethyleneimine.
Moreover, 2 or more types of compounds can also be used together as a terminal blocker among compounds, such as the carbodiimide compound mentioned above as an end blocker which can be used for this invention, an epoxy compound, an oxazoline compound, an oxazine compound, and an aziridine compound.

In the polylactic acid resin composition of the present invention, the carboxyl end group may be appropriately blocked according to the use. As a specific degree of carboxyl group end blocking, the concentration of the carboxyl group end of the polylactic acid unit is 10 equivalents. / 10 ³ kg or less is preferable from the viewpoint of improving hydrolysis resistance, and more preferably 6 equivalents / 10 ³ kg or less.

  As a method of blocking the carboxyl group terminal of polylactic acid (component A) in the resin composition constituting the electronic device exterior part of the present invention, a terminal blocking agent such as a condensation reaction type or an addition reaction type may be reacted. As a method of blocking the carboxyl group terminal by a condensation reaction, an appropriate amount of a condensation reaction type terminal blocking agent such as an aliphatic alcohol or an amide compound is added to the polymerization system during polymer polymerization, and a dehydration condensation reaction is performed by reducing the pressure. Although the carboxyl group terminal can be blocked, it is preferable to add a condensation reaction type terminal blocking agent at the end of the polymerization reaction from the viewpoint of increasing the degree of polymerization of the polymer.

As a method for blocking the carboxyl group terminal by addition reaction, it can be obtained by reacting an appropriate amount of a terminal blocking agent such as a carbodiimide compound, an epoxy compound, an oxazoline compound, an oxazine compound, an aziridine compound in the molten state of polylactic acid. It is possible to add and react the end-capping agent after completion of the polymerization reaction, but the polylactic acid unit mainly composed of L-lactic acid units (components A-2 and A-3) and the polybasic composed mainly of D-lactic acid unit. When the lactic acid units (components A-5 and A-6) are mixed in advance, the method of adding them together, and before mixing both polylactic acid units, in each polylactic acid unit In addition, it is possible to take a method of mixing in advance, and a method of mixing the components of the soot together.
The content of the endblocker (component D) is 0.01 to 5 parts by weight, preferably 0.05 to 4 parts by weight, more preferably 0.1 parts per 100 parts by weight of the polylactic acid component (component A). ~ 3 parts by weight.

<About other ingredients>
(I) Flame retardant A flame retardant can also be mix | blended with the resin composition which comprises the electronic device exterior component of this invention. Flame retardants include brominated epoxy resins, brominated polystyrenes, brominated polycarbonates, brominated polyacrylates, halogenated flame retardants such as chlorinated polyethylene, phosphate ester based flame retardants such as monophosphate compounds and phosphate oligomer compounds, Organophosphorous flame retardants other than phosphate ester flame retardants such as phosphonate oligomer compounds, phosphonitrile oligomer compounds, phosphonic acid amide compounds, organic sulfonate alkali (earth) metal salts, borate metal salt flame retardants, and tin Examples include organic metal salt flame retardants such as acid metal salt flame retardants, and silicone flame retardants. Separately, a flame retardant aid (for example, sodium antimonate, antimony trioxide, etc.), an anti-drip agent (polytetrafluoroethylene having fibril-forming ability, etc.), etc. may be blended and used together with the flame retardant.

Among the above-mentioned flame retardants, compounds that do not contain chlorine and bromine atoms have reduced features that are undesirable when performing incineration and thermal recycling. It is more suitable as a flame retardant in the molded article of the present invention.
Furthermore, the phosphate ester flame retardant is particularly preferable because a good hue can be obtained and an effect of improving molding processability is also exhibited. Specific examples of the phosphate ester flame retardant include one or more phosphate ester compounds represented by the following general formula (ii).

（但し上記式中のＸは、ハイドロキノン、レゾルシノール、ビス（４−ヒドロキシジフェニル）メタン、ビスフェノールＡ、ジヒドロキシジフェニル、ジヒドロキシナフタレン、ビス（４−ヒドロキシフェニル）スルホン、ビス（４−ヒドロキシフェニル）ケトン、ビス（４−ヒドロキシフェニル）サルファイドから誘導される基が挙げられ、ｎは０〜５の整数であり、またはｎ数の異なるリン酸エステルの混合物の場合は０〜５の平均値であり、Ｒ¹¹、Ｒ¹²、Ｒ¹³、およびＲ¹⁴はそれぞれ独立して１個以上のハロゲン原子を置換したもしくは置換していないフェノール、クレゾール、キシレノール、イソプロピルフェノール、ブチルフェノール、ｐ−クミルフェノールから誘導される基である。）

(However, X in the above formula is hydroquinone, resorcinol, bis (4-hydroxydiphenyl) methane, bisphenol A, dihydroxydiphenyl, dihydroxynaphthalene, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) ketone, bis A group derived from (4-hydroxyphenyl) sulfide, and n is an integer of 0 to 5, or an average value of 0 to 5 in the case of a mixture of phosphate esters having different numbers of n, R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ are each independently a group derived from phenol, cresol, xylenol, isopropylphenol, butylphenol, or p-cumylphenol substituted or unsubstituted with one or more halogen atoms. .)

More preferable examples include groups in which X in the above formula is derived from hydroquinone, resorcinol, bisphenol A, and dihydroxydiphenyl, and n is an integer of 1 to 3, or a different number of phosphate esters. In the case of blends of R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ each independently of one or more halogen atoms substituted or more preferably substituted phenol, cresol, A group derived from xylenol.

  Among such organophosphate flame retardants, triphenyl phosphate is preferable as a phosphate compound, and resorcinol bis (dixylenyl phosphate) and bisphenol A bis (diphenyl phosphate) are preferable as phosphate oligomers because of excellent hydrolysis resistance. Can be used. More preferable are resorcinol bis (dixylenyl phosphate) and bisphenol A bis (diphenyl phosphate) from the viewpoint of heat resistance. This is because they have good heat resistance and are free from adverse effects such as thermal deterioration and volatilization.

  In the resin composition constituting the electronic device exterior component of the present invention, when these flame retardants are blended, the range of 0.05 to 50 parts by weight per 100 parts by weight of polylactic acid (component A) is preferable. If it is less than 0.05 part by weight, sufficient flame retardancy will not be exhibited, and if it exceeds 50 parts by weight, the strength and heat resistance of the molded product will be impaired.

(Ii) Thermal Stabilizer In the resin composition constituting the electronic device exterior part of the present invention, it is preferable to contain a phosphorus stabilizer in order to obtain a better hue and stable fluidity. In particular, a pentaerythritol-type phosphite compound represented by the following general formula (iii) is preferably blended as a phosphorus stabilizer.

［式中Ｒ¹、Ｒ²はそれぞれ水素原子、炭素数１〜２０のアルキル基、炭素数６〜２０のアリール基ないしアルキルアリール基、炭素数７〜３０のアラルキル基、炭素数４〜２０のシクロアルキル基、炭素数１５〜２５の２−（４−オキシフェニル）プロピル置換アリール基を示す。なお、シクロアルキル基およびアリール基は、アルキル基で置換されていてもよい。］

[Wherein R ¹ and R ² are each a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms or an alkylaryl group, an aralkyl group having 7 to 30 carbon atoms, and an alkyl group having 4 to 20 carbon atoms. A cycloalkyl group, a 2- (4-oxyphenyl) propyl-substituted aryl group having 15 to 25 carbon atoms is shown. In addition, the cycloalkyl group and the aryl group may be substituted with an alkyl group. ]

  More specifically, examples of the pentaerythritol type phosphite compound include distearyl pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, and bis (2,6 -Di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-ethylphenyl) pentaerythritol diphosphite, phenylbisphenol A pentaerythritol diphosphite, Bis (nonylphenyl) pentaerythritol diphosphite, dicyclohexylpentaerythritol diphosphite, and the like are preferable. Among them, distearyl pentaerythritol diphosphite and bis (2,4-di-te) are preferable. Include t- butylphenyl) pentaerythritol diphosphite. Examples of other phosphorus stabilizers include various other phosphite compounds, phosphonite compounds, and phosphate compounds.

  Examples of the phosphite compound include triphenyl phosphite, tris (nonylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl Monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, tris (diethylphenyl) phos Phyto, tris (di-iso-propylphenyl) phosphite, tris (di-n-butylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite Ito, and tris (2,6-di -tert- butylphenyl) phosphite and the like.

  Still other phosphite compounds that react with dihydric phenols and have a cyclic structure can be used. For example, 2,2′-methylenebis (4,6-di-tert-butylphenyl) (2,4-di-tert-butylphenyl) phosphite, 2,2′-methylenebis (4,6-di-tert- Butylphenyl) (2-tert-butyl-4-methylphenyl) phosphite, 2,2′-methylenebis (4-methyl-6-tert-butylphenyl) (2-tert-butyl-4-methylphenyl) phosphite 2,2′-ethylidenebis (4-methyl-6-tert-butylphenyl) (2-tert-butyl-4-methylphenyl) phosphite.

  Examples of the phosphate compound include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenyl cresyl phosphate, diphenyl monoorxenyl phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, Examples thereof include diisopropyl phosphate, and triphenyl phosphate and trimethyl phosphate are preferable.

  Examples of the phosphonite compound include tetrakis (2,4-di-tert-butylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,3′-biphenylenedi. Phosphonite, tetrakis (2,4-di-tert-butylphenyl) -3,3′-biphenylenediphosphonite, tetrakis (2,6-di-tert-butylphenyl) -4,4′-biphenylenediphosphonite Tetrakis (2,6-di-tert-butylphenyl) -4,3′-biphenylene diphosphonite, tetrakis (2,6-di-tert-butylphenyl) -3,3′-biphenylene diphosphonite, bis (2,4-di-tert-butylphenyl) -4-phenyl-phenylphosphonite, bis (2,4-di tert-butylphenyl) -3-phenyl-phenylphosphonite, bis (2,6-di-n-butylphenyl) -3-phenyl-phenylphosphonite, bis (2,6-di-tert-butylphenyl)- 4-phenyl-phenylphosphonite, bis (2,6-di-tert-butylphenyl) -3-phenyl-phenylphosphonite, and the like, and tetrakis (di-tert-butylphenyl) -biphenylenediphosphonite, bis (Di-tert-butylphenyl) -phenyl-phenylphosphonite is preferred, tetrakis (2,4-di-tert-butylphenyl) -biphenylenediphosphonite, bis (2,4-di-tert-butylphenyl)- More preferred is phenyl-phenylphosphonite. Such a phosphonite compound is preferable because it can be used in combination with a phosphite compound having an aryl group in which two or more alkyl groups are substituted.

Examples of the phosphonate compound include dimethyl benzenephosphonate, diethyl benzenephosphonate, and dipropyl benzenephosphonate.
Said phosphorus stabilizer can be used individually or in combination of 2 or more types, It is preferable to mix | blend an effective amount of a pentaerythritol type | mold phosphite compound at least. The phosphorus stabilizer is preferably 0.001 to 1 part by weight, more preferably 0.01 to 0.5 part by weight, still more preferably 0.01 to 0.3 part by weight per 100 parts by weight of polylactic acid (component A). Partly formulated.

(Iii) Elastic polymer An elastic polymer can be used as an impact modifier in the resin composition constituting the electronic device exterior part of the present invention. As an example of the elastic polymer, the glass transition temperature is 10 ° C. A graft copolymer obtained by copolymerizing one or more monomers selected from aromatic vinyl, vinyl cyanide, acrylic acid ester, methacrylic acid ester, and vinyl compounds copolymerizable therewith with the following rubber components: A polymer can be mentioned. A more preferable elastic polymer is a core-shell type graft copolymer in which one or more shells of the above-mentioned monomer are graft-copolymerized on the core of the rubber component.

  Moreover, the rubber component and the block copolymer of the said monomer are also mentioned. Specific examples of such block copolymers include thermoplastic elastomers such as styrene / ethylenepropylene / styrene elastomers (hydrogenated styrene / isoprene / styrene elastomers) and hydrogenated styrene / butadiene / styrene elastomers. Furthermore, various elastic polymers known as other thermoplastic elastomers such as polyurethane elastomers, polyester elastomers, polyether amide elastomers and the like can also be used.

  A core-shell type graft copolymer is more suitable as an impact modifier. In the core-shell type graft copolymer, the core particle size is preferably 0.05 to 0.8 μm, more preferably 0.1 to 0.6 μm, and more preferably 0.1 to 0.5 μm in weight average particle size. Is more preferable. If it is in the range of 0.05 to 0.8 μm, better impact resistance is achieved. The elastic polymer preferably contains 40% or more of a rubber component, and more preferably contains 60% or more.

  Rubber components include butadiene rubber, butadiene-acrylic composite rubber, acrylic rubber, acrylic-silicone composite rubber, isobutylene-silicone composite rubber, isoprene rubber, styrene-butadiene rubber, chloroprene rubber, ethylene-propylene rubber, nitrile rubber, ethylene- Acrylic rubber, silicone rubber, epichlorohydrin rubber, fluororubber, and those in which hydrogen is added to these unsaturated bonds may include halogen atoms because of concerns about the generation of harmful substances during combustion. No rubber component is preferable in terms of environmental load.

  The glass transition temperature of the rubber component is preferably −10 ° C. or lower, more preferably −30 ° C. or lower. As the rubber component, butadiene rubber, butadiene-acrylic composite rubber, acrylic rubber, and acrylic-silicone composite rubber are particularly preferable. The composite rubber is a rubber obtained by copolymerizing two kinds of rubber components or a rubber polymerized so as to have an IPN structure entangled with each other so as not to be separated.

  Examples of the aromatic vinyl in the vinyl compound copolymerized with the rubber component include styrene, α-methylstyrene, p-methylstyrene, alkoxystyrene, halogenated styrene and the like, and styrene is particularly preferable. Examples of acrylic esters include methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, octyl acrylate, etc., and examples of methacrylic esters include methyl methacrylate, ethyl methacrylate, methacrylic acid. Examples thereof include butyl, cyclohexyl methacrylate, octyl methacrylate and the like, and methyl methacrylate is particularly preferable. Among these, it is particularly preferable to contain a methacrylic acid ester such as methyl methacrylate as an essential component. More specifically, the methacrylic acid ester is contained in 100% by weight of the graft component (in the case of 100% by weight of the shell in the case of the core-shell type polymer), preferably 10% by weight or more, more preferably 15% by weight or more. Is done.

  The elastic polymer containing a rubber component having a glass transition temperature of 10 ° C. or less may be produced by any polymerization method including bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. It can be a single-stage graft or a multi-stage graft. Moreover, the mixture with the copolymer of only the graft component byproduced in the case of manufacture may be sufficient. Furthermore, examples of the polymerization method include a general emulsion polymerization method, a soap-free polymerization method using an initiator such as potassium persulfate, a seed polymerization method, and a two-stage swelling polymerization method. In the suspension polymerization method, the aqueous phase and the monomer phase are individually maintained, both are accurately supplied to the continuous disperser, and the particle diameter is controlled by the rotation speed of the disperser, and the continuous production is performed. In the method, a method may be used in which the monomer phase is supplied by passing it through a fine orifice having a diameter of several to several tens of μm or a porous filter in an aqueous liquid having dispersibility to control the particle size. In the case of a core-shell type graft polymer, the reaction may be one stage or multistage for both the core and the shell.

  Such elastic polymers are commercially available and can be easily obtained. For example, as rubber components mainly composed of butadiene rubber, acrylic rubber or butadiene-acrylic composite rubber, Kane Ace B series (for example, B-56 etc.) of Kanegafuchi Chemical Industry Co., Ltd. and Metabrene of Mitsubishi Rayon Co., Ltd. C series (for example, C-223A), W series (for example, W-450A), paraloid EXL series (for example, EXL-2602) by Kureha Chemical Industry, HIA series (for example, HIA-15), BTA series (E.g., BTA-III), KCA series, Rohm and Haas Paraloid EXL series, KM series (e.g., KM-336P, KM-357P, etc.) and UCL modifier resin series (UMG) of Ube Saikon Co., Ltd.・ ABS's MG AXS Resin Series) and the like, and those mainly composed of acrylic-silicone composite rubber as the rubber component are those commercially available from Mitsubishi Rayon Co., Ltd. under the trade name Methbrene S-2001 or SRK-200. It is done.

  The composition ratio of the impact modifier is preferably 0.2 to 50 parts by weight, preferably 1 to 30 parts by weight, and more preferably 1.5 to 20 parts by weight per 100 parts by weight of polylactic acid (component A). Such a composition range can give good impact resistance to the composition while suppressing a decrease in rigidity.

(Iv) Other additives In the resin composition constituting the electronic device exterior part of the present invention, other thermoplastic resins (for example, polycarbonate resin, polyalkylene terephthalate resin, Arylate resin, liquid crystalline polyester resin, polyamide resin, polyimide resin, polyetherimide resin, polyurethane resin, silicone resin, polyphenylene ether resin, polyphenylene sulfide resin, polysulfone resin, polyolefin resin such as polyethylene and polypropylene, polystyrene resin, acrylonitrile / styrene Copolymer (AS resin), acrylonitrile / butadiene / styrene copolymer (ABS resin), polystyrene resin, high impact polystyrene resin, syndiotactic polystyrene resin, polymeta Acrylate resins, phenoxy or epoxy resins, etc.), antioxidants (eg hindered phenol compounds, sulfur antioxidants, etc.), UV absorbers (benzotriazoles, triazines, benzophenones, etc.), light Stabilizers (such as HALS), mold release agents (saturated fatty acid esters, unsaturated fatty acid esters, polyolefin waxes, fluorine compounds, paraffin wax, beeswax, etc.), flow modifiers (such as polycaprolactone), colorants (carbon black, Titanium dioxide, various organic dyes, metallic pigments, etc.), light diffusing agents (acrylic crosslinked particles, silicone crosslinked particles, etc.), fluorescent brighteners, phosphorescent pigments, fluorescent dyes, antistatic agents, inorganic and organic antibacterial agents, Photocatalytic antifouling agents (fine particle titanium oxide, fine particle zinc oxide, etc.), infrared absorbers, and Like photochromic agent ultraviolet absorber may be blended. These various additives can be used in known blending amounts when blended with a thermoplastic resin such as polylactic acid.

<About the manufacturing method of a resin composition>
In order to produce the resin composition constituting the electronic device exterior part of the present invention, any method is adopted. For example, each component and optionally other components can be premixed and then melt-kneaded and pelletized. Examples of the premixing means include a Nauter mixer, a V-type blender, a Henschel mixer, a mechanochemical apparatus, and an extrusion mixer. In the preliminary mixing, granulation can be performed by an extrusion granulator or a briquetting machine depending on the case. After the preliminary mixing, the mixture is melt-kneaded by a melt-kneader represented by a vent type twin-screw extruder and pelletized by a device such as a pelletizer. Other examples of the melt kneader include a Banbury mixer, a kneading roll, and a constant temperature stirring vessel, but a vent type twin screw extruder is preferred. In addition, each component and optionally other components can be independently supplied to a melt-kneader represented by a twin-screw extruder without being premixed.

<Manufacture of molded products>
The electronic device exterior component of the present invention is usually obtained by injection molding of polylactic acid pellets produced by the above-described method at a mold temperature of 80 to 130 ° C. More preferably, it is the range of 100-120 degreeC. Ordinary polylactic acid (poly-L-lactic acid or poly-D-lactic acid) is a crystalline polymer, but its crystallization rate is very slow. Even if a crystal nucleating agent is added, a molded product crystallized by injection molding can be obtained. It is very difficult to obtain, and stereocomplex polylactic acid also has a crystallization speed higher than that of polylactic acid. However, even when a crystal nucleating agent is added, a mold temperature of 140 ° C. or higher is required. However, the stereocomplex polylactic acid of the present invention is a crystalline polymer so that a crystallized molded article can be well injection-molded at a mold temperature of 80 ° C. to 130 ° C., which is a preferable range in terms of productivity. Become. When the mold temperature is higher than 130 ° C., the cooling rate of the molded product becomes slow, which is not preferable because the molding cycle becomes long. A temperature lower than 80 ° C. is not preferable because the solidification is very slow or can be obtained in an amorphous state.

  Regarding the injection molding for obtaining the electronic device exterior component of the present invention, not only a normal cold runner molding method but also a hot runner molding method is possible. In such injection molding, not only a normal molding method but also an injection compression molding, an injection press molding, a gas assist injection molding, a foam molding (including those by injection of a supercritical fluid), an insert molding, depending on the purpose as appropriate. A molded product can be obtained using an injection molding method such as in-mold coating molding, heat insulating mold molding, rapid heating / cooling mold molding, two-color molding, sandwich molding, and ultrahigh-speed injection molding. The advantages of these various molding methods are already widely known.

  In the electronic equipment exterior component of the present invention, the proportion of the melting peak at 195 ° C. or higher is 70% or more in the melting peak derived from polylactic acid in the temperature rising process of differential scanning calorimeter (DSC) measurement also in the electronic equipment exterior component. Preferably, it is 80% or more, more preferably 90% or more, and particularly preferably 95% or more. The larger the ratio of the melting peak at 195 ° C. or higher, the higher the hydrolysis resistance of the molded product.

The melting point is preferably in the range of 195 to 250 ° C, more preferably in the range of 200 to 220 ° C. The melting enthalpy is preferably 20 J / g or more, more preferably 30 J / g or more.
Specifically, in the melting peak derived from polylactic acid in the temperature rising process of the differential scanning calorimeter (DSC) measurement, the ratio of the melting peak at 195 ° C. or higher is 70% or higher, and the melting point is in the range of 195 to 250 ° C. The melting enthalpy is preferably 20 J / g or more.

Examples of the electronic device exterior parts of the present invention include exterior parts of personal computers such as desktop personal computers and notebook personal computers.
Furthermore, the electronic device exterior component of the present invention can be further provided with other functions by surface modification. Surface modification here means a new layer on the surface of resin molded products such as vapor deposition (physical vapor deposition, chemical vapor deposition, etc.), plating (electroplating, electroless plating, hot dipping, etc.), painting, coating, printing, etc. The method used for normal resin molded products can be applied.

Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to these.
Polylactic acid units were produced by the method shown in the production examples below. Moreover, each value in an Example was calculated | required with the following method.
(1) Reduced viscosity: 0.12 g of polylactic acid unit was dissolved in 10 mL of tetrachloroethane / phenol (volume ratio 1/1), and the reduced viscosity (mL / g) at 35 ° C. was measured.
(2) Weight average molecular weight (Mw): The weight average molecular weight of the polylactic acid unit was determined by GPC (column temperature 40 ° C., chloroform) in comparison with a polystyrene standard sample.
(3) Crystallization point, melting point, melting enthalpy: The polylactic acid unit was measured using a DSC in a nitrogen atmosphere at a heating rate of 20 ° C./minute, and the crystallization point (Tc), melting point (Tm) and melting enthalpy were measured. (ΔHm) was determined.

<Production Example 1: Production of polylactic acid unit A-3 component>
After adding 50 parts by weight of L-lactide (Musashino Chemical Laboratory Co., Ltd.) to the polymerization tank and replacing the system with nitrogen, 0.05 parts by weight of stearyl alcohol and 25 × 10 ⁻³ parts by weight of tin octylate as a catalyst were added. Polymerization was carried out at 190 ° C. for 2 hours to obtain a polylactic acid unit A-3 component. The resulting polylactic acid unit A-3 component had a reduced viscosity of 1.48 (mL / g) and a weight average molecular weight of 110,000. The melting point (Tm) was 158 ° C. The crystallization point (Tc) was 117 ° C.

<Production Example 2: Production of polylactic acid unit A-6 component>
After adding 50 parts by weight of D-lactide (Musashino Chemical Laboratory Co., Ltd.) to the polymerization tank and replacing the system with nitrogen, 0.05 parts by weight of stearyl alcohol and 25 × 10 ⁻³ parts by weight of tin octylate as a catalyst were added. Polymerization was carried out at 190 ° C. for 2 hours to obtain a polylactic acid unit A-6 component. The resulting polylactic acid unit A-6 component had a reduced viscosity of 1.95 (mL / g) and a weight average molecular weight of 110,000. The melting point (Tm) was 158 ° C. The crystallization point (Tc) was 121 ° C.

<Production Example 3: Production of polylactic acid unit A-2 component>
48.75 parts by weight of L-lactide (made by Musashino Chemical Laboratories Co., Ltd.) and 1.25 parts by weight of D-lactide (made by Musashino Chemical Laboratories Co., Ltd.) were added to the polymerization tank, and the inside of the system was replaced with nitrogen. 0.05 parts by weight of alcohol and 25 × 10 ⁻³ parts by weight of tin octylate as a catalyst were added, and polymerization was carried out at 190 ° C. for 2 hours to produce a polymer. This polymer was washed with an acetone solution of 7% 5N hydrochloric acid to remove the catalyst to obtain a polylactic acid unit A-2 component. The resulting polylactic acid unit A-2 component had a reduced viscosity of 1.47 (mL / g) and a weight average molecular weight of 100,000. The melting point (Tm) was 159 ° C. The crystallization point (Tc) was 120 ° C.

<Production Example 4: Production of polylactic acid unit A-5 component>
1.25 parts by weight of L-lactide (Musashino Chemical Laboratory Co., Ltd.) and 48.75 parts by weight of D-lactide (Musashino Chemical Laboratory Co., Ltd.) were added to the polymerization tank, and the system was purged with nitrogen. 0.05 parts by weight and 25 × 10 ⁻³ parts by weight of tin octylate as a catalyst were added, and polymerization was carried out at 190 ° C. for 2 hours to produce a polymer. This polymer was washed with an acetone solution of 7% 5N hydrochloric acid to remove the catalyst to obtain a polylactic acid unit A-5 component. The resulting polylactic acid unit A-5 component had a reduced viscosity of 1.76 (mL / g) and a weight average molecular weight of 120,000. The melting point (Tm) was 156 ° C. The crystallization point (Tc) was 120 ° C.

<Production Example 5: Production of polylactic acid 1>
100 parts by weight of the polylactic acid unit A-3 component obtained in Production Example 1 and 100 parts by weight of the polylactic acid unit A-6 component obtained in Production Example 2 were added to a vent type twin screw extruder [(stock) ) Nippon Steel Works TEX30XSST] was melt-extruded and pelletized at a cylinder temperature of 280 ° C., a screw rotation speed of 150 rpm, a discharge rate of 10 kg / h, and a vent vacuum of 3 kPa to obtain polylactic acid 1.

<Production Example 6: Production of polylactic acid 2>
100 parts by weight of the polylactic acid unit A-2 component obtained in Production Example 3 and 100 parts by weight of the polylactic acid unit A-5 component obtained in Production Example 4 were added to a bent type twin screw extruder [(stock) ) Nippon Steel Works TEX30XSST] was melt-extruded and pelletized at a cylinder temperature of 230 ° C., a screw rotation speed of 150 rpm, a discharge rate of 10 kg / h, and a vent vacuum of 3 kPa to obtain polylactic acid 2.

<Production Example 7: Production of polylactic acid 3>
Polylactic acid 3 was obtained under the same conditions as in Production Example 6 except that the cylinder temperature was 260 ° C.

<Production Example 8: Production of polylactic acid 4>
Polylactic acid 4 was obtained under the same conditions as in Production Example 6 except that the cylinder temperature was 280 ° C.

<Production Example 9: Production of polylactic acid 5>
100 parts by weight of the polylactic acid unit A-2 component obtained in Production Example 3, 100 parts by weight of the polylactic acid unit A-5 component obtained in Production Example 4, and a carbodiimide compound (Carbodilite HMV-8CA: manufactured by Nisshinbo Co., Ltd.) ) 1 part by weight is supplied to a vent type twin screw extruder [TEX30XSST, manufactured by Nippon Steel Works, Ltd.] with a diameter of 30 mmφ, a cylinder temperature of 280 ° C., a screw rotation speed of 150 rpm, a discharge rate of 10 kg / h, and a vent pressure reduction degree of 3 kPa. To obtain polylactic acid 5.

Molded articles were produced by the methods shown in the following examples and comparative examples. Moreover, each value in an Example was calculated | required with the following method.
(1) Melting peak ratio of 195 ° C. or higher: Measured at a heating rate of 20 ° C./min under a nitrogen atmosphere using DSC, and the melting peak ratio (%) of 195 ° C. or higher is 195 ° C. or higher (high temperature ) And a melting peak area of 140 to 180 ° C. (low temperature).
R _{195 or more} (%) = A _{195 or more} / (A _{195 or more} + A _{140 to 180} ) × 100
R _{195 or higher} : ratio of melting peak of 195 ° C. or _higher A _{195 or higher} : melting peak area A of 195 ° C. or higher A _{140 to 180} : melting peak area of _{140 to} 180 ° C. (2) Bending strength: bending strength in accordance with ISO178 It was measured. Test piece shape: length 80 mm × width 10 mm × thickness 4 mm.
(3) Flexural modulus: The flexural modulus was measured according to ISO178. Test piece shape: length 80 mm × width 10 mm × thickness 4 mm.
(4) Heat resistance: The deflection temperature under load was measured according to ISO75-1 and 2. Load: 1.80 MPa.
(5) Chemical resistance: After simulating a notebook personal computer housing molded article in methanol at room temperature for 1 week, the surface condition was observed and evaluated according to the following criteria.
○: No change △: Slight surface roughness is observed, not possible as a product ×: Surface roughness is clearly recognized, not possible as a product (6) Hydrolysis resistance: pressure cooker tester for simulated molding of a notebook PC housing Then, the molecular weight after the treatment for 8 hours under the condition of 120 ° C. × 100% relative humidity was evaluated by the retention ratio with respect to the value before the treatment.

The following were used as raw materials.
(B component)
B-1: Talc (manufactured by Sakai Kogyo Co., Ltd .: HiTalc Premium HTP ultra 5C)
(C component)
C-1: Glass fiber (manufactured by Nippon Electric Glass Co., Ltd .: ECS-03T-511, chopped strand having an average diameter of 13 μm and a cut length of 3 mm)

<Examples 1-4, Comparative Examples 1-5>
Polylactic acid, a crystal nucleating agent, and an inorganic filler having the composition shown in Table 2 are supplied to a vent type twin-screw extruder having a diameter of 30 mmφ [TEX30XSST manufactured by Nippon Steel Works, Ltd.], a cylinder temperature of 260 ° C., and a screw rotational speed. It was pelletized by melt extrusion at 150 rpm, a discharge rate of 20 kg / h, and a vent vacuum of 3 kPa.
The screw configuration is the first kneading zone (consisting of feed kneading disk x 2, feed rotor x 1, return rotor x 1 and return kneading disk x 1) before the side feeder position. A second-stage kneading zone (consisting of a feed rotor × 1 and a return rotor × 1) was provided after the feeder position.

In each of the examples and comparative examples, the production of such pellets was carried out as follows (components are described with the above symbols).
(I) Examples 1 to 3 and Comparative Examples 1 to 4
All the components were uniformly mixed using a tumbler to prepare a premix, and the mixture was fed from the first feed port of the extruder.
(Ii) Example 4 and Comparative Example 5
C-1 of the inorganic filler was supplied from the second supply port using a side feeder, and all the remaining components were premixed with a tumbler and supplied from the first supply port.
The obtained pellets were dried with a hot air circulation dryer at 100 ° C. for 5 hours. After drying, using an injection molding machine (Toshiba Machine Co., Ltd .: IS-150EN), the mold temperature is as shown in Table 2, the cylinder temperature is 240 ° C., the molding cycle is 180 seconds, bending strength, flexural modulus, and load deflection. A test piece for temperature evaluation was molded. Each characteristic was measured using these molded articles. Their injection moldability and measurement results are shown in Table 2.

  As is apparent from the results in Table 2, the composition obtained by mixing the polylactic acid obtained in a specific combination by a specific method is excellent in injection moldability, and the resulting molded product has a large hydrolysis resistance. It can be seen that the chemical resistance is improved with the improvement. Furthermore, it turns out that the improvement of the mechanical characteristic by containing an inorganic filler and the further improvement of the hydrolysis resistance by containing a terminal blocker are also acquired.

1 Molded product body imitating the housing of a notebook PC 2 Matte surface part 3 Mirror surface part 4 Gate (pin gate 0.8mmφ, 5 locations)
5 Ratio of melting peak at 195 ° C or higher (R ₁₉₅ or higher) Sample sampling position for measurement 6 Ribbed boss (corresponding to the back side of mirror surface)
7 Ribbed boss (corresponding to the back side of matte surface)

Claims (2)

(I) Polylactic acid (component A) consists of the following combination 1,
Combination 1 comprises (A-2) a polylactic acid unit (component A-2) and (A-5) a polylactic acid unit (component A-5), and the weight ratio of the component A-2 to the component A-5 (A-2 component / A-5 component) is in the range of 40/60 to 60/40,
The polylactic acid unit (A-2) is composed of 90 to 99 mol% of L-lactic acid units and 1 to 10 mol% of D-lactic acid units and / or copolymer component units other than lactic acid (A- Two components)
The polylactic acid unit (A-5) is composed of 90 to 99 mol% of D-lactic acid units and 1 to 10 mol% of L-lactic acid units and / or copolymerization component units other than lactic acid (A- 5 components)
(Ii) Polylactic acid (component A) is heat-treated at 280 to 300 ° C., and in the differential scanning calorimeter (DSC) measurement, the proportion of the melting peak at 195 ° C. or higher is 80% or higher in the melting peak in the temperature rising process. Producing a stereocomplex polylactic acid,
(Iii) Stereocomplex polylactic acid resin composition by melt-kneading 100 parts by weight of stereocomplex polylactic acid (component A), 0.01 to 5 parts by weight of talc and 0.3 to 200 parts by weight of glass fiber Obtaining a step,
(IV) a step of injection-molding the stereocomplex polylactic acid resin composition in a mold range of 80 to 130 ° C .;
A method for manufacturing an electronic device exterior component comprising: (D) The manufacturing method of the electronic device exterior component of Claim 1 which contains 0.01-5 weight part per 100 weight part of polylactic acid components (A component) for terminal blocker (D component).

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