Method for producing polycarbonate resin molded product

Abstract

To produce a polycarbonate resin molded product with excellent optical properties, especially transparency and yellowing YI by directly injection molding polycarbonate resin granules.SOLUTION: In a method for producing a molded product by directly injection molding a polycarbonate resin material containing granules of polycarbonate resin using an injection molding machine having an injection cylinder equipped with a hopper, a feeder, and a screw, the polycarbonate resin granules have a moisture content of 500 ppm or more. The polycarbonate resin material is fed from the hopper into the injection cylinder by the feeder, and melt-kneaded while leaving gaps between flights of the injection cylinder screw.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a polycarbonate resin molded article. More specifically, it relates to a method for directly injection molding powdery or granular polycarbonate resin without passing through an extrusion melting and kneading process to produce a polycarbonate resin molded article having excellent optical properties, particularly transparency and yellowness index YI.

Background Art

[0002] Polycarbonate resin is excellent in transparency, impact resistance, heat resistance, electrical insulation, dimensional stability, etc., and has the advantage of being light and difficult to break. Therefore, it is widely used in various fields. In particular, as a substitute material for glass, it is adopted in automotive parts, building materials, and optical parts such as lenses. In recent years, it has also been actively used in members for panels of display devices, light guide plates, power meter covers, lighting lenses, lighting covers, light guides, light guiding members, etc. that require transparency, such as various portable terminals such as smartphones, tablet computers, car navigation systems, car audio systems, portable game machines, and digital cameras.

[0003] In order to mold these molded articles, a polycarbonate resin raw material is blended with various additives as necessary, melted and kneaded by an extruder, and pelletized polycarbonate resin composition is used (see, for example, Patent Document 1). However, the polycarbonate resin undergoes a heat history by being melted and kneaded by an extruder, and the resulting polycarbonate resin composition pellets are subject to heat deterioration, thermal decomposition, etc. to a certain extent. Therefore, polycarbonate resin injection molded articles obtained by injection molding pellets obtained through an extrusion melting and kneading process by an extruder tend to be inferior in appearance, mechanical strength, heat resistance, impact resistance, and chemical resistance.

[0004] A common method for producing polycarbonate resins is the interfacial polymerization method. However, the polycarbonate resins produced by this method are usually discharged as powder particles from the polymerization and purification equipment. Therefore, it is energy - saving effective to obtain products by molding with an injection molding machine without pelletizing these powder particles with an extruder. In recent years, from the perspective of the growing awareness of issues such as climate change and the realization of a sustainable society, there is an increasing demand both at home and abroad for products that contribute to carbon neutrality.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made in view of such circumstances, and the problem thereof is to provide a method for directly injection - molding a polycarbonate resin molded product excellent in optical properties, particularly transparency and yellowness index YI, from powder particles of a polycarbonate resin.

Means for Solving the Problems

[0007] As a result of intensive studies to achieve the above problems, the present inventor found that when polycarbonate resin powder particles are supplied by free - falling from a hopper attached to the proximal end side of the injection cylinder of an injection molding machine, the portion reaching the screw through the supply port of the injection cylinder becomes over - filled with polycarbonate resin powder particles due to screw rotation, and an unmelted resin and a melted resin are mixed, and excessive shear heat and gas are generated, and the gas, moisture, and air generated in the cylinder are also injected simultaneously. However, by adjusting the supply of polycarbonate resin powder particles and so on, and melt - kneading so as to create voids between the flights of the injection cylinder screw, the above problems can be solved. The present invention relates to a method for manufacturing the following polycarbonate resin molded article.

[0008] 1. A method for manufacturing a molded article by directly injection molding a polycarbonate resin material containing polycarbonate resin powder particles using an injection molding machine having an injection cylinder equipped with a hopper, a feeder, and a screw, wherein the water content of the polycarbonate resin powder particles is 500 ppm or more, and the polycarbonate resin material is charged from the hopper into the injection cylinder by the feeder and melt-kneaded so that voids are formed between the flights of the injection cylinder screw. A method for manufacturing a polycarbonate resin molded article, characterized by this. 2. The manufacturing method according to 1 above, wherein the injection molding machine does not have a vent function or is not used. 3. The manufacturing method according to 1 or 2 above, wherein the void between the flights of the injection cylinder screw is 13% by volume or more and 90% by volume or less as the filling rate of the polycarbonate resin material. 4. The manufacturing method according to 1 or 2 above, wherein a hue improver is added to the polycarbonate resin material in addition to the polycarbonate resin powder particles.

Effect of the Invention

[0009] According to the manufacturing method of the present invention, a polycarbonate resin molded product excellent in optical properties, particularly transparency and yellowness index YI, can be manufactured by directly injection molding from polycarbonate resin powder particles. By performing melt kneading so that voids are formed between the flights of the injection cylinder screw, the shear heat generation during melt kneading can be reduced, and gas and moisture can be easily discharged from the hopper opening. With excellent transparency and yellowness index YI, when the moisture content of the polycarbonate resin powder particles is 500 ppm or more, the YI can be further improved. Such an effect is more easily achieved when the injection molding machine does not have a vent portion or does not use the vent function, and when nitrogen gas or inert gas is not introduced either. The molded product obtained by injection molding can achieve excellent transparency and YI even with a long optical path of 300 mm, so it can also be suitably used as a light guiding member such as a high-end light guide plate or a light guide.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described in detail with reference to embodiments and examples, but the present invention is not to be construed as being limited to such embodiments and examples.

[0012] [Polycarbonate Resin Powder Particles] The raw material used in the manufacturing method of the polycarbonate resin molded product of the present invention is polycarbonate resin powder particles. The polycarbonate resin powder particles refer to those having a particulate shape including, for example, powdery, powdered, powdery, granular, flaky, etc.

[0013] The polycarbonate resin powder particles have a median diameter D by the light scattering wet method 50Preferably, it is in the range of 400 to 1500 μm. The median diameter D of the polycarbonate resin powder 50 If it is less than 400 μm, the resin temperature becomes too high and the color tone is likely to deteriorate. If it is larger than 1500 μm, the amount of unmelted matter is likely to increase. The median diameter D 50 is preferably 450 μm or more, more preferably 500 μm or more, preferably 1400 μm or less, more preferably 1300 μm or less, and even more preferably 1200 μm or less.

[0014] The particle size measurement of the polycarbonate resin powder is the D value obtained by a laser diffraction particle size distribution measuring device. Specifically, it is the value measured by using the laser diffraction particle size distribution measuring device "Mastersizer 3000" manufactured by Malvern Panalytical, by the wet method, with purified water as the dispersion medium used and a surfactant as the dispersant. The measurement range is 0.01 - 3500 μm. 50 The particle size of the polycarbonate resin powder can also be represented by the particle size distribution measured by a method conforming to JIS K0069 (dry sieving test method), and the median diameter D can also be obtained therefrom. The particle size by this method is a powder within the range of 400 - 1500 μm, preferably 450 - 1400 μm, and even more preferably 500 - 1300 μm.

[0015] The polycarbonate resin powder having such a median diameter D and viscosity average molecular weight can also be appropriately selected and adopted from commercially available products. 50 The polycarbonate resin powder having such a median diameter D and viscosity average molecular weight can also be appropriately selected and adopted from commercially available products.

[0016] Such a median diameter D 50 and the polycarbonate resin powder satisfying the viscosity average molecular weight can be appropriately selected and adopted from commercially available products.

[0017] The above polycarbonate resin powder may be 100% by mass of the polycarbonate resin raw material used as a raw material, or more than 50% by mass of the polycarbonate resin raw material used may be in the form of powder. For example, it is also possible to use a combination of polycarbonate resin powder and ordinary polycarbonate resin pellets in an amount of less than 50% by mass as a raw material. The amount of the polycarbonate resin powder is more preferably more than 50% by mass, still more preferably more than 60% by mass, particularly preferably more than 70% by mass, more than 80% by mass, more than 85% by mass, and especially preferably more than 90% by mass, more than 95% by mass.

[0018] [Polycarbonate resin] Examples of the polycarbonate resin include aromatic polycarbonate resins, aliphatic polycarbonate resins, and aromatic-aliphatic polycarbonate resins. Preferably, it is an aromatic polycarbonate resin. Specifically, an aromatic polycarbonate polymer or copolymer obtained by reacting an aromatic dihydroxy compound with phosgene or a diester of carbonic acid is used.

[0019] Examples of the aromatic dihydroxy compound preferably include 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), 2,2-bis(3-methyl-4-hydroxyphenyl)propane (i.e., bisphenol C), tetramethyl bisphenol A, α,α'-bis(4-hydroxyphenyl)-p-diisopropylbenzene, resorcinol, 4,4'-dihydroxydiphenyl, etc.

[0020] Preferred examples of the polycarbonate resin include a polycarbonate resin obtained by using bisphenol A or a combination of bisphenol A and another aromatic dihydroxy compound as the dihydroxy compound, and a polycarbonate resin obtained by using bisphenol C or a combination of bisphenol C and another aromatic dihydroxy compound (especially bisphenol A).

[0021] The polycarbonate resin may be a homopolymer composed of one type of repeating unit, or may be a copolymer having two or more types of repeating units. At this time, for the copolymer, various copolymerization forms such as random copolymers and block copolymers can be selected.

[0022] The viscosity average molecular weight (Mv) of the polycarbonate resin is preferably from 11,000 to 30,000. If it is less than 11,000, the strength of the obtained polycarbonate resin molded article tends to be weak. If it is greater than 30,000, the resin temperature becomes high and the color tone of the obtained molded product tends to deteriorate. The viscosity average molecular weight (Mv) is more preferably 12,000 or more, still more preferably 13,000 or more, more preferably 28,000 or less, still more preferably 27,000 or less, particularly preferably 26,000 or less, and especially preferably 24,000 or less.

[0023] The viscosity average molecular weight (Mv) of the polycarbonate resin is a value calculated from the following Schnell viscosity formula by measuring the viscosity of a methylene chloride solution of the polycarbonate resin at 25 °C using an Ubbelohde viscometer to obtain the intrinsic viscosity ([η]). [η]=1.23×10 -4 Mv 0.83

[0024] The method for producing the polycarbonate resin is not particularly limited, and polycarbonate resins produced by either the phosgene method (interfacial polymerization method) or the melt method (transesterification method) can be used. Polycarbonate resins produced by the interfacial polymerization method are likely to have a small YI value of the color tone, and since they are in a granular state during polymerization production, they can be preferably used in the present invention.

[0025] The polycarbonate resin may use not only virgin raw materials but also powder particles of polycarbonate resin recycled from used products (so-called material-recycled polycarbonate resin), and it is also possible to use both powder particles of virgin raw materials and powder particles of recycled resin. When using recycled polycarbonate resin powder particles, the proportion of recycled polycarbonate resin in the polycarbonate resin is preferably 40% or less, 30% or less, 20% or less, 10% or less. Also, when using recycled polycarbonate resin pellets in combination, it may be preferably used in an amount of 40% or less, 30% or less, 20% or less, 10% or less.

[0026] [Injection molding] The method of the present invention directly manufactures an injection molded product by injection molding a polycarbonate resin material containing the above-mentioned powder particles of polycarbonate resin without going through an extrusion melt kneading process. And in the present invention, as the polycarbonate resin powder particles, those with a moisture content of 500 ppm or more are used, which are fed from a hopper to an injection cylinder by a feeder and melt kneaded so that voids are formed between the flights of the injection cylinder screw. Hereinafter, the present invention will be described with reference to the drawings, but the present invention is not construed as being limited to the following aspects.

[0027] FIG. 1 is a configuration diagram showing an example of an injection molding machine suitably used in the present invention. In FIG. 1, 1 is an injection cylinder, and a screw 2 is arranged inside. The screw 2 has flights 3 formed in a spiral shape. Immediately above the supply port 4 on the proximal end side of the injection cylinder 1, a feeder 5 is provided, and a hopper 6 is provided thereon. An injection nozzle 7 is provided on the tip side in the injection direction of the injection cylinder 1. A heater 8 for heating is attached to the outer periphery of the injection cylinder 1.

[0028] In the present invention, a polycarbonate resin material containing polycarbonate resin powder is supplied to an injection molding machine by charging it from a hopper into an injection cylinder through a feeder, and melt-kneaded while creating a gap between the flights of the injection cylinder screw.

[0029] Figure 2 is an explanatory diagram showing an example of melt-kneading in a state where a gap is created between the flights of the injection cylinder screw. The polycarbonate resin powder a is charged into the hopper 6 and then a predetermined amount is charged into the supply port 4 on the proximal end side of the injection cylinder 1 by the feeder 5 whose supply amount can be adjusted. It is preferable that a feed screw (not shown) for adjusting the feed amount is provided in the feeder 5, and its rotation speed is preferably 10 to 50 rpm. The powder a that has fallen from the hopper 6 to the supply port 4 is pushed by the flight 3 on the screw 2. However, in the present invention, by controlling the input amount of the powder a, the space between the flights 3 of the screw 2 directly below the supply port 4 is not filled with the polycarbonate resin powder a, and a gap s is created between the flights. Then, after advancing several flights, the temperature rises due to the heat from the heater 8, and the powder a in contact with the wall surface of the cylinder 1 melts, melting the unmelted material (this process is also called metering or plasticization), bringing it to a uniform temperature and sending it to the tip of the screw. Injection molding is repeated in the order of mold closing → injection → holding pressure → cooling and simultaneously plasticization (metering) → mold opening.

[0030] By using a polycarbonate resin powder having a water content of 500 ppm or more and performing melt-kneading in a state where a gap is created between the flights of the injection cylinder screw, a space is created inside the injection cylinder 1, reducing the shear heat generation during melting, and making it easier to discharge the generated gas together with water from the hopper 6. After such melt-kneading, when injection molding is performed from the injection nozzle 7 on the tip side of the injection cylinder 1 into a mold, a polycarbonate resin molded product excellent in optical properties, particularly transparency and yellowness index YI, can be obtained.

[0031] The gap between the flights of the injection cylinder screw is preferably 13% by volume or more and 90% by volume or less, more preferably 20% by volume or more, still more preferably 30% by volume or more, particularly 40% by volume or more as the filling rate of the polycarbonate resin material, and more preferably 80% by volume or less, still more preferably 70% by volume. The filling rate refers to the ratio (unit: % by volume) of the amount of resin to the space volume per pitch in the spiral groove formed between the flights in the flight 3 of the screw 2. To adjust the filling rate, as described above, it is possible by adjusting the supply amount with the feeder 5, but it can be further controlled in consideration of the screw rotation speed and the metering time. As the flight, a normal single full flight one can be preferably used, and it is preferable that there is no mixing part such as a damage type, a barrier type, a sub-flight type, a wave type, etc.

[0032] In the method of the present invention, it is preferable not to vent, and even if it is an injection molding machine with a vent, it is preferable not to use the vent function. Also, it is preferable not to supply an inert gas such as N 2 gas into the cylinder.

[0033] The polycarbonate resin powder supplied to the injection molding machine has a water content of 500 ppm or more as described above, preferably 600 ppm or more, more preferably 800 ppm or more, preferably 5000 ppm or less, more preferably 4000 ppm or less, still more preferably 3000 ppm or less. The above water content can also be achieved by adjusting the drying conditions of the polycarbonate resin powder supplied to the injection molding machine, or by using the polycarbonate resin powder as it is without drying.

[0034] Normal conditions can be adopted for the injection molding conditions. For example, the cylinder temperature can be 260 to 320 °C and the mold temperature can be 60 to 120 °C.

[0035] In the present invention, other additives may be added in addition to the polycarbonate resin powder. The additives are not particularly limited, and examples thereof preferably include a hue improver, a stabilizer, an ultraviolet absorber, a mold release agent, and the like.

[0036] [Hue improver] The hue improver is not particularly limited as long as the hue of the obtained molded product can be improved by blending it. Representative hue improvers specifically include aromatic compounds, polyalkylene glycols, epoxy compounds, and oxetane compounds. By adding these, a molded product with an even better hue can be obtained. The amount of the hue improver is preferably 0.0001 to 5 parts by mass, more preferably 0.001 part by mass or more, still more preferably 0.01 part by mass or more, more preferably 3 parts by mass or less, still more preferably 2 parts by mass or less, and particularly 1 part by mass or less with respect to 100 parts by mass of the polycarbonate resin.

[0037] <Aromatic compound> As the aromatic compound, a compound of the following general formula (1) is preferred. [Chemical formula]

[0038] In the above general formula (1), Y is an organic group containing none of the elements nitrogen, sulfur, and halogen, or a hydrogen atom. When Y is a hydrogen atom, X is an alkyl group or an aryl group which may have a substituent. When Y is an organic group containing none of the elements nitrogen, sulfur, and halogen, X is an organic group containing none of the elements nitrogen, sulfur, and halogen. In this case, X and Y may be the same or different. g represents an integer of 1 or 2. n represents an integer of 0 to 5. When n is 2 or more, the n X's may be the same or different. k represents an integer from 1 to 4. When k is 2 or more, two or more of the - (CH 2 ) g OY groups may be the same or different. However, n + k is 6 or less.)

[0039] In the general formula (1), when k = 2 and there are two CH 2 OY groups, the substitution positions of the CH 2 OY groups are preferably the 1,4-positions.

[0040] In the general formula (1), it is preferable that g is 1 and k is 1 from the viewpoint of the hue improvement effect. Therefore, the aromatic compound (C) represented by the general formula (1) is preferably a benzyloxy compound or a benzyl alcohol compound represented by the following general formula (1A).

[0041]

Chemical formula

[0042] In the general formulas (1) and (1A), when X and Y are organic groups containing none of the elements nitrogen, sulfur, and halogen, the organic group may be any group that does not contain any of the elements nitrogen, sulfur, and halogen that cause coloring, and there is no particular limitation. Usually, substituents composed of carbon atoms and hydrogen atoms, or carbon atoms, hydrogen atoms, and oxygen atoms are mentioned. Specifically, alkyl groups, aryl groups, aralkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, groups in which a hydroxyl group, an ether group, or other groups are introduced into these groups, etc. are mentioned.

[0043] When Y is an organic group containing none of the elements nitrogen, sulfur, and halogen, X is particularly preferably an alkyl group or an aryl group which may have a substituent. When Y is an organic group containing none of the elements nitrogen, sulfur, and halogen, or when Y is a hydrogen atom, the aryl group of X is preferably a phenyl group. The phenyl group may have an alkyl group as a substituent. Examples of the alkyl group include those described below for the alkyl group of X.

[0044] When Y is an organic group containing none of the elements nitrogen, sulfur, and halogen, or when Y is a hydrogen atom, the alkyl group of X is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group of X may be a straight-chain alkyl group, a branched-chain alkyl group, or a cyclic alkyl group, but is preferably a straight-chain or branched-chain alkyl group.

[0045] n representing the number of the substituent X in the general formulas (1) and (1A) is 0 to 4. When Y is a hydrogen atom, n is preferably 0 to 3, more preferably 0 to 2, and particularly preferably 0 (unsubstituted) or 1. When n is 2 or more, the plurality of substituents X may be the same as or different from each other.

[0046] As the substitution position of X, when having one -CH 2 OY group, the ortho position and / or para position with respect to the -CH 2 OY group is preferred.

[0047] (When Y is a hydrogen atom) In the case of an aromatic alcohol in which Y in the general formula (1) or (1A) is a hydrogen atom, specific examples of the benzyl alcohol-based compound with k = 1 include benzyl alcohol (i.e., phenylmethanol), 4-methylphenylmethanol, 2-methylphenylmethanol, 3-methylphenylmethanol, 4-ethylphenylmethanol, 2-ethylphenylmethanol, 4-isopropylphenylmethanol, 4-tert-butylphenylmethanol, 4-phenylbenzyl alcohol (i.e., 4-phenylphenylmethanol), 3-phenylphenylmethanol, 2,3-dimethylphenylmethanol, 2,4-dimethylphenylmethanol, 2-methyl-3-phenylphenylmethanol, 3,5-tert-butylphenylmethanol, 2,4,6-trimethylphenylmethanol, 2,3,5,6-tetramethylphenylmethanol, and the like.

[0048] Specific examples of the benzenedimethanol-based compound with k = 2 include 1,4-benzenedimethanol, 1,3-benzenedimethanol, 1,2-benzenedimethanol, and the like.

[0049] Among these, benzyl alcohol, 4-phenylbenzyl alcohol, 2-methylphenylmethanol, 4-methylphenylmethanol, 4-tert-butylphenylmethanol, and 1,4-benzenedimethanol are preferred.

[0050] (When Y is an organic group) When Y in the general formula (1) or (1A) is an organic group that does not contain any of the elements nitrogen, sulfur, and halogen, Y is preferably an alkyl group, an alkenyl group, an alkylcarbonyl group, an arylcarbonyl group which may have a substituent, a hydroxyalkyl group, a hydroxyalkyloxyalkyl group, an aryl group which may have a substituent, or a benzyl group which may have a substituent on the benzene ring.

[0051] The alkyl group of Y is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group of Y may be a linear alkyl group, a branched alkyl group, or a cyclic alkyl group, but is preferably a linear or branched chain alkyl group.

[0052] The alkenyl group of Y is preferably an alkenyl group having 2 to 5 carbon atoms, more preferably an allyl group (-CH 2 -CH=CH 2 ). The alkylcarbonyl group of Y is preferably an alkylcarbonyl group having 2 to 5 carbon atoms (-C(=O)-(CH 2 ) j -CH 3 (j is an integer from 0 to 3)). Examples of the arylcarbonyl group of Y include a phenylcarbonyl group (-C(=O)-C 6 H 5 ) which may have a substituent.

[0053] The aryl group of Y is preferably a phenyl group. Examples of the hydroxyalkyl group include a group represented by -(CH 2 ) m OH (m is an integer from 1 to 4). Examples of the hydroxyalkyloxyalkyl group include -CH 2 CH 2 -O-CH 2 CH 2 -OH.

[0054] Examples of the substituent that the aryl group such as the phenyl group and the benzene ring such as the benzyl group contained in Y may have include an alkyl group. Examples of the alkyl group include those described above for the alkyl group of X.

[0055] Y is preferably an alkyl group such as a methyl group, a benzyl group, a hydroxymethyl group (-CH 2 OH), a hydroxyethyl group (-C 2 H 4 OH), -CH 2-CH=CH 2 、-C(=O)-(CH 2 ) j -CH 3 (j is an integer from 0 to 3), or -C(=O)-C 6 H 5 is.

[0056] Specific examples of the aromatic compound (C) in which Y is an organic group containing none of the elements nitrogen, sulfur, and halogen include dibenzyl ether (C 6 H 5 -CH 2 -O-CH 2 -C 6 H 5 ), benzyl methyl ether (C 6 H 5 -CH 2 -O-CH 3 ), 2-benzyloxyethanol (C 6 H 5 -CH 2 -O-C 2 H 4 OH), allyl benzyl ether (C 6 H 5 -CH 2 -O-CH 2 -CH=CH 2 ), benzyl acetate (C 6 H 5 -CH 2 -O-C(=O)-CH 3 ), benzyl benzoate (C 6 H 5 -CH 2 -O-C(=O)-C 6 H 5 ), benzyl butyrate (C 6 H 5 -CH 2 -O-C(=O)-C 3 H 7 ), 1,4-bis(methoxymethyl)benzene (CH 3 -O-CH 2 -C 6 H 4 -CH 2 -O-CH 3) include the like. Among these, dibenzyl ether, benzyl methyl ether, and 2-benzyloxyethanol are preferred.

[0057] The aromatic compound may be used alone or in combination of two or more.

[0058] The preferred amount when blending the aromatic compound is 0.001 to 1 part by mass with respect to 100 parts by mass of the polycarbonate resin. If the content of the aromatic compound is excessively large, the molded product may become cloudy, or the durability against heat and light may deteriorate. The content is more preferably 0.05 to 1 part by mass, and even more preferably 0.1 to 0.5 part by mass.

[0059] <Polyalkylene glycol> As the polyalkylene glycol, those having at least one or two or more units selected from tetramethylene glycol units, (2-methyl)ethylene glycol units, trimethylene glycol units, and ethylene glycol units are preferred, and it is preferably included as a copolymer obtained by copolymerizing at least two or more units.

[0060] In addition, the polyalkylene glycol preferably has a hydroxyl group at its terminal group. In addition, derivatives in which one or both ends are blocked with an alkyl ether, aryl ether, aralkyl ether, fatty acid ester, aryl ester, etc. have no influence on the performance expression, and etherified products or esterified products can be used in the same manner.

[0061] As the alkyl group constituting the alkyl ether, either linear or branched can be used, and alkyl groups having 1 to 22 carbon atoms, such as methyl group, ethyl group, propyl group, butyl group, octyl group, lauryl group, stearyl group, etc., and methyl ether, ethyl ether, butyl ether, lauryl ether, stearyl ether, etc. of polyalkylene glycol can be preferably exemplified. As the aryl group constituting the aryl ether, an aryl group having 6 to 22 carbon atoms, more preferably 6 to 12 carbon atoms, and still more preferably 6 to 10 carbon atoms is preferred. Examples include a phenyl group, a tolyl group, a naphthyl group, etc., and a phenyl group, a tolyl group, etc. are preferred. As the aralkyl group constituting the aralkyl ether, an aralkyl group having 7 to 23 carbon atoms, more preferably 7 to 13 carbon atoms, and still more preferably 7 to 11 carbon atoms is preferred. Examples include a benzyl group, a phenethyl group, etc., and a benzyl group is particularly preferred.

[0062] As the fatty acid constituting the fatty acid ester, either a linear or branched one can be used, and it may be a saturated fatty acid or an unsaturated fatty acid. As the fatty acid constituting the fatty acid ester, a monovalent or divalent fatty acid having 1 to 22 carbon atoms is used. For example, monovalent saturated fatty acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, capric acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid; monovalent unsaturated fatty acids such as oleic acid, elaidic acid, linoleic acid, linolenic acid, arachidonic acid and other unsaturated fatty acids; and divalent fatty acids having 10 or more carbon atoms such as sebacic acid, undecanedioic acid, dodecanedioic acid, tetradecanedioic acid, tapscic acid and decenedioic acid, undecenedioic acid, dodecenedioic acid.

[0063] As the aryl group constituting the aryl ester, an aryl group having 6 to 22 carbon atoms, more preferably 6 to 12 carbon atoms, and still more preferably 6 to 10 carbon atoms is preferred. Examples include a phenyl group, a tolyl group, a naphthyl group, etc., and a phenyl group, a tolyl group, etc. are preferred. Since the group for terminal capping shows good compatibility with polycarbonate even if it is an aralkyl group, it can exhibit the same action as the aryl group. As the aralkyl group, an aralkyl group having 7 to 23 carbon atoms, more preferably 7 to 13 carbon atoms, and still more preferably 7 to 11 carbon atoms is preferred. Examples include a benzyl group, a phenethyl group, etc., and a benzyl group is particularly preferred.

[0064] The number average molecular weight of the polyalkylene glycol is preferably from 200 to 10,000, more preferably from 500 to 5,000, still more preferably 800 or more, particularly preferably 1,000 or more, especially preferably 1,500 or more, and more preferably 4,500 or less, still more preferably 4,000 or less, particularly preferably 3,500 or less, 3,000 or less, especially 2,500 or less. If it exceeds the upper limit of the above range, the compatibility will decrease, which is not preferable. If it is less than the lower limit of the above range, gas will be generated during molding, which is not preferable. In the present specification, the number average molecular weight of the polyalkylene glycol is defined as a value calculated based on the hydroxyl value measured in accordance with JIS K1577.

[0065] The polyalkylene glycol may be used alone or in combination of two or more. When the polyalkylene glycol is contained, the content is preferably from 0.01 to 5 parts by mass, more preferably 0.05 part by mass or more, and more preferably 4 parts by mass or less, particularly preferably 3 parts by mass or less, 2 parts by mass or less, 1.5 parts by mass or less, especially preferably 1 part by mass or less, based on 100 parts by mass of the polycarbonate resin. When the content is less than 0.01 part by mass of the above range, the hue and heat discoloration resistance tend to be insufficient. When it exceeds 5 parts by mass, the material becomes cloudy and the transparency is likely to be lost.

[0066] <Epoxy compound> As the epoxy compound, a compound having one or more epoxy groups in one molecule is used. Specifically, phenyl glycidyl ether, allyl glycidyl ether, t-butyl phenyl glycidyl ether, 3,4-epoxycyclohexylmethyl-3’,4’-epoxycyclohexyl carboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3’,4’-epoxy-6’-methylcyclohexyl carboxylate, 2,3-epoxycyclohexylmethyl-3’,4’-epoxycyclohexyl carboxylate, 4-(3,4-epoxy-5-methylcyclohexyl)butyl-3’,4’-epoxycyclohexyl carboxylate, 3,4-epoxycyclohexyl ethylene oxide, cyclohexylmethyl 3,4-epoxycyclohexyl carboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6’-methylsilocyclohexyl carboxylate, bisphenol-A diglycidyl ether, tetrabromobisphenol-A glycidyl ether, diglycidyl ester of phthalic acid, diglycidyl ester of hexahydrophthalic acid, bis-epoxy dicyclopentadienyl ether, bis-epoxy ethylene glycol, bis-epoxy cyclohexyl adipate, butadiene diepoxide, tetraphenyl ethylene epoxide, octyl epoxy tallate, epoxidized polybutadiene, 3,4-dimethyl-1,2-epoxycyclohexane, 3,5-dimethyl-1,2-epoxycyclohexane, 3-methyl-5-t-butyl-1,2-epoxycyclohexane, octadecyl-2,2-dimethyl-3,4-epoxycyclohexyl carboxylate, N-butyl-2,2-dimethyl-3,4-epoxycyclohexyl carboxylate, cyclohexyl-2-methyl-3,4-epoxycyclohexyl carboxylate, N-butyl-2-isopropyl-3,4-epoxy-5-methylcyclohexyl carboxylate, octadecyl-3,4-epoxycyclohexyl carboxylate, 2-ethylhexyl-3’,4’-epoxycyclohexyl carboxylate, 4,6-dimethyl-2,3-epoxycyclohexyl-3’,4’-epoxycyclohexyl carboxylate, 4,5-epoxy tetrahydrophthalic anhydride, 3-t-butyl-4,5-Epoxy tetrahydrophthalic anhydride, diethyl 4,5-epoxy-cis-1,2-cyclohexanedicarboxylate, di-n-butyl-3-t-butyl-4,5-epoxy-cis-1,2-cyclohexanedicarboxylate, epoxidized soybean oil, epoxidized linseed oil, etc. can be preferably exemplified.,

[0067] Among these, alicyclic epoxy compounds are preferably used, and in particular, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate is preferred.,

[0068] <Oxetane compound> As the oxetane compound, any compound having one or more oxetane groups in the molecule can be used, and either a mono-oxetane compound having one oxetane group in the molecule or a poly-oxetane compound having two or more oxetane groups in the molecule can be used.,

[0069] Specific examples of the oxetane compound include 3-hydroxymethyl-3-methyloxetane, 3-hydroxymethyl-3-ethyloxetane, 3-hydroxymethyl-3-propyloxetane, 3-hydroxymethyl-3-normal butyloxetane, 3-hydroxymethyl-3-propyloxetane, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, bis(3-methyl-3-oxetanylmethyl)ether, bis(3-ethyl-3-oxetanylmethyl)ether, bis(3-propyl-3-oxetanylmethyl)ether, bis(3-butyl-3-oxetanylmethyl)ether, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 3-ethyl-3{[(3-ethyloxetane-3-yl)methoxy]methyl}oxetane, 4,4'-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl, 1,4-bis[(3-ethyl-3-oxetanyl)methoxymethyl]benzene, etc. can be preferably mentioned.,

[0070] The preferred compounding amount of the epoxy compound and / or oxetane compound (the total content when both the epoxy compound and oxetane compound are included) is preferably 0.0001 part by mass or more, more preferably 0.0005 part by mass or more, particularly preferably 0.001 part by mass or more, 0.003 part by mass or more, especially preferably 0.005 part by mass or more, based on 100 parts by mass of the polycarbonate resin. Also, it is preferably 0.5 part by mass or less, more preferably 0.4 part by mass or less, particularly preferably 0.3 part by mass or less, 0.2 part by mass or less, 0.15 part by mass or less, 0.1 part by mass or less, especially preferably 0.05 part by mass or less.

[0071] [Phosphorus stabilizer] In the production method of the present invention, it is also preferable to add a phosphorus stabilizer. By compounding a phosphorus stabilizer, the hue of the molded product becomes good, and furthermore, the heat discoloration resistance is improved. As the phosphorus stabilizer, a phosphite compound is particularly preferable.

[0072] Here, the phosphite compound is a trivalent phosphorus compound represented by the general formula: P(OR) 3 wherein R represents a monovalent or divalent organic group. Examples of such phosphite compounds include triphenyl phosphite, tris(monononylphenyl) phosphite, tris(monononyl / dinonylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, monooctyldiphenyl phosphite, dioctylmonophenyl phosphite, monodecyldiphenyl phosphite, didecyldiphenyl phosphite, tridecyl phosphite, trilauryl phosphite, tristearyl phosphite, distearyl pentaerythritol diphosphite, bis(2,4-di-tert-butyl-4-methylphenyl) pentaerythritol phosphite, bis(2,6-di-tert-butylphenyl) octyl phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl) octyl phosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene-diphosphite, 6-[3-(3-tert-butyl-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenzod[f][1,3,2]-dioxaphosphepine, and the like.

[0073] Among such phosphite compounds, aromatic phosphite compounds represented by the following formula (3) or (4) are more preferable because they can effectively enhance the heat discoloration resistance of the polycarbonate resin composition of the present invention.

[0074] [Chemical formula] [In formula (3), R 1 , R 2 and R 3 may be the same or different from each other and each represents an aryl group having 6 to 30 carbon atoms.]

[0075] [Chemical formula] [In formula (4), R 4 and R 5may be the same or different and each represents an aryl group having 6 to 30 carbon atoms.

[0076] Among the phosphite compounds represented by the above formula (3), triphenyl phosphite, tris(monononylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite and the like are preferable, and among them, tris(2,4-di-tert-butylphenyl) phosphite is more preferable. Among the phosphite compounds represented by the above formula (4), those having a pentaerythritol diphosphite structure such as bis(2,4-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, and bis(2,4-dicumylphenyl)pentaerythritol diphosphite are particularly preferable.

[0077] The preferable compounding amount of the phosphorus-based stabilizer is 0.005 to 0.5 parts by mass, more preferably 0.007 parts by mass or more, still more preferably 0.008 parts by mass or more, particularly preferably 0.01 parts by mass or more, based on 100 parts by mass of the polycarbonate resin. Also, it is more preferably 0.4 parts by mass or less, still more preferably 0.3 parts by mass or less, particularly 0.2 parts by mass or less, and especially 0.1 parts by mass or less.

[0078] [Ultraviolet absorber] In the production method of the present invention, it is also preferable to further incorporate an ultraviolet absorber. Examples of the ultraviolet absorber include inorganic ultraviolet absorbers such as cerium oxide and zinc oxide; organic ultraviolet absorbers such as benzotriazole compounds, benzophenone compounds, salicylate compounds, cyanoacrylate compounds, triazine compounds, oxanilide compounds, malonic ester compounds, hindered amine compounds, and oxalic anilide compounds. Among these, organic ultraviolet absorbers are preferable, and benzotriazole compounds are more preferable. By selecting an organic ultraviolet absorber, the transparency and mechanical properties of the molded product become good.

[0079] Specific examples of the benzotriazole compound include, for example, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-[2'-hydroxy-3',5'-bis(α,α-dimethylbenzyl)phenyl]-benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butyl-phenyl)-benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butyl-phenyl)-5-chlorobenzotriazole), 2-(2'-hydroxy-3',5'-di-tert-amyl)-benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], etc. Among them, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole and 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol] are preferred, and particularly 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole is preferred.

[0080] Specific examples of the benzophenone compound include, for example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-n-dodecyloxybenzophenone, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, etc.

[0081] Specific examples of the salicylate compound include, for example, phenyl salicylate, 4-tert-butylphenyl salicylate, etc. Specific examples of the cyanoacrylate compound include, for example, ethyl-2-cyano-3,3-diphenylacrylate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate, and the like. Specific examples of the oxanilide compound include, for example, 2-ethoxy-2'-ethyloxalyni c acid bisanilide, and the like. As the malonic ester compound, 2-(alkylidene) malonic esters are preferred, and 2-(1-arylalkylidene) malonic esters are more preferred.

[0082] When blending the ultraviolet absorber, the amount is usually 0.05 parts by mass or more, preferably 0.1 parts by mass or more, and usually 1 part by mass or less, preferably 0.5 parts by mass or less, based on 100 parts by mass of the polycarbonate resin.

[0083] [Release agent] Also, it is preferable to blend a release agent. Examples of the release agent include, for example, aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15000, polysiloxane-based silicone oils, and the like.

[0084] Examples of the aliphatic carboxylic acid can include saturated or unsaturated aliphatic monovalent, divalent or trivalent carboxylic acids. Here, the aliphatic carboxylic acid also includes alicyclic carboxylic acids. Among these, preferred aliphatic carboxylic acids are monovalent or divalent carboxylic acids having 6 to 36 carbon atoms, and aliphatic saturated monovalent carboxylic acids having 6 to 36 carbon atoms are more preferred. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetratriacontanoic acid, montanic acid, adipic acid, azelaic acid, and the like.

[0085] As the aliphatic carboxylic acid in the ester of an aliphatic carboxylic acid and an alcohol, for example, the same as the above aliphatic carboxylic acid can be used. On the other hand, examples of the alcohol include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have substituents such as fluorine atoms and aryl groups. Among these, monohydric or polyhydric saturated alcohols having 30 or fewer carbon atoms are preferred, and aliphatic saturated monohydric alcohols or aliphatic saturated polyhydric alcohols having 30 or fewer carbon atoms are more preferred. Here, aliphatic is used as a term including alicyclic compounds.

[0086] Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, dipentaerythritol, and the like.

[0087] In addition, the above ester may contain an aliphatic carboxylic acid and / or an alcohol as impurities. Further, the above ester may be a pure substance or a mixture of a plurality of compounds. Furthermore, for the aliphatic carboxylic acid and the alcohol that combine to form one ester, each may use one type, or two or more types may be used in combination in any combination and ratio.

[0088] Specific examples of the ester of an aliphatic carboxylic acid and an alcohol include beeswax (a mixture mainly composed of myricyl palmitate), stearyl stearate, behenyl behenate, behenyl stearate, glycerin monopalmitate, glycerin monostearate, glycerin distearate, glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate, and the like.

[0089] Examples of the aliphatic hydrocarbons having a number average molecular weight of 200 to 15,000 include, for example, liquid paraffin, paraffin wax, micro wax, polyethylene wax, Fischer-Tropsch wax, α-olefin oligomers having 3 to 12 carbon atoms, and the like. Here, the aliphatic hydrocarbons include alicyclic hydrocarbons. Further, these hydrocarbons may be partially oxidized. Among these, paraffin wax, polyethylene wax or a partial oxide of polyethylene wax is preferable, and paraffin wax and polyethylene wax are more preferable. Further, the number average molecular weight of the aliphatic hydrocarbon is preferably 5,000 or less. The aliphatic hydrocarbon may be a single substance, or may be a mixture of various components and molecular weights, as long as the main component is within the above range, it can be used.

[0090] Examples of the polysiloxane-based silicone oil include dimethyl silicone oil, methylphenyl silicone oil, diphenyl silicone oil, fluorinated alkyl silicone, and the like.

[0091] The compounding amount of the release agent is usually 0.001 part by mass or more, preferably 0.01 part by mass or more, and usually 2 parts by mass or less, preferably 1 part by mass or less, based on 100 parts by mass of the polycarbonate resin.

[0092] [Other additives, etc.] In addition, other additives other than those described above, for example, additives such as fluorescent brighteners, pigments, dyes, flame retardants, impact resistance improvers, antistatic agents, plasticizers, compatibilizers, or other polymers other than the polycarbonate resin can be contained. These additives may be blended singly or in combination of two or more. However, when containing other polymers other than the polycarbonate resin, the content thereof is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, further preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less, based on 100 parts by mass of the polycarbonate resin.

[0093] Molded article The polycarbonate resin molded article obtained in the present invention is particularly effective for manufacturing long molded articles such as light guiding members.

[0094] As optical components, in vehicle headlights (headlamps), rear lamps, fog lamps, etc. for vehicles such as automobiles or motorcycles, light guides, lenses, etc. that guide light from a light source such as an LED are also suitable, and the present invention can also be suitably used for these.

[0095] As optical components, particularly parts of devices and instruments that directly or indirectly utilize light sources such as LEDs, organic ELs, incandescent bulbs, fluorescent lamps, cathode ray tubes, etc. are exemplified, and light guide plates, members for surface light emitters, etc. are exemplified as typical ones. A light guide plate is for guiding light from a light source such as an LED in a liquid crystal backlight unit, various display devices, and lighting devices. The light introduced from the side or the back surface is diffused by the unevenness usually provided on the surface to emit uniform light. Its shape is usually flat, and it may or may not have unevenness on the surface. The light guide plate can be suitably used in the fields of liquid crystal backlight units, various display devices, and lighting devices. Examples of such devices include various portable terminals such as mobile phones, mobile notebooks, netbooks, slate PCs, tablet PCs, smartphones, tablet-type terminals, cameras, watches, notebook computers, various displays, lighting equipment, etc. In these, it can be particularly suitably used as a high-performance light guide plate, etc. In addition, the molded article of the present invention is also suitable for light guides, etc. Examples include light guides that efficiently guide the light incident from a light source on one side to the other using internal reflection, and it can also be suitably used for lighting light guides installed in vehicles (automobiles and trains) or airplanes.

Examples

[0096] Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not construed as being limited to the following examples.

[0097] (Example 1) As the injection molding machine, the "SE350" injection molding machine manufactured by Sumitomo Heavy Industries, Ltd., which is equipped with a metering feeder at the lower part of the hopper, was used. The diameter D of the screw is 63 mm, and the flight is a full flight. As the powdery and granular polycarbonate resin raw material, an undried product of "S-3000F" manufactured by Mitsubishi Engineering Plastics Corporation (Mv = 21000, median diameter D 50 = 750 μm, moisture content = 1640 ppm) was put into the hopper and fed to the opening of the injection molding machine at the metering feeder rotation speed (rpm) described in Table 1. At this time, 0.03 part by mass of a mold release agent, 0.1 part by mass of a phosphite-based antioxidant, 0.1 part by mass of a hindered phenol-based antioxidant, and 0.15 part by mass of a benzotriazole-based ultraviolet absorber were added to 100 parts by mass of the polycarbonate resin powder and granules, and the mixture was uniformly mixed in a tumbler mixer. Then, the mixture was put into the hopper 6 and fed. The operation was carried out with the rotation speed (rpm) and metering time (sec) of the feeder screw as described in Table 1. There were gaps between the flights and it was in a starving state, and the filling rate between the flights was as described in Table 1. As the set temperatures at the cylinder positions C1 and C2, melt kneading was performed, and at a molding temperature of 320 °C, injection molding was carried out on a sheet mold of 3 mm thickness × 150 mm × 380 mm (the set temperature of the mold was 80 °C) to produce a long optical path molded product.

[0098] Regarding the obtained long optical path molded product, in accordance with JIS K7105, using a SE6000 type spectrocolorimeter manufactured by Nippon Denshoku Industries Co., Ltd., by the reflection method under a D65 / 10° light source, L * 、a * 、b * were measured, and also YI (3.0 mm) and the total light transmittance (3.0 mm) were measured in accordance with ASTM D1925 in the transmission mode with a C light source and a 2° field of view.

[0099] In addition, the appearance of the long optical path molded product obtained above was visually observed, and the occurrence status of silver streaks was evaluated according to the following three criteria (〇, △, ×). 〇: Good △: Slight silver streak ×: Obvious silver streak The results are shown in Table 1 below.

[0100] (Example 2) In Example 1, except that the weighing time was set to the time described in Table 1, the set temperatures at positions C1 and C2 were made the same as those in Table 1, and the weighing (melting) in the hungry state was stabilized, the operation was carried out in the same manner.

[0101] (Example 3) In Example 2, except that the weighing time was further extended to the time described in Table 1 and the rotation speed of the feeder screw was decreased, the operation was carried out in the same manner.

[0102] (Example 4) In Example 1, except that the weighing time was set to the time described in Table 1, the set temperatures of C1 and C2 were made the same as those in Table 1, and the temperature gradient was reversed, the operation was carried out in the same manner.

[0103] (Example 5) In Example 4, except that the weighing time was made longer than the time described in Table 1 and the rotation speeds of the feeder screw and the screw were made the same as those described in Table 1, the operation was carried out in the same manner.

[0104] (Example 6) In Example 4, except that the weighing time was made even longer as described in Table 1 and the rotation speeds of the feeder screw and the screw were made the same as those described in Table 1, the operation was carried out in the same manner.

[0105] (Example 7) In Example 6, except that the weighing time was made even longer as described in Table 1 and the set temperatures of C1 and C2 were made the same as those in Table 1, the operation was carried out in the same manner.

[0106] (Comparative Example 1) In Example 1, the raw materials charged into the hopper were pellets of the following polycarbonate resin composition. "S-3000" (Mv = 21000) manufactured by Mitsubishi Engineering-Plastics Corporation, a mold release agent, a phosphite antioxidant, a hindered phenol antioxidant, and a benzotriazole ultraviolet absorber were uniformly mixed using a tumbler mixer so as to have the same composition as in Example 1. Then, using a twin-screw extruder ("TEX30α" manufactured by Japan Steel Works, Ltd.), they were fed into the extruder from the barrel at the upstream part of the extruder at a cylinder temperature of 260°C, a screw rotation speed of 200 rpm, and a discharge rate of 40 kg / hr, and melt-kneaded to obtain pellets of the polycarbonate resin composition (diameter 3 mm × length 3 mm). These dried pellets (moisture content 130 ppm) were charged into a hopper and fed into the opening of an injection molding machine at the screw feeder rotation speed (rpm) shown in Table 1. The operation was carried out with the screw rotation speed (rpm) and the metering time (sec) as shown in Table 1. There was no gap between the flights (hereinafter also referred to as standard feed), and the filling rate between these flights was set to 100%. The filling rates of other Examples and Comparative Examples were also indicated based on this 100% standard. Thereafter, in the same manner as in Example 1, long optical path molded products were manufactured and evaluated.

[0107] (Comparative Example 2) In Comparative Example 1, it was carried out in the same manner except that the metering time was made longer than the time shown in Table 1 and the feeder screw rotation speed and the screw rotation speed were as shown in Table 1.

[0108] (Comparative Example 3) In Comparative Example 2, it was carried out in the same manner except that undried pellets (moisture content 2400 ppm) were used as the pellets of the polycarbonate resin composition.

[0109] (Comparative Example 4) In Example 1, it was carried out in the same manner except that the rotation speed (rpm) of the feeder screw, the screw rotation speed, and the metering time (sec) were as shown in Table 1 and the conditions were close to the same standard feed as in Comparative Example 1. The above results are shown in Table 1 below.

[0110]

Table 1

Industrial Applicability

[0111] According to the method of the present invention, a polycarbonate resin molded article excellent in optical properties, particularly transparency and YI, can be produced, so the industrial applicability is very high.

Explanation of Signs

[0112] 1: Injection cylinder 2: Screw 3: Flight 4: Supply port 4 5: Feeder 6: Hopper 7: Injection nozzle 8: Heater for heating a: Granular powder s: Gap between flights

Claims

1. A method for manufacturing a molded article by directly injection molding a polycarbonate resin material containing polycarbonate resin powder using an injection molding machine having a hopper, a feeder, and an injection cylinder equipped with a screw, wherein the moisture content of the polycarbonate resin powder is 500 ppm or more, the polycarbonate resin material is charged from the hopper into the injection cylinder by the feeder and melt-kneaded so that a gap is formed between the flights of the injection cylinder screw. A method for manufacturing a polycarbonate resin molded article, characterized by this.

2. The manufacturing method according to claim 1, wherein the injection molding machine does not have a vent function or is not used.

3. The manufacturing method according to claim 1 or 2, wherein the gap between the flights of the injection cylinder screw is 13% by volume or more and 90% by volume or less as the filling rate of the polycarbonate resin material.

4. The manufacturing method according to claim 1 or 2, wherein a hue improver is added to the polycarbonate resin material in addition to the polycarbonate resin powder.

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