JP2015116742A - Method for producing polycarbonate resin molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method capable of producing a polycarbonate resin molded article having transparency free from coloration and transparency with clear feeling with low percent defective (%) of a molded article and high productivity.SOLUTION: The method for producing a molded article comprises introducing a polycarbonate resin including a structural unit derived from a specific dihydroxy compound into a molding machine provided with a cylinder and a screw where the polycarbonate resin is heated to a temperature equal to or higher than a glass transition temperature of the polycarbonate resin, melted and discharged. In the molding machine, the moisture percentage of the polycarbonate resin at an inlet of the molding machine is 0.01-0.1%.

Description

  The present invention relates to a method for producing a molded article of a polycarbonate resin with little coloring and low appearance defects such as silver streak.

  Generally, bisphenol compounds such as bisphenol A used as a monomer are produced from petroleum-derived raw materials in polycarbonate resins. However, in recent years, the concept of carbon neutral has become widespread due to an increase in environmental aspects, and can be obtained from biomass resources. A polycarbonate resin using a monomer as a raw material has been proposed. In particular, polycarbonate resins containing cyclic dihydroxy compound monomer units with an ether bond in the molecule, such as isosorbide made from sorbitol, a biomass resource, have excellent heat resistance, mechanical strength, transparency, and light resistance. It has been known.

  In addition, as a use of transparent resin, transparency with a clear feeling without yellowishness is required as a front protective plate or a housing protective cover of a display device of an information terminal device. Therefore, there are known attempts such as a method for producing an isosorbide-containing polycarbonate resin having a specific double bond terminal amount and a polycarbonate resin having a low formic acid content of isosorbide (see Patent Documents 1 and 2).

JP 2009-091405 A JP 2009-161745 A

  However, isosorbide has low thermal stability with respect to bisphenol compounds, which causes thermal degradation during melt polymerization during polycarbonate production and during melt plasticization during the production of molded polycarbonate resin products, resulting in coloring and poor appearance. To do. Therefore, when molding a polycarbonate resin using isosorbide as a raw material as described above, a molded product having a clear and transparent feeling without coloring at the time of molding cannot be obtained, and the defective rate (%) of the molded product is high. There was a problem of low productivity.

In addition, the resins obtained by the production methods described in Patent Documents 1 and 2 do not provide a clear transparency with no yellowishness, have a high defective rate (%) of molded products, and are highly productive. Was low.
The object of the present invention is to solve the above-mentioned conventional problems, and to produce a polycarbonate resin molded product having a clear transparency without coloring with a low defective rate (%) of the molded product and high productivity. It is to provide a method.

  As a result of intensive studies, the inventor determined the moisture content of the polycarbonate resin at the inlet of the molding machine when molding the polycarbonate resin containing a structural unit derived from the dihydroxy compound represented by the following formula (1). By controlling to a specific range, it has been found that the clear transparency without coloration is satisfied, the defective rate (%) of the molded product is low, and the molded product can be provided with high productivity. did.

That is, the gist of the present invention is as follows.
(1) A polycarbonate resin containing a structural unit derived from a dihydroxy compound represented by the following formula (1) is introduced into a molding machine equipped with a cylinder and a screw,
In a molding machine that heats, melts and releases the polycarbonate resin above its glass transition temperature,
A method for producing a molded article, wherein the moisture content of the polycarbonate resin at the inlet of the molding machine is 0.01 to 0.1%.

(2) The manufacturing method according to (1), wherein a cylinder temperature of the molding machine is 200 ° C. or higher and 260 ° C. or lower.
(3) The production method according to (1) or (2), wherein the polycarbonate resin contains a catalyst deactivator.
(4) The production method according to any one of (1) to (3), wherein the polycarbonate resin contains a phosphorus compound as a catalyst deactivator.
(5) The production method according to any one of (1) to (4), wherein the polycarbonate resin contains a bluing agent.
(6) The manufacturing method according to any one of (1) to (5), wherein the molding machine is a molding machine capable of injection molding or extrusion molding.
(7) The manufacturing method according to any one of (1) to (6), wherein an oxygen concentration at an inlet of the molding machine is 21% or less.

  The method for producing a polycarbonate resin molded product of the present invention can provide a molded product having a clear transparency without coloration, and a molded product with few appearance defects such as silver streak. is there. Therefore, the obtained molded product can be applied as a transparent molded product such as a front protective plate or a housing protective cover of a display device of an information terminal device.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the invention will be described in detail below, but the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention. The content is not limited.

<Polycarbonate resin>
The polycarbonate resin used in the present invention is a polycarbonate resin containing a structural unit derived from a dihydroxy compound represented by the following general formula (1).

The dihydroxy compound represented by the general formula (1) has a stereoisomeric relationship.
Examples include isosorbide, isomide, and isoidet, and these may be used alone or in combination of two or more.
Among them, isosorbide obtained by dehydration condensation of sorbitol, which is abundant as a plant-derived resource and is produced from a number of readily available starches, is easy to obtain and manufacture, moldability, heat resistance, impact resistance Most preferable from the viewpoints of properties, surface hardness, and carbon neutral.

  The ratio of the structural unit derived from the dihydroxy compound represented by the general formula (1) to the structural unit derived from all the dihydroxy compounds constituting the polycarbonate resin used in the present invention is preferably 90 mol% or less, more preferably It is 85 mol% or less, particularly preferably 80 mol% or less. On the other hand, it is preferably at least 20 mol%, more preferably at least 30 mol%, particularly preferably at least 40 mol%.

When the proportion of the structural unit derived from the dihydroxy compound represented by the general formula (1) is in the above range, the water absorption rate of the polycarbonate can be controlled, and the moisture content (weight%) during molding can be prevented from increasing. Therefore, it is preferable. Further, the various properties of the polycarbonate resin are in a preferable range, and a favorable molded product is obtained, which is preferable.
Since the dihydroxy compound represented by the general formula (1) has a cyclic ether structure, it is likely to be gradually oxidized by oxygen. Therefore, during storage and production, in order to prevent decomposition by oxygen, water should not be mixed, It is important to use an oxygen scavenger and handle under a nitrogen atmosphere. When isosorbide is oxidized, decomposition products such as formic acid may be generated. For example, when isosorbide containing these decomposition products is used as a raw material for polycarbonate resin, it may cause coloring of the obtained polycarbonate resin, and may not only significantly deteriorate the physical properties but also affect the polymerization reaction. In some cases, a high molecular weight polymer cannot be obtained.

As structural units other than the structural unit derived from the dihydroxy compound represented by the general formula (1), ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3 -Structural units derived from aliphatic dihydroxy compounds such as butanediol, 1,2-butanediol, 1,5-heptanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexane Dimethanol, 1,2-cyclohexanedimethanol, tricyclodecane dimethanol, pentacyclopentadecane dimethanol, 2,6-decalin dimethanol, 1,5-decalin dimethanol, 2,3-decalin dimethanol, 2,3 -Norbornane dimethanol, 2,5-norbornane dimethanol, 1,3 Structural units derived from alicyclic dihydroxy compounds such as adamantanedimethanol, 2,2-bis (4-hydroxyphenyl) propane [= bisphenol A], 2,2-bis (4-hydroxy-3,5-dimethylphenyl) ) Propane, 2
, 2-bis (4-hydroxy-3,5-diethylphenyl) propane, 2,2-bis (4-hydroxy- (3,5-diphenyl) phenyl) propane, 2,2-bis (4-hydroxy-3) , 5-Dibromophenyl) propane, 2,2-bis (4-hydroxyphenyl) pentane, 2,4′-dihydroxy-diphenylmethane, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-5-nitrophenyl) Methane, 1,1-bis (4-hydroxyphenyl) ethane, 3,3-bis (4-hydroxyphenyl) pentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, 2,4′-dihydroxydiphenylsulfone, bis (4-hydroxyphenyl) sulfide, 4,4′-dihydro Sidiphenyl ether, 4,4′-dihydroxy-3,3′-dichlorodiphenyl ether, 9,9-bis (4- (2-hydroxyethoxy-2-methyl) phenyl) fluorene, 9,9-bis (4-hydroxyphenyl) ) A structural unit derived from an aromatic bisphenol compound such as fluorene or 9,9-bis (4-hydroxy-2-methylphenyl) fluorene may be included.

  Among them, from the viewpoint of light resistance of a molded article made of a polycarbonate resin, a structural unit derived from a dihydroxy compound having no aromatic ring in the molecule, that is, a structural unit derived from an aliphatic dihydroxy compound and / or an alicyclic dihydroxy compound. In particular, as the aliphatic dihydroxy compound, 1,3-propanediol, 1,4-butanediol, and 1,6-hexanediol are preferable, and as the dihydroxy compound of the alicyclic hydrocarbon, In particular, 1,4-cyclohexanedimethanol and tricyclodecane dimethanol are preferable.

  The ratio of structural units other than the structural unit derived from the dihydroxy compound represented by the general formula (1) to the structural units derived from all the dihydroxy compounds constituting the polycarbonate resin used in the present invention is preferably 80 mol% or less. More preferably, it is at most 70 mol%, particularly preferably at most 60 mol%. On the other hand, it is preferably at least 10 mol%, more preferably at least 15 mol%, particularly preferably at least 20 mol%.

When the proportion of the structural unit derived from the dihydroxy compound represented by the general formula (1) is in the above range, the water absorption rate of the polycarbonate can be controlled, and the moisture content (weight%) during molding can be prevented from increasing. Therefore, it is preferable. Further, the various properties of the polycarbonate resin are in a preferable range, and a favorable molded product is obtained, which is preferable.
The structural unit other than the structural unit derived from the dihydroxy compound represented by the general formula (1) is preferably less than 50 mol% of the structural unit derived from all the dihydroxy compounds of the polycarbonate resin, and less than 40 mol%. More preferably.

The polycarbonate resin used in the present invention can be produced by a generally used production method, and the production method may be any of a solution polymerization method using phosgene and a melt polymerization method of reacting with a carbonic acid diester. A melt polymerization method in which a dihydroxy compound is reacted with a diester carbonate having lower toxicity to the environment in the presence of a polymerization catalyst is preferred.
In addition, as a polymerization catalyst (transesterification catalyst) in melt polymerization, a known alkali metal compound and / or alkaline earth metal compound is used. It is also possible to use a basic compound such as a basic boron compound, a basic phosphorus compound, a basic ammonium compound, and an amine compound together with an alkali metal compound and / or an alkaline earth metal compound.

As the polymerization reaction, a known method can be used, and any method of a batch method, a continuous method, or a combination of a batch method and a continuous method may be used.
Examples of the carbonic acid diester used in the melt polymerization method include those represented by the following general formula (2). These carbonic acid diesters may be used alone or in combination of two or more.

(In the general formula (2), A ^1, A ² is an aliphatic or optionally substituted aromatic group having 1 to 18 carbon atoms which may have a substituent group, A ¹ And A ² may be the same or different.)
Examples of the carbonic acid diester represented by the general formula (2) include substituted diphenyl carbonates such as diphenyl carbonate and ditolyl carbonate; dimethyl carbonate, diethyl carbonate and di-t-butyl carbonate. Among these, diphenyl carbonate and substituted diphenyl carbonate are preferable, and diphenyl carbonate is particularly preferable.

  In the melt polymerization method described above, the carbonic acid diester represented by the general formula (2) is 0.90 to 1 with respect to all dihydroxy compounds including at least the dihydroxy compound represented by the general formula (1) used in the reaction. The molar ratio is preferably 10.10, and more preferably 0.96 to 1.04. When the molar ratio of the carbonic acid diester used in the melt polymerization method is excessively small, the terminal hydroxyl group of the produced polycarbonate resin increases, the thermal stability of the polymer deteriorates, and the desired molecular weight tends not to be obtained. On the other hand, if the molar ratio of the carbonic acid diester used is excessively large, the rate of the polycondensation reaction decreases under the same polymerization conditions, and it tends to be difficult to produce a polycarbonate resin having a desired molecular weight.

  A method in which a dihydroxy compound represented by the general formula (I) and / or a dihydroxy compound containing a dihydroxy compound other than the dihydroxy compound represented by the general formula (1) is reacted with a carbonic acid diester in the presence of a polymerization catalyst. Usually, it is preferably carried out in a multistage process of two or more stages. Specifically, the first stage reaction is carried out at a temperature of 140 ° C. to 220 ° C., preferably 150 ° C. to 200 ° C. for 0.1 hour to 10 hours, preferably 0.5 hour to 3 hours. In the second and subsequent stages, the reaction temperature is raised while gradually reducing the pressure of the reaction system from the pressure in the first stage, and the aromatic monohydroxy compound such as phenol that is generated at the same time is removed from the reaction system. Specifically, the polycondensation reaction is performed under a temperature range of 210 ° C. to 280 ° C. under a reaction system pressure of 200 Pa or less.

  In the pressure reduction in the polycondensation reaction, it is important to control the balance between temperature and pressure in the reaction system. In particular, if either one of the temperature and the pressure changes excessively quickly, unreacted monomers are distilled out, the molar ratio of the dihydroxy compound and the carbonic acid diester is changed, and the degree of polymerization may be lowered. For example, when isosorbide and 1,4-cyclohexanedimethanol are used as the dihydroxy compound, 1,4-cyclohexanedimethanol is used when the molar ratio of 1,4-cyclohexanedimethanol exceeds 50 mol% with respect to the total dihydroxy compound. Since methanol easily distills out as a monomer, the reaction is carried out under a reduced pressure of about 13 kPa while the temperature is increased at a rate of temperature increase of 40 ° C. or less per hour, and further up to about 6.67 kPa. When the polycondensation reaction is performed at a temperature of 200 ° C. to 250 ° C. at a pressure of 200 Pa or less at a temperature rising rate of 40 ° C. or less per hour under the pressure of Since the raised polycarbonate resin is obtained, it is preferable.

  When producing a polycarbonate resin, it is desirable to install a filter in the production process of the polycarbonate resin to remove the foreign matter in order to prevent foreign matters from entering. The position of the filter is preferably, for example, during the polycondensation reaction or after the completion of the polycondensation reaction, and the opening of the filter is usually preferably 100 μm or less, more preferably 40 μm or less, and more preferably 10 μm or less as a 99% removal filtration accuracy. preferable.

The polycarbonate resin is usually extruded and pelletized after being kneaded with various additives by an extruder or the like at the final stage of production, and in order to prevent foreign matters from being mixed, the pelletization is preferably JIS B 9920. It is desirable to implement in a clean room having a higher degree of cleanliness than class 7, as defined in (2002), more preferably class 6.
Moreover, when cooling and pelletizing the extruded polycarbonate resin, it is preferable to use a cooling method such as air cooling or water cooling. The air used for air cooling is preferably air from which foreign substances in the air have been removed in advance with a hepa filter or the like to prevent reattachment of foreign substances in the air. When using water cooling, it is preferable to use water from which metal in water has been removed with an ion exchange resin or the like, and further, foreign matter in water has been removed with a filter. The opening of the filter to be used is preferably 10 μm to 0.45 μm as 99% removal filtration accuracy.

The yellowness index of the polycarbonate resin used in the present invention is preferably 5 or less. Further, it is more preferably 3 or less. If the yellowness index is greater than 5, the blueness is lost, the clearness is lost, and the transparency may be lowered.
The molecular weight of the polycarbonate resin used in the present invention can be represented by a reduced viscosity, and the reduced viscosity is usually preferably 0.30 dL / g or more, and more preferably 0.35 dL / g or more. The upper limit of the reduced viscosity is preferably 1.20 dL / g or less, more preferably 1.00 dL / g or less, and still more preferably 0.80 dL / g or less.

If the reduced viscosity of the polycarbonate resin is too low, the impact resistance of the molded product may be small, and if the reduced viscosity is too large, the fluidity when molding the molded product will be reduced, resulting in productivity and moldability. There is a tendency to lower. In addition, the molding temperature must be higher than appropriate, and the color tone may deteriorate.
The reduced viscosity is measured using a Ubbelohde viscometer at a temperature of 20.0 ° C. ± 0.1 ° C., precisely prepared at a polycarbonate concentration of 0.6 g / dL using methylene chloride as a solvent.

  The glass transition temperature of the polycarbonate resin used in the present invention is preferably 80 ° C. or higher and 145 ° C. or lower, more preferably 90 ° C. or higher and 135 ° C. or lower, and particularly preferably 100 ° C. or higher and 125 ° C. or lower. If the glass transition temperature is less than 80 ° C., the heat resistance is insufficient, and if it exceeds 145 ° C., the fluidity is insufficient at the time of molding, and the resin composition is not filled to the end of the product, or the strength at the weld part is reduced. Sometimes.

  The polycarbonate resin used in the present invention may contain a catalyst deactivator that deactivates a polymerization catalyst (transesterification catalyst) in melt polymerization. Although it will not specifically limit if it is a substance which has the deactivation function of a polymerization catalyst as a catalyst deactivator, For example, an acidic compound and a phosphorus compound are mentioned.

  Examples of acidic compounds include hydrochloric acid, nitric acid, boric acid, sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, adipic acid, ascorbic acid, aspartic acid, azelaic acid, adenosine phosphoric acid, benzoic acid Acid, formic acid, valeric acid, citric acid, glycolic acid, glutamic acid, glutaric acid, cinnamic acid, succinic acid, acetic acid, tartaric acid, oxalic acid, p-toluenesulfinic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, nicotinic acid , Bronsted acids such as picric acid, picolinic acid, phthalic acid, terephthalic acid, propionic acid, benzenesulfinic acid, benzenesulfonic acid, malonic acid, maleic acid, and esters thereof. Among these acidic compounds or derivatives thereof, sulfonic acids or esters thereof are preferable, and p-toluenesulfonic acid, methyl p-toluenesulfonate, and butyl p-toluenesulfonate are particularly preferable.

  The phosphorus compound includes at least one selected from the group consisting of phosphoric acid, phosphorous acid, phosphonic acid, hypophosphorous acid, polyphosphoric acid, phosphonic acid ester, acidic phosphoric acid ester, and aliphatic cyclic phosphite ester. It is preferable to use it. Among them, phosphorous acid, phosphonic acid, and phosphonic acid ester are more excellent in catalyst deactivation and coloring suppression effects, and phosphonic acid ester is particularly preferable.

  Examples of phosphonic acid include phosphonic acid (phosphorous acid), methylphosphonic acid, ethylphosphonic acid, vinylphosphonic acid, decylphosphonic acid, phenylphosphonic acid, benzylphosphonic acid, aminomethylphosphonic acid, methylenediphosphonic acid, 1-hydroxyethane- Examples include 1,1-diphosphonic acid, 4-methoxyphenylphosphonic acid, nitrilotris (methylenephosphonic acid), and propylphosphonic anhydride.

Examples of phosphonates include dimethyl phosphonate, diethyl phosphonate, bis (2-ethylhexyl) phosphonate, dilauryl phosphonate, dioleyl phosphonate, diphenyl phosphonate, dibenzyl phosphonate, dimethyl methylphosphonate, diphenyl methylphosphonate, and ethylphosphonic acid. Diethyl, diethyl benzylphosphonate, dimethyl phenylphosphonate, diethyl phenylphosphonate, dipropyl phenylphosphonate, diethyl (methoxymethyl) phosphonate, diethyl vinylphosphonate, diethyl hydroxymethylphosphonate, dimethyl (2-hydroxyethyl) phosphonate, p-methylbenzylphosphonate diethyl, diethylphosphonoacetic acid, diethylphosphonoacetic acid ethyl, diethylphosphonoacetic acid tert-butyl, (Robenzyl) diethyl phosphonate, diethyl cyanophosphonate, diethyl cyanomethylphosphonate, diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, diethylphosphonoacetaldehyde diethyl acetal, diethyl (methylthiomethyl) phosphonate Can be mentioned.

  Acid phosphate esters include dimethyl phosphate, diethyl phosphate, divinyl phosphate, dipropyl phosphate, dibutyl phosphate, bis (butoxyethyl) phosphate, bis (2-ethylhexyl) phosphate, diisotridecyl phosphate, phosphate Examples include phosphoric acid diesters such as dioleyl, distearyl phosphate, diphenyl phosphate, and dibenzyl phosphate, or mixtures of diesters and monoesters, diethyl chlorophosphate, and zinc stearyl phosphate.

  An aliphatic cyclic phosphite is defined as a phosphite compound that does not contain an aromatic group in a cyclic structure containing a phosphorus atom. For example, bis (decyl) pentaerythritol diphosphite, bis (tridecyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, bis (2,6-tert-butylphenyl) pentaerythritol diphosphite, bis (nonyl) Phenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, Examples thereof include a polymer type compound composed of a dihydroxy compound such as hydrogenated bisphenol A / pentaerythritol phosphite polymer and pentaerythritol diphosphite.

Of these, phosphorus-based compounds are preferred as the catalyst deactivator.
These may be used alone or in a combination of two or more in any combination and ratio.
These catalyst deactivators can be added in the production process of the polycarbonate resin as a compound that neutralizes the basic transesterification catalyst used in the polycondensation reaction of the polycarbonate resin described above.

The addition amount of the catalyst deactivator used in the present invention is at least one kind of 0.00001 part by weight or more and 1 part by weight or less, preferably 0.0001 part by weight or more and 0.1 part by weight with respect to 100 parts by weight of the polycarbonate resin. Hereinafter, it is more preferably 0.0002 parts by weight or more and 0.05 parts by weight or less.
In particular, when the catalyst deactivator is a phosphorus compound, the content of the phosphorus compound is preferably 1 ppm by weight or more and 8 ppm by weight or less as the content of phosphorus atoms in the polycarbonate resin. .2 ppm by weight to 7 ppm by weight is preferable, and 1.5 ppm by weight to 6 ppm by weight is particularly preferable.

The polycarbonate resin used in the present invention may contain an antioxidant. Various antioxidants commonly used for resins can be used as the antioxidant. From the viewpoints of oxidation stability, thermal stability, retention colorability at the time of molding, etc., phosphite-based antioxidants, sulfur-based antioxidants Antioxidants and phenolic antioxidants are preferred.
Here, the addition amount of the antioxidant is usually 0. 100 parts by weight of the polycarbonate resin.
001 parts by weight or more, preferably 0.002 parts by weight or more, more preferably 0.005 parts by weight or more, and usually 5 parts by weight or less, preferably 3 parts by weight or less, more preferably 2 parts by weight or less.
If the amount of the antioxidant added is more than 5 parts by weight, the mold may be contaminated during molding, and a molded product having an excellent surface appearance may not be obtained. When the amount is less than 0.001 part by weight, there is a tendency that a sufficient improvement effect for the weather resistance test cannot be obtained.

(Phosphite antioxidant)
Phosphite antioxidants include triphenyl phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) 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, bis (2,6-di-tert- Butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, bis (nonylphenyl) pentaerythritol Diphosphite, bis (2,4-di -tert- butylphenyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, and the like.

  Among these, trisnonylphenyl phosphite, trimethyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite is preferably used. These compounds can be used alone or in combination of two or more.

(Sulfur-based antioxidant)
Examples of the sulfur-based antioxidant include dilauryl-3,3′-thiodipropionate, ditridecyl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, diester Stearyl-3,3′-thiodipropionate, laurylstearyl-3,3′-thiodipropionate, pentaerythritol tetrakis (3-laurylthiopropionate), bis [2-methyl-4- (3 -Laurylthiopropionyloxy) -5-tert-butylphenyl] sulfide, octadecyl disulfide, mercaptobenzimidazole, 2-mercapto-6-methylbenzimidazole, 1,1′-thiobis (2-naphthol) and the like. . Among the above, pentaerythritol tetrakis (3-lauryl thiopropionate) is preferable.

(Phenolic antioxidant)
Examples of the phenolic antioxidant include pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-laurylthiopropionate), glycerol-3-stearylthiopropionate, triethylene glycol-bis [ 3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] , Pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1 , 3,5-trimethyl-2 4,6-tris (3,5-di-tert-bull-4-hydroxybenzyl) benzene, N, N-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 4,4′-biphenylenediphosphinic acid tetrakis ( 2,4-di-tert-butylphenyl), 3,9-bis {1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} -2,4,8,10-tetraoxaspiro (5,5) undecane, 2,6-di-tert-butyl-p-cresol, 2 Compounds such as 6-di -tert- butyl-4-ethyl phenol.

  Among these compounds, an aromatic monohydroxy compound substituted with one or more alkyl groups having 5 or more carbon atoms is preferable. Specifically, octadecyl-3- (3,5-di-tert-butyl-4- Hydroxyphenyl) propionate, pentaerythrityl-tetrakis {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate}, 1,6-hexanediol-bis [3- (3,5-di- tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene and the like, preferably pentaerythris Lithyl-tetrakis {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate is more preferred.

<Release agent>
The polycarbonate resin composition of the present invention preferably further contains a release agent in order to further improve the releasability from the mold during melt molding.
Release agents include higher fatty acids, higher fatty acid esters of mono- or polyhydric alcohols, natural animal waxes such as beeswax, natural plant waxes such as carnauba wax, natural petroleum waxes such as paraffin wax, and montan wax. Natural coal wax, olefin wax, silicone oil, organopolysiloxane and the like can be mentioned, and higher fatty acid and higher fatty acid ester of monohydric or polyhydric alcohol are particularly preferable.

  The higher fatty acid ester is preferably a partial ester or a total ester of a substituted or unsubstituted monovalent or polyhydric alcohol having 1 to 20 carbon atoms and a substituted or unsubstituted saturated fatty acid having 10 to 30 carbon atoms. . Such partial esters or total esters of monohydric or polyhydric alcohols and saturated fatty acids include stearic acid monoglyceride, stearic acid diglyceride, stearic acid triglyceride, stearic acid monosorbite, stearyl stearate, behenic acid monoglyceride, behenyl behenate, Pentaerythritol monostearate, pentaerythritol tetrastearate, pentaerythritol tetrapelargonate, propylene glycol monostearate, stearyl stearate, palmityl palmitate, butyl stearate, methyl laurate, isopropyl palmitate, biphenyl biphenate Sorbitan monostearate, 2-ethylhexyl stearate, ethylene glycol distearate, etc. That. Of these, stearic acid monoglyceride, stearic acid triglyceride, pentaerythritol tetrastearate, behenyl behenate, and ethylene glycol distearate are preferably used.

As the higher fatty acid, a substituted or unsubstituted saturated fatty acid having 10 to 30 carbon atoms is preferable. Examples of such saturated fatty acids include myristic acid, lauric acid, palmitic acid, stearic acid, behenic acid and the like.
One of these release agents may be used alone, or two or more thereof may be mixed and used.
The content of the mold release agent is preferably 0.0001 parts by weight or more, more preferably 0.01 parts by weight or more, particularly preferably 0.1 parts by weight or more, on the other hand, preferably 100 parts by weight of the polycarbonate resin. 1 part by weight or less, more preferably 0.7 part by weight or less, particularly preferably 0.5 part by weight or less.
If the amount of the release agent added is more than 1 part by weight, the mold may be contaminated during molding, and a molded product having an excellent surface appearance may not be obtained. If it is less than 0.0001 part by weight, there is a tendency that a sufficient improvement effect cannot be obtained at the time of mold release during molding.

<Bluing agent>
Examples of bluing agents include C.I. I. Monoazo dyes represented by Solvent Violet 21, C.I. I. A triarylmethane dye represented by Solvent Blue 2, C.I. I. Phthalocyanine dyes represented by Solvent Blue 25, C.I. I. Solvent Violet 13 [CA. Anthraquinone dyes represented by No. 60725] and the like. Among these, anthraquinone dyes are preferable. In the present invention, “CI” means Color Index Number (color index number).

Specific examples of the bluing agent preferably used in the present invention include C.I. I. Solvent Violet 13 (e.g., "Malexex (registered trademark) Violet B" manufactured by LANXESS, "Diaresin (registered trademark) Blue G" manufactured by Mitsubishi Chemical Corporation, "Sumiplus (registered trademark) Violet B" manufactured by Sumika Chemtex, etc.); C. I. Solvent Violet 14; C.I. I. Solvent Violet 31 (e.g. "Diaresin (registered trademark) Violet D" manufactured by Mitsubishi Chemical Corporation); I. Solvent Violet 33 (e.g. "Diaresin (registered trademark) Blue J" manufactured by Mitsubishi Chemical Corporation); I. Solvent Violet 36 (e.g., "Macrolex (registered trademark) Violet 3R" manufactured by LANXESS); I. Solvent Blue 35 (eg, “Sumiplus (registered trademark) Blue S” manufactured by Sumika Chemtex Co., Ltd.); I. Solvent
Blue 45 (e.g., "Tetrazole (registered trademark) Blue RLS" manufactured by Sand Corp.); I. Solvent Blue 78 (for example, “Sumiplus (registered trademark) Blue GP” manufactured by Sumika Chemtex Co., Ltd.); I. Solvent Blue 87 (e.g. Disperse (registered trademark) Violet 28, "Sumiplus (registered trademark) Blue SR" manufactured by Sumika Chemtex Co., Ltd.)); I. Solvent Blue 94 (e.g. "Diaresin (registered trademark) Blue N" manufactured by Mitsubishi Chemical Corporation); I. Solvent Blue 97 (for example, “Macrolex (registered trademark) Blue RR” manufactured by LANXESS) and the like.

Among the bluing agents mentioned above, C.I. I. Solvent Blue 87, C.I. I. Solvent Violet 13, C.I. I. Solvent Blue 35 and C.I. I. Solvent Blue78.
The blueing agents mentioned above may be used alone or in combination of two or more. However, it is preferable that the amount of the bluing agent used is small, and it is preferable that the type of bluing agent used is small.

<Other additives>
Further, in the range not impairing the effect of the present invention, a neutralizer, ultraviolet absorber, light stabilizer, mold release agent, antistatic agent, lubricant, lubricant, pigment, plasticizer, compatibilizer, flame retardant, etc. It can also be added.
In addition, glass fiber, glass milled fiber, glass flake, glass beads, silica, alumina, titanium oxide, calcium sulfate powder, gypsum, gypsum whisker, barium sulfate, talc, mica, wax, and the like within the range not impairing the effects of the present invention. Calcium silicates such as rustonite; carbon black, graphite, iron powder, copper powder, molybdenum disulfide, silicon carbide, silicon carbide fiber, silicon nitride, silicon nitride fiber, brass fiber, stainless steel fiber, potassium titanate fiber, whisker, etc. Inorganic fillers and powdered organic fillers such as wood powder, bamboo powder, coconut starch, cork powder, pulp powder; balun / spherical organic fillers such as crosslinked polyester, polystyrene, styrene / acrylic copolymer, urea resin ; Add fibrous organic fillers such as carbon fiber, synthetic fiber, natural fiber, etc. And it can also be.

  In the present embodiment, the mixing timing and mixing method of the catalyst deactivator, bluing agent, antioxidant and other additives to be blended with the polycarbonate resin are not particularly limited. As the mixing time, for example, when the polycarbonate resin is produced by the transesterification method, at the end of the polymerization reaction; and regardless of the polymerization method, the polycarbonate resin in the middle of kneading the polycarbonate resin and other compounding agents is melted A case where it is blended and kneaded with a polycarbonate resin in a solid state such as pellets or powder using an extruder or the like. As a mixing method, a method of directly mixing or kneading the acid value inhibitor with a polycarbonate resin; a high-concentration master batch prepared using a small amount of a polycarbonate resin or other resin and an antioxidant or the like may be used. it can.

The molding machine used in the present invention is provided with a cylinder and a screw. Polycarbonate resin is supplied from the inlet of the cylinder and is melted in the cylinder by the cylinder and screw heated to a temperature higher than the glass transition temperature of the polycarbonate resin. This is a device for discharging the molten polycarbonate resin from the tip of the cylinder.
Such a molding machine is preferably a molding machine capable of injection molding or extrusion molding, depending on the shape and dimensions of the molded product, and more specifically, an injection molding machine, an injection compression molding machine, a sheet and a film molding machine. , Pipe, round bar and profile extrusion molding machine, monofilament molding machine, injection blow molding machine, direct blow molding machine and the like. Among these, an injection molding machine and an injection compression molding machine are preferable.

  The cylinder temperature of the molding machine used in the present invention is preferably 200 ° C. or higher and 260 ° C. or lower, and more preferably 220 ° C. or higher and 250 ° C. or lower. When the cylinder temperature is less than 200 ° C., the flowability of the polycarbonate resin is low, and in the case of injection molding, the mold may not be sufficiently filled with the polycarbonate resin and a molded product may not be obtained. On the other hand, when the cylinder temperature is higher than 260 ° C., the polycarbonate resin is remarkably colored due to the retention, and the obtained molded product does not have a clear and clear transparency without coloring.

  The method for producing a molded article of the present invention is characterized in that the moisture content of the polycarbonate resin at the inlet of the cylinder of the molding machine, that is, the raw material hopper is 0.01 to 0.15% by weight. The moisture content is more preferably 0.02 to 0.07% by weight, and further preferably 0.03 to 0.05% by weight. When the moisture content of the polycarbonate resin at the cylinder inlet of the molding machine is less than 0.01% by weight, the obtained molded product is colored and does not become a molded product having a clear and transparent feeling. Further, when the moisture content is 0.15% by weight or more, appearance defects such as silver streak are observed in the obtained molded product.

The moisture content of the polycarbonate resin can be measured using a Karl Fischer micro moisture meter. In detail, it is the method of the Example mentioned later.
The method for controlling the moisture content at the molding machine inlet of the polycarbonate resin of the present invention is, for example, drying the polycarbonate resin with a resin dryer such as a shelf-type box dryer or a vacuum dryer and supplying the polycarbonate resin to the molding machine cylinder inlet. Alternatively, the polycarbonate resin may be dried using a raw material hopper with a dryer and supplied to the molding machine cylinder inlet. The drying temperature of the polycarbonate resin is 80 ° C. or higher and glass transition temperature + 5 ° C. or lower, preferably 85 ° C. or higher and glass transition temperature or lower, and 90 ° C. or higher and glass transition temperature −5 ° C. or lower is more preferable.

The drying time of the polycarbonate resin of the present invention varies depending on the drying temperature and the like, but is usually 1 hour or more and 8 hours or less. More preferably, it is more preferably 2 hours or more and 7 hours or less, and 3 hours or more and 6 hours or less. When the drying time is less than 1 hour, the appearance of the molded product may be poor. When the drying time is longer than 8 hours, the polycarbonate resin pellets are colored.
In the method for producing a molded article of the present invention, it is preferable to manage the oxygen concentration at the inlet (hopper) of the cylinder of the molding machine by purging with nitrogen or the like.

The oxygen concentration at the cylinder inlet of the molding machine of the present invention is preferably 21% by volume or less. More preferably, it is 20.5 volume% or less. If the oxygen concentration at the inlet of the molding machine is greater than 21% by volume, the resulting molded product may be colored.
The oxygen concentration at the inlet (hopper part) of the molding machine can be measured with an oxygen concentration meter.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by a following example, unless the summary is exceeded.
In the following, physical properties or characteristics of resin molded products were evaluated by the following methods.

1) Moisture content of polycarbonate resin Using the Karl Fischer micro moisture meter (model CA-200: manufactured by Dia Instruments Co., Ltd.), the polycarbonate resin obtained in the examples was heated to 220 ° C. while being heated to a high purity nitrogen. The flow rate is adjusted to 200 ml / min, and the test apparatus is started up. After 0.1 to 0.2 g of polycarbonate resin was weighed with an electronic balance, the measurement was started by putting it in a tray in the heating unit. The temperature was raised from room temperature to 220 ° C. at a rate of 5 ° C./min and measured.

2) Yellowness index of molded product The polycarbonate resin obtained in the examples was 75 mm at a cylinder temperature of 210 to 240 ° C. and a mold of 70 ° C. using an in-line injection molding machine (company name: Toshiba Machine, model: EC75SX). A x50 mm three-stage plate (1, 2, 3 mmt) was molded. The obtained three-stage plate was conditioned at room temperature for 24 hours, and then the yellowness index (YI) was measured using a colorimetric color difference meter (ZE-2000: manufactured by Nippon Denshoku Industries Co., Ltd.).
In addition, YI is a thing with little coloration and light resistance, so that it is a value close | similar to 0.

3) Defect rate of molded product 2) Ten shots were visually inspected with a three-stage plate (1, 2, 3 mmt) molded for measuring the yellowness index of the molded product, and the number of silver streak occurrences was divided by the number of inspections. The value was defined as the defective rate.

4) Oxygen concentration at the molding machine inlet (hopper part) The oxygen concentration at the molding machine inlet (hopper part) was measured with an oxygen concentration meter (model: JKO-25 Co., Ltd.). In all Examples and Comparative Examples, the content was 20.0 to 20.5% by volume.
Hereinafter, the abbreviations of the compounds used in Examples and Comparative Examples are as follows.

<Polycarbonate resin raw material>
ISB: Isosorbide (Rocket Fleure, trade name POLYSORB PS)
CHDM: 1,4-cyclohexanedimethanol (manufactured by SK Chemical Co.)
DPC: Diphenyl carbonate (Mitsubishi Chemical Corporation)
<Polycarbonate resin>
A-PC: Polycarbonate resin (Mitsubishi Chemical Corporation, Novalex M7022J)

<Antioxidant>
AO-1: Phosphite antioxidant (Tris (2,4-di-tert-butylphenyl) phosphite (manufactured by ADEKA, trade name: ADK STAB 2112))
AO-2: Phenolic antioxidant (pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], manufactured by BASF Japan Ltd., trade name: Irganox 1010)

<Release agent>
E-275: Ethylene glycol distearate (manufactured by NOF Corporation, trade name: Unistar E-275)

<Catalyst deactivator>
PTSB: p-toluenesulfonic acid ester (manufactured by Tokyo Chemical Industry Co., _{Ltd., CH 3 C 6 H 4 SO} 3 (CH 2) 3 CH 3)
JPE208: Bis (2-ethylhexyl) hydrogen phosphite (Johoku Chemical Co., Ltd., trade name: JPE-208)

[Production Example 1] Polycarbonate resin A (PC resin A)
Polycarbonate resin was polymerized using a continuous polymerization facility comprising three vertical stirring reactors, one horizontal stirring reactor, and a twin screw extruder. ISB, CHDM, and DPC were respectively melted in tanks and continuously fed to the first vertical stirring reactor so that the molar ratio was ISB / CHDM / DPC = 0.500 / 0.500 / 1.005. . At the same time, an aqueous solution of calcium acetate monohydrate as a catalyst was supplied to the first vertical stirring reactor so as to be 1.5 μmol with respect to 1 mol of all dihydroxy compounds. The liquid level was kept constant while controlling the opening degree of the valve provided in the transfer pipe at the bottom of the reactor so that the average residence time in the first vertical stirring reactor was 90 minutes. The reaction liquid discharged from the bottom of the reactor was continuously continuously supplied to the second vertical stirring reactor, the third vertical stirring reactor, and the fourth horizontal stirring reactor. The reaction temperature, internal pressure and residence time of each reactor are as follows: first vertical stirring reactor: 190 ° C., 25 kPa, 90 minutes, second vertical stirring reactor: 195 ° C., 10 kPa, 45 minutes, third vertical type Stirring reactor: 210 ° C., 3 kPa, 45 minutes, fourth horizontal stirring reactor: 225 ° C., 0.5 kPa, 90 minutes. The operation was carried out while finely adjusting the internal pressure of the fourth horizontal stirring reactor so that the reduced viscosity of the obtained polycarbonate resin was 0.61 dL / g to 0.64 dL / g.

  The molten polycarbonate resin was extracted from the fourth horizontal stirring reactor, and then the resin was supplied in a molten state to a twin screw extruder. The extruder had three vacuum vents, and the remaining low molecular components in the resin were removed by devolatilization. From before the first vent, 12 times molar equivalent of JPE208 relative to the amount of catalytic metal was added. Water was added 2,000 ppm by weight with respect to the resin before the second vent, and water injection was devolatilized. From the front of the third vent, 500 ppm by weight of ADK STAB 2112, 1000 ppm by weight of Irganox 1010, and 3000 ppm by weight of Unistar E-275 were added to the polycarbonate resin.

  The polycarbonate resin that passed through the extruder was subsequently filtered through the filter while in a molten state, and then discharged from the die into strands, cooled with water, and pelletized with a rotary cutter.

[Production Example 2] Polycarbonate resin B (PC resin B)
Reduction of polycarbonate resin obtained by continuously supplying ISB / CHDM / DPC to the first vertical stirring reactor so that the molar ratio of ISB / CHDM / DPC = 0.700 / 0.300 / 1.008 The viscosity was adjusted from 0.41 dL / g to 0.44 dL / g. Further, the same procedure as in Production Example 1 was conducted except that the supply of the catalyst deactivator added before the first vent was stopped and the catalyst deactivator (JPE208) was not added.

[Example 1]
The obtained polycarbonate resin A pellets were dried at 90 ° C. for 1 hour using a dryer (Company name: Matsui Seisakusho, Model: PO-80). The dried polycarbonate resin pellets were supplied to the hopper of the above-described injection molding machine, a part was taken out for moisture content measurement, and the moisture content was measured. Further, a three-stage plate was molded, and the yellowness index and the defective rate at the time of molding were calculated by the method described above.
The results are shown in Table 1.

[Example 2]
The catalyst deactivator was used under the same conditions as in Example 1 except that “12 times molar equivalent of JPE208” to “equal molar phosphorous acid” was added to the amount of catalyst metal.
The results are shown in Table 1.

[Example 3]
It carried out on the conditions similar to Example 1 except not having added a catalyst deactivator.
The results are shown in Table 1.

[Example 4]
The test was performed under the same conditions as in Example 3 except that the polycarbonate resin was changed from the PC resin A to the PC resin B.
The results are shown in Table 1.

[Comparative Example 1]
The test was performed under the same conditions as in Example 1 except that the PC resin A that had been dried to reduce the moisture content was replaced with the undried PC resin A.
The results are shown in Table 1.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that the polycarbonate resin A (PC resin A) was changed to A-PC and the cylinder temperature of the molding conditions was changed from 250 ° C to 280 ° C. In addition, NOVAREX M7022J used as A-PC does not contain ADK STAB 2112, Irganox 1010 and Unistar E-275, and PTSB as a catalyst deactivator is added 5.6 times by mole with respect to the amount of catalyst metal. ing.
The results are shown in Table 1.

[Comparative Example 3]
The test was carried out under the same conditions as in Example 4 except that the PC resin B that had been dried to reduce the water content was replaced with the undried PC resin B.
The results are shown in Table 1.

  From Table 1 above, the examples of the present application, in which the amount of moisture is defined in comparison with the examples and the comparative examples, have a YI of the molded product close to 0 and a lower defect rate (%) of the molded product than the comparative examples. Good productivity.

  The method for producing a molded article of the polycarbonate resin of the present invention has not only a appearance defect such as silver streak but also a molded article having transparency with no clearness of coloration, as well as heat resistance, impact resistance and Since it has light resistance, the obtained molded product can be applied as a transparent molded product such as a front protective plate or a housing protective cover of a display device of an information terminal device.

Claims (7)

A polycarbonate resin containing a structural unit derived from a dihydroxy compound represented by the following formula (1) is introduced into a molding machine equipped with a cylinder and a screw,
In a molding machine that heats, melts and releases the polycarbonate resin above its glass transition temperature,
A method for producing a molded article, wherein the moisture content of the polycarbonate resin at the inlet of the molding machine is 0.01 to 0.1%.

  The manufacturing method according to claim 1, wherein a cylinder temperature of the molding machine is 200 ° C. or more and 260 ° C. or less.   The production method according to claim 1 or 2, wherein the polycarbonate resin contains a catalyst deactivator.   The production method according to any one of claims 1 to 3, wherein the polycarbonate resin contains a phosphorus compound as a catalyst deactivator.   The production method according to claim 1, wherein the polycarbonate resin contains a bluing agent.   The manufacturing method according to claim 1, wherein the molding machine is a molding machine capable of injection molding or extrusion molding.   The manufacturing method according to claim 1, wherein an oxygen concentration at an inlet of the molding machine is 21% or less.