JP6702615B2 - Polycarbonate resin composition and optical molded article - Google Patents

Description

The present invention relates to a polycarbonate resin composition and an optical molded article.

Aromatic polycarbonate has excellent transparency, mechanical properties, thermal properties, electrical properties, weather resistance, etc., and makes full use of these properties to guide light members (such as light guides for daytime running lights and light guide plates for liquid crystals). It is used for optical molded products such as lens, optical fiber and so on. However, the light transmittance, which is one of the indicators of its transparency, is lower than that of polymethylmethacrylate (PMMA) and the like, and when used for a light guide member, the brightness tends to be low. Therefore, development of a method for increasing the brightness and the light transmittance of the light guide member made of aromatic polycarbonate is underway.

In Patent Document 1, for the purpose of providing a polycarbonate resin composition for a light guide plate which is free from cloudiness and a decrease in transmittance and has a good transmittance and a hue, polyethylene glycol and polypropylene glycol are used with respect to an aromatic polycarbonate resin. There is disclosed an aromatic polycarbonate resin composition for a light guide plate, which contains a polyoxyalkylene glycol or a fatty acid ester thereof mainly composed of.
However, in the method of Patent Document 1, since the heat resistance of polyoxyalkylene glycol is low, if the molding is performed at a temperature higher than 320° C. or if the molding cycle is long, the yellowing is increased, and the brightness and the light transmittance are increased. The optical performance of the light guide product may be adversely affected. Further, when molded at a temperature exceeding 340° C., decomposition gas of polyoxyalkylene glycol causes silver marks on the surface of the molded product, and the function as a light guide product cannot be achieved. For this reason, it is difficult to mold a thin-walled, large-area light guide plate because the temperature is limited to increase in order to increase fluidity, and polycarbonate is used as a molding material for some small light guide plates that are molded at a low temperature of about 280°C. The use of the resin composition is limited, its practical range is narrow, and it is not sufficient.

Patent Document 2 discloses an aromatic polycarbonate resin composition which is polyoxygenated with an aromatic polycarbonate resin composition for the purpose of providing an aromatic polycarbonate resin composition capable of withstanding the shortage of heat resistance, which is a drawback of the method of Patent Document 1, and capable of withstanding molding at high temperatures. An aromatic polycarbonate resin composition prepared by blending tetramethylene polyoxyethylene glycol is disclosed. According to the method of Patent Document 2, molding can be performed in the temperature range of 280° C. or higher and 340° C. or lower without yellowing.

On the other hand, Patent Document 3 provides a resin composition which is excellent in heat stability during high-temperature molding, is excellent in light transmittance and brightness, and is capable of obtaining a molded product that does not cause discoloration or internal cracks after a moisture heat resistance test. For that purpose, an aromatic polycarbonate resin composition in which an aromatic polycarbonate resin contains a specific diphosphite compound and an alicyclic epoxy compound is disclosed. According to the method of Patent Document 3, it is possible to mold at a temperature exceeding 340° C. without yellowing.
In addition, depending on the use of the light guide member, it may be required that the yellowing is small even when used for a long period of time under high temperature and high humidity conditions.

Japanese Patent No. 4069364 International Publication No. 2011/083635 International Publication No. 2013/088796

The problem to be solved by the present invention is to provide a polycarbonate resin composition in which optical characteristics are not deteriorated due to deterioration during molding even when molded in a wide temperature range.
Another object of the present invention is to provide a polycarbonate resin composition capable of obtaining a light guide member which is less likely to turn yellow even when used for a long period of time under severe environmental conditions for automotive applications and whose light guide performance is not deteriorated.

As a result of intensive studies, the inventors of the present invention have added a specific amount of a specific phosphorus compound and polycaprolactone polyol, which are excellent in heat resistance and hydrolysis resistance, to an aromatic polycarbonate resin in a wide temperature range. It has been found that it is possible to obtain a polycarbonate resin composition which is free from deterioration in optical properties due to deterioration during molding even when molded with. Furthermore, the optical lens molded with the present polycarbonate resin composition maintains higher optical performance than the polycarbonate resin composition containing no polycaprolactone polyol even in a severe environmental test such as 1,000 hours in a 120° C. oven. The present invention has been completed and the present invention has been completed.
That is, the present invention relates to the following polycarbonate resin composition, method for producing an optical molded article, and optical molded article.

<1> A polycarbonate resin composition containing an aromatic polycarbonate resin (A), a phosphorus-based compound (B) having an aryl group, and a polycaprolactone polyol (C),
With respect to 100 parts by mass of the aromatic polycarbonate resin (A), 0.005 parts by mass or more and 1 part by mass or less of the phosphorus compound (B) and 0.005 parts by mass or more and 5 parts by mass or less of the polycaprolactone polyol (C). Containing
In the phosphorus compound (B), the amount of the compound having a phenol structure generated by decomposing after 1,500 hours when left at 40° C. and humidity of 90% is the same as the phosphorus compound (B). On the other hand, the compound is 5% by mass or less,
The phosphorus compound (B) has a temperature of 340 at which the weight decreases by 2% from the weight before measurement when the weight is measured using a differential thermal-thermogravimetric (TG-DTA) machine under a nitrogen atmosphere. A polycarbonate resin composition, which is a compound having a temperature of not less than °C.
<2> The polycarbonate resin composition according to <1>, further containing 5 parts by mass or less of the polyether compound (D) represented by the following formula (1) with respect to 100 parts by mass of the aromatic polycarbonate resin (A). ..
R ^D3 O-(R ^D1 O) _m (R ^D2 O) _n -R ^D4 (1)
(In the formula, R ^D1 and R ^D2 represent an alkylene group having 1 or more carbon atoms, and R ^D1 and R ^D2 may be the same or different. m+n is 5 or more and less than 300. When m is 2 or more And R ^D1 may be the same or different, and when n is 2 or more, R ^D2 may be the same or different, and R ^D3 and R ^D4 are a hydrogen atom and have 1 carbon atom. A hydrocarbon group having 30 to 30 carbon atoms, an alkanoyl group having 1 to 30 carbon atoms, an alkenoyl group having 2 to 30 carbon atoms or a glycidyl group are shown, and R ^D3 and R ^D4 may be the same or different.
<3> The polycarbonate resin composition according to <1> or <2>, wherein the aromatic polycarbonate resin (A) is a polycarbonate whose main chain has a repeating unit represented by the following general formula (I).

(In the formula, R ^A1 and R ^A2 represent an alkyl group or an alkoxy group having 1 to 6 carbon atoms, and R ^A1 and R ^A2 may be the same or different. X is a single bond, C 1 or more. 8 following an alkylene group, having 2 to 8 alkylidene group having a carbon, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, -S -, - SO -, - SO 2 - , -O- or -CO-, and a and b each independently represent an integer of 0 or more and 4 or less, and when a is 2 or more, R ^A1 may be the same or different, and b is 2 In the above cases, R ^A2 may be the same or different.)
<4> The polycarbonate resin composition according to any one of <1> to <3>, wherein the phosphorus compound (B) is a phosphorus compound having a phosphite structure.
<5> The polycarbonate resin composition according to any one of <1> to <4>, wherein the phosphorus compound (B) is a pentaerythritol diphosphite compound represented by the following general formula (II). object.

(In the formula, Y ^{1 to} Y ⁴ represent a hydrocarbon group having 6 to 15 carbon atoms and may be the same or different.)
<6> Y ^{1 to} Y ⁴ in the formula (II) are each independently a cumyl group which may be unsubstituted or substituted, a phenyl group which may be unsubstituted or substituted, or an unsubstituted or substituted phenyl group. Is a naphthyl group which may be substituted, or a biphenyl group which may be unsubstituted or substituted, The polycarbonate resin composition according to <5> above.
<7> The polycarbonate according to any one of <1> to <6>, wherein the phosphorus compound (B) is a pentaerythritol diphosphite compound represented by the following general formula (II-1). Resin composition.

(In the formula, R ^{B1 to} R ^B8 represent an alkyl group or an alkenyl group, and may be the same or different. R ^B1 and R ^B2 , R ^B3 and R ^B4 , R ^B5 and R ^B6 , and R ^B7 R ^B8 may combine with each other to form a ring, R ^{B9 to} R ^B12 represent a hydrogen atom or an alkyl group, and may be the same or different, and m1 to m4 are integers of 0 or more and 5 or less. Z ^{1 to} Z ⁴ represent a single bond or a carbon atom, and may be the same or different, and when Z ^{1 to} Z ⁴ represent a single bond, R ^{B1 to} R ^B8 are generally Excluded from formula (II-1).)
<8> The polycarbonate resin composition according to any one of <1> to <7>, wherein the phosphorus compound (B) is bis(2,4-dicumylphenyl)pentaerythritol diphosphite. ..
<9> The polycaprolactone polyol (C) is at least one selected from the group consisting of polycaprolactone diols, polycaprolactone triols and polycaprolactone tetraols having a molecular weight of 500 or more and 5,000 or less, <1. > To <8>, the polycarbonate resin composition according to any one of.
<10> The polyether compound (D) is a polyether compound in which R ^D1 and R ^D2 in the formula (1) are alkylene groups having 2 to 5 carbon atoms and R ^D3 and R ^D4 are hydrogen atoms. The polycarbonate resin composition according to any one of the above items <2> to <9>.
<11> The polycarbonate resin composition according to any one of <1> to <10>, wherein the aromatic polycarbonate resin (A) has a viscosity average molecular weight (Mv) of 9,000 or more and 50,000 or less. ..
<12> A method for producing an optical molded article, which comprises molding the polycarbonate resin composition according to any one of <1> to <11>.
<13> An optical molded product obtained by the manufacturing method according to <12>.
<14> An optical molded article including the polycarbonate resin composition according to any one of <1> to <11>.
<15> The optical molded article according to <13> or <14>, wherein the optical molded article is a light guide member.
<16> The optical molded article according to any one of <13> to <15>, wherein the optical molded article is a light guide component for a vehicle.
<17> A light guide component for a vehicle, which is used for a daytime running lamp and is formed of the molded article according to <16>.
<18> A daytime running light containing the optical molded article according to <16>.

According to the present invention, there is no deterioration in optical properties due to deterioration during molding even when molded in a wide temperature range, and a polycarbonate resin composition that shows little yellowing deterioration even after long-term use under severe environmental conditions, and an optical molded article. It is possible to provide a manufacturing method and an optical molded article.

The present invention will be described below. In addition, in this invention, the combination of a preferable aspect is a more preferable aspect.

Depending on the use of the light guide member, there are cases where thinning is required, and there is a case where the polycarbonate resin composition is molded at a temperature higher than 340°C, particularly higher than 360°C. From this point of view, the method of International Publication No. 2011/083635 is not sufficient and further improvement is required.
On the other hand, the daylight lamps called Daytime Running Lights (or Daytime Running Lamps) (DRL for short), which are attached to the outer circumferences of automobile headlights and taillights, are light guide rings with a thick lens structure. The DRL having such a thick structure is often molded at a low temperature of around 280°C. The reason is that since the DRL has a thick structure, if the cooling time is not taken sufficiently, the product surface will be drawn or contracted and distortion will occur, so it is necessary to take a long molding cycle. If the molding cycle is long and the molding temperature is high, the molten resin remaining in the molding machine will be burnt. Therefore, it is necessary to lower the molding temperature as much as possible to prevent the residue burning. Further, in order to suppress the burning, there are many examples in which the burning is prevented while performing nitrogen molding or the like in which the air inside the molding machine is replaced with nitrogen. As described above, the polycarbonate resin used for the light guiding application is required to have a performance capable of being molded without yellowing even in the molding requiring a wide temperature range and a long residence time.

In addition, for optical polycarbonate resins used for automobiles such as DRL, strict environmental tests such as heat-resistant oven tests at 120° C. for 1000 hours or more are performed. Polyether polyols such as those disclosed in Japanese Patent No. 4069364, International Publication No. 2011/083635, and International Publication No. 2013/088796 show remarkable effects in improving optical performance, but have low long-term heat resistance. However, there is a drawback that the optical performance remarkably deteriorates in a severe environmental test such as a 120° C. oven test. This is a problem of the heat resistance of the polyether polyols themselves, so that the heat resistance performance cannot be improved by other additives. Therefore, a polycarbonate resin composition that can be used for an optical lens for an automobile can only rely on the optical performance of the polycarbonate itself, but there is a strong demand for improvement in brightness and blue phase.

The present inventors provide a polycarbonate resin composition that meets the performances and demands in each of the above applications.
The polycarbonate resin composition of the present invention is a polycarbonate resin composition containing an aromatic polycarbonate resin (A), a phosphorus-based compound (B) having an aryl group, and a polycaprolactone polyol (C), wherein the aromatic polycarbonate resin (A) containing 0.005 parts by mass or more and 1 part by mass or less of the phosphorus compound (B) and 0.005 parts by mass or more and 5 parts by mass or less of the polycaprolactone polyol (C) with respect to 100 parts by mass, and The phosphorus compound (B) has an amount of a compound having a phenol structure which is decomposed and generated after 1500 hours when left standing under the conditions of 40° C. and a humidity of 90% is 5 relative to the phosphorus compound (B). When the weight of the phosphorus-based compound (B) is measured using a differential thermal-thermogravimetric (TG-DTA) machine under a nitrogen atmosphere, the phosphorus-based compound (B) is 2% from the weight before the measurement. % Weight loss temperature is 340° C. or higher.

[Component (A): aromatic polycarbonate resin]
The aromatic polycarbonate resin (A) contained in the polycarbonate resin composition of the present invention is not particularly limited, and those produced by a known method can be used.
For example, a product produced by reacting a dihydric phenol and a carbonate precursor by a solution method (interfacial polycondensation method) or a melting method (transesterification method), that is, a dihydric phenol and phosgene in the presence of a terminal stopper. It is preferable to use as the aromatic polycarbonate resin (A), an interfacial polycondensation method of reacting with or a product produced by reacting a dihydric phenol with diphenyl carbonate or the like by a transesterification method or the like in the presence of a terminal terminating agent. it can.

As the dihydric phenol, various ones can be mentioned, but in particular, 2,2-bis(4-hydroxyphenyl)propane [bisphenol A], bis(4-hydroxyphenyl)methane, 1,1-bis(4 -Hydroxyphenyl)ethane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl)cycloalkane, bis(4-hydroxyphenyl) Examples thereof include oxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide and bis(4-hydroxyphenyl)ketone. In addition to these, hydroquinone, resorcin, catechol and the like can also be mentioned. These may be used alone or in combination of two or more, and of these, bis(hydroxyphenyl)alkane type is preferable, and bisphenol A is particularly preferable.

The carbonate precursor is carbonyl halide, carbonyl ester, haloformate, or the like, and specifically, phosgene, dihaloformate of dihydric phenol, diphenyl carbonate, dimethyl carbonate, diethyl carbonate, or the like.
In the present invention, the component (A) may have a branched structure, and as the branching agent, 1,1,1-tris(4-hydroxyphenyl)ethane, α,α′,α″-tris is used. Examples include (4-hydroxyphenyl)-1,3,5-triisopropylbenzene, phloroglucin, trimellitic acid, and 1,3-bis(o-cresol).

As the terminal terminator, a monovalent carboxylic acid and its derivative, or a monovalent phenol can be used. For example, p-tert-butyl-phenol, p-phenylphenol, p-cumylphenol, p-perfluorononylphenol, p-(perfluorononylphenyl)phenol, p-(perfluorohexylphenyl)phenol, p- tert-perfluorobutylphenol, 1-(p-hydroxybenzyl)perfluorodecane, p-[2-(1H,1H-perfluorotridodecyloxy)-1,1,1,3,3,3-hexafluoropropyl ] Phenol, 3,5-bis(perfluorohexyloxycarbonyl)phenol, perfluorododecyl p-hydroxybenzoate, p-(1H,1H-perfluorooctyloxy)phenol, 2H,2H,9H-perfluorononanoic acid , 1,1,1,3,3,3-hexafluoro-2-propanol and the like.

The aromatic polycarbonate resin (A) is preferably a polycarbonate whose main chain has a repeating unit represented by the following general formula (I).

(In the formula, R ^A1 and R ^A2 each independently represent an alkyl group or an alkoxy group having 1 to 6 carbon atoms, and R ^A1 and R ^A2 may be the same or different. X is a single bond or carbon number. 1 to 8 alkylene group, 2 to 8 carbon alkylidene group, 5 to 15 carbon cycloalkylene group, 5 to 15 carbon cycloalkylidene group, -S-, -SO-, -SO _2- , -O- or -CO- is shown, and a and b are each independently an integer of 0 or more and 4 or less, and when a is 2 or more, R ^A1 may be the same or different, and b is When two or more, R ^A2 may be the same or different.)

The alkyl group represented by R ^A1 and R ^A2 includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and various butyl groups (the term “various” includes linear and all branched chain groups). And the same shall apply hereinafter), various pentyl groups, and various hexyl groups. ^Examples of the alkoxy group represented by R ^A1 and R ^A2 include the case where the alkyl group moiety is the above alkyl group.
^Each of R ^A1 and R ^A2 is preferably an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms.

Examples of the alkylene group represented by X include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a hexamethylene group, and an alkylene group having 1 to 5 carbon atoms is preferable. Examples of the alkylidene group represented by X include an ethylidene group and an isopropylidene group. Examples of the cycloalkylene group represented by X include a cyclopentanediyl group, a cyclohexanediyl group and a cyclooctanediyl group, and a cycloalkylene group having 5 to 10 carbon atoms is preferable. Examples of the cycloalkylidene group represented by X include a cyclohexylidene group, a 3,5,5-trimethylcyclohexylidene group, a 2-adamantylidene group, and the like, and a cycloalkylidene group having 5 to 10 carbon atoms. Is preferred, and a cycloalkylidene group having 5 to 8 carbon atoms is more preferred.
a and b each independently represent an integer of 0 or more and 4 or less, preferably 0 or more and 2 or less, and more preferably 0 or 1.

In the present invention, the aromatic polycarbonate resin (A) preferably contains a polycarbonate resin having a bisphenol A structure from the viewpoint of transparency, mechanical properties, thermal properties, etc. of the obtained molded product. Specific examples of the polycarbonate resin having a bisphenol A structure include those of the general formula (I) in which X is an isopropylidene group. The content of the polycarbonate resin having a bisphenol A structure in the aromatic polycarbonate resin (A) is preferably 50% by mass or more and 100% by mass or less, more preferably 75% by mass or more and 100% by mass or less, and further preferably 85% by mass. It is 100 mass% or less.

In the present invention, the viscosity average molecular weight (Mv) of the component (A) is preferably 9,000 or more and 50,000 or less, more preferably 10,000 or more and 30,000 or less, and further preferably 11 from the viewpoint of fluidity. It is 2,000 or more and 25,000 or less. In particular, when the polycarbonate resin composition of the present invention is used as a thin-walled optical molded product such as a light guide plate, the Mv of the aromatic polycarbonate resin (A) is preferably 9,000 or more and 17,000 or less.
In the present invention, this viscosity average molecular weight (Mv) is determined by measuring the viscosity of a methylene chloride solution (concentration unit: g/L) at 20° C. using an Ubbelohde viscometer and determining the intrinsic viscosity [η] from this. , Is calculated by the following formula.
[Η]=1.23×10 ⁻⁵ Mv ^0.83

[Component (B): Phosphorus Compound Having Aryl Group]
The phosphorus-based compound (B) having an aryl group contained in the polycarbonate resin composition of the present invention has a phenol structure which is decomposed and generated after 1,500 hours when left standing under the conditions of 40° C. and a humidity of 90%. The compound has an amount of 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less with respect to the phosphorus compound (B). That is, the phosphorus-based compound (B) having an aryl group used in the present invention is excellent in hydrolysis resistance and produces a small amount of a compound having a phenol structure. The amount of the above-mentioned compound having a phenol structure can be quantified by a gas chromatograph, and is specifically measured by the method described in Examples.
The phosphorus compound (B) contained in the polycarbonate resin composition of the present invention is the weight before measurement when the weight is measured by using a differential thermal-thermogravimetric (TG-DTA) machine under a nitrogen atmosphere. The temperature at which the weight is reduced by 2% is 340° C. or higher. In the present specification, the temperature at which the weight decreases by 2% is also referred to as "98% holding temperature".
Here, the temperature at which the weight is reduced by 2% is preferably 345°C or higher, and more preferably 350°C or higher.

A conventional phosphite-based antioxidant having a pentaerythritol diphosphite structure exhibits a good antioxidant action at a processing temperature of a usual polycarbonate resin, but causes thermal decomposition at a high temperature exceeding 340°C, Sudden loss of antioxidant action. Further, thermal decomposition causes yellowing itself to occur, and thus insufficient heat resistance is a problem. In addition, many phosphite antioxidants are easily hydrolyzed, and in the heat resistance test of the light guide plate, the antioxidant in the light guide plate is hydrolyzed, and the light guide plate is discolored or clouded due to the influence of the decomposed product. Problem is likely to occur. In WO 2013/088796, a specific compound represented by bis(2,4-dicumylphenyl)pentaerythritol diphosphite is used as an antioxidant capable of satisfying both required properties of heat resistance and hydrolysis resistance. It has been disclosed that diphosphite antioxidants are effective.
However, the method of WO 2013/088796 requires an alicyclic epoxy compound from the viewpoint of resistance to moist heat. Further, according to this method, although the thermal stability during high temperature molding is excellent, sufficient performance cannot be exhibited in the molding temperature range of less than 300°C.
The present inventors have used a specific phosphorus compound (B) and a polycaprolactone polyol (C) in combination, whereby a polycarbonate resin composition which does not deteriorate in optical characteristics due to deterioration during molding even when molded in a wide temperature range. I found that I can get things.

The phosphorus-based compound (B) having an aryl group used in the present invention is preferably a phosphorus-based compound having a phosphite structure, more preferably a pentaerythritol diphosphite compound represented by the following general formula (II). Is.

(In the formula, Y ^{1 to} Y ⁴ represent a hydrocarbon group having 6 to 15 carbon atoms and may be the same or different.)

Y ^{1 to} Y ⁴ are preferably each independently unsubstituted or substituted cumyl group, unsubstituted or optionally substituted phenyl group, unsubstituted or optionally substituted naphthyl group, or unsubstituted It is a biphenyl group which may be substituted or substituted.

The phosphorus compound (B) used in the present invention is preferably a pentaerythritol diphosphite compound represented by the following general formula (II-1).

(In the formula, R ^{B1 to} R ^B8 represent an alkyl group or an alkenyl group and may be the same or different. R ^B1 and R ^B2 , R ^B3 and R ^B4 , R ^B5 and R ^B6 , R ^B7 and R ^B8 may combine with each other to form a ring, R ^{B9 to} R ^B12 represent a hydrogen atom or an alkyl group, and may be the same or different, and m1 to m4 are integers of 0 or more and 5 or less. Z ^{1 to} Z ⁴ represent a single bond or a carbon atom, and may be the same or different, and when Z ^{1 to} Z ⁴ represent a single bond, R ^{B1 to} R ^B8 are generally Excluded from formula (II-1).)

R ^{B1 to} R ^B8 preferably have 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and most preferably 1 carbon atom. R ^{B9 to} R ^B12 are preferably hydrogen atoms. m1 to m4 are preferably 0 or more and 3 or less, more preferably 0 or more and 1 or less, and most preferably 0. Z ^{1 to} Z ⁴ are preferably carbon atoms.

The pentaerythritol diphosphite compound represented by the general formula (II) or (II-1) is obtained by adding a chlorine-based solvent to phosphorus trichloride and pentaerythritol to obtain pentaerythritol dichlorophosphite, and then using an aromatic compound. It can be obtained by heating and mixing in the presence of a solvent and an organic nitrogen-containing basic compound (for example, see JP-A-2004-018406).

Among the pentaerythritol diphosphite compounds represented by the above general formula (II) or (II-1), it is possible to satisfactorily impart heat resistance and hydrolysis resistance to the polycarbonate resin composition, and obtain it. Bis(2,4-dicumylphenyl)pentaerythritol diphosphite represented by the following formula (II-2) is particularly preferable because it is easy. This compound is commercially available, and for example, "Doverphos (registered trademark) S-9228PC" manufactured by Dover Chemical can be used.

The heat resistance of a general pentaerythritol diphosphite compound is measured by a differential thermal-thermogravimetric (TG-DTA) machine in a nitrogen atmosphere at a 98% holding temperature of 240°C or higher and 280°C or lower. is there. In contrast, bis(2,4-dicumylphenyl)pentaerythritol diphosphite shown above has a 98% holding temperature of 340°C or higher. Since it has such heat resistance, its performance is not impaired even at high temperature molding at 340° C. or higher. Rather, molding at a high temperature tends to activate the antioxidant effect.
The hydrolysis of the polycarbonate resin molded body is caused mainly by the free phenol and phosphoric acid produced by the hydrolysis of the phosphorus-based antioxidant contained therein. For this reason, if a phosphorus-based antioxidant that is easily hydrolyzed is used, the polycarbonate molded body itself is hydrolyzed to lower the molecular weight and become clouded.
The phosphorus-based compound (B) having an aryl group used in the present invention has an amount of free phenol and phosphoric acid generated by hydrolysis after 1,500 hours when left standing at 40° C. and a humidity of 90%. It is 1/100 or less as compared with a general compound having a pentaerythritol diphosphite structure. Since it is excellent in hydrolysis resistance as described above, even if it is stored for a long period of time, the hydrolyzate does not enter, and hydrolysis is unlikely to occur even after being incorporated into the molded body. Therefore, the molded product using the polycarbonate resin composition containing the phosphorus compound (B) can be stably used for a long period of time without deteriorating the optical characteristics.

The content of the phosphorus-based compound (B) having an aryl group in the aromatic polycarbonate resin of the present invention is from the viewpoint of obtaining a polycarbonate resin composition in which optical characteristics are not deteriorated due to deterioration during molding even when molded in a wide temperature range. , 0.005 parts by mass or more and 1 part by mass or less, preferably 0.01 parts by mass or more and 0.8 parts by mass or less, more preferably 0.03 parts by mass with respect to 100 parts by mass of the aromatic polycarbonate resin (A). Or more and 0.5 parts by mass or less, more preferably 0.03 parts by mass or more and 0.3 parts by mass or less.

[Component (C): Polycaprolactone Polyol]
The polycaprolactone polyol can be obtained by ring-opening polymerization of a lactone monomer using a polyhydric alcohol as an initiator.
Specific examples of the polyhydric alcohol include, for example, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-. Propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3 -Pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, glycerin, tri Methylolpropane, trimethyloloctane, pentaerythritol and the like can be mentioned.
Examples of the lactone monomer include ε-caprolactone, α-methyl-ε-caprolactone, β-methyl-ε-caprolactone, γ-methyl-ε-caprolactone, β,δ-dimethyl-ε-caprolactone, 3,3,5-trimethyl. Caprolactones such as -ε-caprolactone; polyvalerolactones such as δ-valerolactone and β-methyl-δ-valerolactone; propiolactones; butyrolactones; enanthlactone; dodecanolactone and the like. It may be a derivative of a lactone monomer.

As the polycaprolactone polyol (C), those described in paragraph [0016] of JP-A No. 11-228905 can be exemplified. As this polycaprolactone polyol, for example,

(In the formula, m+n is an integer of 4 or more and 35 or less, and R is C ₂ H ₄ , C ₂ H ₄ OC ₂ H ₄ , or C(CH ₃ ) ₂ (CH ₂ ) ₂ )
Bifunctional polycaprolactone diols such as

(In the formula, l+m+n is an integer of 3 or more and 30 or less, and R is CH ₂ CHCH ₂ , CH ₃ C(CH ₂ ) ₃ , or CH ₃ CH ₂ C(CH ₂ ) ₃ )
Such trifunctional polycaprolactone triols and tetrafunctional polycaprolactone tetraol can be used. The polycaprolactone polyol (C) is preferably at least one selected from the group consisting of the above polycaprolactone diol, polycaprolactone triol and polycaprolactone tetraol. The molecular weight (number average molecular weight) is in the range of 500 or more and 5,000 or less, preferably 850 or more and 4,000 or less, and more preferably 1,000 or more and 3,000 or less. When the molecular weight is less than 500, the heat resistance is low and it cannot be applied during high temperature molding. If the molecular weight exceeds 5,000, it solidifies and does not dissolve easily, making it difficult to handle. When the molecular weight is about 10,000, it can be pelletized as a thermoplastic resin, but it is difficult to disperse in the polycarbonate, the compatibility with the antioxidant (B) is poor, and the color tone deteriorates.

Specific examples of the polycaprolactone polyol (C) include commercially available products such as "Plaxel 205", "Plaxel 208", "Plaxel 210", "Plaxel 210CP", and "Plaxel 212" manufactured by Daicel Corporation. , "Plaxel 220", "Plaxel 220 CPB" (polycaprolactone diol), "Plaxel 305", "Plaxel 308", "Plaxel 312", "Plaxel 320" (polycaprolactone triol), "Plaxel 410" (polycaprolactone tetra) All) etc. The polycaprolactone polyol is preferably polycaprolactone diol.
The content of the polycaprolactone polyol (C) in the aromatic polycarbonate resin of the present invention is 0.005 parts by mass or more and 5 parts by mass or less, preferably 0.01 parts by mass with respect to 100 parts by mass of the aromatic polycarbonate resin (A). Parts by mass to 5 parts by mass, more preferably 0.02 parts by mass to 3 parts by mass, still more preferably 0.03 parts by mass to 2 parts by mass, still more preferably 0.1 parts by mass to 2 parts by mass. , And most preferably 0.3 part by mass or more and 1.5 parts by mass or less.

[Component (D): Polyether Compound Having Polyoxyalkylene Structure]
The polycarbonate resin composition of the present invention preferably contains a polyether compound (D) having a polyoxyalkylene structure. The polyether compound (D) is a compound represented by the following formula (1).
R ^D3 O-(R ^D1 O) _m (R ^D2 O) _n -R ^D4 (1)
(In the formula, R ^D1 and R ^D2 represent an alkylene group having 1 or more carbon atoms, and R ^D1 and R ^D2 may be the same or different. m+n is 5 or more and less than 300. m is 2 or more. In this case, R ^D1 may be the same or different, and R ^D2 may be the same or different when n is 2 or more: R ^D3 and R ^D4 are a hydrogen atom and have 1 or more carbon atoms. A hydrocarbon group having 30 or less, an alkanoyl group having 1 to 30 carbon atoms, an alkenoyl group having 2 to 30 carbon atoms, or a glycidyl group is shown, and R ^D3 and R ^D4 may be the same or different.)

R ^D1 and R ^D2 preferably have 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, and most preferably 1 to 5 carbon atoms. For example, methylene group, ethylene group, trimethylene group, propylene group, tetramethylene group, hexamethylene group and the like can be mentioned.
The polyoxyalkylene group represented by (R ^D1 O) _m is not limited to those having a single oxyalkylene unit such as a polyoxyethylene group or a polyoxypropylene group as a repeating unit, and may include an oxyethylene unit and an oxypropylene group. It may have a plurality of oxyalkylene units having different carbon numbers such as units as repeating units.
The polyoxyalkylene group represented by (R ^D2 O) _m is not limited to those having a single oxyalkylene unit such as a polyoxyethylene group or a polyoxypropylene group as a repeating unit, and may include an oxyethylene unit and an oxypropylene group. It may have a plurality of oxyalkylene units having different carbon numbers such as units as repeating units.

Examples of the hydrocarbon group having 1 to 30 carbon atoms represented by R ^D3 and R ^D4 include an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, and an aryl group having 6 to 30 carbon atoms. Alternatively, an aralkyl group having 7 to 30 carbon atoms can be used.
The alkyl group and alkenyl group may be linear, branched or cyclic, and include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, various butyl groups, various pentyl groups, various hexyl groups. , Various octyl groups, cyclopentyl groups, cyclohexyl groups, allyl groups, propenyl groups, various butenyl groups, various hexenyl groups, various octenyl groups, cyclopentenyl groups, cyclohexenyl groups and the like. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group and the like. Examples of the aralkyl group include a benzyl group, a phenethyl group, a methylbenzyl group and the like.
The alkanoyl group having 1 to 30 carbon atoms represented by R ^D3 and R ^D4 may be linear or branched and includes, for example, methanoyl group, ethanoyl group, n-propanoyl group, isopropanoyl group, n-butanoyl group. Group, t-butanoyl group, n-hexanoyl group, n-octanoyl group, n-decanoyl group, n-dodecanoyl group, benzoyl group and the like. Among these, an alkanoyl group having 1 to 20 carbon atoms is preferable from the viewpoints of compatibility, thermal stability and easiness of production.
The alkenoyl group having 2 to 30 carbon atoms represented by R ^D3 and R ^D4 may be linear or branched and includes, for example, ethenoyl group, n-propenoyl group, isopropenoyl group, n-butenoyl group, t-butenoyl group. Group, n-hexenoyl group, n-octenoyl group, n-decenoyl group, n-dodecenoyl group and the like. Among these, an alkenoyl group having 2 to 10 carbon atoms is preferable, and an alkenoyl group having 2 to 6 carbon atoms is more preferable, from the viewpoints of low molecular weight, compatibility and solubility, and production easiness.
Further, in the general formula (1), R ^D1 and R ^D2 are alkylene groups having 2 to 5 carbon atoms, and R ^D3 and R ^D4 are hydrogen atoms, and a polyether compound (D) having a polyoxyalkylene structure. Is particularly preferable.

Specific examples of the polyether compound (D) having a polyoxyalkylene structure represented by the general formula (1) include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxyethylene. Polyoxytetramethylene glycol, polyoxypropylene polyoxytetramethylene glycol, polyoxyethylene monomethyl ether, polyoxyethylene dimethyl ether, polyoxyethylene-bisphenol A ether, polyoxypropylene-bisphenol A ether, polyoxyethylene-polyoxypropylene- Bisphenol A ether, polyethylene glycol-allyl ether, polyethylene glycol-diallyl ether, polypropylene glycol-allyl ether, polypropylene glycol-diallyl ether, polyethylene glycol-polypropylene glycol-allyl ether, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, polypropylene glycol di Stearate and the like can be mentioned.
These are available as commercial products, for example, "UNIOX (registered trademark)", "UNIOR (registered trademark)", "UNILOVE (registered trademark)", and "UNISafe (registered trademark)" manufactured by NOF CORPORATION. , "Polyserin (registered trademark)", "Epiol (registered trademark)" and the like can be used.

Among them, "Unilube DE" series of random copolymerization type of polyoxyethylene glycol and polyoxypropylene glycol having a molecular weight (average molecular weight) of 1,000 or more and 5,000 or less, polyoxyethylene glycol and polyoxytetramethylene glycol The "polyserine DC" series of random copolymerization type and the "polyserine DCB" series of random copolymerization type of polyoxypropylene glycol and polyoxytetramethylene glycol are particularly preferable.

The polyether compound (D) is superior to polycaprolactone polyol in processing stability during processing, but is inferior in long-term heat resistance such as oven heat resistance. Therefore, in optical products that require long-term heat resistance, it is desirable to suppress the addition amount of the polyether compound (D). The content of the polyether compound (D) having a polyoxyalkylene structure in the aromatic polycarbonate resin of the present invention is 0 part by mass or more and 5 parts by mass or less, preferably 100 parts by mass of the aromatic polycarbonate resin (A). Is 0 parts by mass or more and 4 parts by mass or less, and more preferably 0 parts by mass or more and 3 parts by mass or less. In order to suppress an increase in the YI value, it is preferably 0.05 parts by mass or more and 5 parts by mass or less, and more preferably 0.1 parts by mass or more and 3 parts by mass or less.
For example, the polyether (D) is not added for products such as DRL that require long-term heat resistance at high temperatures.

[Additive]
In addition to the components (A) to (D) described above, any additive such as polyorganosiloxane may be appropriately added to the polycarbonate resin composition of the present invention within a range that does not impair the effects of the present invention.

[Polyorganosiloxane]
The polyorganosiloxane is preferably a compound having at least one functional group such as an alkoxy group, an aryloxy group, a polyoxyalkylene group, a carboxy group, a silanol group, an amino group, a mercapto group, an epoxy group and a vinyl group. ..
The addition amount of the polyorganosiloxane is preferably 0.01 parts by mass or more and 0.15 parts by mass or less, more preferably 0.02 parts by mass or more and 0.15 parts by mass with respect to 100 parts by mass of the aromatic polycarbonate resin (A). Parts or less, more preferably 0.05 parts by mass or more and 0.1 parts by mass or less. Within the above range, the mold releasability can be improved in cooperation with other components, and even under high-temperature molding conditions of over 340° C., particularly continuous molding conditions, the occurrence of silver or gold Die deposits can be significantly reduced.

The kinematic viscosity of the polyorganosiloxane is preferably 10 mm ² /s or more at 25° C. from the viewpoint of slipping effect as releasability, and preferably 200 mm ² /s from the viewpoint of dispersibility in the polycarbonate resin. It is below. From the above viewpoint, the viscosity of the polyorganosiloxane is more preferably 20 mm ² /s or more and 150 mm ² /s or less, and even more preferably 40 mm ² /s or more and 120 mm ² /s or less.
The refractive index of the polyorganosiloxane is preferably as small as possible so that the difference in the refractive index from the polycarbonate is as small as possible so as not to reduce the transparency when added to the polycarbonate. Since the refractive index of polycarbonate is 1.58, the refractive index of polyorganosiloxane is preferably 1.45 or more, more preferably 1.50 or more, and further preferably 1.52 or more.

[Aliphatic cyclic epoxy compound]
The aromatic polycarbonate resin composition of the present invention may contain an aliphatic cyclic epoxy compound in order to further improve the hydrolysis resistance. The alicyclic epoxy compound means a cycloaliphatic compound having an alicyclic epoxy group, that is, an epoxy group in which one oxygen atom is added to an ethylene bond in the aliphatic ring, and specifically, JP-A No. 11-158364. Those represented by the following formulas (1) to (10) shown in the publication are preferably used.

(In the formula, R is H or CH ₃ )

(In the formula, R is H or CH ₃ )

(In the formula, a+b=1 or 2)

(In the formula, a+b+c+d=1 or more and 3 or less)

(In the formula, a+b+c=n (integer), R is a hydrocarbon group)

(Where n is an integer)

(In the formula, R is a hydrocarbon group)

(In the formula, n is an integer and R is a hydrocarbon group)

Among the above alicyclic epoxy compounds, the compound represented by formula (1), formula (7) or formula (10) has excellent compatibility with an aromatic polycarbonate resin and does not impair transparency. More preferably used. For example, the compound represented by the formula (1) is obtained as 3,4-epoxycyclohexylmethyl-3′,4′-epoxycyclohexanecarboxylate (“Celoxide 2021P” (registered trademark), manufactured by Daicel Corporation). be able to. Further, as the compound represented by the formula (10), 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol (“EHPE3150” (registered trademark) ), manufactured by Daicel Co., Ltd.).
Further, as a mixture of “Celoxide 2021P” and “EHPE3150”, “EHPE3150CE” (registered trademark) commercially available from Daicel Corporation can also be preferably used.
By adding an alicyclic epoxy compound to the aromatic polycarbonate resin composition of the present invention, it becomes possible to further improve the hydrolysis resistance and further improve the transparency as described above. The compounding amount of the alicyclic epoxy compound is usually about 0.001 part by mass or more and 0.5 part by mass or less, and preferably 0.005 part by mass or more and 0.1 part by mass with respect to 100 parts by mass of the (A) aromatic polycarbonate resin. It is 2 parts by mass or less, and more preferably 0.01 parts by mass or more and 0.1 parts by mass or less.

[Aromatic Polycarbonate Resin Composition and Optically Molded Article]
The method for producing the polycarbonate resin composition of the present invention is not particularly limited.
For example, the components (A) to (C), and optionally the component (D), and other additives are mixed and melt-kneaded. Melt kneading is a commonly used method, for example, after mixing with a ribbon blender, a Henschel mixer, a Banbury mixer, a drum tumbler, a single-screw extruder, a twin-screw extruder, a co-kneader, a multi-screw extruder, etc. It can be used for melting and kneading. Regarding the polycaprolactone polyol (C) and the polyether (D), it is generally performed by appropriately heating to reduce the viscosity, blending while dropping in a blender or directly dropping into a kneader hopper port. .. The heating temperature at the time of melt-kneading is usually appropriately selected in the range of 220° C. or higher and 300° C. or lower.

The polycarbonate resin composition of the present invention is the above-mentioned melt-kneaded product, or, using the obtained resin pellets as a raw material, a known molding method, for example, a hollow molding method, an injection molding method, an injection compression molding method, an extrusion molding method, a vacuum method. A molding method such as a molding method, a blow molding method, a press molding method, a pressure molding method, a foam molding method, a heat bending molding method, a compression molding method, a calender molding method and a rotational molding method can be applied.
INDUSTRIAL APPLICABILITY The polycarbonate resin composition of the present invention has an improved heat resistance deficiency and can withstand molding at a high temperature of more than 340° C. Therefore, it is suitable for molding methods such as injection molding that require high fluidity of molding materials. It is suitable. It is also suitable for molding with a long molding cycle, such as thick lens molding such as DRL, and nitrogen molding in which nitrogen is introduced into the molding machine. On the other hand, in the extrusion molding method, a product such as a sheet or film having high transparency and high optical characteristics without yellowing can be obtained by molding at a low temperature of 220° C. or higher and 280° C. or lower.

The polycarbonate resin composition according to the present invention has a YI value of 1.2 or less measured by the following measurement methods (1) and (2), and a difference between the YI values measured by the following measurement methods (1) and (2). Is preferably 0.1 or less.
More preferably, the polycarbonate resin composition according to the present invention has a YI value of 1.15 or less measured by the following measuring methods (1) and (2), and is measured by the following measuring methods (1) and (2). The difference in YI value is 0.08 or less.
Further, the polycarbonate resin composition according to the present invention preferably has a YI value measured by the following measurement method (1) of 1.25 or less, and a YI value measured by the following measurement method (2) is 1. It is preferably 10 or less.

Measuring method (1)
The polycarbonate resin molding material is pelletized and then dried. Next, a 50 mm×80 mm×5 mm thick molded body is molded by injection molding at a cylinder temperature of 360° C., a mold temperature of 80° C., and a cycle time of 50 seconds. Using a spectrophotometer, the YI value of the molded body is measured under the conditions of C light source and 2 degree visual field.

Measuring method (2)
The polycarbonate resin molding material is pelletized and then dried. Next, a molded body of 50 mm×80 mm×thickness of 5 mm is molded by injection molding at a cylinder temperature of 280° C., a mold temperature of 80° C., and a cycle time of 50 seconds. Using a spectrophotometer, the YI value of the molded body is measured under the conditions of C light source and 2 degree visual field.

Further, in the polycarbonate resin composition of the present invention, it is preferable that a difference ΔYI in YI values of molded articles before and after the test is 0.2 (0.20) or less when the following moisture and heat resistance test is performed.
[Moisture and heat resistance test method]
After pelletizing the polycarbonate resin molding material and drying it, a molded body of 40 mm×80 mm×thickness of 3 mm is molded at a cylinder temperature of 350° C., a mold temperature of 80° C. and a cycle time of 30 seconds. This molded body is placed in a constant temperature and humidity chamber set at a temperature of 85° C. and a relative humidity of 95% for 500 hours.

Further, in the polycarbonate resin composition of the present invention, when the following heat resistance test is carried out, it is preferable that the difference ΔYI between the YI values of the molded product before and after the test is 0.5 (0.50) or less.
[Heat resistance test method]
After pelletizing the polycarbonate resin molding material and drying it, a molded body of 40 mm×80 mm×thickness of 3 mm is molded at a cylinder temperature of 350° C., a mold temperature of 80° C. and a cycle time of 30 seconds. This molded product is placed in a gear oven heat resistance tester at a temperature of 120° C. for 1,000 hours.

One preferred embodiment of the polycarbonate resin composition of the present invention is a polycarbonate resin composition comprising only the aromatic polycarbonate resin (A), the phosphorus compound (B) and the polycaprolactone polyol (C). Further, another preferred embodiment of the polycarbonate resin composition of the present invention comprises only the above aromatic polycarbonate resin (A), phosphorus compound (B), polycaprolactone polyol (C) and polyether compound (D). Is a polycarbonate resin composition.

INDUSTRIAL APPLICABILITY The polycarbonate resin composition of the present invention is a resin composition which has excellent light transmittance and brightness and can withstand molding at high temperatures and long molding cycles, and is particularly suitable for injection molding. On the other hand, since it is highly suitable for low-temperature molding, it is possible to obtain a molded product having excellent light transmittance even by molding other than injection molding, and it is useful as an optical molded product, particularly as a light guide member.
The polycarbonate resin composition of the present invention can be stably molded in a wide temperature range as described above, and an optical molded product can be obtained by preferably molding at a temperature of 280° C. or higher and 360° C. or lower.
Further, since the molded product has excellent moisture resistance and heat resistance, it can be used in applications where moisture resistance and heat resistance are required.
Examples of the optical molded product include a light guide part for a vehicle, and particularly a light guide part for a vehicle used for DRL. It is more preferable that the thickness of the DRL of the molded product is 5 mm or more.
The light guide plate is not particularly limited, and may be a flat plate having a thickness of several mm to several hundred μm, a curved plate having a lens effect, or a prism transfer plate. The molding method is also not particularly limited, and the shape and the molding method may be appropriately selected according to the purpose and application.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[Measurement of viscosity average molecular weight (Mv)]
The viscosity of the methylene chloride solution (concentration unit: g/L) at 20° C. was measured with an Ubbelohde viscometer, and the intrinsic viscosity [η] was calculated from this, and then calculated by the following formula.
[Η]=1.23×10 ⁻⁵ Mv ^0.83

[Differential heat-thermogravimetric measurement of phosphorus compounds (TG-DTA)]
10 to 15 mg of a phosphorus-based compound was collected, and using a differential thermal-thermogravimetric analyzer “TG/DTA7200 type” manufactured by SII Co., Ltd., a temperature rising rate of 20° C./min under a nitrogen atmosphere was obtained. The change in weight when the temperature was raised to 550° C. was measured and recorded at each temperature. Taking the initial weight as 100%, the temperature when the weight was reduced by 2% was checked, and the temperature was set at 98% holding temperature.
[Hydrolysis resistance test of phosphorus compounds]
The phosphorus compound was allowed to stand for 1,500 hours under the conditions of 40° C. and humidity of 90%. Then, the mass of the compound having a phenol structure generated by decomposition was quantified using a gas chromatograph “GC-2014” manufactured by Shimadzu Corporation, and the ratio to the phosphorus compound was measured.

The components used in the examples and comparative examples are as follows.
<Aromatic polycarbonate resin (A)>
(A1): "Taflon FN1500" (manufactured by Idemitsu Kosan Co., Ltd., bisphenol A polycarbonate resin, viscosity average molecular weight (Mv) = 14,500)
(A2): "Taflon FN1200" (manufactured by Idemitsu Kosan Co., Ltd., bisphenol A polycarbonate resin, viscosity average molecular weight (Mv) = 11,500)

<Phosphorus compound (B)>
(B1): "Doverphos S-9228PC" (manufactured by Dover Chemical, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, 0.15% by mass of dicumylphenol was produced after the hydrolysis resistance test. )
(B2): "Adeka Stab PEP-36" (manufactured by ADEKA, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,6- after the hydrolysis resistance test. 45 mass% of di-tert-butyl-4-methylphenol was produced.)
The results of the above-mentioned differential thermal-thermogravimetric measurement (TG-DTA) and hydrolysis resistance test for each phosphorus compound are summarized in Table 3 below.

<Polycaprolactone polyol (C)>
(C1): “Plaxel 210CP” (Polycaprolactone diol, molecular weight 1000, manufactured by Daicel Corporation)
(C2): “Plaxel 220 CPB” (manufactured by Daicel Corp., polycaprolactone diol, molecular weight 2000)
(C3): “Plaxel H1P” (manufactured by Daicel Corporation, high molecular weight polycaprolactone (thermoplastic resin), molecular weight 10,000)

<Polyether compound (D)>
(D1): "Unilube 50 DE-25" (manufactured by NOF CORPORATION, polyoxyethylene glycol-polyoxypropylene glycol, molecular weight 1750)
<Other additives>
"Celoxide 2021P" (manufactured by Daicel Corporation, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate)
"KR-511" (polyorganosiloxane compound manufactured by Shin-Etsu Chemical Co., Ltd.)

Examples 1-10 and Comparative Examples 1-9
In each example, a polycarbonate resin composition was prepared by blending the components in the quantitative ratios shown in Tables 1 and 2. Using a single screw extruder with a screw diameter of 40 mm with a vent (“VS-40” manufactured by Tanabe Plastics Machinery Co., Ltd.), the polycarbonate resin composition was melt-kneaded at a cylinder temperature of 250° C., and pellets were obtained by strand cutting. It was After drying the obtained pellets at 110° C. for 5 hours, using an injection molding machine (“ES1000” manufactured by Nissei Plastic Industry Co., Ltd.), at cylinder temperature settings of 280° C. and 360° C., a cycle time of 50 seconds, A flat plate test piece of 50 mm×80 mm×thickness of 5 mm was molded.
In addition, a moisture and heat resistance test was conducted as follows. Using the injection molding machine ("EC40N" manufactured by Toshiba Machine Co., Ltd.), the dried pellets were molded into flat plate test pieces of 40 mm x 80 mm x thickness 3 mm at a cylinder temperature of 350°C and a cycle time of 30 seconds. .. This flat plate test piece was placed in a constant temperature and humidity chamber of model name "LH33-12P" manufactured by Nagano Science Co., Ltd., which was set to a temperature of 85°C and a relative humidity of 95% for 500 hours.
Further, the dried pellets were 40 mm×80 mm×thick at a cylinder temperature of 350° C., a mold temperature of 80° C. and a cycle time of 30 seconds using an injection molding machine (“EC40N” manufactured by Toshiba Machine Co., Ltd.). A flat test piece having a size of 3 mm was molded. This flat plate test piece was put in a gear oven “GPS-222” manufactured by TABAI Co., Ltd., which was adjusted to a temperature of 120° C., for 1,000 hours.
The YI value of the test piece obtained above was measured using a spectrophotometer (“U-4100” manufactured by Hitachi High-Technologies Corporation) under the conditions of a C light source and a 2 degree visual field. The results are shown in Tables 1 and 2. In addition, the acceptance criteria for the 5 mm-thick test piece are that the YI value (280° C. molding) of the test piece molded at 280° C. is 1.10 or less, and the YI value (360° C. molding at 360° C.). ) Is 1.25 or less (indicated as "Plate YI" value in the table). Further, the difference in color tone between 280° C. molding and 360° C. molding is indicated by ΔYI.
The YI after the moisture and heat resistance test (500 hours) using a constant temperature and constant humidity test tank is not particularly specified, but ΔYI before and after the test is required to be 0.2 (0.20) or less. The YI after the heat resistance test (1,000 hours) using a gear oven heat resistance tester is not particularly specified, but ΔYI before and after the test is preferably 0.5 (0.50) or less.

In Comparative Examples 1 and 6 which do not contain the specific phosphorus compound (B) and polycaprolactone polyol (C), the color tone is good in the low temperature molding, but the color tone is poor in the high temperature molding, and the color tone difference between the low temperature molding and the high temperature molding is high. (ΔYI) is large. In Comparative Example 2 which does not contain the polycaprolactone polyol (C) but contains the specific phosphorus compound (B), the color tone in the high temperature molding is fair, but the color tone in the low temperature molding is insufficient. In Comparative Examples 3, 4, 7 and 8, no specific phosphorus-based antioxidant was used as the antioxidant, and polycaprolactone polyol was contained, but the color tone of the high temperature molding was poor. Comparative Examples 5 and 9 contain high molecular weight polycaprolactone, but the color tone at the time of high temperature molding (at 360° C. molding) is worse. Except for Comparative Example 2, there was a large decrease in color tone after the moisture and heat resistance test, and there is a high possibility that hydrolysis had occurred.
On the other hand, an implementation including a phosphorus-based compound (B) having an aryl group having a decomposition temperature of 5% by mass or less and a polycaprolactone polyol (C) having a phenol structure, which is generated after a hydrolysis resistance test, is performed. In Examples 1 to 10, the color tone difference during high temperature molding is small. Further, in Examples 5 and 6 in which the polyether compound (D) was used in combination, the color tone at the time of low temperature molding (at 280° C. molding) was improved. It also showed high hydrolysis resistance in the moisture and heat resistance test.

The polycarbonate resin composition of the present invention has excellent thermal stability in high-temperature molding, and even when molded in a wide temperature range, it is possible to obtain a molded product without deterioration of optical properties due to deterioration at the time of molding and moisture resistance. Excellent heat resistance and long-term heat resistance. From this, it is suitable for optical products such as light guide plates, specifically for large-screen thin light guide plates for smartphones and tablet PCs, and also for thick lenses such as DRL for automobiles.

Claims (13)

A polycarbonate resin composition comprising an aromatic polycarbonate resin (A), a phosphorus-based compound (B) having an aryl group, and a polycaprolactone polyol (C),
With respect to 100 parts by mass of the aromatic polycarbonate resin (A), 0.005 parts by mass or more and 1 part by mass or less of the phosphorus compound (B) and 0.005 parts by mass or more and 5 parts by mass or less of the polycaprolactone polyol (C). Containing
The phosphorus compound (B) is a pentaerythritol diphosphite compound represented by the following general formula (II), which decomposes after 1,500 hours when left at 40° C. and 90% humidity. The amount of the compound having a phenol structure generated by the above is 5% by mass or less with respect to the phosphorus compound (B),
The phosphorus compound (B) has a temperature of 340 at which the weight decreases by 2% from the weight before measurement when the weight is measured using a differential thermal-thermogravimetric (TG-DTA) machine under a nitrogen atmosphere. A polycarbonate resin composition, which is a compound having a temperature of not less than °C.

(Wherein, Y ¹ to Y ⁴ represents a hydrocarbon group having 6 to 15 carbon atoms, it may be the same or different.) The polycarbonate resin composition according to claim 1, further comprising 5 parts by mass or less of the polyether compound (D) represented by the following formula (1) with respect to 100 parts by mass of the aromatic polycarbonate resin (A).
R ^D3 O-(R ^D1 O) _m (R ^D2 O) _n -R ^D4 (1)
(In the formula, R ^D1 and R ^D2 represent an alkylene group having 1 or more carbon atoms, and R ^D1 and R ^D2 may be the same or different. m+n is 5 or more and less than 300. When m is 2 or more And R ^D1 may be the same or different, and when n is 2 or more, R ^D2 may be the same or different, and R ^D3 and R ^D4 are a hydrogen atom and have 1 carbon atom. A hydrocarbon group having 30 to 30 carbon atoms, an alkanoyl group having 1 to 30 carbon atoms, an alkenoyl group having 2 to 30 carbon atoms or a glycidyl group are shown, and R ^D3 and R ^D4 may be the same or different. The polycarbonate resin composition according to claim 1, wherein the aromatic polycarbonate resin (A) is a polycarbonate whose main chain has a repeating unit represented by the following general formula (I).

(In the formula, R ^A1 and R ^A2 represent an alkyl group or an alkoxy group having 1 to 6 carbon atoms, and R ^A1 and R ^A2 may be the same or different. X is a single bond, C 1 or more. 8 following an alkylene group, having 2 to 8 alkylidene group having a carbon, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, -S -, - SO -, - SO 2 - , -O- or -CO-, and a and b each independently represent an integer of 0 or more and 4 or less, and when a is 2 or more, R ^A1 may be the same or different, and b is 2 In the above cases, R ^A2 may be the same or different.) Y ^{1 to} Y ⁴ in the formula (II) are each independently a cumyl group which may be unsubstituted or substituted, a phenyl group which may be unsubstituted or substituted, or a naphthyl which may be unsubstituted or substituted. The polycarbonate resin composition according to any one of claims 1 to 3 , which is a group or a biphenyl group which may be unsubstituted or substituted. The phosphorus compound (B) is a pentaerythritol diphosphite compound represented by the following general formula (II-1), polycarbonate resin composition according to any one of claims 1-4.

(In the formula, R ^{B1 to} R ^B8 represent an alkyl group or an alkenyl group and may be the same or different. R ^B1 and R ^B2 , R ^B3 and R ^B4 , R ^B5 and R ^B6 , R ^B7 and R ^B8 may combine with each other to form a ring, R ^{B9 to} R ^B12 represent a hydrogen atom or an alkyl group, and may be the same or different, and m1 to m4 are integers of 0 or more and 5 or less. Z ^{1 to} Z ⁴ represent a single bond or a carbon atom, and may be the same or different, and when Z ^{1 to} Z ⁴ represent a single bond, R ^{B1 to} R ^B8 are generally Excluded from formula (II-1).) The phosphorus compound (B) is bis (2,4-dicumylphenyl) pentaerythritol diphosphite, polycarbonate resin composition according to any one of claims 1-5. The polycaprolactone polyol (C) is a molecular weight of 500 to 5,000, polycaprolactone diols, is at least one selected from polycaprolactone triol and the group consisting of polycaprolactone tetraol of claim 1-6 The polycarbonate resin composition according to any one of claims. The polyether compound (D) is a polyether compound in which R ^D1 and R ^D2 in the formula (1) are alkylene groups having 2 to 5 carbon atoms, and R ^D3 and R ^D4 are hydrogen atoms. Item 9. The polycarbonate resin composition according to any one of items 2 to 8 . The viscosity average molecular weight (Mv) is 9,000 to 50,000 of the aromatic polycarbonate resin (A), the polycarbonate resin composition according to any one of claims 1-8. Optical molded article comprising the polycarbonate resin composition according to any one of claims 1-9. The optical molded article according to claim 10 , wherein the optical molded article is a light guide member. The optical molded article according to claim 10 or 11 , wherein the optical molded article is a vehicle light guide component. A daytime running light containing the optical molded article according to claim 12 .