JP5235052B2 - Antistatic polycarbonate resin composition - Google Patents

Description

  The present invention relates to an antistatic polycarbonate resin composition excellent in thermal stability and transparency.

Polycarbonate resins are excellent in impact resistance, heat resistance, and transparency, and are widely used in fields such as electrical / electronic, optical, building materials, medical, food, and vehicles. However, products obtained from polycarbonate resin are easily charged with static electricity, and there are problems associated with static electricity, such as dust adhering to packaging materials and molded products, electric shock during molding and use, and malfunction of OA equipment. Conventionally, the application of various antistatic agents has been studied.
Further, office equipment exterior parts such as optical disk cartridges are also required to have transparency so that the inside can be fully visually recognized simultaneously with the antistatic performance.

In order to impart antistatic performance to the polycarbonate resin, a fatty acid monoglyceride is blended as an antistatic agent as an antistatic agent. However, this composition did not fully satisfy all of the antistatic performance, transparency and thermal stability (Japanese Patent Publication No. 55-4141). In addition, a diglycerin fatty acid ester and a phosphorus-based antioxidant are blended in a polycarbonate resin. This composition has satisfactory antistatic performance and transparency to some extent, but has a problem of poor thermal stability (Patent Document 2, JP-A-2-196852).
JP-B 55-4141 JP-A-2-196852

An object of the present invention is to provide an antistatic polycarbonate resin composition excellent in thermal stability and transparency.

  As a result of diligent research in view of the above-mentioned problems, the present inventor has achieved thermal stability by using a diglycerin fatty acid ester and a specific cyclic phosphite antioxidant as an antistatic agent for a polycarbonate resin. And it discovered that the antistatic polycarbonate resin composition excellent in transparency was obtained, and came to complete this invention.

  That is, the present invention provides 0.1 to 5 parts by weight of diglycerin fatty acid ester (B) and 0.005 to 1 part by weight of cyclic phosphite antioxidant (C) per 100 parts by weight of polycarbonate resin (A). The present invention relates to an antistatic polycarbonate resin composition characterized by being blended and a molded article comprising the same.

  The antistatic polycarbonate resin composition of the present invention is excellent not only in antistatic properties but also in transparency and appearance, is transparent, and is used for applications where dust adhesion is avoided, such as molding of light source peripheral members and contents It is suitably used for products.

  The polycarbonate resin (A) used in the present invention is a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted or a transesterification method obtained by reacting a dihydroxydiaryl compound and a carbonate such as diphenyl carbonate. A typical example is an aromatic polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (bisphenol A).

  Examples of the dihydroxydiaryl compound include bisphenol 4-, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2, 2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3) -Tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis ( Bis (hydroxyaryl) alkanes such as 4-hydroxy-3,5-dichlorophenyl) propane, 1,1- (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3 Dihydroxy diaryl ethers such as 3,3'-dimethyldiphenyl ether, dihydroxy diaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3 ' Dihydroxy diaryl sulfoxides such as dimethyldiphenyl sulfoxide, dihydroxy diary such as 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone Sulfone, and the like.

These are used individually or in mixture of 2 or more types. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, and the like may be mixed and used.

Furthermore, the above dihydroxyaryl compound and a trivalent or higher phenol compound as shown below may be used in combination. Trihydric or higher phenols include phloroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptene, 2,4,6-dimethyl-2,4,6-tri- (4 -Hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzol, 1,1,1-tri- (4-hydroxyphenyl) -ethane and 2,2-bis- [4 4- (4,4′-dihydroxydiphenyl) -cyclohexyl] -propane and the like.

  The viscosity average molecular weight of the polycarbonate resin (A) is usually 10,000 to 100,000, preferably 15,000 to 35,000. In producing such a polycarbonate resin, a molecular weight regulator, a catalyst and the like can be used as necessary.

  The diglycerin fatty acid ester (B) used in the present invention can be obtained by esterification of diglycerin obtained by polymerizing glycerin and a fatty acid.

As the diglycerin fatty acid ester (B), an ester compound of a fatty acid having 12 to 18 carbon atoms and diglycerin is preferably used.
If the fatty acid has less than 12 carbon atoms, the sustainability of the antistatic property is inferior. If the number of carbon atoms exceeds 18, the antistatic property is inferior.

Examples of the fatty acid having 12 to 18 carbon atoms include lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, and the like.

Specific examples of the diglycerin fatty acid ester (B) include diglycerin monolaurate, diglycerin monomyristate, and diglycerin monostearate. Diglycerin monolaurate is preferably used, and RIKEN vitamins It is easily available as Poem DL-100 made by the company

  The compounding amount of the diglycerin fatty acid ester (B) of the present invention is 0.1 to 5 parts by weight per 100 parts by weight of the polycarbonate resin (A). If the blending amount is less than 0.1 parts by weight, the antistatic property is inferior, and if it exceeds 5 parts by weight, the transparency and the appearance are deteriorated. More preferably, it is the range of 0.5-3 weight part.

Examples of the cyclic phosphite antioxidant (C) used in the present invention include those produced by reacting phenols or bisphenols, phosphorus trihalide and amine compounds. As a reaction method, a two-step reaction method is generally employed in which phenols or bisphenols and phosphorus trihalide are first reacted to form an intermediate, and then an amine compound is reacted. The reaction is usually performed in an organic solvent in an environment of 0 to 200 ° C. Among the cyclic phosphite antioxidants (C), in particular, 2,4,8,10-tetra-t-butyl-6- [3- (3-methyl-4 - hydroxy-5-t-butylphenyl) ) Propoxy] dibenzo [d, f] [1,3,2] dioxaphosphine is suitable, and is available as a commercially available product, and Sumitomo Chemical's Sumilizer GP.

The amount of the cyclic phosphite antioxidant (C) is 0.005 to 1 part by weight per 100 parts by weight of the polycarbonate resin (A). If the blending amount is less than 0.005 parts by weight, the thermal stability is poor, which is not preferable. On the other hand, when the amount exceeds 1 part by weight, the light transmittance decreases, which is not preferable. This amount is preferably in the range of 0.01 to 0.5 parts by weight, more preferably 0.02 to 1 parts by weight.

The diglycerin fatty acid ester (B) of the present invention can be used in combination with other antistatic agents. As other antistatic agents that can be used in combination, widely known ones can be used, and examples thereof include alkylsulfonates, alkylbenzenesulfonates, ammonium salts, and other phosphonium salts. It is not limited to.

The mixing method and mixing order of the polycarbonate resin (A), the diglycerin fatty acid ester (B) and the cyclic phosphorous ester antioxidant (C) are not particularly limited, and known mixers such as tumblers, ribbon blenders, They can be mixed by a high-speed mixer or the like and then melt-kneaded by a single screw or twin screw extruder.

  Furthermore, a known additive such as a heat stabilizer, a release agent, an ultraviolet absorber, a flame retardant, and a dye / pigment may be blended as necessary within a range not impairing the effects of the present invention. .

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. “Parts” are based on weight unless otherwise specified.

  Based on the blending components and blending amounts shown in Tables 1 and 2, various blending components were mixed using a tumbler and melt kneaded at a cylinder temperature of 250 ° C. using a twin screw extruder (TEX-30α manufactured by Nippon Steel). Various pellets were obtained.

The compounding components used are as follows.
1. Polycarbonate resin:
Caliber 200-5 manufactured by Sumitomo Dow (viscosity average molecular weight: 25000)
Hereinafter, abbreviated as “PC”. )
2. Antistatic agent:
Poem DL-100 manufactured by Riken Vitamin
Diglycerin monolaurate (hereinafter abbreviated as antistatic agent)
3. Antioxidant:
Sumitomo Chemical Sumitizer GP
2,4,8,10-tetra-tert-butyl-6- [3- (3-methyl-4 - hydroxy-5-tert-butylphenyl) propoxy] dibenzo [d, f] [1,3,2] Dioxaphosphepine (cyclic phosphite antioxidant, hereinafter abbreviated as “cyclic AO”)

  Using the obtained pellets, various test pieces were prepared using an injection molding machine (J100SAII manufactured by Nippon Steel Works) at a set temperature of the cylinder of 300 ° C. and subjected to each test.

The test method is as follows.
Melt flow rate (MFR):
Measured according to ASTM D-1238. 30 g / 10 min or less was accepted.
・ Surface resistivity:
A 70 × 40 × 3 mm flat plate was prepared by injection molding and measured under the following conditions.
After the plate test piece was conditioned for 24 hours under conditions of 23 ° C. and 55% relative humidity, a high resistivity meter (Hirester UP MCP-HT450 manufactured by Mitsubishi Chemical Corporation) was used, and the measurement voltage was 1000 V and the sampling time was 30 seconds. The surface resistivity was measured under the conditions.
A surface resistivity of less than 1 × 10 ¹⁴ Ω / sq was accepted.
・ Total light transmittance:
Measured according to ASTM D1003. More than 87% was accepted.
ΔYI:
A 70 × 40 × 3 mm flat plate was formed by injection molding, then retained in a cylinder at a set temperature of 340 ° C. for 30 minutes, and further molded. The yellowness index (YI) of the molded product before residence and the molded product after residence was measured in accordance with ASTM D-1925. The difference between YI before retention and YI after residence was ΔYI, and 2 or less was accepted.

  The test results are shown in Tables 1 and 2.

  As shown in Examples 1 to 3, the polycarbonate resin composition having the requirements of the present invention satisfies all the required performances including the surface specific resistance value.

On the other hand, in the case where the requirements of the present invention were not satisfied, each case had some drawbacks.
Comparative Example 1 was a case where no cyclic phosphite antioxidant was blended. In this case, the heat resistance represented by ΔYI was inferior.
Comparative Example 2 is a case in which 2 parts of a cyclic phosphite-based antioxidant is blended exceeding the blending amount range which is a requirement of the present invention. In this case, the ΔYI value and the total light transmittance satisfy the required levels. There wasn't.
Comparative Example 3 is a case where 0.05 part of the antistatic agent is blended in an amount smaller than the blending amount range that is a requirement of the present invention, and the total light transmittance, MFR value, and ΔYI value are at a satisfactory level, but the surface resistance. The rate did not meet the required level.
Comparative Example 4 is a case in which 6 parts of the antistatic agent was blended exceeding the blending amount range which is a requirement of the present invention, and the surface resistivity was at a level with no problem, but the total light transmittance, MFR value and ΔYI value were The requested level was not satisfied.

Claims (6)

Polycarbonate resin (A) per 100 parts by weight of diglycerol fatty acid ester (B) 0.1 to 5 parts by weight of the cyclic phosphorous ester antioxidant (C) 0.005 to 1 by blending the parts by weight of the resin composition The cyclic phosphite antioxidant (C) is 2,4,8,10-tetra-t-butyl-6- [3- (3-methyl-4-hydroxy-5-t- An antistatic polycarbonate resin composition, which is butylphenyl) propoxy] dibenzo [d, f] [1,3,2] dioxaphosphine . The antistatic polycarbonate resin composition according to claim 1, wherein the diglycerin fatty acid ester (B) is an ester compound of a fatty acid having 12 to 18 carbon atoms and diglycerin. 2. The antistatic polycarbonate resin composition according to claim 1, wherein the diglycerin fatty acid ester (B) is diglycerin monolaurate. 2. The antistatic polycarbonate resin composition according to claim 1, wherein the amount of the diglycerin fatty acid ester (B) is 0.5 to 3 parts by weight per 100 parts by weight of the polycarbonate resin (A). The antistatic property according to claim 1, wherein the amount of the cyclic phosphite antioxidant (C) is 0.01 to 0.5 parts by weight per 100 parts by weight of the polycarbonate resin (A). Polycarbonate resin composition. A molded article formed by molding the polycarbonate resin composition according to any one of claims 1 to 5 .