JP4577712B2 - Flame retardant polycarbonate resin composition - Google Patents

Description

  The present invention relates to a flame retardant polycarbonate resin composition. More specifically, the present invention relates to a flame retardant polycarbonate resin composition having improved flame retardancy without impairing excellent mechanical properties and thermal properties inherently possessed by the polycarbonate resin.

  Polycarbonate resins are used in a wide range of fields including electrical, electronic and office automation as engineering plastics with excellent transparency, impact resistance, heat resistance and electrical properties.

  In these electric, electronic, and OA fields, there are many parts that require high flame resistance (UL94V), such as personal computer exterior parts. Polycarbonate resin is a highly flame-retardant plastic material with self-extinguishing properties. However, in order to meet safety requirements in the electric, electronic, and OA fields, higher flame resistance equivalent to UL94V-0 and UL94V-1 Is required.

Therefore, in order to improve the flame retardancy of the polycarbonate resin, conventionally, a method of blending a fine inorganic compound has been adopted.
JP 2002-285209 A

  However, in order to improve dispersibility, prior melt extrusion may be necessary, and there is a problem that it is difficult to develop stable dispersibility and further flame retardancy.

  As a result of intensive studies in view of the above-mentioned problems, the present inventors have blended neutral clay with polycarbonate resin, and in addition to this, by adding a small amount of a fiber-forming fluoropolymer, tensile strength and bending It has been found that a flame-retardant polycarbonate resin composition having improved flame retardancy equivalent to UL94V-0 or UL94V-1 without deteriorating mechanical properties such as strength, and has completed the present invention.

  That is, the present invention relates to polycarbonate resin (A) 85 to 99.45 wt%, pH 5.6 to 7.3 neutral clay (B) 0.5 to 10 wt% and fiber-forming fluorine-containing polymer (C The present invention provides a flame retardant polycarbonate resin composition characterized by comprising 0.05 to 5% by weight.

  Since the flame-retardant polycarbonate resin composition of the present invention exhibits high flame retardancy without causing defects such as silver streaks on the surface of molded products, it can be used for a wide range of industrial products that require high flame retardancy. Can be applied.

  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 a 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 valent 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. More preferably, it is 17000-26000. In producing such a polycarbonate resin, a molecular weight regulator, a catalyst and the like can be used as necessary.

The compounding quantity of polycarbonate resin (A) is the range of 85-99.45 weight%. If it is less than 85 % by weight, the decrease in the molecular weight of the polycarbonate resin (A) increases, resulting in poor mechanical strength. If it exceeds 99.45 % by weight, the flame retardancy is poor. More preferably, it is in the range of 92 to 99% by weight. More preferably, it is in the range of 94.5 to 98.5% by weight, and in this range, particularly, the balance between flame retardancy and moldability is further improved.

The neutral clay (B) used in the present invention has a pH of 5.6 to 7.3. The method for measuring the pH is as follows.
A 40-gram sample of neutral clay (B) is put into a beaker containing 160 ml of distilled water, and a suspension obtained by stirring with a stir bar or mixer is charged with a pH electrode bar of a commercially available pH meter. Insert and measure.

Neutral clay (B) has an average particle size of 0.1 to 0.3 μm as measured by Microscan (Quantachrome) Analyzer, an average specific surface area of 9000 to 12000 cm 3 / g by BET method, and ASTM D281 (crude linseed oil) Those having an average oil absorption of 30 to 50 (lbs / 100 lbs) measured according to the above are particularly preferably used.

  The blending amount of the neutral clay (B) is in the range of 0.5 to 10% by weight. If it is less than 0.5% by weight, the flame retardancy is inferior, and if it exceeds 10% by weight, appearance defects due to silver streaks on the surface of the molded article of the polycarbonate resin composition are not preferable. More preferably, it is 1 to 8% by weight. Even more preferably, it is in the range of 1.5 to 5.5% by weight. In this range, in particular, the balance between flame retardancy and moldability is further improved.

  As the fiber-forming fluorine-containing polymer (C) used in the present invention, those that form a fiber structure (fibril structure) in a flame-retardant polycarbonate resin composition are preferable. Polytetrafluoroethylene, tetrafluoro Examples thereof include ethylene copolymers (for example, tetrafluoroethylene / hexafluoropropylene copolymers, etc.), partially fluorinated polymers as shown in US Pat. No. 4,379,910, polycarbonates produced from fluorinated diphenols, and the like. . By using these in combination with the neutral clay (B), not only the conventional dripping prevention effect but also the effect of specifically reducing the combustion time is obtained.

  The amount of the fiber-forming fluoropolymer (C) is 0.05 to 5% by weight. If the blending amount is less than 0.05% by weight, the effect of preventing dripping at the time of combustion is inferior, and if it exceeds 5% by weight, granulation becomes difficult, which may hinder stable production. More preferably, it is 0.1 to 1 weight%, More preferably, it is the range of 0.2 to 0.5 weight%. In this range, the balance between flame retardancy and moldability is further improved.

  Furthermore, various heat stabilizers, antioxidants, colorants, fluorescent brighteners, fillers, mold release agents, softening materials are added to the flame-retardant polycarbonate resin composition of the present invention within a range not impairing the effects of the present invention. , Additives such as antistatic agents, impact modifiers, and other polymers may be blended.

  There are no particular limitations on the method of mixing the various components in the flame-retardant resin composition of the present invention, and examples thereof include mixing with a known mixer such as a tumbler or ribbon blender, and melt kneading with an extruder.

  There is no restriction | limiting in particular as a method of shape | molding the flame-retardant resin composition of this invention, A well-known injection molding method, injection / compression molding method, etc. can be used.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise noted, based on weight standards.

(Examples 1-2 and Comparative Examples 1-5)
The polycarbonate resin produced from bisphenol A and phosgene and various blending components were mixed together by a tumbler based on the blending amounts shown in Tables 1 and 2, and then a 37 mm diameter twin screw extruder (KTX-37 manufactured by Kobe Steel). ) Was melt kneaded at a cylinder temperature of 280 ° C. to obtain various pellets.

Details of the used blending components are as follows.
1. Polycarbonate resin (hereinafter abbreviated as PC):
Caliber 200-20 (Sumitomo Dow) Viscosity average molecular weight 19000
2. Neutral clay (hereinafter abbreviated as neutral clay):
Burgess No. 28 (Burges Pigment) pH = 7.0
3. Clay (hereinafter abbreviated as Clay A):
Hageth No. 30 (Burges Pigment) pH = 5.5
4). Clay (hereinafter abbreviated as Clay B):
HAGES KE (Burges Pigment) pH = 7.6
5). Fiber-forming fluorine-containing polymer (hereinafter abbreviated as PTFE):
Polyflon FA-500 (Daikin)

The various pellets obtained were dried at 120 ° C. for 4 hours, and then evaluated for flame retardancy at 260 ° C. and an injection pressure of 1600 Kg / cm ² using an injection molding machine (J100-E-C5 manufactured by Nippon Steel Works). A test piece (125 × 13 × 1.5 mm) was molded, and the appearance of the molded product was visually observed. When appearance defects such as silver streak occurred, the evaluation result was “bad”.

The test piece is allowed to stand for 48 hours in a temperature-controlled room with a temperature of 23 ° C. and a humidity of 50%, and is flame retardant in accordance with UL94 test (flammability test for plastic materials for equipment parts) established by Underwriters Laboratories. Sexuality was evaluated. UL94V is a method of evaluating flame retardance from the afterflame time and drip properties after indirect flames of a burner for 10 seconds on a test piece of a predetermined size held vertically, and is divided into the following classes: .
V-0 V-1 V-2 NR
Afterflame time of each sample 10 seconds or less 30 seconds or less 30 seconds or less 30 seconds or more Total afterflame time of 5 samples 50 seconds or less 250 seconds or less 250 seconds or less 250 seconds or more Cotton ignition by drip No No Yes No / Yes Above The after-flame time shown is the length of time that the specimen continues to burn in flame after the ignition source is moved away. The ignition of cotton by drip is an indicator about 300 mm below the lower end of the specimen. This is determined by whether the cotton used is ignited by a drip from the specimen. The flame retardant class was V-0 or V-1.

As shown in Examples 1 and 2, the resin composition containing a specified amount of neutral clay and PTFE exhibited excellent appearance and flame retardancy from V-1 to V-0. However, the neutral clay, the resin composition not containing PTFE (Comparative Example 1), and the resin composition not containing PTFE (Comparative Example 2) that satisfies the specified amount of filler, but the test piece dripped during the combustion test. -2 flame retardancy. Although a specified amount of clay and PTFE is blended, the resin composition using the clay having a clay pH outside of 5.6 to 7.4 (Comparative Examples 3 and 4) has a long burning time and is extremely inferior in flame retardancy. It was. When the blending amount of the neutral clay was larger than the specified amount, the combustion time was prolonged, and not only the flame retardance was very inferior, but also the appearance defect that silver streaks occurred on the surface of the molded product occurred (Comparative Example 5). The resin composition (Comparative Example 6) in which the blending amount of the neutral clay was less than the specified amount had a long burning time and very poor flame retardancy.

Claims (2)

  Polycarbonate resin (A) 85-99.45% by weight, pH 5.6-7.3 neutral clay (B) 0.5-10% by weight, and fiber-forming fluoropolymer (C) 0.05-5 A flame retardant polycarbonate resin composition, comprising: The average particle size of the neutral clay (B) is 0.1 to 0.3 μm as measured by Microscan (Quantachrome) Analyzer, the average specific surface area by BET method is 9000 to 12000 cm 3 / g, and conforms to ASTM D281 (crude linseed oil) The flame retardant polycarbonate resin composition according to claim 1, wherein the average oil absorption measured is 30 to 50 (lbs / 100 lbs).