MXPA00005250A - Flame-retardant polycarbonate resin composition - Google Patents

Abstract

A flame-retardant polycarbonate resin composition characterized by comprising 100 parts by weight of a polycarbonate resin (A), about 0.01 to 8 parts by weight of a silicone compound (B) whose main chain has a branched structure and whose organic substituents bear aromatic groups, either about 0. 03 to 5 parts by weight of a metal salt (C) of an aromatic sulfur compound or about 0.01 to 5 parts by weight of a metal salt (D) of a perfluoroalkanesulfonic acid and, if necessary, about 0.05 to 5 parts by weight of a fiber-forming fluoropolymer (E). This composition is remarkably improved in flame retardance without impairing the impact resistance and moldability, and is out of danger of generating a halogen-containing gas due to a flame retardant in burning by virtue of its being free from a flame retardant comprising a chlorine or bromine compound, thus being advantageous in respect to environmental protection.

Description

RESIDUAL COMPOSITION OF FLAME RETARDANT POLYCARBONATE RESIDUE TECHNICAL FIELD This invention relates to flame retardant polycarbonate resin compositions. More particularly, it relates to enhanced flame retardant polycarbonate resin compositions in flame retardation without sacrificing the inherent protruding properties of the polycarbonate resin, such as, impact strength and other mechanical properties, flow properties and outer appearance of molded parts, and that do not cin a halogen-type flame retardant cining a chlorine or bromine compound, nor a phosphorus-type flame retardant.

BACKGROUND OF THE PRIOR ART Polycarbonate resins, a class of engineering plastics with excellent transparency, impact strength, heat resistance and electrical properties, are used extensively in electrical, electronic, office automation, and many other applications. ications. In the electric-electronic and OA fields there are many components, such as personal computer housings, that are required to possess high flame retardancy (in accordance with the 94 V ratings of Underwriters' Laboratories (UL)) and high impact resistance . Polycarbonate resins are plastics by themselves highly flame retardant and self-extinguishing. Even so, in electric-electronic and OA applications where safety is the primary consideration, it is required that they have even greater flame retardancy, high enough to satisfy the requirements of U L94V-0 and 94V-1. A method commonly used to improve the flame retardancy of the polycarbonate resin has been to mix it with a large proportion of an oligomer or polymer of a brominated bisphenol A carbonate derivative.

Problems encountered The large addition of an oligomer or polymer of a brominated bisphenol A carbonate derivative improves the flame retardancy of the polycarbonate resin. However, it reduces the resistance to impact of the resin and therefore has a problem of frequent cracking of articles molded from the resin. On the other hand, mixing the resin with a large amount of a halogen-cining compound cining bromine can emit a gaseous product cining the particular halogen on the combustion. In this way, from environmental considerations, there is a demand for the use of a flame retardant free of chlorine, bromine or the like. In the meantime, many attempts have been made so far to use silcone components as flame retardants. The compounds have high heat resistance, produce negligibly noxious gas on combustion and are remarkably safe in use.

The silicone compound as a flame retardant is a polymer resulting from the polymerization of at least any of the following four siloxane units (unit M, unit D, unit T and unit Q). (1) Unit M R Structure: R - Si - O - Chemical formula: R3SiO0 R where R represents an organic group. (2) Unit D Structure: - O - Si - O - Chemical formula: R2SiO. 0 R where R represents an organic g rupo (3) Unit T Structure: - O - Si - O Chemical formula: RSiO. 5 O where R represents an organic group. (4) Unit Q O I Structure: - O - Si - O - Chemical formula: SiO2 0 O Of these units, the unit T and / or unit Q, when they are cined in the com position, form a branched structure. In order to use silicone compounds as flame retardants, various silicone compounds having organic groups have been tested to date, as shown in the Japanese patent application public description (Kokai) No. 1 -31 8069 , Japanese patent application publication (Kokoku) No. 62-60421, etc. However, very few of these compounds can achieve an appreciable flame retardant effect when added individually. Even one that was found to be relatively effective must be added in a large quantity if the strict standards for electrical-electronic equipment are to be met. A large addition is not practicable because it affects the molding properties unfavorably, training and other necessary of the resulting plastics, and also because it is added to the cost. Methods for combining a silicone compound with a metal salt have been reported as attempts to intensify the flame retardant effect of a silicone compound while reducing the amount to be added. I nclude the combined use of poly idimethyl silicone, a metal hydroxide and a zinc compound (public description of Japanese Patent Solitaire (Kokai) No. 2-1 50436); polydimethyl silicone and a metal salt of Group I of an organic acid (Japanese Patent Application (Kokai) public disclosure No. 56-1 00853); and silicone resin, especially one represented by the M and Q units, silicone oil and a metal salt of Group I of an organic acid (Japanese Patent Application Publication (Kokoki) No. 3-48947). Common fundamental problems for those methods are an inadequate flame retardant effect and difficulty in substantially reducing the amount to be added. A further combination of an organopolysiloxane having an epoxy group (β-glycidoxypropyl group) and phenyl group and / or vinylo group and an alkali metal salt and alkaline earth metal salt of an organic sulfonic acid has been reported (public description of sun Japanese patent application (Kokai) No. 8-1,76425). Because this silicate compound contains highly reactive vinyl and epoxy groups, the silicon compound can react with itself to form high molecular weight gels when mixed with the polycarbonate resin, due to the high temperature, dulling mixing and increasing the viscosity of the mixture. This presents problems of undesirable moldability of polycarbonate resin, especially melting, collapse and / or irregularity of the surface of the molded part. Moreover, the gelification does not allow the silicone compound to be deeply dispersed in the polycarbonate resin. This, in turn, causes problems of difficulty in obtaining a noticeable flame retardant effect and declining strength properties, such as impact strength of the molded articles.

BRIEF DESCRIPTION OF THE INVENTION The present inventors have intensively searched for a solution to the above-described problems of the prior art. They have now found, as a result, that the combined use of a specific silicone compound and a metal salt of an aromatic sulfur compound or a metal salt of a perfluoroalkanesulfonic acid as a flame retardant, to be mixed with a A polycarbonate resin and the additional use of a fiber-forming fluoropolymer, provides flame retardant polycarbonate resin compositions, which possess high flame retardancy without sacrificing their impact and molding resistance properties. The finding has led to the improvement of the present invention. The flame retardant polycarbonate resin compositions according to the invention, free of a bromine or other halogen type flame retardant, are not endangered at the moment of combustion by the emission of gases containing the resulting halogen. of the halogen type flame retardant, and for it exhibit an outstanding performance from the point of view of environmental protection. Briefly, the invention concerns a flame retardant polycarbonate resin composition characterized by mixing a polycarbonate resin (A) with a silicate compound (B), whose skeleton structure is branched and having aromatic groups in the organic groups it contains, and a metal salt of an aromatic sulfur compound (C) or a metal salt of a perfluoroalkanesulphonic acid (D). It also concerns a flame retardant polycarbonate resin composition characterized by the addition of a fiber-forming fluoropolymer (E). The flame retardant polycarbonate resin compositions according to the invention will be described in detail below.

DETAILED DESCRIPTION OF THE INVENTION The polycarbonate resin (A) to be used in this invention is any of the polymers obtained either by the phosgene process, in which a compound of varying dihydroxydiaryl is reacted with phosgene, or by ester exchange process, in which a dihydroxydiaryl compound is reacted with a ico carbon ester, such as, diphenyl carbonate. A polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) is normal. Examples of the dihydroxyaryl compounds, in addition to bisphenol A, are: bis (hydroxyaryl) alkanes, such as, 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.-butylphenol 1) propene, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3, 5-dibromophenyl) propane and 2,2 bis (4-hydroxy-3,5-dichlorophenyl) propane; bis (hydroxyaryl) cycloalkanes, such as 1,1-bis (4-hydroxy-phenyl) -cyclopentane and 1,1-bis (4-hydroxyphenyl) -cyclohexane; dihydroxydiaryl ethers, such as, 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether; dihydroxydiaryl sulfides, such as, 4,4'-dihydroxydiphenyl sulfide; dihydroxyaryl sulfoxide, such as 4,4'-hydrodiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide; and dihydroxydiarylsulphones, such as, 4,4'-dihydroxydiphenyl sulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone. These are used simply or as a mixture of two or more. It is preferred that these compounds are not halogenated, so that they do not release halogen-containing gases into the atmosphere during combustion. Such a compound or compounds can be used in mixture with piperazine, dipiperidylhydroquinone, resorcin, 4,4'-dihydroxydiphenyl, etc. The dihydroxyaryl compound or compounds can be used in combination with a trivalent or more polyvalent phenol compound, as follows. Tri- or polyvalent phenols include phloroglucin, 4,5-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) benzole, 1,1-tri (4-hydroxyphenyl) ethane and 2,2-bis [4,4- (4,4'-dihydroxydiphenyl) cyclohexyl] propane The viscosity-average molecular weight of a polycarbonate resin (A) is usually between about 10,000 and about 100,000, preferably between about 15,000 and about 35,000.To prepare such a polycarbonate resin, it is possible to use a molecular weight modifier, catalyst and / or other additive according to the invention. to the need.

The silicone compound (B) to be used in the invention is one whose skeleton structure is branched and which contains aromatic groups, such as organic groups (R, R2 and R3), as represented by the general formula (1). General formula (1) where R1, R2 and R3 represent organic groups in the main chain, X represents a terminal functional group, and n, m and I represent the number of each unit. The compound is characterized by having a unit T and / or unit Q as the branching unit. It is desirable that the amount of such units contained in the compound respond by at least about 20 mol% of the total content of siloxane units. If it is less than about 20 mol%, the resulting silicone compound (B) has an inadequately low heat resistance and a reduced flame retardant effect, and exhibits such a low viscosity, that it can have adverse effects on m iscibility with a polycarbonate resin (A) and on the moldability of the resulting composition. A more desirable range is between about 30 and about 95 mol%. A proportion of excess amounts of about 30 mol% further increases the heat resistance of the silicone component (B) and substantially enhances the flame retardancy of the polycarbonate resin containing the com pound. However, beyond 95 mol%, the units decrease the degree of freedom of the silicone backbone, often hindering the condensation of the aromatic ring during combustion and making it more difficult to exhibit a noticeable flame retardation. It is also advisable that the silicone compound (B) should contain organic groups, of which the aromatic groups respond by at least about 20 mol%. Below this limit, condensation between the aromatic rings tends to occur hardly during combustion, thus reducing the flame retardant effect. A preferred range is between about 40 and about 95 mol%. Above about 40 mol%, the aromatic groups are condensed more effectively during combustion, while, at the same time, the dispersibility of the silicone compound (B) in the polycarbonate resin (A) is substantially enhanced, and a very high flame retardant effect is achieved. However, beyond about 95%, the spherical obstruction between the aromatic groups tends to obstruct their condensation, making it sometimes difficult to obtain a remarkable flame retarding effect. The aromatic groups to be contained are phenyl, biphenyl, naphthalene or their derivatives. The phenyl group is preferred from the point of view of industrial hygiene of the silicone compound (B). Of the organic groups in the silicone compound (B), the organic group other than the aromatic group is preferably methyl group. It is also desirable that the terminal group be one or a mixture of two to four different groups selected from the class consisting of methyl group, phenyl group, hydroxyl group and alkoxy groups (especially methoxy group). These final groups, with low reactivity, rarely cause the gelation (crosslinking) of the silicone compound (B) during the mixing of the com pound with the polycarbonate resin (A). Accordingly, the silicone compound (B) can be uniformly dispersed in the polycarbonate resin (A), whereby a better flame retardant effect is achieved and an enhanced moldability is obtained. Particularly desirable is the methyl group, which, with exceptionally low reactivity, produces an extremely desirable dispersibility and a further improvement in flame retardancy. The average molecular weight (weight) of the silicone compound (B) desirably varies from about 5,000 to about 500,000. If it is less than about 5,000, the heat resistance of the silicone compound itself is insufficient, with a reduced flame retardant effect. In addition, the melt viscosity is so low that the silicone compound can be exuded to the surface of a molded part of the polycarbonate resin (A) at the time of molding, often adversely affecting the moldability unfavorably. On the other hand, if it is more than about 500,000, the melt viscosity increases excessively to obstruct the niform dispersion of the compound in the polycarbonate resin (A). This sometimes decreases the flame retardant or moldability effect. A more desirable range is from about 1000 to about 270,000. In this range, the melting viscosity of the silicone compound (B) is optimal, allowing the compound to be dispersed more evenly in the polycarbonate resin. (A) without excessive exudate to the surface, thus making flame retardancy and moldability even better. The amount of silicone compound (B) to be used desirably varies from about 0.01 to about 8 parts by weight per 1000 parts by weight of the polycarbonate resin (A), when the amount is less than about 0.01 parts by weight , the flame retardant effect is sometimes insufficient. When it is greater than about 8 parts by weight, demolition can damage the appearance of the molded articles. A more desirable range is from about 0. 1 to about 5 parts by weight, and an even more desirable range is from about 0.5 to about 2 parts by weight. In the last mentioned range, a better equilibrium is achieved between flame retardancy and moldability and between flame and force of impact. The metal salt of an aromatic sulfur compound (C) to be used in the present invention is either a metal salt of an aromatic sulfonamide of the general formula (2) or (3) below, or a salt of an aromatic sulfonic acid of the general formula (4) below.

General formula (2) O O A r - S - N "- S - A r M + (In the general formula (2) Ar is a phenyl or substituted phenyl group and M is a metal cation.) General formula (3) A r - S - N ~ M + R ' (In the general formula (3) Ar is a phenyl or substituted phenyl group, R 'is an organic group which may contain a sulfonyl or carbonyl group and M is a metal cation, with the proviso that Ar may be a phenylene to be linked with R '.) General formula (4) (In the general formula (4) R "and R '" are identical or different, and represent aliphatic groups containing 1 to 6 carbon atoms, substituted phenyl, biphenylyl or phenyl or biphenylyl groups, and A represents a SO3M group, which M is a metal cation.) Desirable examples of metal salts of aromatic sulfonamides are metal salts of saccharin, metal salts of N- (p-tolylsulfonyl) -p-toluenesulfoimide, metal salts of N- (N '-benzylaminocarbonyl) sulfanilimide, and metal salts of N- (phenylcarboxyl) -sulfanylimide. The metal salts of aromatic sulfonic acids are, for example, metal salts of diphenylsulfone-3-sulfonic acid, diphenylsulphone-3, 3'-disulfonic acid and diphenylsulfone-3,4'-disulfonic acid. They can also be used alone or in combination. Suitable metals are Group I metals (alkali metals), such as sodium and potassium, Group I I metals (alkaline earth metals), copper, aluminum, etc. , especially alkali metals. These are preferred over potassium salts, such as potassium salt of N- (p-tolylsulfonyl) -p-toluenesulfoimide, potassium salt of N- (N'-benzylaminocarbonyl) sulfanylimide, and potassium salt of acid diphenylsulfone-3-sulfonic acid. More preferred are the potassium salt of N- (p-tolylsulfonyl) -p-toluenesulfoim and potassium salt of N- (N '-benzylaminocarbonyl) sulfanilimide. The amount of a metal salt of an aromatic sulfur compound (C) to be used desirably varies from about 0.03 to about 5 parts by weight per 1000 parts by weight of a polycarbonate resin (A). When the amount is less than about 0.03 parts by weight, it is sometimes difficult to obtain a noticeable flame retardant effect, with adverse effects on moldability and impact strength. A preferred range is between about 0.05 and about 2 parts by weight, and a more preferred range is between about 0.06 and about 0.4 parts by weight. In this range, above all, flame retardancy, moldability and impact strength are better balanced. The metal salt of a perfluoroalkanesulfonic acid (D) to be used in this invention is a metal salt of the formula (5) below: wherein M is a metal cation and n is an integer from 1 to 8. The metal salt of a perfluoroalkanesulfonic acid (D) i includes a metal salt of a perfluoromethanesulfonic acid, a metal salt of a perfluoroethanesulfonic acid, a salt metal of a perfluoropropanesulfonic acid, a metal salt of a perfluorobutane sulfonic acid, a metal salt of a perfluoropentanesulfonic acid, a metal salt of a perfluorohexanesulfonic acid, a metal salt of a perfluoroheptanesulfonic acid, a metal salt of an acid pefluorooctanesulfonic acid and the like or a mixture of the same. The metal salt of a perfluoroalkanesulfonic acid can be used in combination with the aromatic sulfur compound (C) described above. The metal used in the metal salt of a perfluoroalkanesulfonic acid (D) includes metals of Group I (alkali metals), such as sodium and potassium, metals of Group I I (alkaline earth metals), copper and aluminum. The alkali metal is preferred. The preferred metal salt of a perfluoroalkanesulfonic acid (D) is a potassium salt of a perfluorobutane sulfonic acid. The amount of a metal salt of a perfluoroalkanesulfonic acid (D) is about 0.01 to about 5 parts by weight based on 1000 parts by weight of polycarbonate resin (A). If the amount is less than about 0.01 parts by weight, its flame retardancy is sometimes insufficient, while an amount beyond about 5 parts by weight, may result in poor thermal stability in injection molding, which it can negatively influence moldability or impact force. The amount is preferably approximately 0.02 hast approximately 2 parts by weight, and more preferably about 0.03 to about 0.2 parts by weight. The last range leads particularly to a good balance between flame retardancy, moldability and impact force. The fiber-forming fluoropolymer (E) to be used in this invention desirably is one that forms a fiber structure (fiber-like structure) in a polycarbonate resin (A). Useful are polytetrafluoroethylenes, tetrafluoroethylene copolymers (e.g., tetrafluoroethylene copolymer hexafluoropropylene), partially fluorinated polymers as shown by U.S. Patent 4, 379, 910, and polycarbonates produced from fluorocarbon diphenol. When used such a polymer together with a combination of a compound of whether con (B) and a metal salt of an aro- matic sulfur compound (C), or a combination of a metal compound (B) and a metal salt of a perfluoroalkanesulfonic acid (D) according to the invention, proves to be effective not only to prevent dripping, but also specifically shortens the combustion time. The amount of a fluoropolymer fiber forming (E) to be used is in the range from about 0 05 up to about 5 parts by weight per 1 00 parts by weight of a polycarbonate ream (A) If the amount is less than about 0 05 parts by weight, the effect of p Dripping prevention during combustion is sometimes insufficient, while a quantity greater than about 5 parts by weight can make it difficult for the resulting composition to be granulated, thereby hindering stable production. A preferred range is between about 0 and about 1 part by weight and a most preferred range is between about 0 1 and about 0 5 parts by weight In this range, the balance between flame retardancy, moldability and impact force is further improved Polycarbonate resin (A) can be mixed , unless the addition does not impair the advantageous effects of the invention, with other additives, such as any of several heat stabilizers, antioxidants, colorants, fluorescent brighteners, fillers, mold release agents, softening agents, antistatic agents, improvers of impact properties and other polymers. Heat stabilizers are, for example, metal acid sulfates, such as, sodium acid sulfate, potassium acid sulfate and lithium acid sulfate, and their metal phosphates, such as aluminum sulfate. Such a stabilizer is usually used in an amount of from about 0 to about 0.5 parts by weight per 1000 parts by weight of a polycarbonate resin (A). The fillers include fiberglass, glass beads, glass flakes, carbon fiber, talc, clay powder, mica, potassium titanate scoops, wollastonite powder, and silica powder. Among the impact property improvers are acrylic elastomers, polyester elastomers, methyl-butadiene-styrene methacrylate-core-shell type copolymer, methyl methacrylate-acrylonitrile-styrene copolymer, ethylene-propylene rubber and ethylene-propylene-diene rubber. Examples of other polymers are polyesters, such as polyethylene terephthalate and polybutylene terephthalate; polystyrene; Stretchable polymers, such as high-impact polystyrenes, acrylonitrile-styrene copolymer and their acrylic gum modification products, acrylonitrile-butadiene-styrene copolymer copolymer and acrylonitrile-ethylene-propylene-gum copolymer diene (EPDM) -styrene; polypropylenes; and polymers usually used as alloys with polycarbonate resins.

There is no special limitation for the method for mixing the various components in the flame retardant polycarbonate resin composition of the invention. For example, it may be used either mixed by means of a conventional mixer, such as, a drum, a ribbon blender or by melt mixing by means of an extruder. As for the method for molding the flame retardant polycarbonate resin composition of the invention, it can be employed, without special limitation, injection molding, compression molding by injection or other conventional molding technique.

Examples The following examples illustrate the invention without limiting it. All parts are in weight. Examples 1 to 61 and comparative examples 1 to 30 1 00 portions are mixed in parts of a polycarbonate resin derived from bisphenol A with 0.03 parts of potassium acid sulfate each, and varied proportions of other components listed in Tables 2 to 1 3. The resulting mixtures are melt blended using a 37 mm diameter twin screw extruder (Model "KTX-37" manufactured by Kobe Steel, Ltd.) at a cylinder temperature of 280 ° C. In this way, several pelleted products were obtained. The particulars of the materials used are as follows: 1. Polycarbonate resin (A): Made by Sumitomo Dow Limited under the tradename "Caliber 200-20" (viscosity-average molecular weight = 19,000). 2. Silicone compound (B): The silicone compound (B) is produced by a conventional process. In proportion to the molecular weight of a silicone compound component and to the proportions of the M, D, T and Q units constituting a silicone compound, a suitable amount of diorganodichlorosilane, monoorganotrichlorosilane, tetrachlorosilane or a partially hydrolyzed condensate of such a silane, it dissolves in an organic solvent. The hydrolysis is carried out by the addition of water, and a partially condensed silicone compound is formed. It is further reacted with the addition of triorganochlorosilane to conclude the polymerization. The solvent is subsequently removed by distillation or other technique. The structural properties of 1 9 different silicone compounds thus synthesized by the above method are shown in Table 1.

Table 1 * The phenyl groups in the silicone compound are provided through a unit T. If all the phenyl groups can not be added through the units T, then the additional phenyl groups are provided by units D. The units D will only contain a phenyl group if all additional phenyl groups can be provided in that manner. If even more phenyl groups are needed, then D units containing two phenyl groups are used. Except for the phenyl groups and the final groups as indicated in Table I, all organic groups are methyl. ** For the average molecular weight-weight, the significant figures are two. 3. Metal salt of an aromatic sulfur compound (C): • N- (p-tolylsulfonyl) -p-toluenesulfoimide potassium salt (hereinafter referred to as "C-1"). • Potassium salt of N- (N'-benzylaminocarbonyl) sulfanilimide (hereinafter referred to as "C-2"). • Potassium diphenolsulfone-3-sulfonate (hereinafter referred to as "C-3"). 4. Metal salt of a perfluoroalkanesulfonic acid (D): • Potassium salt of a perfluorobutanesulfonic acid (hereinafter referred to as "D metal salt") 5. Fluoropolymer forming fiber (E): • Polytetrafluoroethylene ("Polyfuron FA") -500"made by Daikin Kogyo Co., Ltd.) (hereinafter referred to as" PTFE "). 6. Oligomer of tetrabromobisphenol carbonate A: • "BC-52" by Great Lakes Chem icals (hereinafter referred to as "Br oligomer"). The various pellets thus obtained are dried at 1 25 ° C for 4 hours and then molded by means of an injection molding machine (Model "J-1 00-E-C5" manufactured by N ippon Seiko KK) at 280 ° C. C and at an injection pressure of 1600 kg / cm2, and test specimens (1 25 x 1 3 x 1 .6 mm and 1 24 x 1 3 x 3.2 mm) are formed for the evaluation of flame retardancy. The specimens are allowed to remain in a thermostatically controlled chamber at a temperature of 23 ° C and a humidity of 50% for 48 hours. They are then tested for flame retardancy and evaluated in accordance with the Underwriters' Laboratories U L94 test test standards (for the evaluation of combustibility of plastic materials for appliance components). U L94V designates the evaluation of the flame retardancy after the flame and dripping after the exposure of a test specimen of a given size, held on top of a burner in contact for 1 0 seconds. The classifications are as follows: The term "after the flame", as used herein, refers to the period in which a test specimen continues to burn after the source of ignition has been removed. "Trickle cotton ignition" means if a piece of cotton placed approximately 300 mm below the lower end of a specimen is ignited or not from a drop of specimen melting. The results are given in Tables 2 to 1 3. The various pellets obtained are injection molded in the same way to form test specimens (3.2 x 1 2.7 x 63.5 mm) for the evaluation of their impact force. The marked impact force values of the specimens are measured in accordance with ASTM D-256. Regarding the outer appearance of the molded parts, the specimens are visually inspected, before the measurement of impact strength, to see if they had signaled dislodging or subsidence on the surface. The results are shown in Tables 2 to 1 3. In Table 2 to 1 3, the numerical values of the Br, silicone, metal salt and PTFE type oligomer represent the amounts (parts by weight) added per 1000 parts of a polycarbonate resin. In the evaluation of the flame retardancy, the values in parentheses () indicate the total (in seconds) of after the flame (duration of combustion after ignition) of five specimens. The values in [] are the number of specimens (among five specimens) that caused fire to mark cotton by drip. Moldability is evaluated by inspecting molded specimens for deslamination, surface irregularities and subsidence. (Or designates any defect found,? Designates defects in 1 to 2 specimens, and X designates defects in 3 or more specimens of five specimens.) Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 Table 9 Table 10 Table 11 Table 1 2 Table 1 3 As indicated by Examples 1 to 61, the polycarbonate resin compositions characterized to contain from 0.01 to 8 parts by weight of a silicone compound (B), whose skeleton structure is branched and containing aromatic groups, and from 0.03 to 5 parts by weight of a metal salt of an aromatic sulfur compound (C) or from 0.01 to 5 parts by weight of a metal salt of a perfluoroalkanesulfonic acid (D), and containing the polycarbonate resin compositions, in addition to the two above compounds, from 0.05 to 5 parts by weight of a fiber-forming fluoropolymer (E), exhibited much greater flame retardant effects than a polycarbonate resin alone that did not contain any such additives (Comparative Example 1), the compositions of polycarbonate resin that did not contain either a silicon compound (B) or a metal salt of an aromatic sulfur compound (C) (Comparative Examples 2 to 4, 13 to 15, & a 22), and polycarbonate resin compositions containing a silicone compound of a structure different from that in accordance with the present invention (Comparative Examples 16 to 18 & 23 to 26). The examples of the invention also demonstrate marked improvements in the impact strength of polycarbonate resin compositions which has been a common problmea for conventional compositions containing a bromine-type flame retardant. With regard to the amount of a silicone compound (B) to be added, Examples 12 to 18 and Comparative Examples 9 to 12 reveal that when the amount is less than 0.01 part by weight, the flame retardancy falls (Comparative Examples 9 to 10), but when it is greater than 8 parts by weight the moldability, in particular, is adversely affected (Comparative Examples 11 to 12). As for the amount of a metal salt of an aromatic sulfur compound (C), Examples 4 to 11 and Comparative Examples 6 to 8 indicate that when the amount is below 0.03 parts by weight, the flame retardation is low (Comparative Example 6) and when it is above 5 parts by weight, the moldability and impact strength decline (Examples 7 to 8). Concerning the fluoropolymer fiber former (E) which is used in combination with a silicon compound (B) and a metal salt of an aromatic sulfur compound (C), Examples 22 to 28, 29 to 30, 33 to 34, 35 to 36, 37 to 38, 39 to 40, 41 to 42 and 43 to 44, show that the addition not only enhances the effect of preventing dripping of a polycarbonate resin composition that is burning, but substantially shortens the time of combustion. Thus, examples show that the fluoropolymer (E) does not simply function as an anti-drip agent, but achieves a unique synergistic effect of improving the flame retardancy of a combination system of the silicone compound (B) and the salt of metal (C) according to the invention. Incidentally, an attempt to form a com position by adding 6 parts by weight of the fluoropolymer (E) to the formulation of Example 22 failed because it could not be granulated for the evaluation. As for the amount of a metal salt of a perfluoroalkanesulfonic acid (D), Examples 54 to 57 and Comparative Examples 29 to 30 indicate that when the amount is below 0.01 part by weight, the flame retardancy is low ( Comparative Example 29) and when it is above 5 parts by weight, the flame retardancy, moldability and impact force decline (Comparative Example 30). As regards a fiber-forming fluoropolymer (E) which is used in conjunction with a silicone compound (B) and a metal salt of a perfluoroalkanesulfonic acid (D), Examples 55 and 58 show that Addition not only enhances the drip prevention effect of a burning polycarbonate resin composition, but also substantially shortens the combustion time. Thus, the examples demonstrate that the fluoropolymer (E) does not simply function as an anti-drip agent, but achieves a synergistic effect to improve the flame retardancy of a combined system of the silicone com pound (B) and the metal salt (D) according to the invention. Finally, an attempt to form a composition by adding 6 parts by weight of the fluoropolymer (E) to the formulation of Example 55 failed because it could not be ranched for evaluation. As far as the structure of the silicone compound is concerned, Examples 20 to 36 and Comparative Examples 1 6 to 1 8 indicate that when the skeleton structure of the compound contains branching units, that is, the unit of the formula RsiO? 5 (unit T) and / or the unit of the formula SiO2 0 (a Q-value), notably improves the flame retardancy, moldability and impact force of the resultant polycarbonate resin compositions on the compositions using silicone that they do not contain those ones (Comparative Examples 1 6 to 1 8). First of all, compositions in which the units respond to more than 20 mol% of the total siloxane unit (R3.0 SiO2.0 5) (Examples 29 to 34) show additional improvements in those properties. It will also be obvious from a comparison between pairs of Examples 29, 30 and 33, 34, that silicone compounds containing more than 30 mol% branching units (Examples 29, 30) possess flame retardancy properties. and impact even better. However, when the proportion of ramification units exceeds 95 mol%, the resulting compositions are sometimes unable to achieve a noticeable flame retardant effect. Thus, it is desirable for the flame retardancy, moldability and impact force, that the branching units, ie the unit of the RsiO formula. 5 (unit T) and / or the unit of the formula SiO2 0 (unit Q), respond by 20 mol% or more, preferably between 30 and 95 mol%, of the total units of if loxane (R3.0SiO2.0 5) . further, as is evident from Examples 30, 31, the compounds having the unit of the formula SiO2 or (Q unit) alone as the branching unit, exhibit flame retardancy equal to or better than that of the com positions that have only the unit of the RsiO form. 5 (unit T). As shown in Examples 37 to 42 and also Examples 43 to 44 and Comparative Examples 23 to 26, the content of aromatic group (phenyl group) in the organic groups of a silicon compound (B) improves the retardation of Flame, moldability and impact strength of the polycarbonate resin compositions on those which do not contain the aromatic group (Examples of components 23 to 26). When the content of the aromatic group exceeds 20 mol% (Examples 37 to 42), further improvements in flame retardancy, moldability and impact strength are achieved. As is apparent from Examples 37 to 40 and Examples 41 to 42, when 40 mol% is exceeded (Examples 37 to 40), the flame retardancy is more markedly enhanced. However, when the content of aromatic group (phenyl group) in the organic groups is greater than 95 mol%, such a remarkable flame retardant effect sometimes can not be obtained. Thus, the aromatic group content (phenyl group) in the organic groups of a silicone compound (B) is desirably 20 mol% or greater, and more desirably ranges from 40 to 95 mol%, due to its favorable effects on retardation of flame, moldabilidad and force of impact. With respect to the final group of a silicone compound (B), Examples 13 and 17, 20 to 21, 30 to 32 and 37 to 38, indicate that the silicone compounds containing methyl group (Examples 13, 17, 30), phenyl group (Examples 37 to 38), hydroxyl group (Examples 20 to 21) and alkoxy group (methoxy group) (Example 32) exhibit good flame retardancy, moldability and impact strength. An even better flame retardancy is achieved when the final group is methyl instead of a hydroxyl group, as shown in Examples 13 and 17, 20 and 21, or when it is methyl instead of alkoxy group, as shown in Examples 30 and 32 The same applies to methyl instead of phenyl group. The silicone compound containing an epoxy group (α-glycidoxypropyl) or vinyl group is particularly reactive and the silicone compound reacts with itself to form a gel when mixed with a polycarbonate resin. This gelation substantially affects the moldability of the polycarbonate resin, and the silicone compound (B) itself becomes less dispersible in the resin, making it capable of obtaining a flame retardant effect and adequate impact force. For these reasons, the final group of silicone compound (B) is most preferably methyl group. The molecular weight of the silicone compound (B) is between 5,000 and 500,000, preferably between 10,000 and 270,000, from the point of view of moldability and flame retardancy, as will be apparent from Examples 2, 3, 1 7 and 9. As to the structure of the metal salt of an aromatic sulfur compound (C), Examples 34 to 53 suggest that the potassium salt of N- (p-tolyl-sulfonyl) -p-toluenesulfoimide (C -1), potassium salt of N- (N'-benzylaminocarbonyl) sulfanylimide (C-2"), or potassium diphenilsu-3-sulfonate (C-3) is suitably used and, the salt Potassium N- (p-tolylsulfonyl) -p-toluenesulfoimide or N- (N'-benzylaminocarbonyl) sulfanilimide potassium salt is used more suitably The results of the examples show that the combined use from 0.01 to 8 parts by weight of a silicone compound (B) and from 0.03 to 5 parts by weight of a metal salt of an aromatic sulfur compound (C) or from 0.01 to 5 parts by weight of a a metal salt of a perfluoroalkanesulfonic acid (D) according to the invention, im a much higher flame retardancy to a polycarbonate resin (A) than for the silicone compound alone (B). This is a unique synergistic effect observed only with the particular combination described above. When in addition 0.05 to 5 parts by weight of a fiber-forming fluoropolymer (E) is used together with the previous combinationNot only is the anti-drip effect improved in a burning polycarbonate resin composition, but a very favorable effect in shortening the combustion time is also achieved. Thus, the addition brings a synergistic effect on the improvement of global flame retardancy, only for the combined system of the silicone compound (B) and the metal salt (C), or the silicone compound (B) and the metal salt (D).

The flame retardant polycarbonate resin compositions according to the present invention achieve a flame retardancy higher than the temperature which retains good impact resistance and non-deteriorated moldability. Free of a flame retardant of chlorine, bromine or similar compound, they do not have the danger of emitting gases containing no halogen derived from the retardant during combustion. Because the flame retardant in these compositions does not contain chlorine or bromine or the like, non-halogen-containing gases are formed from the flame retardant when these com positions are quoted, which is outstanding from the standpoint of environmental Protection .

Claims (10)

REIVI NDICATIONS

1 . A flame retardant polycarbonate resin composition comprising 1 00 parts by weight of a polycarbonate resin (A) and about 0.01 to about 8 parts by weight of a silicone compound (B) and also containing about 0.03 to about 5 parts by weight. parts by weight of a metal salt of an aromatic sulfur compound (C) or about 0.01 to about 5 parts by weight of a metal salt of a perfluoroalkanesulfonic acid (D), wherein the skeleton structure of said silicone compound (B) is branched and said silicone compound (B) comprises organic groups that include aromatic groups, wherein said silicone compound (B) comprises a unit of a formula RsíO. 5 (unit T) and / or one unit of a formula SiO2 0 (unit Q) in a proportion of at least 20 mol% of the total siloxane units (R3.0S O2_o 5), in which R is a organic gum, and the metal of the metal salt of said aromatic sulfur compound (C) is an alkali metal.

2. A flame retardant polycarbonate resin composition according to claim 1, which further comprises about 0.05 to about 5 parts by weight of a fiber-forming fluoropolymer (E). 3. The flame retardant polycarbonate resin composition according to claim 1, wherein the amount of said silicone compound (B) is about 0. 1 to about 5 parts by weight and the amount of said metal salt of an aromatic sulfur compound (C) is about 0.05 to about 2 parts by weight. 4. The flame-retardant polycarbonate resin composition according to the re-excitation 1, wherein the amount of said flame retardant compound (B) is about 0. 1 to about 5 parts by weight, and the amount of dich The metal salt of a perfluoroalkanesulfonic acid (D) is about 0.02 to about 2 parts by weight. 5. The flame retardant polycarbonate resin composition according to claim 2, wherein the amount of said flame retardant compound (B) is about 0. 1 to about 5 parts by weight, the amount of salt d The metal of an aromatic sulfur compound (C) is about 0.05 to about 2 parts by weight and the amount of said fiber-forming fluoropolymer (E) is 0.05 to 1 part by weight. 6. The flame retardant polycarbonate resin composition according to claim 2, wherein the amount of said silicone compound (B) is about 0. 1 to about 5 parts by weight, the amount of said metal salt. of perfluoroalkanesulfonic acid (D) is about 0.02 to about 2 parts by weight, and the amount of said fiber-forming fluoropolymer (E) is 0.05 to 1 part by weight. 7. The flame retardant polycarbonate resin composition according to claim 1, wherein the proportion of said aromatic groups is at least 20 mol% to said organic groups. 8. The flame retardant polycarbonate resin composition according to claim 2, wherein the proportion of said aromatic groups is at least 20 mol% to said organic groups. 9. The flame retardant polycarbonate resin composition according to claim 1, said aromatic group is phenyl and the remainder of said organic groups is methyl, the final groups of said compound being comprised of (B) less one selected from the group consisting of the methyl, phenyl, hydroxyl and alkoxy group. 10. The flame retardant polycarbonate resin composition according to claim 2, said aromatic group is phenyl and the remainder of said organic groups is methyl, the final groups of said silicate compound (B) comprising the minus one selected from the group consisting of methyl group, phenyl, hydroxyl and alkoxy. eleven . The flame retardant polycarbonate resin composition according to claim 1, wherein said metal salt of an aromatic sulfur compound (C) is a metal salt of an aromatic sulfonamide or a salt of an aromatic sulfonic acid and said metal salt of a perfluoroalkanesulfonic acid (D) contains 1 to 8 carbon atoms. 12. The flame retardant polycarbonate resin composition according to claim 2, wherein said metal salt of an aromatic sulfur compound (C) is a metal salt of an aromatic sulfonamide or a salt of an acid thereof. Aromatic ionic acid and said metal salt of a perfluoroalkanesulfonic acid (D) contains 1 to 8 carbon atoms.

3. The flame retardant polycarbonate resin composition according to claim 1, wherein said metal salt of an aromatic sulfur compound (C) is a metal salt of at least one selected from the group consisting of: consists of saccharin, N- (p-tolylsulfonyl) -p-toluenesulfonimide, N- (N '-benzylaminocarbonyl) sulfanilimide, N- (phenylcarboxyl) -sulfanilimide, diphenyl sulfone-3-sulfonic acid, diphenyl sulfone-3, 3 '-disulfonic acid and diphenyl sulfone-3,4'-disulfonic acid. 1

4. The flame retardant polycarbonate resin composition according to claim 14, wherein said metal salt of an aromatic sulfur compound (C) is a metal salt of at least one selected from the group consisting of saccharin. , N- (p-tolylsulfonyl) -p-toluenesulfonim ida, N- (N '-benzylaminocarbonyl) sulfanyl imide, N- (phenylcarboxyl) -sulfanylim ida, diphenyl sulfone-3-sulfonic acid, diphenyl sulfone-3,3' -disulfonic acid and diphenyl acid its l-3,4'-disulfonic acid.

5. The flame retardant polycarbonate resin composition according to claim 1, wherein the metal of the metal salt of said perfluoroalkanesulfonic acid (D) is an alkali metal. The flame retardant polycarbonate resin composition according to claim 2, wherein the metal of the metal salt of said perfluoroalkanesulfonic acid (D) is an alkali metal. 7. The flame retardant polycarbonate resin composition according to claim 13, wherein the metal of the metal salt of said perfluoroalkanesulfonic acid (D) is an alkali metal. The flame retardant polycarbonate resin composition according to claim 14, wherein the metal of the metal salt of said perfluoroalkanesulfonic acid (D) is an alkali metal. 9. The flame retardant polycarbonate resin composition according to claim 2, wherein the fluoropolymer fiber (E) is polytetrafluoroethylene. 20. The flame retardant polycarbonate resin composition according to claim 5, wherein said fiber-forming fluoropolymer (E) is polytetrafluoroethylene. twenty-one . The flame retardant polycarbonate resin composition according to claim 6, wherein said fiber-forming fluoropolymer (E) is polytetrafluoroethylene. (54) Title: RESTORATION COMPOSITIONS OF FLAME RETARDANT POLYCARBONATE (57) Summary: A flame retardant polycarbonate resin composition characterized by comprising 1 00 parts by weight of a polycarbonate resin (A), about 0.01 to 8 parts by weight of a silicone compound (B), whose main chain has a branched structure and which organic substituents support aromatic groups, either about 0.03 to 5 parts by weight of a metal salt (C) of an aromatic sulfur com pound, or about 0.01 to 5 parts by weight of a metal salt (D) of a perfluoroalkanesulfonic acid and, if necessary, about 0.05 to 5 parts by weight of a fiber-forming fluoropolymer (E). This composition is remarkably improved in flame retardancy without impairing impact resistance and moldability, and is out of danger to generate a halogen-containing gas due to a flame retardant that is burned by virtue of being free of a flame retardant that is flame retardant. it comprises a chlorine or bromine compound, thus being advantageous with respect to environmental protection.