JP3024846B2 - Flame retardant polyester resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant polyester resin composition, and more particularly to a flame-retardant polyester resin composition having improved heat stability and discoloration resistance during melting or long-term heat aging. It is.

[0002]

2. Description of the Related Art A thermoplastic resin mixture composed of a crystalline polyester resin represented by a polyalkylene terephthalate resin and an aromatic polycarbonate resin has excellent mechanical properties and excellent mechanical properties of the crystalline polyester resin. Because it has both moldability and good molding dimensional stability possessed by the aromatic polycarbonate resin, it is used for a wide variety of applications as engineering plastics. However, these resin mixtures are inherently flammable, which limits their use.
Therefore, various attempts have been made to make the flame retardant. Conventionally, in order to make a thermoplastic resin flame-retardant, an organic halogen compound such as decabromodiphenyl ether or brominated polycarbonate is mainly blended. At that time, it is also known that a more excellent flame retardant effect can be obtained by using antimony oxide such as antimony trioxide and antimony tetroxide in combination. However, these compounds are by no means preferred from the viewpoint of the heat stability of the resin. In particular, antimony compounds represented by antimony trioxide essentially act as catalysts for transesterification reactions,
The heat resistance of a thermoplastic resin mixture comprising a blend of a crystalline polyester resin and an aromatic polycarbonate resin is extremely adversely affected. Therefore, a flame-retardant resin mixture composed of a blend of a crystalline polyester resin and an aromatic polycarbonate resin blended with these flame retardants and antimony oxide stays in the machine during extrusion or molding or performs long-term heat aging. Then, the degree of mechanical property deterioration and discoloration becomes remarkable. Therefore, if the adverse effects on the deterioration of the resin can be suppressed without impairing the flame retardancy imparting of these substances, the use of the resin composition can be further expanded.

[0003]

Means for Solving the Problems The present inventors have made intensive studies to improve these problems, and as a result, a specific ethylene-based copolymer and a thioether-based resin have been added to a flame-retardant resin mixture containing a flame retardant and the like. The flame-retardant polyester resin composition formulated in combination with the compound retains the excellent physical properties of the polyalkylene terephthalate resin and the aromatic polycarbonate resin composition, and has substantially good flame retardancy, The inventors have found that the heat resistance and discoloration resistance during melting or long-term heat aging have been significantly improved, and have reached the present invention. That is, the present invention relates to a flame retardant resin mixture containing a crystalline polyester resin, an aromatic polycarbonate resin, an organic halogen compound and an antimony compound, (A) ethylene and an α-olefin or an unsaturated carboxylic acid ester having 3 or more carbon atoms. And a modified ethylene copolymer (A-2) containing the ethylene copolymer as a main component and a thioether compound (B). A flame-retardant polyester resin composition having improved thermal stability. According to the composition of the present invention, a crystalline polyester resin, an aromatic polycarbonate resin, a heat-resistant stability during melting or long-term heat aging of a flame-retardant resin mixture containing an organic halogen compound and an antimony compound, discoloration resistance, mechanical Characteristic can be significantly improved. Such effects of the present invention are not observed with the stabilizers generally used in conventional thermoplastic polyester compositions. This means that the ethylene copolymer (A-1) or the ethylene-modified copolymer (A
-2) and a thioether-based antioxidant are considered to suppress radical decomposition and transesterification caused by organic halogen compounds, antimony compounds, etc., and prevent deterioration of the resin. .

[0004] The components of the composition of the present invention will be described in detail below. First, the crystalline polyester resin used in the present invention is a polyester obtained by the polycondensation of a dicarboxylic acid compound and a dihydroxy compound, the polycondensation of an oxycarboxylic acid compound, or the polycondensation of a mixture of these three components. The effect of the present invention can be applied to any of the copolyesters. Examples of dicarboxylic acid compounds used here include known dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, and sebacic acid. Acids and their alkyl, alkoxy or halogen substituents. These dicarboxylic acid compounds can also be used for polymerization in the form of a derivative capable of forming an ester, for example, a lower alcohol ester such as dimethyl ester. Two or more of these may be used.
Next, examples of the dihydroxy compound constituting the polyester of the present invention include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, hydroquinone, resorcinol, dihydroxyphenyl, naphthalene diol, dihydroxydiphenyl ether,
Cyclohexanediol, 2,2-bis (4-hydroxyphenyl) propane, dihydroxy compounds such as diethoxylated bisphenol A, polyoxyalkylene glycols and alkyl, alkoxy or halogen-substituted products thereof, and the like. Can be used mixed. Examples of oxycarboxylic acids include oxycarboxylic acids such as oxybenzoic acid, oxynaphthoic acid, and diphenyleneoxycarboxylic acid, and alkyl, alkoxy or halogen-substituted products thereof. Further, derivatives of these compounds capable of forming an ester can also be used. In the present invention, one or more of these compounds are used. In addition, a polyester having a branched or crosslinked structure using a small amount of a trifunctional monomer, that is, trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, trimethylolpropane, or the like may be used. In the present invention, any of the crystalline polyesters produced by polycondensation using the compound as a monomer component as described above can be used, and they can be used alone or as a mixture of two or more, but polyalkylene terephthalate is preferred. More preferably, polybutylene terephthalate and a copolymer based on polybutylene terephthalate are used.

Next, as the aromatic polycarbonate resin used in the present invention, various types of aromatic polycarbonate resins can be used, and 4,4'-dihydroxydiallylalkane-based polycarbonate is particularly preferable. Specifically, a polycarbonate resin obtained by a transesterification method or a phosgene method using bisphenol A as a hydroxy component is most preferable. The amount of addition is 0.5 to 50% by weight, preferably 1 to 50% by weight, based on the whole composition.
It is 40% by weight, particularly preferably 1 to 30% by weight. If the amount is too large, the heat resistance of the composition deteriorates.

The organic halogen compound used in the present invention may be any organic halogen flame retardant which is generally used as a flame retardant for thermoplastic polyesters, and is preferably an aromatic bromine compound. Low molecular weight bromine compounds such as 5 to 10 bromine-substituted compounds of diphenyl ether, or low molecular weight organic halogen compounds of tetrabromobisphenol A, halogenated polycarbonates (for example, polycarbonate oligomers produced from brominated bisphenol A), Halogenated epoxy compounds (for example, a diepoxy compound produced by reacting brominated bisphenol A with epichlorohydrin or a monoepoxy compound obtained by reacting brominated phenols with epichlorohydrin),
Brominated polystyrene, brominated bisimide compounds (for example, lower alkylenebistetrabromophthalimide) and the like. The organic halogenated flame retardants may be used alone or in combination of two or more. If the amount of the flame retardant is increased, the mechanical properties of the composition are reduced. The amount added is generally 1 to 30% by weight, preferably 2 to 20% by weight, based on the whole composition.

The antimony compound used in the present invention means a compound which synergistically enhances the flame retardancy when used in combination with the above-mentioned organic halogen compound. Representative compounds are antimony trioxide, antimony tetroxide, Examples include antimony oxide and sodium antimonate. The addition amount of the antimony compound is 1 to 15% by weight based on the whole composition
Preferably it is 2 to 10% by weight.

The (A-1) ethylene copolymer used for the purpose of improving the heat resistance, discoloration resistance and the like of the flame-retardant resin mixture is ethylene and α-olefin having 3 or more carbon atoms. It is obtained by polymerizing an unsaturated carboxylic acid ester. Examples of the α-olefin having 3 or more carbon atoms constituting the ethylene copolymer (A-1) include propylene, butene-1, hexene-1, decene-1, 4-methylbutene-1, and 4-methylpentene-1. Etc., but propylene or butene-1 is preferred. The unsaturated carboxylic acid ester constituting the ethylene copolymer (A-1) is an unsaturated carboxylic acid having 3 to 8 carbon atoms, for example, an alkyl ester such as acrylic acid and methacrylic acid. Examples include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, Examples thereof include n-butyl methacrylate and isobutyl methacrylate, and preferably ethyl acrylate or methyl methacrylate, particularly ethyl acrylate. Further, the modified ethylene copolymer (A-2) is the above-mentioned ethylene copolymer (A-
In 1), a random terpolymer, a block copolymer, a graft copolymer and a mixture thereof using an unsaturated dicarboxylic acid or a derivative thereof are also preferable, and a graft copolymer is preferable. Examples of the unsaturated dicarboxylic acid or its derivative include maleic acid, fumaric acid, anhydrides and esters of these acids, and maleic anhydride is particularly preferred. As the modified ethylene copolymer (A-2), preferably 50 to 96.9% by weight of ethylene and 3 carbon atoms
The above α-olefin or unsaturated carboxylic acid ester 3
~ 40% by weight, and unsaturated dicarboxylic acid or its derivative
Those copolymerized in the range of 0.1 to 10% by weight are used. Such a modified ethylene copolymer (A-2) can be produced by any method. For example, a grafted polymer is obtained by adding an unsaturated dicarboxylic acid or the like to a copolymer of ethylene and an α-olefin or an unsaturated carboxylic acid ester, preferably at 120 to 250 ° C. in the presence of a radical initiator. Is obtained. A terpolymer can be obtained by adding a radical initiator to a mixture of ethylene, an unsaturated carboxylic acid ester, an unsaturated dicarboxylic acid, and the like and polymerizing the mixture under a pressure of 1,000 to 2,000 atm. Also, some are available on the market. In the present invention
(A) The amount of the component is 0.1 to 20% by weight based on the total amount of the composition, particularly
0.5 to 10% by weight is preferred. If the amount is too small, the effect of improving the thermal stability (in particular, the retention of mechanical properties during heat aging) cannot be obtained among the effects aimed at by the present invention. Not preferred.

The composition of the present invention is characterized by combining (A) a specific ethylene copolymer and (B) a thioether compound in combination with the flame-retardant resin mixture as described above. For the first time, by combining the components, the excellent physical properties of the crystalline polyester / polycarbonate resin mixture exhibiting flame retardancy, which is the object of the present invention, the heat stability during melting or long-term heat aging while retaining flame retardancy, It has become possible to synergistically improve discoloration resistance and the like. Representative thioether-based compounds (B) compounded for this purpose include dilauryl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, lauryl stearyl thiodipropionate, tetrakis [methylene- 3- (dodecylthio) propionate] methane, dialkyl (C ₁₂ -C ₁₈₎
-3,3-thiodipropionate and the like, in particular,
Tetrakis [methylene-3- (dodecylthio) propionate] methane is preferred. The amount of the component (B) to be added is preferably 0.01 to 3% by weight based on the total weight of the composition, particularly
~ 1.0% by weight is preferred. When the amount is too small, the effect of improving discoloration is insufficient, and when the amount is too large, the mechanical properties are adversely affected.

Next, the inorganic filler (C) used in the present invention is not an essential component, but has properties such as mechanical strength, heat resistance, dimensional stability (deformation resistance and warpage), and electrical properties. In order to obtain a molded article excellent in quality, it is preferable to use a fibrous, powdery or plate-like filler depending on the purpose. As the fibrous filler, glass fiber,
Asbestos fiber, carbon fiber, silica fiber, silica
Inorganic fibrous substances such as alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, and metal fibrous materials such as stainless steel, aluminum, titanium, copper, and brass. Particularly typical fibrous fillers are glass fibers or carbon fibers. High-melting organic fibrous substances such as polyamide and acrylic resin can be used in the same manner as the inorganic fibrous filler. On the other hand, powdery fillers include carbon black, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, silicates such as wollastonite, and iron oxide. Oxides of metals such as titanium oxide, zinc oxide and alumina; carbonates of metals such as calcium carbonate and magnesium carbonate; sulfates of metals such as calcium sulfate and barium sulfate; and other silicon carbide, silicon nitride, boron nitride, various types Metal powder and the like. Examples of the plate-like filler include mica, glass flake, various metal foils, and the like. In particular, fillers mainly composed of glass fibers, glass beads, glass flakes and the like are general and suitable. These inorganic fillers can be used alone or in combination of two or more.
The combined use of a fibrous filler, particularly a glass fiber or a carbon fiber, and a particulate and / or plate-like filler is a preferable combination particularly having both mechanical strength and dimensional accuracy and electrical properties. When using these fillers, it is desirable to use a sizing agent or a surface treatment agent if necessary. This example is a functional compound such as an epoxy compound or an isocyanate compound. These compounds may be used after being subjected to a surface treatment or a convergence treatment, or may be added at the same time as the preparation of the material. In the present invention, such an inorganic filler
The compounding amount of (C) is from 1 to 60% by weight, preferably from 5 to 50% by weight, based on the total amount of the composition. If the amount of the inorganic filler is more than 60% by weight, molding becomes difficult, and there is a problem in the mechanical strength of the molded product. The amount of the functional surface treating agent used in combination is 0 to 10% by weight, preferably 0.05 to 5% by weight, based on the inorganic filler.

The composition of the present invention may further contain a small amount of a thermoplastic resin. In order to further impart desired properties to the composition of the present invention according to the purpose, known substances generally added to thermoplastic resins and thermosetting resins, such as antioxidants, heat stabilizers, ultraviolet absorbers and the like Formulation of stabilizers, antistatic agents, lubricants, mold release agents, coloring agents such as dyes and pigments, lubricants, plasticizers and crystallization accelerators, nucleating agents, etc. within a range that does not impair the object and effects of the present invention. It is of course possible to do so.

The composition of the present invention can be easily prepared by known equipment and methods generally used as a conventional method for preparing a resin composition. For example, i) after mixing each component,
A method in which pellets are prepared by kneading and extruding with an extruder and then molded, ii) Once pellets having a different composition are prepared, the pellets are mixed in a predetermined amount and subjected to molding, and a molded article having a desired composition is obtained after molding. And iii) a method of directly charging one or more of each component to a molding machine.
Mixing and adding a part of the resin component as a fine powder with other components is a preferable method for uniformly blending these components.

[0013]

EXAMPLES The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the scope of the invention. In addition, the measuring method of the characteristic evaluation shown below is as follows. (1) Tensile strength and tensile elongation The test method described in ASTM D-638 was followed. 180 ℃
The value after heating for 100 hours was determined, and the ratio to the initial value was determined. (2) Discoloration degree The heat discoloration resistance during the heat aging test was compared with the discoloration degree (ΔE). That is, the Hunter color system L, a, b of the test piece was measured using a digital colorimeter (Z-300A type manufactured by Nippon Denshoku Industries Co., Ltd.), and the degree of color change ΔE was calculated according to the following equation. The smaller the ΔE is, the better the discoloration resistance is.

[0014]

(Equation 1)

L ₀ , a ₀ , b ₀ ; initial values L, a, b; values after heat aging test Examples 1 to 6 Polybutylene terephthalate resin (PB) having an intrinsic viscosity of 0.8
T) to which polycarbonate, an organic halogen compound, antimony trioxide or glass fiber (C) shown in Table 1 has been added, and various components (A) and (B) added in the proportions shown in Table 1. Then, after mixing using a rocking mixer, the mixture was extruded with an extruder to prepare pellets. The pellet was dried under hot air overnight, and a test piece was prepared using a molding machine. Table 1 shows the results of the evaluation performed using this test piece.

Comparative Examples 1 to 14 Corresponding to the examples, those without any of the components (A) and (B), those with any one of the components (A) and (B) added, Further, Table 2 and Table 3 also show the results of a test conducted under the same conditions as in the examples for the case where a conventionally known hindered phenol-based stabilizer was added to the component (A) in combination.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

Polycarbonate; Iupilon S-3000 brominated polycarbonate manufactured by Mitsubishi Gas Chemical Co., Ltd . ; Fireguard FG-7500 glass fiber manufactured by Teijin Chemicals Limited; CS03MA419 * 1 A-1 EEA resin manufactured by Asahi Fiber Glass Co., Ltd. NUC-6570 manufactured by Nippon Unica A-2 Ethylene-ethyl acrylate copolymer grafted with maleic anhydride (AR-201 manufactured by DuPont-Mitsui Polychemicals Co., Ltd. ) A-3 Graft-copolymerized maleic anhydride Ethylene-propylene copolymer (N-Tafmer manufactured by Mitsui Petrochemical Co., Ltd.) * 2 Pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]

[0021]

As is apparent from the above description and Examples, a specific ethylene copolymer and a thioether compound are added to a flame-retardant resin mixture containing a crystalline polyester resin, an aromatic polycarbonate resin, an organic halogen compound and an antimony compound. The blended composition of the present invention can provide a resin composition exhibiting excellent quality in a high-temperature use environment, because the maintenance and discoloration of mechanical properties during a heat aging test are remarkably improved. Therefore, the resulting composition has excellent mechanical properties, moldability, molding dimensional stability, and heat resistance stability, and especially UL-94-V-0 electrical components (such as connectors, switches, and relays) that require flame retardancy ).

Continuation of the front page (51) Int.Cl. ⁷ identification code FI C08L 23/26 C08L 23/26 69/00 69/00 (58) Field surveyed (Int.Cl. ⁷ , DB name) C08L 67/00, 23 / 08,23 / 26 C08L 69/00

Claims (9)

(57) [Claims] 1. A flame-retardant resin mixture containing a crystalline polyester resin, an aromatic polycarbonate resin, an organic halogen compound and an antimony compound, comprising: (A) ethylene and an α-olefin or unsaturated carboxylic acid ester having 3 or more carbon atoms. And a modified ethylene copolymer (A-2) containing the ethylene copolymer as a main component and a thioether compound (B). A flame-retardant polyester resin composition having improved thermal stability. 2. The modified ethylene copolymer of the component (A-2)
The flame-retardant polyester resin composition according to claim 1, wherein an unsaturated dicarboxylic acid or a derivative thereof is graft-copolymerized on a copolymer of ethylene and an α-olefin having 3 or more carbon atoms. 3. The modified ethylene copolymer of the component (A-2)
In the copolymer of ethylene and unsaturated carboxylic acid ester,
The polyester resin composition according to claim 1, wherein the unsaturated dicarboxylic acid or a derivative thereof is graft-copolymerized. 4. The flame-retardant polyester resin composition according to claim 2, wherein the unsaturated dicarboxylic acid or the derivative thereof constituting the modified ethylene copolymer (A-2) is maleic anhydride. 5. The content of (A-1) the ethylene copolymer or (A-2) the modified ethylene copolymer is from 0.1 to 0.1 with respect to the whole composition.
The flame-retardant polyester resin composition according to any one of claims 1 to 4, which is 20% by weight. 6. The flame-retardant polyester resin composition according to claim 1, wherein the content of the thioether compound (B) is 0.01 to 3% by weight based on the whole composition. 7. The method of claim 1, wherein one or more of the inorganic fillers (C) is 1 to 60.
The flame-retardant polyester resin composition according to any one of claims 1 to 6, which is blended by weight (in the composition). 8. The flame-retardant polyester resin composition according to claim 1, wherein the crystalline polyester resin is a resin mainly composed of polybutylene terephthalate. 9. The thioether compound (B) is tetrakis [methylene-3- (dodecylthio) propionate].
The flame-retardant polyester resin composition according to any one of claims 1 to 8, which is methane.