JP6456291B2 - Flame retardant polybutylene terephthalate resin composition - Google Patents

Description

  The present invention relates to a flame retardant polybutylene terephthalate resin composition.

  Since polybutylene terephthalate resin has excellent mechanical properties, electrical properties, etc., it is widely used as a material for various molded products such as automobile parts and electric / electronic parts. Such a molded body is generally required to have high flame retardancy, for example, from the viewpoint of safety. Therefore, studies have been made to improve the flame retardancy of a composition containing a polybutylene terephthalate resin so that a molded body having high flame retardancy can be obtained. For example, a polybutylene terephthalate resin composition containing an antimony flame retardant aid is known (Patent Document 1).

JP 2010-215827 A

  However, antimony compounds are not only toxic, but also have problems such as fears of supply shortage due to resource depletion and associated price increases. Therefore, there is a need for a flame retardant polybutylene terephthalate resin composition that can obtain a molded article having high flame retardancy without using an antimony flame retardant aid.

  The present invention has been made in order to solve the above problems, and provides a flame retardant polybutylene terephthalate resin composition capable of obtaining a molded article having high flame retardancy without using an antimony flame retardant aid. The purpose is to provide.

  (1) A flame-retardant polybutylene terephthalate resin composition comprising 100 parts by mass of a polybutylene terephthalate resin, 5 to 100 parts by mass of a halogen-based flame retardant, and 10 to 40 parts by mass of calcium borate.

  (2) The flame retardant polybutylene terephthalate resin composition according to (1), wherein the halogen flame retardant is at least one selected from the group consisting of brominated polybenzyl (meth) acrylate resins and bromine-containing epoxy resins. .

  (3) The flame-retardant polybutylene terephthalate resin composition according to (1) or (2), further comprising a fibrous inorganic filler.

  (4) The flame retardant polybutylene terephthalate resin composition according to any one of (1) to (3), which gives a molded article having flame retardancy V-0 based on the UL94 flammability test.

  (5) The flame-retardant polybutylene terephthalate resin composition according to any one of (1) to (4), which does not contain a phosphorus compound as a flame retardant.

  (6) The flame-retardant polybutylene terephthalate resin composition according to any one of (1) to (5), which does not include a metal borate having a dehydration temperature of 300 ° C. or less as a flame retardant.

  (7) The flame-retardant polybutylene terephthalate resin composition according to any one of (1) to (6), which does not contain an antimony compound as a flame retardant.

  ADVANTAGE OF THE INVENTION According to this invention, the flame-retardant polybutylene terephthalate resin composition which can obtain the molded object which has high flame retardance without using an antimony type flame retardant adjuvant can be provided.

  Hereinafter, embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments.

<Flame-retardant polybutylene terephthalate resin composition>
The flame retardant polybutylene terephthalate resin composition according to the present invention includes 100 parts by mass of a polybutylene terephthalate resin, 5 to 100 parts by mass of a halogen-based flame retardant, and 10 to 40 parts by mass of calcium borate. The flame retardant polybutylene terephthalate resin composition according to the present invention preferably does not contain an antimony flame retardant. In the specification of the present application, the flame-retardant polybutylene terephthalate resin composition may be simply referred to as a polybutylene terephthalate resin composition. Hereinafter, each component contained in the flame-retardant polybutylene terephthalate resin composition will be described.

[Polybutylene terephthalate resin]
The polybutylene terephthalate resin (hereinafter sometimes referred to as PBT resin) which is the base resin of the flame-retardant polybutylene terephthalate resin composition according to the present invention is at least terephthalic acid or an ester-forming derivative thereof (lower alcohol ester, etc.) And a polybutylene terephthalate-based resin obtained by polycondensation of a dicarboxylic acid component containing a glycol component containing a C4 alkylene glycol (1,4-butanediol) or an ester-forming derivative thereof. The PBT resin is not limited to a homo PBT resin, but may be a copolymer (copolymerized PBT resin) containing 60 mol% or more (particularly about 75 to 95 mol%) of a butylene terephthalate unit. PBT resin can be used individually by 1 type or in combination of 2 or more types.

In the copolymerized PBT resin, as dicarboxylic acid components (comonomer components) other than terephthalic acid and its ester-forming derivatives, for example, aromatic dicarboxylic acid components (isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, diphenyl ether dicarboxylic acid, etc.) ₆ -C ₁₂ aryl dicarboxylic acid), aliphatic dicarboxylic acid component (e.g., succinic acid, adipic acid, azelaic acid, _C 4 _{-C 16} alkyl dicarboxylic acid such as sebacic acid, _C 5 _{-C 10} cycloalkyl such as cyclohexane dicarboxylic acid Examples thereof include dicarboxylic acids and the like, or ester-forming derivatives thereof. These dicarboxylic acid components can be used alone or in combination of two or more. Preferred dicarboxylic acid components (comonomer components) include aromatic dicarboxylic acid components (especially C ₆ -C ₁₀ aryl dicarboxylic acids such as isophthalic acid), aliphatic dicarboxylic acid components (especially C such as adipic acid, azelaic acid, sebacic acid, etc.) ₆ -C ₁₂ alkyl dicarboxylic acids) are included.

In the copolymerized PBT resin, examples of the glycol component (comonomer component) other than 1,4-butanediol include aliphatic diol components [for example, alkylene glycol (ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butylene, etc.). glycol, hexamethylene glycol, neopentyl glycol, _C 2 _{-C 10} alkylene glycols such as 1,3-octanediol, diethylene glycol, triethylene glycol, polyoxy _C 2 -C ₄ alkylene glycol such as dipropylene glycol, etc.), cyclohexane dimethanol Alicyclic diols such as methanol and hydrogenated bisphenol A], aromatic diol components [aromatic alcohols such as bisphenol A and 4,4-dihydroxybiphenyl, C of bisphenol A ₂ -C ₄ alkylene oxide adduct (e.g., ethylene oxide 2 mol adduct of bisphenol A, propylene oxide 3 mol adduct of bisphenol A, etc.), etc.], or the like thereof ester-forming derivatives. These glycol components can also be used alone or in combination of two or more. Preferred glycol components (comonomer components) include aliphatic diol components (particularly polyoxy C ₂ -C ₃ alkylene glycols such as C ₂ -C ₆ alkylene glycol and diethylene glycol, and alicyclic diols such as cyclohexane dimethanol). .

  Any of the homo PBT resin or copolymer PBT resin produced by polycondensation using the compound as a monomer component can be used as the PBT resin in the present invention. The homo PBT resin and copolymer PBT resin can be used alone or in admixture of two or more. Further, the combined use of an unmodified PBT resin (homo PBT resin) and a copolymerized PBT resin is also useful. As the PBT resin, a thermoplastic branched PBT resin belonging to the category of the copolymerized PBT resin can also be used. This is a polyester resin mainly composed of so-called polybutylene terephthalate or butylene terephthalate monomer and having a branched structure by reaction with a polyfunctional compound. Polyfunctional compounds include aromatic polycarboxylic acid components (trimesic acid, trimellitic acid, pyromellitic acid and alcohol esters thereof), polyol components (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, etc.) Can be illustrated.

[Halogen flame retardant]
Organic halides can be used as the halogen-based flame retardant. The organic halide usually contains at least one halogen atom selected from a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of halogen flame retardants include halogen-containing acrylic resins [halogenated polybenzyl (meth) acrylate resins such as polybrominated polybenzyl (meth) acrylates such as poly (pentabromobenzyl (meth) acrylate), poly (penta) Halogenated benzyl (meth) acrylate homopolymers or copolymers such as chlorobenzyl (meth) acrylate], halogen-containing styrene resins [halogenated polystyrene (brominated polystyrene, chlorinated polystyrene, styrene resins such as Halogenated halides, halogenated styrene monomers alone or copolymers, etc.)], halogen-containing polycarbonate resins (brominated polycarbonates, halogenated polycarbonates such as chlorinated polycarbonate, etc.), halogen-containing epoxies Compound [Halogen-containing phenoxy resins such as bromine-containing epoxy resins (brominated epoxy resins, etc.), halogen-containing epoxy resins (halogenated epoxy resins, etc.) such as chlorinated epoxy resins; Bromine-containing phenoxy resins (brominated phenoxy resins, etc.) (Halogenated phenoxy resins, etc.)], halogen-containing phosphate esters [for example, tris (bromoethyl) phosphate, tris (mono or dibromopropyl) phosphate, tris (mono or dibromobutyl) phosphate, tris (mono to tribromoneopentyl) ) Phosphate, bis (tribromoneopentyl) phenyl phosphate, bromine-containing phosphate esters such as tris (mono to tribromophenyl) phosphate], halogen-containing triazine compounds (for example, tris (tribromophenoxy) to Bromine-containing triazine compounds such as azine), halogen-containing isocyanuric acid compounds [for example, tris (2,3-dibromopropyl) isocyanurate, tris (2,3,4-tribromobutyl) isocyanurate, tris (pentabromobenzyl) ) Bromine-containing isocyanurate compounds such as isocyanurates], halogenated polyaryl ether compounds [for example, bis (halogenated aryl) ethers such as octa to decabromodiphenyl ether, octa to decachlorodiphenyl ether (for example, bis (halogenated phenyl) ) Ethers; halogen-containing polyphenylene oxide resins such as brominated polyphenylene ethers], halogenated aromatic imide compounds [for example, brominated aromatic imide compounds such as ethylenebisbrominated phthalimide (for example, Bisimide compounds, etc.], halogenated bisaryl compounds [eg, bis (halogenated C _6-10 aryl) such as brominated diphenyl; bis (halogenated C _6-10 aryl) C ₁₋ such as brominated diphenylmethane, etc. ₄ Alkanes: Halogenated bisphenols such as brominated bisphenol A or derivatives thereof (brominated polyesters obtained by polymerizing ethylene oxide adducts of halogenated bisphenols, etc.), halogenated alicyclic hydrocarbons (crosslinked cyclic saturated or unsaturated Saturated halogenated alicyclic hydrocarbons such as halogenated polycycloalkadiene such as dodecachloropentacyclooctadeca-7,15-diene). Halogen flame retardants can be used alone or in combination of two or more.

  The halogen-based flame retardant is preferably a compound containing a chlorine atom and / or a bromine atom, and particularly an organic bromide containing a bromine atom [bromine-containing acrylic resin, bromine-containing styrene resin, bromine-containing polycarbonate resin, bromine Containing epoxy compounds (brominated epoxy resins, brominated phenoxy resins, etc.), brominated polyaryl ether compounds (bis (brominated aryl) ether compounds such as octabromodiphenyl ether), brominated aromatic imide compounds, brominated bisaryl compounds Bromine atom-containing flame retardants such as

  Among these bromine atom-containing flame retardants, in particular, brominated polybenzyl (meth) acrylate resins, bromine-containing epoxy resins, alkylene brominated phthalimides, brominated products of styrene resins, and brominated styrene monomers alone or At least one selected from a copolymer (brominated polystyrene or the like) is preferable, and at least one selected from the group consisting of a brominated polybenzyl (meth) acrylate resin and a bromine-containing epoxy resin is more preferable. Further, at least one selected from brominated bisphenol A type epoxy resin, brominated bisphenol A type phenoxy resin and brominated bisphenol A type polycarbonate resin is also preferable.

  In recent years, phosphorus-based flame retardants have been widely used as flame retardants not containing halogen atoms. However, for example, phosphate ester flame retardants have a problem of seepage when used in a high temperature environment, and phosphinate flame retardants and diphosphinate flame retardants are disadvantageous in terms of supply and cost. For this reason, it is desirable that the flame-retardant polybutylene terephthalate resin composition according to the present invention does not contain a phosphorus compound as a flame retardant.

  The blending amount of the halogen-based flame retardant in the flame-retardant polybutylene terephthalate resin composition is usually 5 to 100 parts by mass, preferably 20 to 90 parts by mass, with respect to 100 parts by mass of the polybutylene terephthalate resin. Preferably it is 30-80 mass parts. When the blending amount of the halogen-based flame retardant is in the above range, it is possible to prepare a polybutylene terephthalate resin composition from which a molded article having good flame retardancy can be obtained without sacrificing mechanical properties.

[Calcium borate]
By containing calcium borate, the flame retardant polybutylene terephthalate resin composition according to the present invention can provide a molded article having high flame retardancy without containing an antimony flame retardant aid. . Thus, calcium borate can be used in the polybutylene terephthalate resin composition as a flame retardant aid that replaces the antimony flame retardant aid.

  In addition, examples of borate metal salts other than calcium borate include sodium borate and zinc borate, and calcium borate is advantageous in that it has higher thermal stability than these. When a metal salt having low thermal stability (low dehydration temperature of crystal water in hydrate) is used, the flame retardancy is reduced due to dehydration during the residence when molding the polybutylene terephthalate resin composition. This is not preferable because it may be insufficient or the polybutylene terephthalate resin may be hydrolyzed. For this reason, it is preferable that a flame-retardant polybutylene terephthalate resin composition does not contain the boric-acid metal salt whose dehydration temperature is 300 degrees C or less. The dehydration temperature of the boric acid metal salt can be measured by thermogravimetric analysis (TG) as a starting temperature of a weight decrease corresponding to dehydration (for example, a 5 wt% weight decrease from a normal temperature to a temperature increase of 10 ° C./min).

  The compounding quantity of the calcium borate in a flame-retardant polybutylene terephthalate resin composition is 10-40 mass parts normally with respect to 100 mass parts of polybutylene terephthalate resins, Preferably it is 10-30 mass parts. When the blending amount of calcium borate is in the above range, a polybutylene terephthalate resin composition capable of obtaining a molded product having good flame retardancy without sacrificing mechanical properties such as tensile strength and impact strength is obtained. Can be prepared.

[Fibrous inorganic filler]
The flame-retardant polybutylene terephthalate resin composition according to the present invention may contain a fibrous inorganic filler. Examples of the fibrous inorganic filler include glass fiber, wollastonite, carbon fiber, potassium titanate whisker, boehmite whisker and the like.

  The average fiber length of the fibrous inorganic filler is preferably 300 to 800 μm. When the average fiber length is in the above range, the resulting polybutylene terephthalate resin composition tends to have good fluidity, and the resulting molded article tends to have sufficient mechanical strength.

  The fiber diameter of the fibrous inorganic filler is not particularly limited, but generally about 5 to 20 μm is used.

  The blending amount of the fibrous inorganic filler in the flame retardant polybutylene terephthalate resin composition is preferably 30 to 150 parts by mass, more preferably 50 to 100 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin. It is. When the blending amount of the fibrous inorganic filler is in the above range, a polybutylene terephthalate resin composition from which a molded article having good mechanical properties can be obtained can be prepared.

[Other ingredients]
Components other than the above components may be blended in the flame-retardant polybutylene terephthalate resin composition according to the present invention. Specific examples include fillers other than the fibrous inorganic filler, anti-dripping agents (polytetrafluoroethylene, etc.), antioxidants, antistatic agents, mold release agents, colorants, and the like.

  The content of other components in the flame retardant polybutylene terephthalate resin composition is preferably 0 to 50% by mass, more preferably the total amount is based on the total amount of the flame retardant polybutylene terephthalate resin composition. 10-40 mass% may be sufficient.

<Method for preparing flame retardant polybutylene terephthalate resin composition>
The specific aspect of the preparation method of the flame-retardant polybutylene terephthalate resin composition according to the present invention is not particularly limited. In general, a polybutylene terephthalate resin composition can be prepared by a known facility and method for preparing a resin composition or a molded product thereof. For example, the polybutylene terephthalate resin composition can be prepared as molding pellets by mixing necessary components and kneading them using a single or twin screw extruder or other melt kneading apparatus. A plurality of extruders or other melt kneaders may be used. The kneading temperature (cylinder temperature) of the polybutylene terephthalate resin composition is preferably 250 ° C. or higher and 280 ° C. or lower, more preferably 250 ° C. or higher and 270 ° C. or lower. When the kneading temperature is within the above range, the decomposition of the resin hardly proceeds during the kneading, and the dispersed state of each component in the obtained polybutylene terephthalate resin composition tends to be excellent.

<Method for producing molded body>
Using the flame-retardant polybutylene terephthalate resin composition according to the present invention, a conventionally known molding method (for example, injection molding, extrusion molding, compression molding, blow molding, vacuum molding, foam molding, rotational molding, gas injection molding, etc. In this method, various molded products can be formed.

  The molded body obtained by the above method is excellent in flame retardancy. Specifically, the molded body satisfies the V-0 standard in the UL94 standard vertical combustion test of Underwriters Laboratories. Moreover, the molded object obtained by the above methods is excellent in mechanical characteristics. The mechanical properties of the molded body can be determined by evaluating tensile properties (tensile strength and tensile elongation) in accordance with ISO527-1,2.

  Since the molded product obtained by molding the flame-retardant polybutylene terephthalate resin composition of the present invention has the above properties, it is used as an electric / electronic component, OA device component, home appliance component, automobile component, mechanical mechanism component, etc. It can be preferably used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these.

<Material>
Polybutylene terephthalate resin (in the table, “PBT”, manufactured by Wintech Polymer Co., Ltd., DURANEX (registered trademark), intrinsic viscosity (IV) 0.69)
Halogen-based flame retardant 1 (brominated polybenzyl acrylate, manufactured by ICL-IP, FR-1025)
Halogen flame retardant 2 (bromine-containing epoxy resin, Sakamoto Yakuhin Kogyo Co., Ltd., SRT5000S, no end-capping)
Halogen flame retardant 3 (bromine-containing epoxy resin, manufactured by ICL-IP, F3100, with end sealing)
Halogen flame retardant 4 (brominated polycarbonate, Teijin Limited, Fireguard 7500)
Halogen-based flame retardant 5 (brominated polystyrene, manufactured by Albemarle Japan, SAYTEX HP-7010P)
Halogen flame retardant 6 (brominated phthalimide, Albemarle Japan Co., Ltd., SAYTEX BT-93W)
Calcium borate (Kinsei Tech Co., Ltd., UBP, dehydration temperature: about 380 ° C)
Zinc borate (Kanto Chemical Co., Ltd., product number 48015-01, 3.5 hydrate)
Aluminum borate (Shikoku Chemical Industries, Arbolex M20)
Nitrogen-based flame retardant 1 (melamine cyanurate, manufactured by BASF Japan, MELAPUR MC50)
Nitrogen-based flame retardant 2 (melam polyphosphate, manufactured by Nissan Chemical Industries, Ltd., PHOSMEL-200)
Glass fiber (manufactured by Nitto Boseki Co., Ltd., fiber diameter φ13 μm, length 3 mm, chopped strand)
Anti-dripping agent (Asahi Glass Co., Ltd., “Fullon CD-076”)
Antioxidant (Product name: Irganox 1010, manufactured by BASF Japan Ltd.)
Mold release agent (manufactured by NOF Corporation, Unistar H476)

<Examples 1-4, Comparative Examples 1-9>
A mixture in which the components shown in Table 1 or 2 were mixed at the ratio shown in Table 1 or 2 was prepared, melted and kneaded at 260 ° C. using a 30 mmφ extruder, and extruded to obtain a pellet made of a polybutylene terephthalate resin composition. . Next, various test pieces were prepared by injection molding, and the following physical properties were evaluated.

[Melt viscosity]
After drying the above pellets at 140 ° C. for 3 hours, in accordance with ISO 11443, using a capillograph 1B (manufactured by Toyo Seiki Seisakusho), furnace temperature 260 ° C., residence time 9 minutes, capillary φ1 mm × 20 mmL, shear rate 1000 sec ⁻¹ The melt viscosity was measured at The results are shown in Tables 1 and 2.

[Tensile strength and tensile elongation]
The pellets of each Example and Comparative Example were injection molded at a molding temperature of 250 ° C. and a mold temperature of 80 ° C. to prepare test pieces. About the obtained test piece, based on ISO527-1, 2, the tensile strength and the tensile elongation were measured. The results are shown in Tables 1 and 2.

[Bending strength and flexural modulus]
The pellets of each Example and Comparative Example were molded under the following molding conditions using a molding machine (“SE100DU” manufactured by Sumitomo Heavy Industries, Ltd.) to prepare a bending test piece of 130 mm × 13 mm × 0.8 mm. Using this test piece, the bending strength and the flexural modulus were measured according to ASTM D790. The results are shown in Tables 1 and 2.
〔Molding condition〕
Cylinder temperature: 350 ° C
Mold temperature: 90 ℃
Injection speed: 33mm / sec
Holding pressure: 50 MPa

[Charpy impact strength]
The pellets of each Example and Comparative Example were dried at 140 ° C. for 3 hours, and then injection molded at a molding temperature of 260 ° C. and a mold temperature of 80 ° C. to prepare Charpy impact test pieces. Charpy impact strength was measured at 23 ° C. using the obtained test piece in accordance with ISO 179 / 1eA. The results are shown in Tables 1 and 2.

[Flame retardance]
The pellets of each Example and Comparative Example were injection molded at a molding temperature of 250 ° C. and a mold temperature of 80 ° C. to prepare test pieces (0.75 mm thickness). About the obtained test piece, combustibility was evaluated based on the UL94 standard vertical combustion test of Underwriters Laboratories. The results are shown in Tables 1 and 2. In the table, notV represents that none of V-0, V-1, and V2.

[Pressure Cooker Test (PCT)]
The test piece used for evaluation of tensile strength and tensile elongation was processed with a pressure cooker tester at 121 ° C. and 100% RH. From the start of the treatment, the tensile strength of the treated specimen was measured every 24 hours. At each measurement time, the retention rate of the tensile strength of the test piece after treatment relative to the tensile strength of the test piece before treatment was determined. The results are shown in Table 3.

[Stay stability]
Measurements similar to the above [melt viscosity] were performed at residence times of 15 minutes and 30 minutes, respectively, and the retention ratio with respect to the melt viscosity at a residence time of 9 minutes was determined for each residence time. The results are shown in Table 4.

  As can be seen from Tables 1 and 2, by using calcium borate, V-0 flame retardancy could be achieved without using an antimony compound or a nitrogen compound at the same bromine addition amount.

  When compared at the same bromine addition amount, among the halogen-based flame retardants, only brominated polybenzyl acrylate and bromine-containing epoxy resin were able to achieve V-0 flame retardancy.

  As can be seen from Comparative Examples 3, 4, and 10, when compared in the presence of brominated polybenzyl acrylate or bromine containing epoxy resin, zinc borate and aluminum borate are more flame retardant than the same amount of calcium borate. The sex was inferior. In addition, it is considered that increasing the amount of zinc borate added is disadvantageous in terms of retention stability of the polybutylene terephthalate resin (this is because zinc borate releases crystal water at a lower temperature than calcium borate. Therefore, as shown in Table 3, with zinc borate, the stability under wet heat environment is inferior, and as shown in Table 4, the melt viscosity during residence is greatly reduced, and the polybutylene terephthalate resin is hydrolyzed. It can be seen from the point that it is seen).

  Nitrogen-based flame retardants are inferior in flame retardancy compared to the same amount of calcium borate. Increasing the amount added causes mold deposits (adhering to the mold during molding), impact resistance, etc. It is considered that there is a problem in that the physical properties deteriorate.

Claims (6)

100 parts by mass of polybutylene terephthalate resin, a halogen-based flame retardant from 45.8 to 100 parts by weight, and a calcium borate 10 to 40 parts by weight flame retardant aid seen including,
A flame retardant polybutylene terephthalate resin composition, wherein the halogen flame retardant is at least one selected from the group consisting of brominated polybenzyl (meth) acrylate resins and bromine-containing epoxy resins .   The flame-retardant polybutylene terephthalate resin composition according to claim 1, further comprising a fibrous inorganic filler. The flame-retardant polybutylene terephthalate resin composition according to any one of claims 1 and 2 , which gives a molded article having flame retardancy in accordance with UL94 flammability test of V-0. The flame-retardant polybutylene terephthalate resin composition according to any one of claims 1 to 3 , which does not contain a phosphorus compound as a flame retardant. Dehydration temperature as a flame retardant aid does not contain boric acid metal salt of 300 ° C. or less, the flame-retardant polybutylene terephthalate resin composition according to any one of claims 1 to 4. It does not contain an antimony compound as a flame retardant aid, a flame retardant polybutylene terephthalate resin composition according to any one of claims 1 to 5.