JP6353949B1 - Thermoplastic resin composition - Google Patents

Abstract

A thermoplastic resin composition having high flame retardancy is provided. A cracking furnace temperature of 200 to 600 ° C. is measured based on ASTM D7309 Method A using (A) a thermoplastic resin and (B) a fluoroethylene-based polymer and using a microscale combustion calorimeter. The thermoplastic resin composition has a maximum heat release rate of less than 400 W / g and a total calorific value of 36.0 kJ / g or less. [Selection figure] None

Description

  The present invention relates to a thermoplastic resin composition having high flame retardancy.

  Thermoplastic resins are used in various fields such as office automation equipment such as word processors, personal computers, printers, and copiers, and home appliances such as TVs, VTRs, and audios. A flame retardant study for imparting flame retardancy has been conducted by adding a flame retardant to a plastic resin (see Patent Documents 1 and 2).

  In particular, exterior covers used in large-sized or fixed copying machines and printers have a role of preventing combustion or scattering of high-temperature substances or blowing out flames as fireproof enclosures, and have high flame resistance. Required.

JP-A-11-217482 Japanese Patent Laid-Open No. 08-283525

  The subject of this invention is providing the thermoplastic resin composition provided with the high flame retardance.

The present invention comprises (A) a thermoplastic resin, (B) a fluoroethylene polymer, (C) a bromine flame retardant, and (D) a flame retardant aid ,
The (A) thermoplastic resin is a rubber-modified styrenic resin,
(A) 0.01-2.0 parts by mass of the (B) fluoroethylene polymer, 5-30 parts by mass of the brominated flame retardant (C), and 100 parts by mass of the thermoplastic resin. (D) containing 1.0 to 10.0 parts by mass of a flame retardant aid,
Measured based on ASTM D7309 Method A using a micro-scale combustion calorimeter, with a maximum heat release rate of less than 400 W / g and a total calorific value of 36.0 kJ / g or less at a cracking furnace temperature of 200 to 600 ° C. It is a thermoplastic resin composition characterized by being.

The present invention includes the following configurations as preferred embodiments.
The content of 4-tert-butylcatechol included before Symbol rubber-modified styrene resin is less than 6 mg / kg.

  According to the present invention, a thermoplastic resin composition having a high degree of flame retardancy can be obtained by defining the maximum heat release rate and the total calorific value measured using a microscale combustion calorimeter. Therefore, by using the thermoplastic resin composition of the present invention, it is advantageous for use in OA equipment and home appliance parts that require flame retardancy, and it is also high in exterior covers used in copying machines and printers. Flame resistance is realized.

It is a figure which shows an example of the heat dissipation rate characteristic curve obtained by the measurement based on ASTM D7309.

  As a result of various studies on flame retardancy of the thermoplastic resin composition, the present inventors have used a microscale combustion calorimeter (MCC) and measured the maximum heat dissipation rate based on ASTM D7309 method A. And the total calorific value can be used as indicators of flame retardancy in a thermoplastic resin composition, and the present invention has been achieved.

  MCC is an apparatus for evaluating the combustion characteristics of combustible materials based on ASTM D7309, and has a decomposition furnace and a combustion furnace in the apparatus. In ASTM D7309, a sample is placed in an MCC cracking furnace, and the cracking furnace is heated at an arbitrary speed while flowing a mixed gas of nitrogen or nitrogen and oxygen into the cracking furnace, and the cracked gas generated therefrom is burned. It introduce | transduces into a furnace, burns cracked gas in presence of nitrogen and oxygen, and calculates a heat release rate (Heat Release Rate, HRR) from the amount of oxygen consumed. In such a method, the form of the sample is not limited, the reproducibility is good, and the combustion characteristics can be quantitatively shown.

In the present invention, based on ASTM D7309 Method A, the heat release rate (HRR) [W / g] per 1 g of sample is measured over time under the following conditions. Since the temperature of the cracking furnace is increased at a constant rate, the temperature of the cracking furnace corresponding to the measurement time is plotted on the horizontal axis, and the heat release rate obtained from the amount of oxygen consumed measured at the time is plotted on the vertical axis. A heat dissipation characteristic curve as shown is obtained. In addition, FIG. 1 is an example and is not limited to the heat dissipation rate characteristic curve according to the present invention.
Sample mass: 3.0mg
Decomposition furnace heating rate: 1.0 ° C / sec
Decomposition furnace temperature: 850 ° C
Combustion furnace temperature: 900 ° C (constant)
Decomposition furnace atmosphere: Nitrogen (anaerobic condition) (80 ml / min)
Combustion furnace atmosphere: oxygen / nitrogen mixed gas (oxygen 20 ml / min, nitrogen 80 ml / min)

  The thermoplastic resin composition of the present invention has a maximum heat release rate of less than 400 W / g at a decomposition furnace temperature of 200 to 600 ° C. in the heat release rate characteristic curve. The maximum heat dissipation rate is the peak apex of the heat dissipation rate characteristic curve. For example, in the case of FIG. 1, it is 375 W / g.

  Further, the thermoplastic resin composition of the present invention has a total heat generation amount between the decomposition furnace temperature of 200 to 600 ° C., that is, a heat release rate at each measurement point in the temperature range in the heat release rate characteristic curve. ) Is 36.0 kJ / g or less. In the curve of FIG. 1, the horizontal axis represents the cracking furnace temperature, but since the cracking furnace temperature is raised at a constant rate, the horizontal axis corresponds to the time from the start of the temperature raising. Therefore, in the curve with time on the horizontal axis, the integral value of the heat release rate during the time when the cracking furnace temperature reaches 200 ° C. and 600 ° C. is the total calorific value between 200 to 600 ° C.

  In the present invention, in the thermoplastic resin composition containing (A) a thermoplastic resin and (B) a fluoroethylene polymer, the maximum heat dissipation rate is less than 400 W / g and the total calorific value is 36. If it has a heat dissipation rate characteristic of 0 kJ / g or less, a high flame retardancy equivalent to 5 VB can be obtained with Subject No. 94 (UL94) of Underwriters Laboratories, USA.

  The thermoplastic resin (A) used in the present invention is not particularly limited as long as it is a polymer having thermoplasticity. Polystyrene (GPPS), acrylonitrile-styrene copolymer (AS resin), methyl methacrylate-styrene General-purpose styrene resins such as copolymer (MS resin), maleic anhydride-styrene copolymer, acrylic acid (or methacrylic acid) ester / styrene copolymer; high impact polystyrene (HIPS), acrylonitrile-butadiene-styrene Copolymer (ABS resin), acrylonitrile-acrylic rubber-styrene copolymer (AAS resin), acrylonitrile-ethylenepropylene-styrene copolymer (AES resin), methyl methacrylate-butadiene-styrene copolymer (MBS resin), etc. Rubber-modified styrenic resin; poly Α-olefin polymers and copolymers of at least one of α-olefins having 2 to 10 carbon atoms, such as ethylene (PE), polypropylene (PP), and ethylene / propylene copolymers, and chlorinated polyethylenes thereof Olefin resins such as modified polymers and modified copolymers, cyclic olefin copolymers, etc .; ethylene copolymers such as ionomers, ethylene / vinyl acetate copolymers, ethylene / vinyl alcohol copolymers; polyvinyl chloride Resin (PVC), ethylene-vinyl chloride polymer, polyvinyl chloride resin such as polyvinylidene chloride (PVDC); heavy weight using one or more of acrylic acid (or methacrylic acid) ester such as polymethyl methacrylate (PMMA) Acrylic resins such as coalesces and copolymers; polyamide 6, polyamide 6,6, polyamide 6,1 Polyamide resins (PA) such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyester resins such as polyethylene naphthalate; polyacetal (POM); polycarbonate (PC); polyarylate (PAR); PPE); polyphenylene sulfide (PPS); fluorine resin such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF); liquid crystal polymer; polyimide resin (PI), polyamideimide (PAI), polyetherimide (PEI), etc. Imide resins; ketone resins such as polyether ketone and polyether ether ketone (PEEK); sulfone resins such as polysulfone (PSU) and polyether sulfone (PES); urethane Fat (PU); polyvinyl acetate (PVAc); polyethylene oxide (PEO), polyvinyl alcohol (PVA); polyvinyl ethers, polyvinyl butyral, phenoxy resin, polylactic acid resin (PLA) and the like. These can be used alone or in combination of two or more. Of these, general-purpose styrene resins, rubber-modified styrene resins, olefin resins, acrylic resins, vinyl chloride resins, polycarbonate resins, polyester resins, polyamide resins, and polyphenylene ether are preferable, and rubber modified resins are particularly preferable. Styrenic resins, olefinic resins, acrylic resins, polycarbonate resins, polyester resins, and polyphenylene ethers are preferable, and rubber-modified styrene resins are more preferable.

  The styrene resin is obtained by polymerizing an aromatic vinyl compound monomer, and a styrene resin that has been rubber-modified by adding a rubbery polymer is referred to as a rubber-modified styrene resin. As the polymerization method, it can be produced by a known method, for example, a bulk polymerization method, a bulk / suspension two-stage polymerization method, a solution polymerization method or the like. As the aromatic vinyl compound monomer, known monomers such as styrene, α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene can be used, and styrene is preferable. In addition, styrene monomers such as acrylonitrile, acrylic acid, methacrylic acid, acrylic acid (or methacrylic acid) ester, maleic anhydride, etc. that are copolymerizable with these aromatic vinyl compound monomers The body may be of a level that does not impair the performance of the thermoplastic resin composition. Furthermore, in the present invention, a polymer obtained by adding a crosslinking agent such as divinylbenzene to a styrene monomer may be used.

  The rubber-like polymer used for the rubber-modified styrene resin includes polybutadiene, styrene-butadiene random or block copolymer, polyisoprene, polychloroprene, styrene-isoprene random, block or graft copolymer, and ethylene-propylene rubber. , Ethylene-propylene-diene rubber, and the like, and in particular, random, block or graft copolymers of polybutadiene and styrene-butadiene are preferable. These may be partially hydrogenated, or may be used alone or in combination of two or more.

  The content of the rubbery polymer in the rubber-modified styrenic resin is preferably 3 to 15% by mass. If the content of the rubbery polymer is in the range of 3 to 15% by mass, the impact resistance of the resin composition can be sufficiently enhanced.

  The content of 4-tert-butylcatechol (TBC) contained in the rubber-modified styrene resin is preferably 6 mg / kg or less. More preferably, it is 0.1-5 mg / kg. TBC is a polymerization initiator, and if the content of TBC is 6 mg / kg or less, the flame retardancy stability is increased, which is preferable.

  The (B) fluoroethylene-based polymer used in the present invention imparts an effect of reducing the calorific value during resin combustion, and (A) is preferably finely dispersed in a fibril form in the thermoplastic resin. Specific examples of fluoroethylene polymers include polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene copolymer, and tetrafluoroethylene / ethylene copolymer, each of which is used alone or in combination. May be used. (B) The fluoroethylene polymer is desirably supplied as an aqueous latex or dispersion.

  (B) Although there is no restriction | limiting in particular about the addition amount of a fluoroethylene polymer, It is preferable to use in 0.01-2.0 mass parts with respect to 100 mass parts of (A) thermoplastic resins. More preferably, it is 0.1-1.0 mass part. (B) If the addition amount of a fluoroethylene-type polymer is 0.01-2.0 mass parts, the flame retardance of a thermoplastic resin composition, impact resistance, and a molded article external appearance can fully be improved.

  In the present invention, it is preferable to further contain (C) a brominated flame retardant and (D) a flame retardant aid.

  Examples of the (C) brominated flame retardant used in the present invention include tris (polybromophenoxy) triazine compound, brominated diphenylalkane compound, brominated phthalimide compound, brominated polystyrene, brominated styrene-butadiene copolymer, bromine Modified polyacrylates, brominated polyphenylene ethers, brominated bisphenol A type epoxy resins, brominated bisphenol A type epoxy resins, modified products in which part or all of the glycidyl groups at the molecular chain terminals are sealed, and the like. Bromophenoxy) triazine compounds, brominated diphenylalkane compounds, and brominated phthalimide compounds are preferably used.

  These (C) brominated flame retardants can be used alone or in combination of two or more. (C) The amount of brominated flame retardant added is determined according to the required flame retardant level, but it is preferably used in the range of 5 to 30 parts by mass with respect to 100 parts by mass of (A) thermoplastic resin. . More preferably, it is 10-20 mass parts.

  (D) The flame retardant aid functions to further enhance the flame retardant effect of the brominated flame retardant (C), for example, as antimony oxide, antimony trioxide, antimony tetraoxide, antimony pentoxide, sodium antimonate, etc. Zinc borate, barium metaborate, anhydrous zinc borate, anhydrous boric acid, etc. as boron compounds, stannic oxide, zinc stannate, zinc hydroxystannate, etc. as tin compounds, molybdenum oxide, molybdenum as molybdenum compounds Examples of the ammonium compound include zirconium oxide and zirconium hydroxide as the zirconium compound, and zinc sulfide as the zinc compound. Among them, it is particularly preferable to use antimony trioxide. (D) Although there is no restriction | limiting in particular about the addition amount of a flame-retardant adjuvant, It is preferable to use in the range of 1.0-10.0 mass parts with respect to 100 mass parts of (A) thermoplastic resins.

  In addition, the thermoplastic resin composition of the present invention has various additives such as dyes, pigments, anti-coloring agents, lubricants, antioxidants, anti-aging agents, light stabilizers, antistatic agents to the extent that the effects of the present invention are obtained. Known additives such as additives, fillers and compatibilizers, and modifiers such as colorants such as titanium oxide and carbon black can be added. These addition methods are not particularly limited, and known methods, for example, before the start of polymerization of the styrenic resin to be used, with respect to the reaction solution in the middle of the polymerization, or after the completion of the polymerization, and flame retardants, flame retardant aids. When blending the agent, it can also be added in an extruder or a molding machine.

  A known mixing technique can be applied to the method for mixing the thermoplastic resin composition of the present invention. For example, a uniform resin composition can be obtained by melt-kneading a mixture preliminarily mixed with a mixing apparatus such as a mixer-type mixer, a V-type blender, and a tumbler-type mixer. There are no particular restrictions on the melt kneader. Suitable melt kneaders include Banbury mixers, kneaders, rolls, single screw extruders, special single screw extruders, and twin screw extruders. Furthermore, there is a method of separately adding an additive such as a flame retardant from the middle of a melt-kneading apparatus such as an extruder.

  Examples of a molding method for obtaining a molded product from the resin composition of the present invention include injection molding.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(A) Thermoplastic resin Impact-modified polystyrene resin modified with rubber (the rubber-like polymer is polybutadiene rubber, the content of the rubber-like polymer in the matrix portion is 9.4% by mass, the volume average particle diameter of the rubber-like polymer is 2.8 μm) , High-cis polybutadiene rubber containing cis 1,4 bonds in a proportion of 90 mol% or more, TBC content of the matrix part 2.0 mg / kg)

<Measurement of rubbery polymer content>
Dissolve the sample in chloroform, add a certain amount of iodine monochloride / carbon tetrachloride solution, leave it in the dark for about 1 hour, add 15% by weight potassium iodide solution and 50 ml of pure water, and add excess iodine monochloride. The solution was titrated with 0.1N sodium thiosulfate / ethanol aqueous solution and calculated from the amount of added iodine monochloride.

<Measurement of volume average particle diameter of rubbery polymer>
The sample was dissolved in dimethylformamide and measured with a laser diffraction particle size distribution apparatus (Laser diffraction particle analyzer “LS-230” manufactured by Beckman Coulter, Inc.).

<Measurement of TBC content>
Dissolve 2 g of the sample in 100 ml of tetrahydrofuran (THF), remove the rubber-like dispersed particles with a centrifuge (“H-2000B” (rotor: H) manufactured by Kokusan Co., Ltd.), and collect the supernatant to 10 ml. 200 μl of N, O-bis (trimethylsilyl) trifluoroacetamide was added to the sample, and the TBC content in the sample was measured with a gas chromatograph / mass spectrometer (GC / MS).
Apparatus: “HP7890 / HP5974” manufactured by Agilent Technologies
Column: “DB-5MS” manufactured by Agilent Technologies
Oven: 50 ° C
Inlet: 300 ° C
Carrier: helium, 1 ml / min
Detector: Mass spectrometer

(B) Fluoroethylene-based polymer Aqueous dispersion of polytetrafluoroethylene (“PTFE 31-JR” manufactured by Mitsui DuPont Fluorochemicals)

(C) Brominated flame retardant C-1: Decabromodiphenylethane (“SAYTEX 8010” manufactured by Albemarle)
C-2: Ethylenebistetrabromophthalimide ("SAYTEX BT-93" manufactured by Albemarle)
C-3: 2,4,6-tris (2,4,6-tribromophenoxy) -1,3,5-triazine ("Pyroguard SR245" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

(D) Flame retardant auxiliary antimony trioxide ("AT-3CN" manufactured by Suzuhiro Chemical Co., Ltd.)

  The above (A) thermoplastic resin, (B) fluoroethylene polymer, (C) bromine flame retardant, and (D) flame retardant aid are blended in parts by mass shown in Table 1, and Henschel mixer (Nippon Coke Industries, Ltd.). After being premixed with “FM20B” manufactured by the company, it was supplied to a twin screw extruder (“TEM26SS” manufactured by Toshiba Machine Co., Ltd.) to form a strand, which was cooled to water and led to a pelletizer to be pelletized. At this time, the cylinder temperature was 230 ° C. and the supply amount was 30 kg / hour.

  Using the obtained pellet, MCC ("MCC-3" manufactured by DETAK) was used, and based on ASTM D7309 Method A, the heat dissipation rate [W / g] was measured under the above-described conditions, and the cracking furnace temperature was 200 to 600. The maximum heat release rate [W / g] and total calorific value [kJ / g] at 0 ° C. were obtained. Moreover, flame retardance was evaluated by the method shown below using the obtained pellet. The results are shown in Table 1.

<Flame retardance>
A test piece for combustion having a length of 127 mm, a width of 12.7 mm, and a thickness of 2.5 mm was molded using an injection molding machine (“J100E-P” manufactured by Nippon Steel Works). At this time, the cylinder temperature of the injection molding machine was 220 ° C., and the mold temperature was 45 ° C. Using this test piece, the combustibility was evaluated in accordance with the vertical combustion test method of UL94. When this test method did not satisfy V-2, it was determined as NG.

  From Table 1, in Examples where the maximum heat dissipation rate is less than 400 W / g and the total calorific value is 36.0 kJ / g or less, high flame retardancy of 5 VB level was obtained, while in Comparative Examples, flame retardancy was obtained. The properties were inferior to those of the examples.

Claims (2)

(A) a thermoplastic resin, (B) a fluoroethylene polymer, (C) a brominated flame retardant, and (D) a flame retardant aid ,
The (A) thermoplastic resin is a rubber-modified styrenic resin,
(A) 0.01-2.0 parts by mass of the (B) fluoroethylene polymer, 5-30 parts by mass of the brominated flame retardant (C), and 100 parts by mass of the thermoplastic resin. (D) containing 1.0 to 10.0 parts by mass of a flame retardant aid,
Measured based on ASTM D7309 Method A using a micro-scale combustion calorimeter, with a maximum heat release rate of less than 400 W / g and a total calorific value of 36.0 kJ / g or less at a cracking furnace temperature of 200 to 600 ° C. A thermoplastic resin composition characterized in that it is present. The thermoplastic resin composition according to claim 1 , wherein the content of 4-tert-butylcatechol contained in the rubber-modified styrene resin is 6 mg / kg or less.

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