JP2014084435A - Flame-retardant resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, by using a specified thermoplastic polyurethane resin (TPU) and a specified non-halogen-based flame retardant, a non-halogen-based flame-retardant resin composition having excellent flame retardance satisfying Grade V0 of UL94 Standard on flame retardance, being free from fears of occurrences of problems such as appearance defects, surface property defects, etc. of moldings due to bleeding or blooming, etc., and having excellent durability (especially, hydrolysis resistance).SOLUTION: The provided flame-retardant resin composition contains a TPU and a non-halogen-based flame retardant. The TPU contains: a polymer diol having a number-average molecular weight of 800-3000 including at least one selected from polyether diols and polycarbonate diols; 1,4-butanediol; and diphenylmethane diisocyanate (MDI). The non-halogen-based flame retardant contains a liquid non-halogen-based triaryl phosphate having a molecular weight of at least 380 and a melamine cyanurate having an average particle diameter of below 2 μm. A mass ratio of the non-halogen-based triaryl phosphate and the melamine cyanurate is 40/60 to 90/10, and a mass ratio of the TPU and the non-halogen-based flame retardant is 80/20 to 70/30.

Description

  The present invention relates to a flame retardant resin composition containing a thermoplastic polyurethane resin (hereinafter abbreviated as TPU) obtained by reacting a diol component and a diisocyanate component and a non-halogen flame retardant.

  When preparing a flame retardant resin composition by making TPU flame retardant, from the viewpoint of preservation of the global environment, non-halogen flame retardants, for example, metal hydroxide flame retardants such as aluminum hydroxide, phosphate esters Attempts have been made to mix a flame retardant or a melamine derivative flame retardant into the TPU.

  However, in the case of a metal hydroxide flame retardant, since the flame retardant effect on TPU is small, it must be mixed in large quantities, causing a significant decrease in the tensile strength and workability of the flame retardant resin composition, Practically, it could not be applied to make TPU flame retardant.

  On the other hand, phosphate ester flame retardants and melamine derivative flame retardants are considered to have a greater flame retardant effect on TPU than metal hydroxide flame retardants. In the case of a flame retardant, since it has the property of acting as a plasticizer, when it is mixed with TPU at a level that achieves flame retardancy satisfying the V94 standard of UL94 standard regarding flame retardancy, flame retardancy There is a problem that not only the physical properties such as hardness of the resin composition are lowered, but also problems such as poor appearance and poor surface properties of the molded product due to the occurrence of bleed and bloom occur. Also, in the case of the latter melamine derivative flame retardant, when mixed with TPU at a level that achieves flame retardancy satisfying the UL94 V-0 standard for flame retardancy, the hardness of the flame retardant resin composition, etc. Not only the physical properties deteriorate, but also problems such as poor appearance and surface properties of molded products due to the occurrence of bleed and bloom, foaming during molding processing, and relatively high melting point, during mixing and molding Since it exists as a powder, the impact resistance of the flame retardant resin composition is lowered, and there is a problem that a melamine derivative flame retardant adheres in the vicinity of the exit of the extruder.

  Therefore, as a clue to solve these problems, as a flame retardant to be mixed with the TPU constituting the flame retardant resin composition, an organic phosphate compound (that is, a phosphate ester flame retardant) and a melamine flame retardant It has been proposed to use (in particular, melamine cyanurate) in combination (Patent Document 1). Moreover, what is a high molecular diol (polyether diol or polyester diol) whose molecular weight is 500-8000 is used as TPU.

JP 7-48509 A

  However, in Patent Document 1, a phosphoric acid ester oligomer having a polymerization degree of 3 to 6 linked by a 1,3-phenylene group, which is disclosed as a preferred organic phosphate compound, has a property of acting as a plasticizer. For this reason, the compatibility with TPU cannot be said to be sufficient, and there is a concern that bleed, bloom or the like is generated, and it cannot be said that a good appearance and surface property are necessarily ensured for a molded product.

  Patent Document 1 (paragraph 0042) has a description regarding the particle size of the melamine derivative flame retardant that “the particle size is preferably 90% smaller than 10 μm”. From this description, melamine derivative flame retardant It can be inferred that 90% of the total is preferably smaller than 10 μm. However, since it is assumed that melamine derivative-based flame retardants contain some of the vicinity of several μm to 10 μm to some extent, it cannot be said that the compatibility with TPU is sufficient, and the appearance of the molded product (surface property) There is also concern about adversely affecting the smoothness, etc.).

  In addition, TPU with a high molecular weight diol with a molecular weight of 3000 as a constituent diol component has a relatively low urethane group concentration, and durability (hydrolysis resistance, hardness, physical property retention, etc.) is required even for indoor use. It could not be used for a long time, and was unsuitable for long-term use.

  The present invention solves the above-described problems, and uses a specific TPU and a specific non-halogen flame retardant, and is an excellent difficulty that satisfies the V-0 standard of the UL94 standard regarding flame retardancy. Non-halogen flame retardant with excellent durability (especially hydrolysis resistance) that has flammability and does not cause problems such as poor appearance and surface quality of molded products due to bleed and bloom. It aims at providing a resin composition.

  The present inventors use, as TPU, a polymer diol component having an average molecular weight of 800 to 3000 and a specific diisocyanate compound as a diisocyanate component, and a specific aromatic phosphate as a non-halogen flame retardant. And the melamine cyanurate having an average particle diameter of less than 2 μm were used at a specific blending amount with respect to TPU, and the present invention was completed.

That is, the present invention is a flame retardant resin composition comprising a thermoplastic polyurethane resin obtained by reacting a diol component and a diisocyanate component, and a non-halogen flame retardant,
The diol component constituting the thermoplastic polyurethane resin contains a polymer diol having a number average molecular weight of 800 to 3000 and 1,4-butanediol, and the polymer diol contains at least one of a polyether diol and a polycarbonate diol. ,
The diisocyanate component constituting the thermoplastic polyurethane resin contains diphenylmethane diisocyanate,
The non-halogen flame retardant contains a liquid non-halogen triaryl phosphate having a molecular weight of 380 or more and melamine cyanurate having an average particle diameter of less than 2 μm;
The mass ratio between the non-halogen triaryl phosphate and the melamine cyanurate ([non-halogen triaryl phosphate] / [melamine cyanurate]) is 40/60 to 90/10,
Flame retardant, characterized in that the mass ratio ([thermoplastic polyurethane resin] / [non-halogen flame retardant]) between the thermoplastic polyurethane resin and the non-halogen flame retardant is 80/20 to 70/30 A functional resin composition is provided.

  Moreover, this invention provides the molded article formed from the above-mentioned flame-retardant resin composition.

  In the flame-retardant resin composition of the present invention containing a thermoplastic polyurethane resin obtained by reacting a diol component and a diisocyanate component and a non-halogen flame retardant, the molecular weight and type of the diol component constituting the TPU On the other hand, the diisocyanate component is limited to a specific compound, and as a non-halogen flame retardant, a liquid triaryl phosphate having a specific molecular weight range and a melamine cyanurate having a specific particle size are mixed at a predetermined mixing ratio. In addition, the dividend amount range for TPU of non-halogen flame retardants is limited. For this reason, the flame retardant resin composition of the present invention can achieve the desired flame retardancy, and also causes problems such as poor appearance and poor surface properties due to bleed and bloom on the molded product. Furthermore, excellent durability, particularly hydrolysis resistance can be imparted.

  The flame retardant resin composition of the present invention contains a thermoplastic polyurethane resin (TPU) obtained by reacting a diol component and a diisocyanate component, and a non-halogen flame retardant.

  In the present invention, the diol component constituting TPU includes a high molecular diol having a number average molecular weight of 800 to 3000 and 1,4-butanediol.

  The high molecular diol is preferably a diol having hydroxyl groups that react with isocyanate groups at both ends, and has a number average molecular weight of 800 to 3000, preferably 800 to 2000, as will be described below.

  If the number average molecular weight of the polymer diol is less than 800, the TPU urethane group concentration becomes too high, so that the TPU melt becomes highly viscous and molding failure occurs when processing a flame-retardant resin composition containing TPU. In addition, there is a concern that compatibility with non-halogen flame retardants may be reduced, and as a result, appearance defects, surface property defects, and the like of molded products due to bleeding, blooming, and the like may be caused. In addition, the hardness, 100% modulus, tensile strength, and tear strength tend to be improved, but the elongation tends to decrease, making it difficult to make use of the original properties of the thermoplastic resin. On the other hand, if the number average molecular weight of the polymer diol exceeds 3000, the urethane group concentration becomes relatively low, so that the desired physical properties cannot be obtained, and the durability of the molded product of the flame retardant resin composition ( There is a concern that the hydrolysis resistance, hardness, physical property retention, etc.) will be insufficient.

  The number average molecular weight of the polymer diol can be measured in accordance with JISK 7252-3.

  Such a polymer diol contains at least one of a polyether diol and a polycarbonate diol in order to achieve the desired hydrolysis resistance. These polyether diols and polycarbonate diols preferably occupy 90% or more, more preferably 100% of the polymer diol on a mass basis.

  As the polyether diols, ethylene oxide, which can be used as a chain extender, is used as an initiator, such as low molecular diols, low molecular amino alcohols, low molecular glycol ethers, etc. Addition polymerization of alkylene oxides such as propylene oxide, butylene oxide, and amylene oxide, alkyl glycidyl ethers such as methyl glycidyl ether, aryl glycidyl ethers such as phenyl glycidyl ether, and cyclic ether monomers such as tetrahydrofuran, or a mixture thereof by a known method. Can be obtained. Specific examples include polytetramethylene ether glycol having hydroxyl groups at both ends.

  Examples of polycarbonate diols include dealcoholization reactions and dephenol reactions of diols such as 1,6-hexanediol and 1,4-cyclohexanedimethanol with dimethyl carbonate, diethyl carbonate, diphenyl carbonate, diethylene carbonate, etc. Can be obtained.

  The diol component constituting the TPU of the present invention contains 1,4-butanediol as a chain extender from the viewpoint of improving hardness, physical properties, heat resistance and the like, in addition to the above-described polymer diol.

  The blending ratio of 1,4-butanediol and polymer diol in the diol component is the ratio of the number of moles of active hydrogen groups of 1,4-butanediol to the number of moles of all active hydrogen groups of the polymer diol ([1,4-butane The number of moles of active hydrogen groups in the diol] / [the total number of moles of active hydrogen groups in the polymer diol] = (R ′ value)) is preferably 0 from the viewpoint of controlling the amount of hard segments that influence the physical properties of the TPU. 0.1-15, more preferably 0.1-12.

  In addition to 1,4-butanediol, low-molecular diols, low-molecular amino alcohols, and low-molecular glycol ethers are also used as chain extenders as long as the properties of the flame-retardant resin composition of the present invention are not impaired. Can be used.

  Low molecular diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexane Diol, diethylene glycol, dipropylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3- Propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 1,4-bis (β-hydroxyethoxy) benzene, glycerin, trimethylolpropane, pentaerythritol , Diglycerin, sorbitol, sucrose, etc., or a mixture of two or more. That.

  Low molecular amino alcohols include monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-methyldiethanolamine, N-ethylethanolamine, Nn-butylethanolamine, Nn-butyldiethanolamine, A single item or a mixture of two or more of N- (β-aminoethyl) ethanolamine, N- (β-aminoethyl) isopropanolamine and the like can be mentioned.

  Low molecular glycol ethers include, for example, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, ethylene glycol mono-2-ethylhexyl ether. , A single product such as glycol ether such as propylene glycol monomethyl ether or dipropylene glycol monomethyl ether, or a mixture of two or more thereof.

  In the present invention, as the diisocyanate component constituting TPU, diphenylmethane diisocyanate is used from the viewpoint of improving hardness, physical properties, heat resistance and the like. Specifically, 4,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, and 2,4′-diphenylmethane diisocyanate are used. Among these, 4,4′-diphenylmethane diisocyanate can be preferably used.

  In addition to diphenylmethane diisocyanate, paraphenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, naphthylene diisocyanate, 3, 3 as long as the characteristics of the flame retardant resin composition of the present invention are not impaired. '-Dimethylbiphenyl-4,4'-diisocyanate and the like and aromatic diisocyanates comprising these isomers, aliphatic diisocyanates such as 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, trimethyl-hexamethylene diisocyanate, cyclohexane Diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, norbornane diisocyanate Alicyclic diisocyanates such as can be used in combination. Moreover, the isocyanate group terminal compound by reaction of these compounds and an active hydrogen group containing compound, or the polyisocyanate modified body etc. by reaction of these compounds, for example, carbodiimidization reaction, etc. can be used.

  In the present invention, the ratio of the total number of moles of isocyanate groups in the diisocyanate component to the total number of moles of active isocyanate groups in the diol component ([total number of moles of isocyanate groups] / [total moles of active hydrogen groups] The number] = (R value) is preferably 0.7 to 1.3, more preferably 0.8 to 1.2, from the viewpoint of adjusting the molecular weight of the TPU to a preferable range.

  The TPU constituting the flame-retardant resin composition of the present invention described above is a known method for producing TPU such as a one-shot method, a prepolymer method, a polymer diol, 1,4-butanediol and diphenylmethane diisocyanate. It can be prepared by applying a method such as a batch reaction method, a continuous reaction method, a kneader method, or an extruder method. For example, in the method using a kneader, a polymer diol and 1,4-butanediol are charged into a kneader, heated to 80 ° C., charged with diphenylmethane diisocyanate, reacted for 10 to 60 minutes, cooled, and then powdered or blocked. TPU can be prepared. In these methods, a catalyst can be added during the reaction as necessary. Examples of the catalyst include amines such as triethylamine, triethylenediamine, N-methylimidazole, N-ethylmorpholine, 1,8-diazabicyclo-5,4,0-undecene-7 (DBU), potassium acetate, stannous octet Organic compounds such as acrylate, dibutyltin dilaurate and dioctyltin dilaurate, and phosphorus compounds such as tributylphosphine, phospholene and phospholene oxide. These compounds can be used alone or in combination of two or more.

  The non-halogen flame retardant constituting the flame-retardant resin composition of the present invention contains a liquid non-halogen triaryl phosphate having a molecular weight of 380 or more, preferably 390 or more, and melamine cyanurate having an average particle diameter of less than 2 μm. To do. Here, the liquid state means having fluidity of 500,000 mPa · s or less at 20 ° C.

  The reason for using a liquid non-halogen triaryl phosphate is that if it is not liquid, the compatibility with melamine isocyanurate is reduced, and further, the non-halogen flame retardant containing these is also compatible with TPU. This is because there is a concern that the appearance of the molded product may be deteriorated due to bleed, bloom, or the like, and the surface property may be deteriorated.

  The reason why the molecular weight of the non-halogen triaryl phosphate is 380 or more is that triphenyl phosphate (molecular weight = 326, melting point = 49 ° C.), tricresyl phosphate (molecular weight = 368, viscosity = 58 mPa · s / 20 ° C. If the molecular weight is smaller than 380, the volatility is high. For example, the volatilization may occur during continuous molding and adhere to the mold, or transfer to a molded product may cause problems such as poor surface properties. Because it is done.

  As such a non-halogen triaryl phosphate, it is preferable to use one having excellent hydrolysis resistance. For example, cresyl di-2,6-xylenyl phosphate (molecular weight = 396, viscosity = 1,500 mPa · s). s / 20 ° C., trade name “PX-110”, Daihachi Chemical Co., Ltd.), trixylenyl phosphate (molecular weight = 410, viscosity = 172 mPa · s / 20 ° C., trade name “TXP”, Daihachi Chemical Co., Ltd.) ) Etc. can be mentioned preferably.

  On the other hand, as a flame retardant used in combination with non-halogen triaryl phosphate, low water solubility (less than 0.001 g / 100 ml “High performance of flame retardant polymer (CMC Publishing)”, p205, 2007) The reason for using the melamine cyanurate shown is that when using guanidine, a water-soluble guanidine sulfamate known as a non-halogen nitrogen atom-containing flame retardant, or melamine showing higher water solubility than melamine cyanurate, This is because there is a concern that hydrolysis resistance cannot be ensured.

As such a melamine cyanurate, those having an average particle diameter of less than 2 μm are used from the viewpoint of achieving solubility (compatibility) in TPU and improving the appearance of the molded product (surface properties, smoothness, etc.). Specific examples of melamine cyanurate having an average particle size of less than 2 μm include “MC-6000” (particle size D ⁵⁰ of less than 2 μm) manufactured by Nissan Chemical Industries, Ltd. Here, the average particle size is defined as the particle size value [D ⁵⁰ ] when the mass accumulation is 50% when the particle size distribution is measured using a particle size distribution measuring device such as a laser scattering particle size distribution meter.

  The lower limit of the average particle diameter of melamine cyanurate is not particularly limited, and if it is too small, the effect of the invention is not obtained, but if it is too small, the fine particles of melamine cyanurate aggregate and disperse in TPU. It is difficult to mix, and there is a concern that the flame retardant resin composition may be thickened to a level higher than expected, and furthermore, it may be scattered to contaminate the work environment. The average particle size of nurate is preferably 0.3 μm or more.

  In the present invention, the blending ratio of non-halogen triaryl phosphate / melamine cyanurate in the non-halogen flame retardant ([non-halogen triaryl phosphate] / [melamine cyanurate]) is 40/60 to 90/10 (mass). Ratio), preferably 50/50 to 80/20 (mass ratio).

  When the blending ratio of non-halogen triaryl phosphate / melamine cyanurate is larger than 60 (blending ratio), the blending amount of melamine cyanurate having a relatively high melting point increases and flame retardancy There is a concern that the impact strength of the molded product of the adhesive resin composition may decrease, and when molding using an extruder, a substance called `` eye area '' tends to adhere and accumulate near the outlet, There is a concern that the quality may deteriorate due to adhesion or mixing with the molded product. Furthermore, since the melamine cyanurate itself is a powder (solid), the appearance of the melamine cyanurate itself may be whitened and the development of various colors may be restricted.

  On the other hand, when the blending ratio of the non-halogen triaryl phosphate / melamine cyanurate is less than 10 (blending ratio), the blending amount of the non-halogen triaryl phosphate that is relatively liquid is There is a concern that problems such as poor appearance and surface properties of molded products due to bleed, bloom, and the like, and molding processability decrease.

  Further, regarding the blending of the non-halogen flame retardant in the flame retardant resin composition of the present invention, the blending ratio of TPU / non-halogen flame retardant ([thermoplastic polyurethane resin] / [non-halogen flame retardant]) is 80. / 20 to 70/30 (mass ratio), preferably 75/25 (mass ratio).

  In the blending ratio of TPU / non-halogen flame retardant, if the blend ratio of non-halogen flame retardant is less than 20 (blending ratio), there is a concern that the UL94 standard V-0 standard regarding flame retardancy cannot be achieved, If it exceeds 30 (mixing ratio), there is a concern that problems such as a decrease in hardness, a decrease in physical properties, a defective appearance of a molded product due to bleed or bloom, a poor surface property, or a problem that the molding processability deteriorates may occur.

  The flame retardant resin composition of the present invention is prepared by mixing TPU and a non-halogen flame retardant at an appropriate ratio using a Henschel mixer or the like and then supplying the mixture to an extruder to extrude normal TPU (about 150 ° C.). ~ 220 ° C) and melt-kneaded, and can be prepared in the form of pellets by strand cutting or underwater cutting.

  In addition, the flame retardant resin composition of the present invention is prepared by blending a non-halogen flame retardant with a raw material for producing the TPU, for example, a polymer diol component and / or a diphenylmethane diisocyanate component, and mixing them uniformly. Can also be prepared.

  The flame retardant resin composition of the present invention may contain other flame retardants, antioxidants, ultraviolet absorbers, heat resistance improvers, plasticizers, lubricants, antistatic agents, conductivity-imparting agents, colorants, inorganic and Organic fillers, fiber reinforcements, hydrolysis inhibitors, reaction retarders, and the like can be added.

  For the molding of the flame retardant resin composition of the present invention, a commonly used TPU molding method can be applied. For example, extrusion molding, injection molding, blow molding, calendaring, roll processing, press processing, centrifugal molding, rotation It can be molded by a molding method such as molding.

  The molded product of the flame-retardant resin composition of the present invention can be applied to a wide range of fields that do not like the generation of halogen gas due to fire, such as interior materials for houses, communication cables, industrial cables, automobiles, and various vehicle interior materials. it can. For example, high pressure hoses, medical tubes, oil / pneumatic tubes, sprinkling tubes, tube hoses such as fire hoses, air mats, diaphragms, keyboard sheets, synthetic leather, life jackets, wet suits, films such as flexible containers, Electric power / communication cables, computer wiring, automobile wiring, electric wires / cables such as various curled cords, various ropes, various driving belts, various types of extrusion molding products such as anti-slip, etc. Auto parts such as dust covers, pedal stoppers, door lock strikers, bushes, spring covers, bearings, vibration-proof parts, various gears, seals, packing, connectors, rubber screens, printing drums and other mechanical parts, sports shoe soles and Point, lady Shoe-related parts of the top lift, etc., rollers, casters, grip, can also be effectively applied to snow chains and the like.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited at all by these. In Examples and Comparative Examples, “part” means “part by mass”.

Examples 1-7, Comparative Examples 1-12
(Sample preparation)
In a reaction vessel equipped with a stirrer and a thermometer, polymer diol (component A), 1,4-butanediol (component B), antioxidant (Irganox 1010), ultraviolet absorber (tinuvin P), Tables 1 to 3 show halogen flame retardants (component C (of which non-halogen aromatic phosphate is component C-1 and non-halogen nitrogen atom-containing cyclic compound is component C-2)). The indicated amount was mixed uniformly.

  After heating the obtained liquid mixture at 100 degreeC, the amount of diphenylmethane diisocyanate (component D) described in Table 1-Table 3 was added, and the urethanation reaction was performed. When the reaction product reached 90 ° C., it was poured onto a vat and solidified. The obtained solid was aged in an electric furnace at 80 ° C. for 16 hours and cooled, and then the solid was pulverized to obtain a flaky TPU.

  The obtained flaky TPU was dried in an electric furnace at 80 ° C. for 16 hours, and then a strand was extruded with a single-screw extruder to produce a cylindrical pellet using a cutter. Samples of Examples 1 to 12 were used.

  In Tables 1 to 3, "TPU / flame retardant (mass ratio)" and "C-1 / C-2 (mass ratio)" are shown.

                The raw materials used in Tables 1 to 3 are as follows.

<A (polymer diol)>
* PTMG650: Polytetramethylene ether glycol (number average molecular weight: 650), manufactured by Mitsubishi Chemical Corporation * PTMG850: Polytetramethylene ether glycol (number average molecular weight: 850), manufactured by Mitsubishi Chemical Corporation * PTMG1000: Polytetramethylene ether glycol (Number average molecular weight: 1000), manufactured by Mitsubishi Chemical Corporation * PTMG2000: polytetramethylene ether glycol (number average molecular weight: 2000), manufactured by Mitsubishi Chemical Corporation * Nipporan 981: polycarbonate diol (number average molecular weight: 1000), Nippon Polyurethane * Nipporan 4009 manufactured by Kogyo Co., Ltd .: polyester diol (number average molecular weight: 1000), manufactured by Nippon Polyurethane Industry Co., Ltd. * Sanix PP-4000: polyoxypropylene glycol (number Average molecular weight: 4160), Sanyo Chemical Industries, Ltd.

<B (1,4-butanediol (1,4-BG))>
* 1,4-butanediol, manufactured by Mitsubishi Chemical Corporation

<C (phosphate ester)>
C-1 (Non-halogen aromatic phosphate)
* PX-110: Cresyl di-2,6-xylenyl phosphate (liquid, molecular weight: 396), manufactured by Daihachi Chemical Industry Co., Ltd. * TXP: Trixylenyl phosphate (liquid, molecular weight: 410), Daihachi Chemical Co., Ltd. * TPP: Triphenyl phosphate (liquid, molecular weight: 326) manufactured by company * TCP: tricresyl phosphate (liquid, molecular weight: 368) manufactured by Daihachi Chemical Industry Co., Ltd. * PX-200: 1 , 3-phenylene-bis- (di-2,6-xylenyl) -phosphate (powder, molecular weight: 686), manufactured by Daihachi Chemical Industry Co., Ltd.

C-2 (Non-halogen nitrogen atom-containing cyclic compound)
* MC-6000: Melamine cyanurate (powder, average particle size: less than 2 μm), manufactured by Nissan Chemical Industries, Ltd. * MC-4000: Melamine cyanurate (powder, average particle size: less than 14 μm), Nissan Chemical Industries Ltd. * Melamine (reagent, powder) manufactured by company: Wako Pure Chemical Industries, Ltd. * AP-101: Guanidine sulfamate (powder), manufactured by Sanwa Chemical Co., Ltd.

<D (diisocyanate compound)>
* MDI: 4,4'-diphenylmethane diisocyanate, manufactured by Nippon Polyurethane Industry Co., Ltd.

(Characteristic test)
Various characteristics of the sample prepared by the above procedure were evaluated as described below. The obtained results are shown in Tables 4-6.

(1) Mechanical properties [Hardness (JIS-A hardness)]
[100% modulus (tensile stress, MPa)]
[Tensile strength (MPa)]
[Elongation (%)]
[Tear strength (kN / m)]
The obtained pellets were injection molded to produce a sheet, which was annealed at 105 ° C. for 16 hours, and then measured according to the measurement method described in JIS K 7311 (Testing method for polyurethane-based thermoplastic elastomer). The properties that should be provided in practice are as follows.

[Hardness (JIS-A hardness)]
Practically, it is desired to be 56 or more.
[100% modulus (tensile stress, MPa)]
Practically, it is desired to be 1.4 MPa or more.
[Tensile strength (MPa)]
Practically, it is desired to be 12 MPa or more.
[Elongation (%)]
Practically, it is desired to be 300% or more.
[Tear strength (kN / m)]
Practically, it is desired to be 40 kN / m or more.

(2) Flame retardancy A test piece for UL94 standard vertical flammability test was prepared from the injection-molded sheet obtained in (1) above, and measured in accordance with the evaluation standards of the fifth edition and chapter 8 of the test method. did.

(3) Drip identification In the above flame retardancy test, the presence or absence of dripping (drip) from the test piece was observed, and evaluated according to the following criteria. AA and A were accepted, and B and C were rejected.

Rank: Content AA: Almost none A: A little B: Somewhat C: Many

(4) Bleed-bloom characteristics The surface condition of the injection-molded sheet obtained in (1) above was evaluated by visual and tactile sensation according to the following criteria, AA and A were accepted, and B and C were rejected. .

Rank: Contents AA: None A: A little B: Somewhat C: Many

(5) Appearance The condition of the surface of the injection-molded sheet obtained in the above (1) is evaluated by visual inspection based on the presence / absence of bubbles, lumps, foreign matters, etc., AA and A are accepted, and B and C are unacceptable. Passed.

Rank: Contents AA: Good A: Partially defective B: The majority of defective parts C: Almost all defective

(6) Hydrolysis resistance Using the injection-molded sheet obtained in the above (1), it was punched into a dumbbell shape defined by JIS K7311 (Testing method for polyurethane-based thermoplastic elastomer) to obtain a test piece. The test piece was immersed in warm water at 70 ° C. for 60 days, and the tensile strength was measured using a tensile tester. Compared with the physical properties of the film before the test (100% modulus), the hydrolysis resistance was evaluated according to the retention rate according to the following criteria, AA and A were accepted, and B and C were rejected.

Rank: Content AA: Retention rate 90% or more
A: Retention rate less than 90% 70% or more B: Retention rate less than 70% 50% or more C: Retention rate less than 50%

<Discussion>
In the case of the flame-retardant resin compositions of Examples 1 to 7, all show flame retardancy satisfying the V94 standard of UL94 standard, and mechanical properties (hardness, 100% modulus (tensile stress, MPa), (Tensile strength, elongation, tear strength) also ensured the desired properties. The drip characteristics, bleed / bloom characteristics, appearance, and hydrolysis resistance were preferably evaluated as AA or A. In particular, in the case of the flame retardant resin compositions of Examples 3 and 5-7, the molecular weight of the polymer diol constituting the TPU, and the blending amount of the non-halogen triaryl phosphate and melamine cyanurate are appropriate amounts. The properties, bleed / bloom properties, appearance, and hydrolysis resistance were all evaluated by AA.

  On the other hand, in the case of the flame retardant resin composition of Comparative Example 1, the desired properties are obtained for the mechanical properties, the flame retardancy satisfies the V-0 standard of the UL94 standard, and the hydrolysis resistance is Although it was A evaluation, regarding the mass ratio of TPU / flame retardant, since the amount of the flame retardant was too large, it was out of the scope of the present invention. Therefore, for drip characteristics, bleed / bloom characteristics and appearance, C It was evaluation.

  In the case of the flame retardant resin composition of Comparative Example 2, the desired properties were obtained for the mechanical properties, and the drip properties, bleed / bloom properties, appearance, and hydrolysis resistance were evaluated as A. As for the flame retardant mass ratio, the flame retardant blending amount is too small, so that the scope of the present invention has been exceeded. Therefore, the UL94 standard regarding flame retardancy cannot satisfy the V-0 standard, and V -2 standards remained.

  In the case of the flame retardant resin composition of Comparative Example 3, the desired properties were obtained for the mechanical properties, the flame retardancy also satisfied the V94 standard of the UL94 standard, and the drip properties were evaluated as A. However, since 326 solid triphenyl phosphate having a molecular weight of significantly less than 380 was used as the non-halogen aromatic phosphate ester, the bleed-bloom characteristics and appearance were evaluated by C. Since 1000 polyester diols were used, the hydrolysis resistance was also evaluated as C.

  In the case of the flame retardant resin composition of Comparative Example 4, 4160 polyether diol having a number average molecular weight of more than 3000 was used as the polymer diol, so that the expected properties were not obtained for the mechanical properties. Although the flame retardancy satisfied the V-0 standard of the UL94 standard, the drip characteristics, bleed / bloom characteristics, appearance, and hydrolysis resistance were evaluated as B.

  In the case of the flame retardant resin composition of Comparative Example 5, the desired properties were obtained for the mechanical properties, the flame retardancy also satisfied the V94 standard of the UL94 standard, and the hydrolysis resistance was evaluated as A. However, since 368 liquid tricresyl phosphate having a molecular weight of less than 380 was used as the non-halogen aromatic phosphate, the drip characteristics were evaluated as B, and the bleed / bloom characteristics and appearance were evaluated as C. It was evaluation.

  In the case of the flame retardant resin composition of Comparative Example 6, the desired properties are obtained for the mechanical properties, the flame retardancy satisfies the V94 standard of the UL94 standard, and the hydrolysis resistance is evaluated as A. However, since the powdered 1,3-phenylene-bis- (di-2,6-xylenyl) -phosphate was used as the phosphate ester flame retardant, the drip characteristics were evaluated as B. The bloom characteristics and appearance were rated C.

  In the case of the flame-retardant resin composition of Comparative Example 7, the desired properties were obtained for the mechanical properties, the flame retardancy also satisfied the V94 standard of the UL94 standard, and the drip properties were evaluated as A. However, since water-soluble guanidine sulfamate was used in place of melamine cyanurate, the bleed-bloom characteristics and appearance were evaluated as B, and the hydrolysis resistance was evaluated as C.

  In the case of the flame retardant resin composition of Comparative Example 8, the desired properties were obtained for the mechanical properties, and the flame retardancy also satisfied the V94 standard of the UL94 standard, and drip characteristics, bleed / bloom characteristics and The hydrolysis resistance was evaluated as A. However, since melamine cyanurate having an average particle size of less than 14 μm was used, the appearance was evaluated as C.

  In the case of the flame retardant resin composition of Comparative Example 9, the desired properties were obtained for the mechanical properties, and instead of melamine cyanurate, powdered melamine with better water solubility was used, so that the flame retardant The UL94 standard for water quality cannot satisfy the V-0 standard, but remains at the V-2 standard. The drip characteristics, bleed / bloom characteristics and appearance are rated as B, and the hydrolysis resistance is rated as C. It was.

  In the case of the flame retardant resin composition of Comparative Example 10, the desired properties were obtained for the mechanical properties, the flame retardancy also satisfied the UL94 standard V-0 standard, and the drip properties and hydrolysis resistance. Was the A evaluation, but regarding the mass ratio of C-1 / C-2, since the blending amount of C-1 was too large, it was out of the scope of the present invention. Was a B rating.

  In the case of the flame retardant resin composition of Comparative Example 11, the desired properties were obtained for the mechanical properties, and the hydrolysis resistance was A evaluation, but the mass ratio of C-1 / C-2 As a result of having too little blending amount of C-1, it was out of the scope of the present invention. Therefore, the UL94 standard regarding flame retardancy cannot satisfy the V-0 standard, but remains at the V-2 standard. The drip characteristics, bleed / bloom characteristics and appearance were rated as C.

  In the case of the flame retardant resin composition of Comparative Example 12, the desired properties were obtained for the mechanical properties, the flame retardancy also satisfied the V94 standard of the UL94 standard, and the drip properties and hydrolysis resistance. However, since the polymer diol having a number average molecular weight of less than 800 was used, the bleed and bloom characteristics were evaluated as B, and the appearance was evaluated as C.

  In the flame-retardant resin composition of the present invention containing TPU obtained by reacting a diol component and a diisocyanate component and a non-halogen flame retardant, the molecular weight and type of the diol component constituting the TPU are limited. On the other hand, the diisocyanate component is limited to a specific compound, and further, as a non-halogen flame retardant, a liquid triaryl phosphate having a specific molecular weight range and a melamine cyanurate having a specific particle size are used in a predetermined mixing ratio. In addition, the dividend amount range for TPU of non-halogen flame retardants is limited. For this reason, the flame retardant resin composition of the present invention can achieve the desired flame retardancy, and also causes problems such as poor appearance and poor surface properties due to bleed and bloom on the molded product. Furthermore, excellent durability, particularly hydrolysis resistance can be imparted. Therefore, the flame-retardant resin composition of the present invention is molded by injection molding, extrusion molding, calendar molding, etc., and products requiring a non-halogen flame retardant, such as house interior materials, communication cables, industrial cables, It is useful for automobiles, various vehicle interior materials, etc. that do not like the generation of halogen gas due to fire, and applications that require durability (hydrolysis resistance, hardness, physical property retention, etc.).

Claims (3)

A flame retardant resin composition comprising a thermoplastic polyurethane resin obtained by reacting a diol component and a diisocyanate component, and a non-halogen flame retardant,
The diol component constituting the thermoplastic polyurethane resin contains a polymer diol having a number average molecular weight of 800 to 3000 and 1,4-butanediol, and the polymer diol contains at least one of a polyether diol and a polycarbonate diol. ,
The diisocyanate component constituting the thermoplastic polyurethane resin contains diphenylmethane diisocyanate,
The non-halogen flame retardant contains a liquid non-halogen triaryl phosphate having a molecular weight of 380 or more and melamine cyanurate having an average particle diameter of less than 2 μm;
The mass ratio between the non-halogen triaryl phosphate and the melamine cyanurate ([non-halogen triaryl phosphate] / [melamine cyanurate]) is 40/60 to 90/10,
Flame retardant, characterized in that the mass ratio ([thermoplastic polyurethane resin] / [non-halogen flame retardant]) between the thermoplastic polyurethane resin and the non-halogen flame retardant is 80/20 to 70/30 Resin composition.   The flame retardant resin composition according to claim 1, wherein the non-halogen triaryl phosphate is cresyl di-2,6-xylenyl phosphate.   A molded article formed from the flame retardant resin composition according to claim 1.