JP5151890B2 - Method for producing non-halogen flame retardant thermoplastic composition and non-halogen flame retardant thermoplastic composition - Google Patents

Description

  The present invention comprises a non-halogen flame retardant comprising a silane-crosslinked rubber or resin, a non-crosslinked rubber or resin, and a metal hydroxide and having high mechanical strength, heat resistance, oil resistance, flame retardancy, and recyclability. In particular, the present invention relates to a method for producing a non-halogen flame retardant thermoplastic composition capable of producing a non-halogen flame retardant thermoplastic composition without quality variations, and to a non-halogen flame retardant thermoplastic composition. Is.

  The activities for environmental conservation are increasing worldwide, and toxic gases are not generated during combustion, environmental pollution during disposal is low, and materials that can be recycled are rapidly spreading.

  A typical material is a composition in which a thermoplastic polymer is mixed with a non-halogen flame retardant such as a metal hydroxide. In order to enhance the mechanical strength, heat resistance, oil resistance, etc. of these materials, it is effective to introduce cross-linking. However, if the cross-linking range extends to the entire polymer, fluidity is lost and material recycling is difficult. It becomes.

  As a material for solving this difficulty, there is a dynamically crosslinked thermoplastic composition having thermoplasticity even after the introduction of crosslinking. That is, this dynamically crosslinked thermoplastic composition can maintain fluidity by a structure in which a crosslinked polymer phase (island phase) is dispersed in a continuous phase (sea phase) of a thermoplastic polymer.

  The present inventor has newly proposed silane crosslinking as a crosslinking method for such a dynamically crosslinked thermoplastic composition. According to the present invention, any kind and combination of rubber and resin can be used to prepare a dynamically crosslinked thermoplastic composition by previously graft-copolymerizing a silane compound to rubber or resin.

Japanese Laid-Open Patent Publication No. 1-254751 JP-A-2-19639 Japanese Patent Laid-Open No. 6-136066 JP-A-11-158233 JP-A-11-181102 JP-A-6-15716 JP-A-9-208620 JP 2007-70602 A

  However, since this dynamically cross-linked non-halogen flame retardant thermoplastic composition is a novel material that has not been developed so far, the establishment of a production method with high reproducibility and excellent mass productivity has been established. is necessary.

  Accordingly, an object of the present invention is to provide a method for producing a non-halogen flame retardant thermoplastic composition that can be produced without variation in quality, and a non-halogen flame retardant thermoplastic composition.

  In order to achieve the above object, the present invention of claim 1 comprises components (A) and (B) made of rubber or resin, and component (C) made of a metal hydroxide, wherein the component (A) is crosslinked with silane. When a non-halogen flame retardant thermoplastic composition is produced, the component (A) is graft-copolymerized with a silane compound having a boiling point of 180 ° C. or higher under normal pressure to continuously move the component (A) dynamically. A process for producing a non-halogen flame retardant thermoplastic composition characterized in that it is crosslinked with silane.

  In the invention of claim 2, after the component (A) is charged into a batch kneader, a solution of a silane compound having an boiling point of 180 ° C. or higher under normal pressure and an organic peroxide is added, and the silane is added to the component (A). The component (B) and the component (C) are added continuously by graft copolymerization, and finally the silanol condensation catalyst is added, and the component (A) is dynamically silane-crosslinked. This is a method for producing a non-halogen flame retardant thermoplastic composition.

  The invention of claim 3 is a non-halogen flame retardant thermoplastic composition produced by the production method of claim 1 or 2.

  According to the present invention, it is possible to produce a non-halogen flame retardant thermoplastic composition having high mechanical strength, heat resistance, oil resistance, flame retardancy, and recyclability without quality variations.

  Hereinafter, a preferred embodiment of the present invention will be described in detail.

  In order to achieve the above-mentioned object, the present inventors have studied a production method and a compounding agent.

  In producing a non-halogen flame retardant thermoplastic composition, a step of graft copolymerizing a silane compound with the component (A) made of rubber or resin and a step of dynamically crosslinking the component (A) are required. Become. When these two steps are performed in separate and independent apparatuses, the rubber or resin in which the silane compound is graft-copolymerized is allowed to stand for a certain period of time. There is a concern about the problem that scorch (early vulcanization) occurs in the rubber or resin due to the progress of the crosslinking reaction, and it is disadvantageous in terms of production cost because it cannot be produced continuously. Therefore, it is desirable that the material (non-halogen flame retardant thermoplastic composition) is manufactured by performing two steps in one apparatus by one kneading.

  When two steps are carried out by one kneading in one apparatus, it is generally considered that a batch type kneader such as a kneader or a Banbury mixer is used as the apparatus.

  However, when these batch-type kneaders are used, in the step of graft copolymerizing the silane compound with the rubber or resin, if the temperature is raised to a temperature at which the organic peroxide is decomposed to generate free radicals, the kneader is sealed. There was a problem that the silane compound volatilizes because of insufficient properties. The silane compound here has both an organic functional group capable of reacting with a polymer and an alkoxy group that forms a crosslink by hydrolysis and silanol condensation, and is particularly excellent in reactivity with the polymer and crosslink rate. As such, vinyltrimethoxysilane (boiling point: 123 ° C.), vinyltriethoxysilane (boiling point: 161 ° C.) and the like were generally used. As a result, there are problems such as insufficient graft amount of the silane compound and inability to obtain reproducibility.

  Therefore, as a result of the study by the present inventors, when producing the material using a batch kneader, by graft-copolymerizing a silane compound having a boiling point of 180 ° C. or higher under normal pressure to rubber or resin, It was found that the above problems could be solved. Thus, using a batch-type kneader, the step of graft copolymerizing the silane compound to the component (A) made of rubber or resin and the step of dynamically crosslinking the component (A) are carried out in a single kneading, It was found that a non-halogen flame retardant thermoplastic composition can be produced.

  The component (A) and the component (B) made of rubber or resin specified by the method for producing a non-halogen flame retardant thermoplastic composition according to a preferred embodiment of the present invention can be selected from the following.

  As rubber, ethylene-propylene-diene copolymer, ethylene-propylene copolymer, ethylene-butene-1-diene copolymer, ethylene-octene-1-diene copolymer, acrylonitrile butadiene rubber, acrylic rubber, styrene Styrene-diene copolymer represented by butadiene rubber and styrene isoprene rubber, or styrene-diene-styrene copolymer represented by styrene-butadiene-styrene rubber and styrene-isoprene-styrene rubber, or hydrogenated thereof. Styrenic rubber obtained from the above can be used.

  As the resin, known resins can be used, such as polypropylene, high density polyethylene, linear low density polyethylene, low density polyethylene, ultra low density polyethylene, ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer. Polymer, ethylene-octene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polybutene, poly-4-methyl-pentene-1, ethylene-butene-hexene terpolymer, Examples thereof include an ethylene-methyl methacrylate copolymer, an ethylene-methyl acrylate copolymer, and an ethylene-glycidyl methacrylate copolymer. Two or more of these may be blended and used.

  In the present invention, the mixing ratio of the component (A) and the component (B) made of rubber or resin is arbitrary, and can be freely set depending on the required physical properties.

  The silane compound is required to have both an organic functional group capable of reacting with the polymer and an alkoxy group that forms a crosslink by hydrolysis and silanol condensation. In the present invention, it is necessary to use a silane compound having a boiling point of 180 ° C. or higher under normal pressure (1013 hPa). Specifically, vinylsilane compounds such as vinyltris (2-methoxyethoxy) silane (boiling point: 285 ° C), 3-aminopropyltrimethoxysilane (boiling point: 194 ° C), 3-aminopropyltriethoxysilane (boiling point: 217 ° C). ), N-2- (aminoethyl) -3-aminopropyltrimethoxysilane (boiling point: 261 ° C.), N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane (boiling point: 265 ° C.), N— Aminosilane compounds such as phenyl-3-aminopropyltrimethoxysilane (boiling point: 312 ° C), 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane (boiling point: 310 ° C), 3-glycidoxypropyltrimethoxysilane ( Boiling point: 290 ° C), 3-glycidoxypropyltriethoxysilane (boiling point: 140) / 4 hPa (boiling point 180 ° C. or higher under normal pressure (1013 hPa))), 3-glycidoxypropylmethyldimethoxysilane (boiling point: 100 ° C./5.3 hPa (boiling point 180 ° C. or higher under normal pressure (1013 hPa))) Epoxysilane compounds such as 3-glycidoxypropylmethyldiethoxysilane (boiling point: 259 ° C), 3-methacryloxypropyltrimethoxysilane (boiling point: 255 ° C), 3-methacryloxypropyltriethoxysilane (boiling point: 80 ° C) /0.5 hPa (boiling point 180 ° C. or higher under normal pressure (1013 hPa)), 3-methacryloxypropylmethyldimethoxysilane (boiling point: 65 ° C./0.5 hPa (boiling point 180 ° C. or higher under normal pressure (1013 hPa))) 3-methacryloxypropylmethyldiethoxysilane (boiling point: 265 ° C.), -Acrylic silane compounds such as acryloxypropyltrimethoxysilane (boiling point: 98 ° C / 1.3 hPa (boiling point: 180 ° C or higher under normal pressure (1013 hPa))), 3-mercaptopropyltrimethoxysilane (boiling point: 219 ° C), Examples include mercaptosilane compounds such as 3-mercaptopropylmethyldimethoxysilane (boiling point: 204 ° C.) and 3-mercaptopropyltriethoxysilane (boiling point: 210 ° C.).

  Examples of the organic peroxide include dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di- (t-butylperoxy) hexane, 2, Dialkyl peroxides such as 5-dimethyl-2,5-di- (t-butylperoxy) hexyne-3, 1,3-bis (t-butylperoxyisopropyl) benzene, and diacyl peroxides such as dimethylbenzoyl peroxide Peroxyketals such as oxides, n-butyl-4,4-bis (t-butylperoxy) valerate, 1,1-bis (t-butylperoxy) cyclohexane can be used and are not particularly limited.

  The addition amount of the silane compound and organic peroxide is not particularly specified, and is appropriately determined in light of the physical properties of the obtained material (target non-halogen flame-retardant thermoplastic composition). .

  The component (C) comprising a metal hydroxide used in the present embodiment imparts flame retardancy to the composition, and examples thereof include magnesium hydroxide, aluminum hydroxide, calcium hydroxide, and the like. Magnesium hydroxide having the highest effect is preferred. The metal hydroxide is desirably surface-treated from the viewpoint of dispersibility.

  As the surface treatment agent used for this surface treatment, a silane coupling agent, a titanate coupling agent, a fatty acid or a fatty acid metal salt, etc. can be used, and in particular, the adhesion between the resin and the metal hydroxide is enhanced. A coupling agent is desirable.

  Examples of silane coupling agents that can be used include vinylsilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris (2-methoxyethoxy) silane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N Aminosilane compounds such as 2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane; -(3,4 epoxy cyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylme Epoxysilane compounds such as rudiethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxy Acrylic silane compounds such as propyltrimethoxysilane, polysulfide silane compounds such as bis (3- (triethoxysilyl) propyl) disulfide, bis (3- (triethoxysilyl) propyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, And mercaptosilane compounds such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltriethoxysilane.

  The amount of the component (C) made of the metal hydroxide is arbitrary, and can be freely set according to the flame retardancy required for the composition.

  Further, the silanol condensation catalyst that can be used in the present embodiment is dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctate, dioctyltin dilaurate, stannous acetate, stannous caprylate, zinc caprylate, naphthenic acid. There are lead, cobalt naphthenate, and the like, and the addition amount depends on the kind of the catalyst, but 0.001 to 1 part by weight per 100 parts by weight of the component (A) is preferable.

  As a method for adding the silanol condensation catalyst, there is a method of using a master batch in which a silanol condensation catalyst is mixed in advance with a resin, in addition to the method of adding it as it is.

  In addition to the above, process oil, processing aid, flame retardant aid, crosslinking agent, crosslinking aid, antioxidant, lubricant, inorganic filler, compatibilizer, stabilizer, carbon black, colorant, etc. It is also possible to add other additives.

  The manufacturing apparatus used in the manufacturing method according to the present embodiment is preferably a batch kneader such as a kneader or a Banbury mixer.

  As a kneading procedure, first, a component (A) composed of rubber or resin, a silane compound having a boiling point of 180 ° C. or higher under normal pressure, and a solution in which an organic peroxide is dissolved are reacted in a batch kneader. A) is graft copolymerized with a silane compound. At this time, it is necessary to raise the temperature of the kneader to a temperature at which the organic peroxide decomposes and generates free radicals. The optimum temperature depends on the relationship between the temperature and half-life of the organic peroxide and the kneading time. It can be determined and is not specified. Subsequently, by adding a silanol condensation catalyst, the component (A) is silane-crosslinked to produce a non-halogen flame retardant thermoplastic composition. The temperature of the kneader at this time is not particularly specified, but is preferably 160 ° C. or higher in consideration of silane crosslinking reactivity. Further, the component (B) made of rubber or resin and the component (C) made of metal hydroxide may be added at any timing.

  As a more preferable kneading procedure, first, a component (A) made of rubber or resin is introduced into a batch kneader, and then a solution in which a silane compound having a boiling point of 180 ° C. or higher under normal pressure and an organic peroxide is dissolved. Add. While raising the temperature of the kneader to a temperature at which the organic peroxide is decomposed to produce free radicals, the silane compound is graft copolymerized with the component (A) by kneading. Thereafter, the component (B) composed of rubber or resin, the component (C) composed of metal hydroxide, and the silanol condensation catalyst are added in the final order of addition of the silanol condensation catalyst. Thereafter, the component (A) is dynamically subjected to a silane crosslinking reaction in a kneader to produce a non-halogen flame retardant thermoplastic composition.

  According to this procedure, the solution of the silane compound and the organic peroxide is reacted only with the component (A), so that the graft copolymerization of the silane compound onto the component (B), and then the component (B) is crosslinked with silane. This can prevent the fluidity of the material of the present invention from decreasing. Moreover, before component (A) is silane-crosslinked by adding a silanol condensation catalyst, component (B) and component (C) are added and kneaded to prevent the component (A) from becoming coarse, Deterioration of appearance and physical properties can be suppressed.

  Other timings of additives such as process oils, processing aids, flame retardant aids, crosslinking agents, crosslinking aids, antioxidants, lubricants, inorganic fillers, compatibilizers, stabilizers, carbon black, and colorants You can add it.

  As described above, according to the manufacturing method according to the embodiment of the present invention, after the silane compound having a boiling point of 180 ° C. or higher is applied to the component (A) with a batch kneader, Since the component (A) is dynamically silane-crosslinked continuously as it is, all the reactions are completed by one kneading and there is no possibility that the rubber or resin (component (A)) is scorched. As a result, since there is no quality variation, a non-halogen flame retardant thermoplastic composition having high reproducibility and excellent mass productivity can be obtained at a low manufacturing cost. Since the kneader used for these manufactures can use existing general-purpose products, it is not necessary to design and manufacture a new apparatus.

  Since this non-halogen flame retardant thermoplastic composition is a composition in which a non-halogen flame retardant such as a metal hydroxide is mixed with a thermoplastic polymer, the flame retardant is high, and crosslinking is introduced. Therefore, mechanical strength, heat resistance, and oil resistance are also high. And since it is a dynamic bridge | crosslinking type thermoplastic composition which has thermoplasticity after bridge | crosslinking introduction | transduction, it also has recyclability.

  In addition, this non-halogen flame retardant thermoplastic composition can be applied to electric wires and cables as insulators and sheaths, and in particular, covers for electric wires and cables such as power cords and cabtyre cables that require excellent flexibility. Suitable as a material.

  FIG. 1 shows the structure of a non-halogen flame retardant thermoplastic composition obtained by the production method of the present invention, wherein the component (A) is in the continuous phase (sea phase). The composition has a structure in which the polymer phase (island phase) is dispersed. Moreover, the magnitude | size of the phase of a component (A) is manufactured in the range of 10 nm-10 micrometers by the combination of a component (A) and a component (B).

  Examples of the present invention will be specifically described below.

  As component (A) rubber or resin, ethylene-vinyl acetate copolymer (vinyl acetate content 42 mass%) or ethylene-propylene copolymer (ethylene content 56 mass%) is used as component (B) rubber or resin. , Styrene-ethylenebutylene-styrene copolymer (styrene content 28 mass%), ethylene-vinyl acetate copolymer (vinyl acetate content 20 mass%), magnesium hydroxide (silane) as the component (C) metal hydroxide Treatment, average particle size 1 μm) was used.

  Examples of silane compounds include vinyltris (2-methoxyethoxy) silane (boiling point: 285 ° C.), 3-aminopropyltrimethoxysilane (boiling point: 194 ° C.), 3-methacryloxypropyltrimethoxysilane (boiling point: 255 ° C.), vinyltri Methoxysilane (boiling point: 123 ° C.) was used.

  In addition, dicumyl peroxide as an organic peroxide and dibutyltin dilaurate as a silanol condensation catalyst were mixed in a low density polyethylene in a proportion of 3 mass% and pelletized.

  The blending ratio of each component is shown in Table 1.

  A 75-liter kneader was used as a batch kneader for the production apparatus.

  In producing the non-halogen flame retardant thermoplastic composition in the present invention, a step of graft copolymerizing the silane compound with the component (A) and a step of dynamically crosslinking the component (A) are required. In the graft copolymerization step, a solution obtained by dissolving an organic peroxide in a silane compound was added, and then the reaction was carried out by kneading at 180 ° C. for 5 minutes. In the step of dynamically crosslinking, the component (A) was dynamically allowed to undergo a silane crosslinking reaction in a kneader by adding a silanol condensation catalyst and kneading at 200 ° C. for 5 minutes. Moreover, in the stage which added the component (B) and the component (C), in order to improve a dispersibility, it knead | mixed for about 3 minutes at 180 to 200 degreeC. The rotation speed of the kneader was 30 rpm. The kneaded product was passed through a feeder ruder into a strand shape (string shape) and used for evaluation.

  In order to evaluate reproducibility, the production was performed 5 times. Table 2 shows the composition and the raw material charging order in each Example and Comparative Example.

  Each evaluation (crosslinking degree, quality stability, appearance) was performed by the following methods.

<Degree of crosslinking>
In order to measure the degree of crosslinking of component (A), the sample was wrapped in a 40 mesh stainless wire mesh, extracted in hot xylene at 130 ° C. for 24 hours, and then the wire mesh was vacuum dried at 80 ° C. for 4 hours. The residual insoluble polymer weight is regarded as the crosslinked component (A), and {(component (A) weight after extraction and drying) / (component (A) weight in initial sample)} × 100 is the gel fraction (%) It was. The gel fraction of 10 samples was measured per production, and the calculated average value was taken as the degree of crosslinking.

<Quality stability>
The stability of quality was evaluated by the variation in the degree of cross-linking among the five productions. Evaluation was based on the ratio of the maximum value and the minimum value of the gel fraction (average value).

<Appearance>
The appearance such as the smoothness of the strand surface and the dispersibility of the metal hydroxide was evaluated visually and by touch. A good appearance (smooth surface) was acceptable, a slightly rough surface was acceptable, and an extremely rough surface was not acceptable.

  Table 3 shows the evaluation results.

  In Examples 1 to 4, materials with high reproducibility and good appearance are obtained.

  On the other hand, in Comparative Example 1, since the silane compound having a boiling point under atmospheric pressure lower than 180 ° C. is used, the silane compound is volatilized at the stage of graft copolymerization of the silane compound with the component (A), and the degree of crosslinking is reduced. Variation is large.

  In Example 5, the silane compound is also graft copolymerized with the component (B), and the fluidity of the material slightly decreases. As a result, the external appearance is poor as compared with Examples 1 to 4.

  In Example 6, since the order of adding the silanol condensation catalyst is early, crosslinking of the component (A) occurs before the component (B) and the component (C) are kneaded, and it becomes easy to coarsen. As a result, the appearance is slightly roughened. Therefore, the last order of the silanol condensation catalyst is preferable.

It is a figure which shows the structure of the non-halogen flame-retardant thermoplastic composition obtained with the manufacturing method of this invention.

Explanation of symbols

A component (A)
B component (B)

Claims (3)

  A non-halogen flame-retardant thermoplastic composition comprising components (A) and (B) made of rubber or resin and a component (C) made of a metal hydroxide, wherein the component (A) is silane-crosslinked. On the other hand, non-halogen flame retardant, characterized in that component (A) is graft-copolymerized with a silane compound having a boiling point of 180 ° C. or higher under normal pressure, and component (A) is dynamically crosslinked with silane continuously. A method for producing a thermoplastic composition.   After adding the component (A) to the batch kneader, a solution of a silane compound having a boiling point of 180 ° C. or higher under normal pressure and an organic peroxide is added, and the above silane compound is graft copolymerized with the component (A). 2. The non-halogen flame-retardant heat according to claim 1, wherein component (B) and component (C) are continuously added, and finally a silanol condensation catalyst is added to dynamically silane-crosslink component (A). A method for producing a plastic composition.   A non-halogen flame retardant thermoplastic composition produced by the production method according to claim 1.

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