JP5128143B2 - Polyolefin flame retardant foam composition and olefin flame retardant foam - Google Patents

Description

  The present invention relates to a polyolefin-based flame retardant foam composition containing an intercalation compound and a polyolefin-based flame retardant foam.

  Insulating pipes such as heat insulating sheets for construction and home appliances are manufactured by processing inorganic materials such as glass fibers and rock wool or various plastic foams into sheets, tapes, or cylinders. Among these materials, plastic foams are often used because they are excellent in properties such as lightness, heat insulation and shock absorption. In particular, polyolefin foams have excellent cold resistance, water resistance, chemical resistance, and mechanical properties compared to other plastic foams, and also have excellent heat resistance when cross-linked. In addition, it is excellent in that it is excellent in molding processability such as thermoforming, and various molding techniques can be applied to give the shape. For these reasons, the polyolefin-based foam is regarded as an optimum material for the above-mentioned heat insulation application.

  However, polyolefin-based materials have high combustion heat, low decomposition temperature of around 400 ° C, low melting point, and short-term combustion speed when ignited compared to vinyl chloride resin, phenol resin, aromatic polyester, etc. There is. Therefore, in the case of a fire, heat insulation sheets or piping materials used as building materials from the viewpoint of safety have a high demand for flame retardant performance against fires from the Building Law and Fire Service Law, especially for flame-retardant polyolefin materials. Therefore, it was necessary to apply advanced flame retardant treatment without impairing the original excellent workability and mechanical properties as much as possible. Hitherto, inorganic highly filled polyolefin crosslinked foams have been proposed as such polyolefin-based flame retardant materials (see, for example, Patent Documents 1 to 4).

  The foams of Patent Documents 1 to 4 described above have high flame retardancy, but a large amount of flame retardant must be added to the resin in order to impart flame retardancy, leading to a reduction in foaming ratio. It has been difficult to obtain sufficient heat insulation performance due to a decrease in the compression recovery property of the foam. In addition, since a large amount of flame retardant is used, from the viewpoint of environmental protection when it is handled as waste in the future, elimination of environmental disturbance factors, safety of gas generated from decomposition of flame retardant in the event of fire, toxic fuming gas Countermeasures were required. For this reason, it has been desired to reduce the amount of the flame retardant used in the polyolefin-based flame retardant material and to use a flame retardant that does not become an environmental disturbance factor during disposal.

  Further, as a problem when adding the flame retardant to the resin, the flame retardant may be partially decomposed due to the heat history during extrusion kneading, or the flame retardant may be aggregated, resulting in a decrease in flame retardant addition efficiency. As a technique for solving these problems, for example, Patent Document 5 discloses a method using an intercalation compound in which a flame retardant or the like is inserted into a layered substance. Specifically, using the fact that layered materials such as swellable clay minerals swell with electron donors such as alcohol and ether, a flame retardant such as melamine is inserted into the layered material with the same grinding energy as grinding. This is a method using an intercalation compound obtained. However, the intercalation compound of this method has not reached the level of practical flame retardancy, such as the amount of inserted flame retardant such as melamine inserted is insufficient, and it fails in the UL combustion test. . In addition, this method has manufacturing problems such as a slow insertion speed and inability to perform stable insertion, and is difficult to use industrially.

Japanese Patent Publication No. 60-26500 Japanese Patent Publication No.62-16216 Japanese Examined Patent Publication No. 4-50936 JP-A-5-16256 JP 2006-290723 A

  The present invention has been made in view of the above-described circumstances, and is intended to reduce the use of a flame retardant that is excellent in flame retardancy, has a high expansion ratio, and does not become an environmental disturbance factor during disposal. It is an object of the present invention to provide a polyolefin-based flame retardant foam that can be used.

In order to achieve the above object, the present invention provides a layered material (a), a Lewis acid or acid adduct (b) comprising an organic electron donor and a proton donor, a flame retardant (c), a foaming agent ( and (d) mechanical energy is applied to the layered material (a) by intercalating the flame retardant (c) and the foaming agent (d) into the layered material (a). Provided is a polyolefin-based flame-retardant foam composition characterized by containing.

In order to achieve the above object, the present invention grinds into a layered material (a), a Lewis acid or acid adduct (b) comprising an organic electron donor and a proton donor, and a flame retardant (c). , Applying mechanical energy by grinding or friction , intercalation of the flame retardant (c) into the layered material (a), an intercalation compound (f), the layered material (a), and organic electron donation A mechanical energy is applied to the Lewis acid or acid adduct (b) composed of a body and a proton donor and the foaming agent (d) by grinding, grinding or friction, and the foaming agent (a) is added to the layered material (a). Provided is a polyolefin-based flame retardant foam composition comprising an interlayer compound (g) obtained by intercalating d).

  Furthermore, the present invention provides an olefin-based flame retardant foam characterized by foaming the olefin-based flame retardant foam composition.

  In the present invention, the layered substance (a) is preferably a swellable layered clay mineral.

  In the present invention, the Lewis acid or acid adduct (b) comprising an organic electron donor and a proton donor is an organic compound having a lone pair of electrons, an ether compound group, a ketone group and a compound group having a hetero atom. It is preferable that it is a Lewis acid or an acid adduct obtained by mixing at least one selected from the group consisting of at least one selected from an inorganic anhydride having a proton and an organic acid.

  In the present invention, the polyolefin-based flame retardant foam composition is obtained by mixing the polyolefin material (h) with a mixture (i) in which the interlayer compound (e) or (f) and / or (g) is mixed at a high concentration. It is preferable to be mixed with the polyolefin material (j) having a lower viscosity than the system material (h).

  In the present invention, the mixture (h) is a composite dispersion in which an interlayer compound having an interlayer thickness of 2.6 to 300 nm and an interlayer compound that has been peeled off and dispersed in a molecular form are dispersed in a polyolefin-based material (h). It is preferable that

  In producing the polyolefin-based flame retardant foam of the present invention, for example, an interlayer compound in which a flame retardant and / or a foaming agent is intercalated in a layered material is dispersed in a thermoplastic resin, and the interlayer thickness is 2.6 to A composite dispersion (polyolefin-based flame retardant foam composition) of an intercalation compound having a thickness of 300 nm and an interlaminar compound that has been peeled off and dispersed in a molecular form is prepared and foamed. In this polyolefin-based flame retardant foam, a flame retardant and / or a foaming agent is inserted between layers of an interlayer compound having an interlayer thickness of 2.6 to 300 nm in the foam. The flame retardant decomposes, and the decomposition gas blocks combustion oxygen and traps combustion radicals, or the flame retardant decomposes to form a carbonized heat blocking layer.

  If a flame retardant is used in the resin, it may cause partial degradation before preparing the flame retardant dispersion due to the heat history during extrusion kneading, or may cause reduction in efficiency as a reagent due to aggregation of the flame retardant due to kneading of the extruder. . From such a problem, the layered material is organically treated with a quaternary ammonium salt to form an intercalation compound, and then finely dispersed in the resin. Since the peeled intercalation compound develops a barrier property, as a result, the average process of transferring the resin decomposition gas to the gas phase becomes longer. Attempts have been made to make flame retardant by delaying ignition in the gas phase and to make it highly flame retardant by adding a small amount by fine dispersion, but intercalant quaternary ammonium inserted for the purpose of fine dispersion Since the salt is an alkylammonium salt and is soot flammable, even if other flame retardants are used, the above attempt is effective in reducing the amount of heat dissipated in the corn calorimeter test, but the oxygen index Not only a significant improvement has not been observed, but also the failure to pass the UL combustion test has not reached the point where practical flame retardancy is obtained.

  As a result of intensive studies, the present inventors have made an intercalation compound in which the flame retardant itself is intercalated in place of the alkyl ammonium salt. Interlayer compounds that are arranged in a single molecule in the interlayer partly peel and disperse for the first time when the resin is dispersed, and the flame retardant disperses in a single molecule state from the interlayer. It was found that the flame retardant acts effectively upon ignition. It was also confirmed from thermal balance analysis that a fractal intercalation compound having an interlayer thickness of 2.6 nm to 300 nm decomposes at a higher thermal decomposition temperature than the flame retardant is present alone in the resin. Such a fractal intercalation compound does not thermally decompose until it reaches the combustion temperature of the resin. After the intercalation compound is peeled and dispersed to exhibit flame retardancy by thermal decomposition of the flame retardant present in the resin, the fractal intercalation compound is thermally decomposed at a higher combustion temperature and exhibits flame retardancy. As a result, a resin dispersion containing a dispersion of a fractal intercalation compound with a partially fractal intercalation compound is obtained in a wide range of flame retardant than when a flame retardant is added alone. It was found to show sex. As a result, it becomes clear that a small amount of flame retardant exhibits high flame retardancy. For example, compared with the case of using a combination of a conventional resin and a flame retardant, the performance is equivalent at 50 mol% or less of the flame retardant. I found out that In addition, when it is dispersed in the resin, if it is made into an intercalation compound, it is less likely to be oxidized by heat than when it is kneaded into the resin alone, and the decomposition reaction occurs only at the combustion temperature. Then it is stable. Therefore, even if it recycles, it is excellent also in a flame-retardant performance maintenance.

  Further, the layered substance partially dispersed in a molecular shape is oriented in the extrusion direction when a molding means such as a sheet or injection molding is used in the resin. The layered material originally has a high gas barrier property, and in a dispersion in which the layered material is oriented and dispersed in the resin, the oriented layered material shields the permeated gas, so that the permeated gas avoids the oriented layered viscosity mineral between the resins. The permeation diffuses while detouring, and the average process distance of permeation becomes apparently long. For this reason, it is known that the gas barrier property of the resin molding is enhanced. As described above, when the foaming agent generates gas by thermal decomposition, gas permeation until the foam is cooled and solidified can be suppressed, so that a high expansion ratio can be maintained.

  The polyolefin-based flame retardant foam of the present invention is excellent in flame retardancy and has a high expansion ratio, reduces the amount of flame retardant used, and uses a flame retardant that does not become an environmental disturbance factor during disposal. Can be achieved.

  Hereinafter, the present invention will be described in more detail. First, the production of the substances (a), (b), (c), (d) and the intercalation compounds (e), (f), (g) using them will be described.

[Layered material (a)]
As the layered substance (a), swellable layered clay minerals such as smectite type clay, natural smectite type clay, synthetic smectite type clay, and swellable mica can be suitably used. More specifically, swelling mica, vermiculite, smectite, montmorillonite, savonite, beidellite, sepiolite, teniolite, zeolite, kaolinite, synthetic tetrasilicic mica, hectorite, barygorskite, pyrosite, talc, nontronite , Stevensite, halloysite, bentonite, dickite, nacrite, antigolite, chrysotile, pyrophyllite, margarite, xanthophyllite, chlorite, muscovite, phlogopite. Particularly preferred is smectite or synthetic tetralithic mica having Li ions or Na ions between layers.

  When the organic compound is inserted as an intercalant into the layered material by grinding and co-grinding using the above layered material, the moisture content of the layered compound is preferably 2.0% or less. More preferably, it is 1.5% or less. If the amount of moisture is large, the insertion speed is slow, and even if the pulverization time is lengthened, the target insertion amount cannot be obtained, and it is difficult to obtain an industrially stable insertion amount.

[Lewis acid or acid adduct (b) comprising an organic electron donor and a proton donor]
The organic electron donor activates the surface of the layered material (a) and facilitates intercalation of the functional organic compound into the layered material (a), and is treated with an acid or the like to form a Lewis acid or acid adduct. . As the organic electron donor, those having an electron donor structure such as ketones, esters, ethers, amides, amines, nitriles, and aldehydes can be preferably used.

  Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, and benzoquinone. Esters include methyl formate, methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, octyl acetate, cyclohexyl acetate, ethyl propionate, methyl butyrate, methyl chloroacetate, ethyl dichlorate, methyl methacrylate, ethyl crotonate, cyclohexane Ethyl hexanecarboxylate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, octyl benzoate, cyclohexyl benzoate, phenyl benzoate, benzyl benzoate, methyl toluate, γ-butyrolactone, δ-valerolactone , Coumarin, phthalide, ethyl carbonate and the like. Examples of ethers include methyl ether, ethyl ether, isopropyl ether, butyl ether, amyl ether, tetrahydrofuran (THF), anisole and the like.

  Examples of amides include acid amides such as N, N-dimethylamide. Examples of amines include trimethylamine, triethylamine, tributylamine, tribenzylamine, tetramethylethylenediamine, pyridine, piperidone, piperidine, piperazine and the like. Examples of nitriles include acetonitrile, benzonitrile, and trinitrile. Examples of aldehydes include methoxybutyraldehyde, acrylic aldehyde (acrolein), acetaldehyde, cyanoacetaldehyde, and the like as monofunctional aldehyde groups, and glyoxal as bifunctional aldehyde groups. Examples of other organic electron donors include dimethyl sulfoxide, N, N′-dimethylformamide, carbon tetrachloride, carbon disulfide, dimethylacetamide, and the like.

  Particularly preferable as the organic electron donor is a cyclic ether such as tetrahydrofuran, dioxane, γ-butyrolactone, morpholine, etc., and a Lewis acid is used as the substance (b) by combining with anhydrous hydrochloric acid gas or anhydrous nitric acid as a proton donor. Generated. Examples of the substance (b) include acid adducts formed from alcohols, nitroalkanes or ketoenol type ketones as proton donors, and boron trihalides, anhydrous hydrochloric acid or thionyl chloride as electron donors.

  Proton donors include methanol, ethanol, propanol, butanol, pentanol, hexanol, 2-ethylhexanol, octanol, dodecanol, octadecyl alcohol, oleyl alcohol, benzyl alcohol, phenylethyl alcohol, cumyl alcohol, isopropyl alcohol. Alcohols such as isopropylbenzyl alcohol, and halogen-containing alcohols such as trichloromethanol, trichloroethanol, and trichlorohexanol.

[Flame retardant (c) and foaming agent (d)]
The flame retardant and foaming agent may be nonionic, or may be a chemical structure capable of imparting cationicity with an acid. As the flame retardant, any of a halogen flame retardant, an organic phosphate ester flame retardant, and a triazine flame retardant can be used, but a triazine flame retardant is preferable because it is not an environmental disturbance factor, and melamine, melamine isocyanurate, melamine are particularly preferable. A phosphate compound or the like is preferable. Most desirable is a combination of melamine and melamine isocyanurate.

  As the foaming agent, azodicarbonamide (ADCA), p, p′-oxybisbenzenesulfonylhydrazide (OBSH), N, N′-dinitrosopentamethylenetetramine (DPT), p-toluenesulfonylhydrazide, benzenesulfonylhydrazide, Examples thereof include diazoaminobenzene, N, N′-dimethyl-N, N′-dinitroterephthalamide, azobisisobutyronitrile and the like.

  When a flame retardant and a foaming agent are used in combination, the decomposition temperature of the foaming agent must be lower than the decomposition temperature of the flame retardant. In addition, as described later, in the case of post-treatment foaming in which a polyolefin-based flame retardant composition sheet is molded and then subjected to heat treatment to foam, the decomposition temperature of the foaming agent must be higher than the sheet extrusion temperature. When foaming is performed simultaneously with extrusion, the decomposition temperature of the foaming agent must be the same level as or lower than the resin temperature. Thus, when using together a flame retardant and a foaming agent, it is necessary to select a flame retardant and a foaming agent in consideration of the temperature structure of each. In addition, the flame retardant and the foaming agent may be intercalated in the same layered material as the intercalant, but desirably the intercalation amount is increased and the decomposition temperature of the flame retardant and the decomposition temperature of the foaming agent are different. In that respect, it is better to produce an intercalation compound by intercalating the layered material separately.

[Production of Intercalation Compounds (e), (f), (g)]
Interlayer compounds (e), (f), and (g) can be easily produced simply by contacting and mixing the above-mentioned substances (a), (b), (c), and (d). That is, conventionally, in order to insert a flame retardant or a foaming agent into a layered material as an intercalant, the layered material is previously infinitely swollen with water. The intercalant reacts with a proton donor to give a cation charge, dissolves in an aqueous solution or an aqueous solution-organic solvent mixture, performs an ion exchange reaction, and intercalates the layered material. Therefore, the intercalant must be made into a structure that can be ionized in advance. Moreover, if it is not soluble, an ion exchange reaction with the metal ion in a layered substance cannot be performed. Therefore, even if the intercalant is made ionic, it must be soluble in water or a water-organic solvent mixture.

In addition, the layered material must be infinitely swollen with water in advance, but when the layered material exceeds 10% by weight in water, the viscosity increases due to infinite swelling and exceeds 10 × 10 ⁴ poise, and the ionic intercalant Cannot be stirred because of the ion exchange reaction. For this reason, the ion exchange reaction requires a large amount of water, and filtration, drying, and pulverization processes are also required, and a large amount of energy is consumed. In particular, since the use of water for ion exchange reaction and washing becomes large, there is a disadvantage that investment in industrial equipment including abatement equipment becomes enormous.

  On the other hand, the intercalation compound used in the present invention eliminates the above disadvantages and can be easily produced. In the production of the intercalation compound used in the present invention, for example, a Lewis acid or acid adduct (b) comprising an organic electron donor and a proton donor is added to the layered substance (a), and activated by crushing, grinding or friction. To do. Next, the flame retardant (c) and / or the foaming agent (d) is added to the layered material (a), and mechanical energy is similarly applied by pulverization, grinding or friction, and the flame retardant (c) is added to the layered material (a). And / or blowing agent (d) is intercalated to produce an intercalation compound. Further, the activation of the layered substance (a) and the operation of intercalation may be performed simultaneously. That is, the layered material (a), Lewis acid or acid adduct (b) composed of an organic electron donor and a proton donor, and the flame retardant (c) and / or foaming agent (d) are pulverized, ground or rubbed. An intercalation compound can also be produced by applying mechanical energy at the same time.

[Dispersion composite (polyolefin flame retardant foam composition) used for the production of polyolefin flame retardant foam]
The above-described dispersion composite which is preferable as the polyolefin-based flame retardant foam composition of the present invention will be described. When an intercalation compound and a resin are mixed and kneaded by an extruder, if a polar group exists in the resin, the resin is adsorbed on the surface of the intercalation compound via the polar group. If sufficient shear is applied to the resin at that time, the adsorbed intercalation compound is peeled off to disperse the intercalation compound in a molecular form. The adsorption force depends on the polarity value of the resin. It is already known from the report of Hosokawa et al. That the index of adsorption depends on the solubility parameter of the resin (cited literature; Hosokawa, p180-196, June 30, 2000, “Development of inorganic / organic hybrid materials” And application ", issued by CMC Co., Ltd.). Polyolefin-based materials do not exfoliate and disperse in molecular form even when kneaded and dispersed with an intercalation compound, but copolymers with polar groups such as vinyl acetate and maleic anhydride adsorb to the intercalation compound and cause extrusion shearing force. As a result, the interlaminar compound peels off and molecular dispersion is achieved. Therefore, the polyolefin material may be a copolymer of a polyolefin material having a polar group or a mixture of a polyolefin material and a copolymer having a polar group.

  A composite dispersion of an intercalation compound in which a flame retardant is intercalated in a lamellar material is dispersed in a thermoplastic resin, and the interlaminar compound having a thickness of 2.6 to 300 nm between the interlaminar and an interlaminar compound dispersed in layers and separated into molecules. Then, the interlayer compound is partly dispersed in the resin with an interlayer thickness of 2.6 to 300 nm, and the rest is molecularly dispersed. For this purpose, a resin filling in which an intercalation compound in which a flame retardant is inserted into a polyolefin-based material in advance is highly filled is produced by blending. Subsequently, in order to dilute with a resin and leave an intercalation compound having an interlayer thickness of 2.6 to 300 nm in the resin, the shearing force may be weakened and the degree of peeling dispersion may be reduced. Then, when a material having a higher melt flow than the resin material used for the previously high-filled resin filling is selected and diluted and dispersed, an interlayer compound having an interlayer thickness of 2.6 to 300 nm is separated from the layer to form a molecular shape. A composite dispersion with an intercalation compound dispersed in can be obtained. When diluting and dispersing, the dispersion of the title is controlled by kneading, melting, and dispersing three components: an intercalation compound intercalated with a foaming agent, a highly filled flame retardant intercalation compound resin dispersion, and the same resin with a high melt flow. Can be obtained. In this case, a layered material in which flame retardants and foaming agents having different decomposition temperatures are simultaneously inserted may be used.

[Resin used to manufacture polyolefin flame retardant foam]
The thermoplastic resin used for the production of the polyolefin-based flame retardant foam is not particularly limited as long as it is a polyolefin-based material conventionally used for foams. For example, low-density polyethylene manufactured by the high-pressure radical method, linear low-density polyethylene, linear medium-density polyethylene, high-density polyethylene resin, and metallocene catalyst manufactured by medium- and low-pressure methods including Ziegler catalysts. It may be polymerized using. Moreover, the copolymer of ethylene and an alpha olefin is also included. As such a copolymer, an ethylene-α-olefin copolymer using propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, etc. as an α-olefin. Polymers, ethylene-vinyl acetate copolymers and their saponified products, ethylene-carboxylic acid-metal salt (ionomer) copolymers, ethylene-glycidyl methacrylate copolymers, ethylene- Glycidyl methacrylate-vinyl acetate terpolymer, ethylene-maleic anhydride copolymer, ethylene-carbonate carbonate copolymer, ethylene-acrylate copolymer, ethylene-dimethylaminomethacrylate copolymer, ethylene-vinylsilane copolymer Examples thereof include ethylene copolymers such as coalescence. Also, a mixture of two or more of these may be used.

  Moreover, polyolefin resin, such as a polypropylene, a propylene-ethylene random copolymer, a propylene-ethylene block copolymer, the bridge | crosslinking type polypropylene by an electron beam irradiation, a polypten, a polyisoprene, is mentioned. Moreover, according to the objective, you may use individually or in combination of 2 or more types. Depending on the purpose, polymer compounds other than the above thermoplastic resins may be mixed within a range that does not impair foaming properties and physical properties.

  Desirably, the ethylene-α-olefin copolymer is 10 to 70% by weight, and the ethylene copolymer consisting of at least one of an ethylene-vinyl acetate copolymer and an ethylene-ethyl acrylate copolymer is 90 to 30% by weight; The melt composition has a melt flow rate of 0.1 to 20 g / 10 min (190 ° C.) and a melting point of 130 ° C. or less. Alternatively, ethylene-α-olefin copolymer 10 to 70% by weight, ethylene copolymer consisting of at least one of ethylene-vinyl acetate copolymer and ethylene-maleic anhydride copolymer 90-30% by weight, The melt composition has a melt flow rate of 0.1 to 20 g / 10 min and a melting point of 130 ° C. or lower.

  When polypropylene is used in the cross-linking foaming method, if a cross-linking reaction is performed using a peroxide like a polyethylene copolymer, the molecular cleavage reaction takes precedence over the cross-linking reaction, leading to a decrease in molecular weight. Therefore, prior to foam molding, a method of crosslinking with ionizing radiation such as an electron beam in advance is employed. Therefore, polypropylene 90 to 10% to 70% by weight of polypropylene irradiated with an electron beam of about 5 to 40 Mrad with a low level irradiation dose, and polypropylene 90 to at least one of polypropylene-ethylene random copolymer and maleic anhydride graft-polypropylene. 30% by weight of a resin composition having a melt flow rate of 0.1 to 20 g / 10 minutes (230 ° C.) and a melting point of 140 to 160 ° C. It is preferable to accumulate solid radicals therein and to disperse and crosslink at the time of kneading with the intercalation compound. Similarly, it is composed of 10 to 70% by weight of polypropylene irradiated with an electron beam of about 5 to 40 Mrad with a low level irradiation dose, and at least one of polypropylene-ethylene random copolymer and glycidyl-methacrylate graft-polypropylene. A resin composition comprising 90 to 30% by weight of polypropylene, preferably having a melt flow rate of 0.1 to 20 g / 10 minutes (230 ° C.) and a melting point of 140 to 160 ° C. Further, as a polypropylene irradiated with an electron beam, a commercially available high-melt strength polypropylene manufactured by Montel may be used.

[Dispersion degree of intercalation compound in intercalation compound dispersion (polyolefin flame retardant foam composition)]
In an intercalation compound dispersion obtained by contacting and mixing a layered substance, a flame retardant and / or a foaming agent with a polyolefin-based material, the intercalation compound is formed by two silicate sheets by adsorption of the resin to the intercalation compound and shearing of the extruder. The intercalant compound in which the intercalant is inserted is peeled off in a form adsorbed on the resin at the level of one silicate sheet (referred to as molecular dispersion). In such a dispersion process, the flame retardant and / or foaming agent in the intercalation compound is in melt contact with the resin and remains in the intercalation compound until it melts into contact with the resin. It is possible to avoid deterioration due to history.

  Further, since the flame retardant and / or the foaming agent are arranged in a single molecular unit in the intercalation compound during the molecular dispersion, the single molecule contacts the resin at the time of the peeling dispersion and acts effectively without aggregation. Further, when the flame retardant and / or the foaming agent are inserted in the layered material, the intercalation compounds can exhibit a unique function. For example, when an intercalation compound that intercalates a flame retardant is present in the polyolefin dispersion, the intercalation compound is decomposed only by combustion to release the flame retardant. Therefore, it is excellent in heat decomposition resistance compared with the conventional resin dispersion, and its function does not deteriorate even if it is recycled. In addition, since the flame retardant in the interlayer is released in a single molecule by thermal decomposition during combustion, it works more effectively than a conventional resin dispersion. Further, in the foaming agent, if the amount of the state existing between the layers is large in molding, the foaming can be efficiently foamed at the time of heat foaming after the resin molding.

  From the viewpoints described above, in the case of an intercalation compound in which a flame retardant and / or a foaming agent is intercalated, in the case of a resin dispersion, the intercalation compound inserted in the interlaminar layer is more likely to be partly present as an intercalation compound than a molecular dispersion. The currant function can be used more effectively. The quantitative range in which no molecular dispersion was observed was examined. When a cross section perpendicular to the molding orientation of the molded sheet is observed with a transmission electron microscope (hereinafter referred to as “TEM”), the interlaminar compound is oriented in the molding orientation direction, and the laminated interlaminar compound and the layered material separated in a molecular form are separated. (A silicate sheet exfoliated in a molecular form) is observed.

  The basic solid that forms the crystal lattice of the layered substance or intercalation compound is called a unit cell. Corresponding to the vertical, horizontal, and height of this unit cell, coordinate axes are provided along each side, and these are crystallized. Let them be axes (a-axis, b-axis, c-axis). At this time, the laminated interlayer compound was observed to be laminated in the c-axis direction. The thickness was 2.6 to 300 nm, and a molecular dispersion of about 1 nm was observed.

  In the field of view of the resin dispersion of the transmission electron microscope, in the field where 1000 particles of the intercalation compound were observed, the interlaminar compound having a lamination thickness of 2.6 to 300 nm was present in a number average of 5% or more and less than 50% Then, it turned out that it is effective in the improvement of a foaming ratio by post-heating after a flame retardance performance or shaping | molding. In addition, if it is less than 5%, the original flame retardancy is greatly reduced, and it is not only necessary to add a large amount of flame retardant. Inferior. In addition, in the intercalation compound into which the foaming agent is inserted, since the foaming agent released by molecular dispersion already exists in the resin at the time of preparing the pellets as the resin dispersion, the thermal decomposition temperature and the resin melting temperature of the foaming agent are present. Approaches and foaming begins. For this reason, it is necessary to add a large amount of a lubricant capable of low-temperature extrusion in order to lower the extrusion temperature and not to thermally decompose the foaming agent. Further, when the amount is 50% or more, the amount of the remaining molecularly dispersed layered material is small, so that the rigidity of the molded body is low, the heat-resistant deformation temperature is low, and the elastic recovery is low even if the expansion ratio can be kept high. There is. The number average of the intercalation compounds having a lamination thickness of 2.6 to 300 nm is desirably in the range of 10% to less than 45%.

  As described above, the number of particles in which the thickness of the interlayer compound laminate in the resin (thickness in the c-axis direction of the interlayer compound laminate particles) in the resin is 2.6 to 300 nm in a visual field range of about 1000 particles by TEM observation. It was found that a resin dispersion having an average of 5% or more and less than 50% exhibits excellent performance. The characteristic of the performance is that not only the intercalant between layers, that is, the flame retardant and / or the foaming agent, effectively exhibits heat resistance and expansion ratio, but also imparts sustained release properties to them. In addition, although the method by TEM observation was mentioned as mentioned above as an observation method and evaluation method of interlayer distance, it is not limited to this method, For example, you may calculate and evaluate by X-ray diffraction.

[Molding method of polyolefin flame retardant foam]
It does not specifically limit as a method to manufacture a polyolefin-type flame-retardant foam, The existing foaming method can be used. As a typical method, there is a method of crosslinking and foaming the prepared resin composition. In crosslinking, there are a method of crosslinking almost simultaneously with foaming and a method of crosslinking prior to foaming. In the case of the method of cross-linking almost simultaneously with foaming, the cross-linking agent and the foaming agent are blended in a kneading machine such as a pressure kneader or two rolls by mixing a resin composition containing the above components with a pyrolytic foaming agent and a cross-linking agent. Is kneaded at a temperature that does not decompose (about 100 to 130 ° C.) and pelletized, and then a base material sheet having a desired thickness and width is extruded using an extruder (resin temperature is about 100 to 130 ° C.). The base material sheet is put into a heating and foaming furnace adjusted to 180 to 230 ° C. and foamed simultaneously with crosslinking to produce a foam.

  The thermal decomposition type foaming agent is a type of foaming agent that decomposes when heated to generate gas. For example, azodicarbonamide (ADCA), p, p′-oxybisbenzenesulfonylhydrazide (OBSH), N, N ′. -Dinitrosopentamethylenetetramine (DPT), p-toluenesulfonyl hydrazide, benzenesulfonyl hydrazide, diazoaminobenzene, N, N'-dimethyl N, N'-dinitroterephthalamide, azobisisobutyronitrile and the like. These can be used alone or in combination of two or more. Although a compounding quantity is suitably adjusted according to a desired expansion ratio, 2-40 weight part is preferable with respect to 100 weight part of resin components. Examples of the crosslinking agent include dicumyl peroxide, 2,5-dimethyl-2,5-di- (t-butylperoxy) -hexyne-3, α, α′-bis (t-butylperoxydiisopropyl) benzene, t -Butyl peroxycumene, 4,4'-di (t-butylperoxy) valeric acid n-butyl ester, 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1, Examples include organic peroxides such as 1-di (t-butylperoxy) cyclohexane, and the blending amount is preferably 0.3 to 2 parts by weight with respect to 100 parts by weight of the resin component.

  In the case of a method of crosslinking a resin composition prior to foaming, after kneading a resin composition in which the above components are blended with a pyrolytic foaming agent and a silane compound such as vinyltrimethoxysilane, and extruding a base material sheet In the presence of a silanol condensation catalyst such as dibutyltin dilaurate and water, silane crosslinking is carried out by a siloxane condensation reaction and then introduced into a heating furnace to produce a foam. In this case, the organic peroxides listed above can be used as the crosslinking agent, and the blending amount is 0.003 to 2 parts by weight with respect to 100 parts by weight of the resin component. The blending amount of the silanol condensation catalyst is preferably 0.03 to 5 parts by weight with respect to 100 parts by weight of the resin component. In addition, as a method of crosslinking prior to foaming, a method by irradiation with ionizing radiation such as α-ray, β-ray, γ-ray, electron beam, neutron beam, and ultraviolet ray can also be used. A resin composition containing a pyrolytic foaming agent is kneaded, and the base material sheet obtained by extrusion molding is irradiated with ionizing radiation to be crosslinked, and then introduced into a heating foaming furnace to produce a foam. .

  The above crosslinking foaming methods may be used singly or in combination, and by any method, a crosslinking aid such as trimethylolpropane triacrylate or divinylbenzene may be added in an amount of 0.05 to 100 parts by weight based on 100 parts by weight of the resin component. You may mix | blend about 3 weight part.

  In addition, as a typical method for producing a foam, a gas such as nitrogen, carbon dioxide, butane, propane, or flon that does not react with components as a foaming agent in a resin composition melt-plasticized with an extruder or the like There is an extrusion foaming method in which a foam is obtained by injecting a volatile liquid or the like and then extruding it through a mold under atmospheric pressure to release the pressure of the resin composition to grow bubbles. Further, the mixture of the chemical foaming agent and the resin used in the above-mentioned method for producing a crosslinked foam is put into an extruder, and the foaming agent is decomposed in the extruder by heating to a temperature equal to or higher than the decomposition temperature of the foaming agent. There is a method in which the pressure of the resin composition is released to cause foaming by extruding it through atmospheric pressure. The above extrusion foaming method usually uses a non-crosslinked resin, but in order to adjust the viscosity of the resin for the purpose of enhancing foamability, etc., using a resin that has been previously crosslinked within a range that does not impair the extrudability. Alternatively, a method of forming a crosslink by a reaction in an extruder may be used. When utilizing the reaction in the above-mentioned extruder, the resin is modified with a polar group such as carboxylic acid for the purpose of improving the mixing property of the resin and additives or improving the physical properties of the foam. May be.

  In addition, the resin composition is pre-molded into various shapes such as sheets and pellets, and then charged into a mold, and a gas such as nitrogen, carbon dioxide, butane, propane, or chlorofluorocarbon, or a volatile liquid is used as a metal. Even if a batch method is used in which the inside of the mold is filled and the resin is impregnated under moderate heating and pressure, the mold is opened and the inside of the mold is depressurized to expand and foam the gas. Good. Furthermore, the temperature is lowered to such an extent that foaming does not start before decompression, and after decompression, the unfoamed resin composition once impregnated with gas is taken out of the mold and heated again at normal pressure or under pressure in the mold. May be foamed.

  EXAMPLES Hereinafter, although an Example shows this invention more concretely, this invention is not limited to the following Example.

Example 1
1. Manufacture of flame retardant intercalation compound In a rotating ball mill with an internal volume of about 1 liter, 1 kg of 19 mmφ steel balls and 100 g of tetralithic mica (layered clay mineral) are added, and 5 g of adduct liquid in which anhydrous hydrochloric acid gas is absorbed in anhydrous tetrahydrofuran is added. did. The layered clay mineral was activated by grinding for 10 minutes at 50 rpm. Next, 12.6 g (100 meq / 100 g) of melamine was added to the rotating ball mill and pulverized for 60 minutes. The obtained flame retardant intercalation compound (layered silicate melamine complex) showed thermal decomposition peaks at 200 ° C. to 257 ° C. and 350 ° C. to 400 ° C. by thermogravimetric analysis (TGA). Among them, the thermal decomposition peak at 200 ° C. to 257 ° C. is due to melamine adhering to the surface of the layered clay mineral, and the decomposition peak at 350 ° C. to 400 ° C. is due to melamine inserted between the layered clay minerals. . From the weight difference of TGA, the amount of melamine adhering to the surface of the layered clay mineral was 50 meq / 100 g, and the amount of melamine inserted into the layered clay mineral was 50 meq / 100 g. From the X-ray diffraction analysis, the interlayer distance was 13 mm.
2. Production of foamed intercalation compound In a rotating ball mill with an internal volume of about 1 liter, 1 kg of 19 mmφ steel balls and 100 g of tetralithic mica (layered clay mineral) were added, and 5 g of adduct liquid in which anhydrous hydrochloric acid gas was absorbed in anhydrous tetrahydrofuran was added. . The layered clay mineral was activated by grinding for 10 minutes at 50 rpm. Next, 11.6 g (100 meq / 100 g) of azodicarbonamide (ADCA) was added to the rotating ball mill and pulverized for 60 minutes. From the weight difference of TGA, the amount of azodicarbonamide adhering to the surface of the layered clay mineral was 15 meq / 100 g, and the amount of azodicarbonamide intercalated in the layered clay mineral was 80 meq / 100 g. From the X-ray diffraction analysis, the interlayer distance was 12.7 mm.
3. Preparation of Masterbatch 3 kg of layered silicate melamine complex obtained in 1 above and trade name Ultrasen 627 (melt flow rate 0.8 g / 10) which is an ethylene-vinyl acetate copolymer (EVA) manufactured by Tosoh Corporation Min) 7 kg was mixed. In this case, 1 part by weight of stearic acid amide was added to 100 parts by weight of EVA as an additive. The kneading was performed at an extrusion temperature of 130 ° C. using an extruder (PCM30 manufactured by Ikegai Co., Ltd.). The content of the layered silicate melamine complex in the obtained master batch was 30% by weight.
4). Manufacture of a flame retardant resin foam composition by dilution 5 kg of the masterbatch obtained in 3 above, and an ethylene-vinyl acetate copolymer (EVA) manufactured by Tosoh Corporation as a material having a viscosity lower than that of EVA used in the preparation ) 15 kg of the trade name Ultrasen 626 (melt flow rate 2.5 g / 10 min) and 5 kg of 10 phr of the layered silicate azodicarbonamide complex obtained in 2 above with respect to 20 kg of the total composition, 500 g of the agent and 6 phr (1110 g) of azodicarbonamide as the additional foaming agent were mixed at 130 ° C., and dilution blending was performed. Using the material obtained above, it is equipped with a 30mm screw, has a pitch ratio of L / D = 30 (screw length: L, screw diameter: D), and is coated with a single screw extruder having 1 vent. A sheet forming machine equipped with a hanger type T die was used to form a sheet having a thickness of 3 mm. The obtained sheet was put into an oven at 230 ° C. and heated again to obtain a foam sheet having an apparent density of 32.8 kg / m ³ . Moreover, when the flame retardance test was done, in 94UL, the performance of V-2 was shown with the test piece of thickness 9mm. Moreover, when the unfoamed extruded sheet material is re-ground, re-pelletized as a recycled material and re-formed into a sheet, a foam sheet having an apparent density of 33.9 kg / m ³ can be obtained, and a flame retardancy test Then, it turned out that the performance of 94ULV-2 is maintained. Moreover, since the melamine and the foaming agent were hold | maintained by the interlayer compound, it turned out that heat stability is high. Further, as described in the table below, the exothermic test was passed, and the best result was obtained in the evaluation of the oxygen index. Furthermore, in the evaluation of the mechanical properties of the foam, a tensile test, a 25% compression set test, and a measurement of thermal conductivity were performed, and good values were obtained.

[Method for evaluating physical properties of foam]
In this example, the physical property evaluation method of the foam was as follows.
(1) Apparent density of foam The test sheet having a size of 10 × 10 cm is cut out from the obtained foam, and the apparent density (kg / m ³ ) is obtained by dividing the mass (kg) by the volume (m ³ ). It was.
(2) Exothermic test Based on the cone calorimeter method in ISO-5660 or ASTM-E1354, the total calorific value (MJ / m ² ) and the maximum exothermic rate (kW / m ² ) were determined. Further, the case where the total heat generation amount was 8 MJ / m ² or less and the maximum heat generation rate did not exceed 200 kW / m ² was regarded as acceptable, and the others were regarded as unacceptable.
(3) Flame Retardancy Evaluation / UL94 Vertical Flammability Test A combustion test was performed in accordance with the UL94 vertical flammability test standard to determine which of the V-0, V-1, and V-2 standards.
・ Evaluation of Oxygen Index Flame resistance is evaluated according to JIS-K-7201: O with an oxygen index of 25 or more as flame retardant, ◎ with 27 or better as best, ◎ with less than 20 as flame retardant. X, 20 or more and 25 as the property, and Δ as the slightly flammability.
(4) Tensile strength and elongation rate According to the tensile test measurement method of JIS-K-6767, the tensile strength (KPa) and elongation rate (%) at the time of sample breakage were measured. Moreover, the case where the tensile strength is 100 KPa or more and the elongation rate is 60% or more is acceptable, the case where the tensile strength is 150 KPa or more and the elongation rate is 90% or more is the best, and the tensile strength is less than 100 KPa and the elongation rate is less than 60%.
(5) 25% compression set According to the 25% compression set measurement method of JIS-K-6767, a load is applied to the obtained foam at 0.5 kg / cm ² for 24 hours, and the heat insulating layer before and after applying the load. The change rate of the wall thickness was determined from the wall thickness, and those with a change rate of 7% or less were judged to be good in compression recovery, and those over 7% were judged as bad.
(6) Thermal conductivity The thermal conductivity was calculated | required based on the flat plate comparison method in the measuring method of the thermal resistance and thermal conductivity of the heat insulating material of JIS-A-1412. Moreover, 0.041 W / (mk) or less was made favorable.

(Examples 2 to 23)
A flame retardant interlayer compound and / or a foamed interlayer compound were produced in the same manner as in Example 1 except that the materials shown in Tables 1 to 3 were used.

(Comparative Example 1)
In Example 1, without using melamine as a layered silicate composite, 7 kg of EVA used in the examples and an equivalent amount of melamine were masterbatched using an extruder. Then, 50.331630 g of the corresponding amount of azocarbonamide without adding a layered silicate azocarbonamide complex and 15 kg of EVA used for dilution were added to 5 kg of the master batch in the same manner and subjected to dilution extrusion. . Sheet molding was performed in the same manner as in Example 1, and the apparent density was measured. As a result, it was 59.7 kg / m ³ and the thermal conductivity was not possible. Moreover, when the 94UL combustion test was done, it failed in any class. In addition, in order to express the flame retardance performance equivalent to Example 1, it turned out that it expresses only after adding 8 weight part or more of melamine further with respect to 100 weight part of resin total weight. Therefore, it turned out that a flame retardance performance is acquired with few flame retardants by making a flame retardant into an interlayer compound.

(Comparative Example 2)
In Example 1, the layered silicate melamine complex was prepared in the same manner, and instead of the layered silicate azocarbonamide complex at the time of dilution, the corresponding amount of azocarbonamide 1630 g and EVA 15 kg used at the time of dilution were used. Addition and dilution extrusion were performed. Sheet molding was performed in the same manner as in Example 1, and the apparent density was measured and found to be 45.7 kg / m ³ . In addition, when a 94 UL combustion test was performed, it was V-2 for the 9 mm thick test piece, but if the layered clay mineral complex was not present, the apparent density would increase and the thermal conductivity would be impossible. I understood. It was found that the foaming density would not reach 33 kg / m ² without a large amount of foaming agent (ADCA) of 25 parts by weight or more with respect to 100 parts by weight of the total resin weight. Thus, it was found that a foam having a low apparent density can be obtained with a small amount of foaming agent. In addition, the molded foam was judged inappropriate from the overall viewpoint. Therefore, the situation of the resin dispersion was observed. Samples with a cross section perpendicular to the molding flow direction of the molded product are collected, and the distribution table of the thickness of the intercalation compound (thickness in the d (001) direction) is obtained in the field of view of the transmission electron microscope with about 500 or more intercalation compounds In the total number of interlayer compounds in the resin dispersion, the average number of interlayer compounds having a lamination thickness of 2.6 to 300 nm was 53%.

(Comparative Example 3)
In Example 1, dry hydrochloric acid gas was not absorbed by tetrahydrofuran, and an attempt was made to obtain a layered silicate melamine complex by pulverization, but the amount of insertion could not exceed 20 meq / 100 g. The remainder was only adsorbed on the surface of the layered silicate, and it was found from X-ray diffraction that it was not inserted. Moreover, it was found that there was a large variation in interlayer insertion, and a stable one could not be achieved. The flame retardancy was unacceptable in the same manner as in Example 1 except that the 20 meq / 100 g layered silicate melamine complex was used. In the total number of intercalation compounds in the resin dispersion, the number average of interlaminar compounds having a lamination thickness of 2.6 to 300 nm is 53%. If the intercalation amount is low, the effect of the flame retardant is reduced and the laminated clay is laminated As the mineral content increases, the number average of intercalation compounds contributing as a gas barrier is lowered, and as a result, the gas barrier property of the blowing agent is also lowered. For this reason, the apparent density of the sheet is increased, which is inappropriate as a molded body.

(Comparative Example 4 )
In Example 1, instead of the flame retardant, an interlayer compound was prepared using dimethyldidecylammonium chloride, which is an onium salt, and molecular dispersion was performed. As a result, the flame retardance passed the corn calorimeter test. It was found that the oxygen index and UL94 flame retardant test failed. From this, it turned out that the method of adjusting an intercalation compound using flame retardants, such as a melamine, like an Example is very effective.

Example 1-23, the data for Comparative Example 1-4 shown in Table 1-4.

Claims (7)

The layered material (a), Lewis acid or acid adduct (b) comprising an organic electron donor and a proton donor, flame retardant (c), and foaming agent (d) are pulverized, ground or rubbed. A polyolefin-based flame retardant comprising an interlayer compound (e) obtained by adding mechanical energy and intercalating the flame retardant (c) and the foaming agent (d) into the layered material (a) Foam composition. Mechanical energy is applied to the layered material (a), the Lewis acid or acid adduct (b) comprising an organic electron donor and a proton donor (b), and the flame retardant (c) by grinding, grinding or friction , Lewis acid or acid addition comprising an intercalation compound (f) obtained by intercalating the flame retardant (c) into a lamellar material (a), a lamellar material (a), an organic electron donor and a proton donor An intercalation compound obtained by applying mechanical energy to the product (b) and the foaming agent (d) by grinding, grinding or friction and inserting the foaming agent (d) into the layered material (a) ( g) and a polyolefin-based flame retardant foam composition.   The polyolefin flame-retardant foam composition according to claim 1 or 2, wherein the layered substance (a) is a swellable layered clay mineral.   The Lewis acid or acid adduct (b) comprising the organic electron donor and the proton donor is an organic compound having a lone electron pair, and is selected from an ether compound group, a ketone group and a compound group having a hetero atom. 4. A Lewis acid or an acid adduct obtained by mixing at least one kind and at least one kind selected from an inorganic anhydride having a proton and an organic acid. A polyolefin-based flame retardant foam composition as described in 1.   The polyolefin-based flame retardant foamed composition is a composite dispersion in which an interlayer compound having an interlayer thickness of 2.6 to 300 nm and an interlayer compound that has been peeled off and dispersed in a molecular form are dispersed in a polyolefin-based material. The polyolefin-based flame retardant foam composition according to any one of claims 1 to 4.   The polyolefin-based flame retardant foam composition is obtained by mixing the polyolefin-based material (h) with a mixture (i) obtained by mixing the interlayer compound (e) or (f) and / or (g) at a high concentration with the polyolefin-based material (h). The polyolefin-based flame retardant foam composition according to any one of claims 1 to 5, wherein the polyolefin-based flame retardant foam composition is mixed with a polyolefin-based material (j) having a viscosity lower than that of (1).   An olefin-based flame retardant foam obtained by foaming the olefin-based flame retardant foam composition according to any one of claims 1 to 6.