JP2012001572A - Non-halogen-based flame-retardant resin foam and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin foam excellent in heat insulating properties and flexibility because of having adequate apparent density, and having high flame retardancy not generating halogen gases during combustion; and to provide a method for producing the same.SOLUTION: This non-halogen-based flame-retardant resin foam is obtained by crosslinking and foaming a resin composition containing: (B) 151-300 pts.mass of magnesium hydroxide and/or surface-treated aluminum hydroxide as metal hydrates; (C) 2-25 pts.mass of red phosphorus; (D) 5-100 pts.mass of titanium oxide; and (E) 10-40 pts.mass of thermally decomposable foaming agent, based on (A) 100 pts.mass of a resin component containing (A1) an ethylene-vinyl acetate copolymer and/or (A2) an ethylene-ethyl acrylate copolymer. The total content of the vinyl acetate and ethyl acrylate being the constitutional components in the (A1) ethylene-vinyl acetate copolymer and/or (A2) an ethylene-ethyl acrylate copolymer in the (A) resin component is 14-50 mass%.

Description

  The present invention relates to a resin foam having a high degree of flame retardancy that has excellent heat insulation and flexibility because it has an appropriate apparent density and does not generate halogen gas during combustion, and a method for producing the same.

Conventionally, polyolefin resin foams have been used in building materials, electrical appliances, automobiles, energy equipment, etc. because they are excellent in lightness, heat insulation, shock absorption, water resistance, chemical resistance and mechanical properties. Yes. Since polyolefin is flammable, flame retardant resin foams are used in fields where flame retardancy is required.
Usually, a flame retardant resin foam is produced by foaming a resin composition containing a flame retardant. Among the flame retardants, the halogen-based flame retardant can impart high flame retardancy with a small blending amount. However, a flame-retardant resin foam using a halogen-based flame retardant generates harmful halogen gas during combustion. For this reason, a method of producing a foam using a resin composition containing an inorganic substance such as aluminum hydroxide or magnesium hydroxide without using a halogen-based flame retardant (see Patent Document 1), magnesium hydroxide In addition, a method using zinc borate or antimony trioxide in combination (see Patent Document 2) has been proposed. In addition, a method using a resin composition in which magnesium hydroxide or the like is blended with a specific resin (see Patent Document 3) has also been proposed.

Incidentally, in recent years, foams are required to have higher flame retardancy. The standard is UL94 vertical flame retardant test. In this test, it is difficult to pass the flame retardancy at the V-1 or V-2 level where the residual dust must be extinguished within 60 seconds after the second flame contact when flame contact is made from below vertically. There is an increasing demand for flammable resin foams. Further, there may be a V-0 level at which the residual dust must be extinguished within 30 seconds after the second flame contact.
With the flame retardant resin foams described in Patent Documents 1 to 3, the oxygen index can be improved and a certain degree of flame retardancy can be ensured. However, these flame retardant resin foams have insufficient self-extinguishing properties, so it is difficult to pass the V-0 level in the UL94 vertical flame retardant test. In order to improve flame retardancy, when a foam is produced using a resin composition containing a larger amount of flame retardant, it may be difficult to secure a foam having a desired apparent density.
Therefore, in the UL vertical flame retardant test, there is a demand for a non-halogen flame retardant resin foam having flame retardancy of V-1 or V-2 level, further V-0 level, and having an appropriate apparent density. Yes.

Japanese Patent Publication No. 60-26500 JP-A-2-296684 Japanese Patent No. 3580556

  An object of the present invention is to provide a resin foam having a high degree of flame retardancy that has excellent heat insulation and flexibility because it has an appropriate apparent density and does not generate halogen gas during combustion, and a method for producing the same.

Conventionally, as a flame-retardant resin foam, a foam having a high oxygen index, which is a general standard for flame retardance, can be obtained by highly filling a flame retardant such as a metal hydrate. However, in that case, since the expansion ratio is lowered, it is often carried out to add a halogen-based flame retardant, so that it is difficult to obtain a non-halogen, highly foamed flame-retardant resin foam. Furthermore, as described below, the UL94 vertical flame retardant test exhibits flame retardancy of V-1 or V-2 level, more preferably V-0 level, if the self-extinguishing property is not high when flame is contacted from below vertically. Cannot have. Conventionally, it has been difficult to provide a foam that is non-halogen, highly foamed, and has flame retardancy of V-1, V-2 level, or V-0 level in the UL94 vertical flame retardant test.
Therefore, the present inventor has intensively studied to solve the above problems. As a result, a specific ethylene copolymer is crosslinked / foamed using a flame retardant resin composition containing a specific amount of metal hydrate, red phosphorus, titanium oxide, thermal stabilizer and pyrolytic foaming agent. As a result, a non-halogen flame retardant resin foam having a high expansion ratio can be obtained, and it has been found that this foam has an appropriate apparent density and a high degree of vertical flame retardancy. The present invention has been made based on this finding.

That is, the present invention
<1> Water (B) as a metal hydrate with respect to 100 parts by mass of the resin component (A) containing the ethylene-vinyl acetate copolymer (A1) and / or the ethylene-ethyl acrylate copolymer (A2). 151-300 parts by mass of magnesium oxide and / or surface treated aluminum hydroxide, (C) 2-25 parts by mass of red phosphorus, (D) 5-100 parts by mass of titanium oxide, and (E) a pyrolytic foaming agent. 10 to 40 parts by mass of the content of vinyl acetate and ethyl acrylate which are copolymer constituents of the ethylene-vinyl acetate copolymer (A1) and / or ethylene-ethyl acrylate copolymer (A2) A non-halogen flame-retardant resin foam, which is crosslinked and foamed using a resin composition having a total of 14 to 50% by mass in the resin component (A),
<2> When the compounding amount of the metal hydrate with respect to 100 parts by mass of the resin component (A) is (a) parts by mass and the compounding amount of titanium oxide is (b) parts by mass, a / b is 1.5. The halogen-free flame retardant resin foam according to <1>, wherein (a + b) is 180 or more, and <3> a thickness of 2 to 20 mm and an apparent density of 35 to 150 kg / wherein the m is ³ <1> or <2> non-halogen flame retardant resin foam according, and <4> ethylene - vinyl acetate copolymer (A1) and / or ethylene - ethyl acrylate copolymer 151-300 parts by mass of magnesium hydroxide and / or aluminum hydroxide whose surface is treated as (B) metal hydrate with respect to 100 parts by mass of resin component (A) containing polymer (A2), C) 2-25 parts by weight of red phosphorus, ( D) 5-100 parts by mass of titanium oxide and (E) 10-40 parts by mass of pyrolytic foaming agent, and the ethylene-vinyl acetate copolymer (A1) and / or ethylene-ethyl acrylate copolymer (A2) Non-halogenated, which is crosslinked and foamed using a resin composition in which the total content of vinyl acetate and ethyl acrylate, which are copolymer constituents of the resin component, is 14 to 50% by mass in the resin component (A) A method for producing a flame retardant resin foam is provided.

  INDUSTRIAL APPLICABILITY The present invention can provide a resin foam having a high degree of flame retardancy that has excellent heat insulation and flexibility because it has an appropriate apparent density and does not generate halogen gas during combustion, and a method for producing the same.

  The non-halogen flame retardant resin foam of the present invention is a (B) metal hydrate with respect to the resin component (A) containing an ethylene-vinyl acetate copolymer and / or an ethylene-ethyl acrylate copolymer. A specific amount of magnesium hydroxide and / or surface treated aluminum hydroxide, (C) red phosphorus, (D) titanium oxide and (E) a pyrolytic foaming agent is contained, and an ethylene-vinyl acetate copolymer (A1) ) And / or the total content of vinyl acetate and ethyl acrylate which are copolymer constituents of the ethylene-ethyl acrylate copolymer (A2) is within a specific range in the resin component (A). It is made to crosslink and foam using.

(A) Resin Component The resin component (A) constituting the non-halogen flame retardant resin foam of the present invention contains an ethylene-vinyl acetate copolymer and / or an ethylene-ethyl acrylate copolymer. The total content of vinyl acetate and ethyl acrylate which are copolymer constituents of the ethylene-vinyl acetate copolymer (A1) and / or the ethylene-ethyl acrylate copolymer (A2) is 14 in the resin component (A). -50 mass%.
The ethylene-vinyl acetate copolymer (EVA) is blended so that the vinyl acetate content in the resin component (A) is 14 to 50%. The melt flow rate (hereinafter also simply referred to as MFR) of the ethylene-vinyl acetate copolymer is preferably 0.5 to 10 g / 10 min. In the present invention, the melt flow rate refers to a value (condition: load 2.16 kg, temperature 190 ° C.) measured according to JIS K 7210. By setting the MFR within this range, the metal hydrate can be uniformly mixed with the resin, and the moldability at the time of foaming is good, so that an excellent foam can be obtained.
The ethylene-ethyl acrylate copolymer (EEA) is blended so that the ethyl acrylate content in the resin component (A) is 14 to 50%. The MFR of the ethylene-ethyl acrylate copolymer (EEA) is preferably 0.5 to 10 g / 10 min. When the MFR is in the preferred range, it is easy to uniformly mix the flame retardant with the resin, and the moldability at the time of foaming is good, so that an excellent foam can be obtained.

The total content of vinyl acetate and ethyl acrylate, which are copolymer constituents of the ethylene-vinyl acetate copolymer (A1) and / or the ethylene-ethyl acrylate copolymer (A2), is 14 in the resin component (A). By setting it to ˜50% by mass, not only can a metal hydrate described later be highly filled, but also a titanium oxide described later can be sufficiently blended. As a result, it is possible to provide a non-halogen flame retardant resin foam having a high level of flame retardancy in the UL vertical flame retardant test, which has been difficult in the past, and having an appropriate apparent density.
The total content of vinyl acetate and ethyl acrylate, which are copolymer components of the ethylene-vinyl acetate copolymer (A1) and / or the ethylene-ethyl acrylate copolymer (A2), is in the resin component (A). Preferably it is 15-46 mass%.
The total content of vinyl acetate and ethyl acrylate, which are copolymer components of the ethylene-vinyl acetate copolymer (A1) and / or the ethylene-ethyl acrylate copolymer (A2), is 14 in the resin component (A). Within the range of ˜50 mass%, a resin other than the ethylene-vinyl acetate copolymer and the ethylene-ethyl acrylate copolymer may be blended.
The content of vinyl acetate and ethyl acrylate, which are copolymer components of the ethylene-vinyl acetate copolymer and / or ethylene-ethyl acrylate copolymer, is preferably 15 to 46% by mass in the resin component (A). It is.

(B) Metal Hydrate As the metal hydrate, magnesium hydroxide and / or aluminum hydroxide whose surface has been treated is used as the metal hydrate. The compounding quantity of magnesium hydroxide and / or surface-treated aluminum hydroxide is 151 to 300 parts by mass with respect to 100 parts by mass of the resin component (A). If this amount is too small, the flame retardancy becomes insufficient. On the other hand, if the amount is too large, it becomes difficult to uniformly knead magnesium hydroxide and / or aluminum hydroxide whose surface is treated to the resin component, and foaming is also performed. The magnification is significantly reduced.

  Magnesium hydroxide can be appropriately used regardless of whether the surface is treated or the surface is not treated. Examples of magnesium hydroxide that can be used in the present invention include those that have not been surface-treated (such as “Kisuma 5” (trade name, manufactured by Kyowa Chemical Co., Ltd.), and those that have been surface-treated with fatty acids such as stearic acid and oleic acid ( "Kisuma 5A" (trade name, manufactured by Kyowa Chemical Co., Ltd.), phosphate-treated ("Kisuma 5J" (trade name, manufactured by Kyowa Chemical Co., Ltd.), etc., silane having a vinyl group or an epoxy group at the terminal What was surface-treated with a coupling agent (such as “Kisuma 5L” (trade name, manufactured by Kyowa Chemical Co., Ltd.)) can be used. In the present invention, it is more preferable that the surface treatment is performed with a silane coupling agent.

  Since aluminum hydroxide has a low desorption temperature of crystal water, aluminum hydroxide that has not been surface-treated is liable to undergo a dehydration reaction when a resin composition is heated and foamed, resulting in a high-magnification foam. It may not be possible. Therefore, it is necessary to use a surface-treated aluminum hydroxide. As the aluminum hydroxide that can be used in the present invention, one that has been surface-treated with a fatty acid such as stearic acid or oleic acid ("Hijilite H42S" (trade name, manufactured by Showa Denko KK) or the like can be used. .

When the non-halogen flame retardant resin foam of the present invention is produced by the chemical crosslinking foaming method described later, it is preferable to use magnesium hydroxide as the metal hydrate. Furthermore, surface-treated aluminum hydroxide can be used in combination. In this case, the total amount of magnesium hydroxide and surface-treated aluminum hydroxide is 300 parts by mass or less with respect to 100 parts by mass of the resin component (A), and the surface-treated aluminum hydroxide is a resin component (A). The amount is preferably less than 75 parts by mass with respect to 100 parts by mass and less than the blending amount of magnesium hydroxide.
By producing the non-halogen flame-retardant resin foam of the present invention by a method of crosslinking and foaming after irradiating ionizing radiation such as an electron beam on one side or both sides of a resin composition sheet, which will be described later, A decrease in flame retardancy can be minimized. In this case, the resin composition which mix | blended 75 mass parts or more of surface-treated aluminum hydroxide with respect to 100 mass parts of resin components (A) can be used.

(C) Red phosphorus The red phosphorus (C) in the present invention is preferably surface-treated from the viewpoint of stability. The amount of red phosphorus is 2 to 25 parts by weight per 100 parts by weight of the resin component (A). If the amount of red phosphorus is too small, sufficient flame retardancy cannot be obtained. If the amount of red phosphorus is too large, it not only contributes to the improvement of flame retardancy, but also may impair foamability. The preferable amount of red phosphorus is 5 to 15 parts by mass with respect to 100 parts by mass of the resin component (A).

(D) Titanium oxide As the titanium oxide (D) in the present invention, either an atatase type or a rutile type can be used. Titanium oxide may or may not be surface treated. By blending titanium oxide, it is possible to suppress the destruction of bubbles during foaming and increase the number of closed cells, so that it is possible to obtain a foam excellent in compression recovery property.
The compounding quantity of a titanium oxide is 5-100 mass parts with respect to 100 mass parts of resin components (A), Preferably it is 10-50 mass parts. If the blending amount of titanium oxide is too small, flame retardancy is insufficient. When the blending amount of titanium oxide is too large, the foaming ratio is lowered, and the density of titanium oxide is large, so that the lightness that is an advantage of the foam is lost.

(E) Thermal decomposition type foaming agent As another component contained in the resin composition of this invention, a thermal decomposition type foaming agent (E1) is mix | blended. The pyrolytic foaming agent is a foaming agent that decomposes by heating to generate gas. For example, azodicarbonamide (ADCA), p, p′-oxybisbenzenesulfonyl hydrazide (OBSH), N, N′-dinitrosopentamethylenetetramine (DPT), p-toluenesulfonyl hydrazide, benzenesulfonyl hydrazide, diazoaminobenzene N, N′-dimethyl-N, N′-dinitroterephthalamide, azobisisobutyronitrile and the like. These foaming agents can be used alone or in combination of two or more. The compounding amount of the pyrolytic foaming agent is 10 to 40 parts by mass with respect to 100 parts by mass of the resin component (A).

(F) Other components A heat stabilizer can be mix | blended with the resin composition in this invention. As the heat stabilizer, for example, a phenol-based antioxidant, a phosphite-based antioxidant, a thioether-based antioxidant, a metal deactivator, or the like can be used. These heat stabilizers can be used alone or in combination of two or more. When mix | blending a heat stabilizer, it is preferable to set it as 0.1-5 weight part with respect to 100 mass parts of resin components (A). More preferably, the compounding quantity of a heat stabilizer is 0.2-2 weight part with respect to 100 mass parts of resin components (A). When it is necessary to add a heat stabilizer, if the amount of the heat stabilizer is too small, the effect of heat stabilization cannot be obtained, and the resin is thermally deteriorated by heating during foaming, or the foam moldability is poor. In some cases, the foam has a low mechanical strength. On the other hand, if the blending amount of the heat stabilizer is too large, the improvement in the effect of preventing thermal deterioration is not observed, the crosslinking of the resin composition is inhibited, and a good foam may not be obtained.
Furthermore, in addition to the above-mentioned components, a crosslinking agent, a crosslinking aid, a filler, a pigment, a light stabilizer, a lubricant and the like may be added to the resin composition in the present invention as necessary.

The non-halogen flame retardant resin foam of the present invention is a resin composition obtained by melt-kneading one containing at least the above components (A) to (E), and crosslinking and foaming the resin composition, Can be manufactured. The non-halogen flame-retardant resin foam of the present invention has a flame retardancy of V-1 or V-2 level, more preferably V-0 level, and a high expansion ratio foam in UL94 vertical flame retardant test. It is.
Here, the UL94 vertical flame retardant test will be described. The test piece is supported vertically, a burner flame is applied to the lower end of the test piece and held for 10 seconds (first flame contact), and then the burner flame is separated from the test piece. When the flame disappears, apply the burner flame for another 10 seconds (second flame contact) and release the burner flame.
(I) The total of the flaming combustion times of the first and second flame contact (total combustion time (t _t )) of the five test pieces is within 50 seconds, and after the second flame contact The sum of the flammable combustion time and the flameless combustion time (residual time (t _r )) within 30 seconds is defined as V-0.
(Ii) The sum of the flaming combustion times (total combustion time (t _t )) of the first and second flame contact of the five test pieces is within 250 seconds, and after the second flame contact V-1 or V-2 is the sum of the flammable combustion time and the flameless combustion time (residual time (t _r )) within 60 seconds, and V- 1. The case where a drip occurs is V-2.

In the resin composition used for the non-halogen flame retardant resin foam of the present invention, the compounding amount of the metal hydrate with respect to 100 parts by mass of the resin component (A) is (a) mass part, and the compounding amount of titanium oxide is ( b) It is preferable that a / b is 1.5 to 60 and (a + b) is 180 or more when the mass part is used. If a / b is too small, the residual time (t _r ) becomes long in the UL94 vertical flame retardant test. If a / b is too large, the expansion ratio is reduced. On the other hand, if a + b is too small, the flame retardancy decreases. Furthermore, it is more preferable that a / b is 5-40. Moreover, even if ratio a / b is 1.5-60, and a + b is 180 or more, if the (B)-(E) component with respect to resin component (A) is not in said range, desired flame retardance and The expansion ratio cannot be obtained.

The non-halogen flame retardant resin foam of the present invention preferably has a thickness of 2 to 20 mm and an apparent density of 200 kg / m ³ or less. In the present invention, the apparent density of the foam is a value obtained by dividing the mass of the foam of the test piece cut out to a predetermined size (for example, 10 cm × 10 cm) by the volume. The apparent density is more preferably 35 to 150 kg / m ³ . A foam having a thickness and an apparent density within this range is excellent in heat insulation and flexibility.
If the thickness of the foam is too thin, the heat insulation is poor, and if the thickness is too thick, the foam tends to break in the foaming furnace due to the weight of the foam itself during the foaming by cross-linking. On the other hand, if the apparent density is too small, the bubble film is thinned, so that the transmission of radiant heat becomes remarkable and the heat insulation may be lowered. If the apparent density of the foam is too large, the heat insulation is reduced because the expansion ratio is small.

The method for producing the non-halogen flame retardant resin foam of the present invention can be divided into a method in which the resin composition is crosslinked and foamed almost simultaneously and a method in which the resin composition is crosslinked and then foamed.
(1) Method of performing crosslinking and foaming almost simultaneously The resin component (A) described above, components (B) to (E) such as a flame retardant, and, if necessary, a heat stabilizer or a crosslinking agent in the component (F) Is kneaded with a kneader such as a pressure kneader or two rolls at a temperature (about 100 to 130 ° C.) at which the crosslinking agent and the foaming agent are not decomposed to produce pellets of the resin composition. The obtained pellets are supplied to an extruder and extruded at a resin temperature of about 100 to 130 ° C. to form an unfoamed sheet having a desired thickness and width. This non-foamed sheet is put into a heating foaming furnace adjusted to about 180 to 230 ° C. to produce a sheet of the non-halogen flame-retardant resin foam of the present invention. In this method, as the crosslinking agent, dicumyl peroxide, 2,5-dimethyl-2,5-di- (t-butylperoxy) -hexyne-3, α, α′-bis (t-butylperoxy) Diisopropyl) benzene, t-butylperoxycumene, 4,4′-di (t-butylperoxy) valeric acid n-butyl ester, 1,1-di (t-butylperoxy) -3,3,5- It is preferable to use organic peroxides such as trimethylcyclohexane and 1,1-di (t-butylperoxy) cyclohexane. As for the compounding quantity of a crosslinking agent, 0.3-2.0 mass parts is preferable with respect to 100 mass parts of said resin components (A).

  As a method of foaming after crosslinking the resin composition, a method in which a silane compound is grafted to the resin component and then the grafted functional groups are reacted to crosslink the resin composition, followed by heating and foaming. ((2a) below). In addition, there is a method (following (2b)) in which the resin composition is heated and foamed after being irradiated with ionizing radiation to be crosslinked. Hereinafter, the method (2a) is also referred to as “a method of heating and foaming after silane crosslinking”. Hereinafter, the method (2b) is also referred to as “a method of heating and foaming after ionizing radiation irradiation crosslinking”.

(2a) Method of heating and foaming after silane crosslinking In addition to the resin component (A) and the components (B) to (E) such as a flame retardant, a silane compound such as vinyltrimethoxysilane and a radical polymerization initiator, Furthermore, if necessary, a resin composition pellet is prepared by kneading a blend of a heat stabilizer in component (F). The obtained pellets are supplied to an extruder together with a silanol condensation catalyst such as dibutyltin dilaurate, and extruded to form an unfoamed sheet. In this unfoamed sheet, a silane compound is grafted to the resin component by the action of a radical polymerization initiator. Let Next, the grafted resin component is crosslinked by a condensation reaction in the presence of water. This sheet is put into a heating furnace to produce a non-halogen flame retardant resin foam sheet of the present invention. In this case, as the radical polymerization initiator, the organic peroxide used in the method of crosslinking the resin composition almost simultaneously with the foaming in the above (1) can be similarly used. As for the compounding quantity of a radical polymerization initiator, 0.003-2 mass parts is preferable with respect to 100 mass parts of resin components (A). As for the compounding quantity of a silanol condensation catalyst, 0.03-5 mass parts is preferable with respect to 100 mass parts of resin components (A).

(2b) Method of heating and foaming after ionizing radiation irradiation crosslinking In addition to (B) to (E) components such as the resin component (A) and the flame retardant described above, a heat stabilizer in the (F) component as necessary. A resin composition pellet is prepared by kneading a mixture of the above. The pellets of the obtained resin composition are supplied to an extruder and extruded to produce an unfoamed sheet. The resulting unfoamed sheet is crosslinked by irradiating with ionizing radiation such as α, β, γ rays, electron beams, neutron rays. This sheet is put into a heating furnace to produce a non-halogen flame retardant resin foam sheet of the present invention.
The above methods (1), (2a) and (2b) may be used alone or in combination of two or more methods. In any method, if necessary, a crosslinking aid such as trimethylolpropane triacrylate and divinylbenzene may be blended in an amount of 0.05 to 3 parts by mass with respect to 100 parts by mass of the resin component (A).

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

Except for Examples 18 and 19 and Comparative Examples 8 and 10, the components were blended in the ratios shown in Tables 1 to 3, and melted and kneaded at 120 ° C. to obtain resin composition pellets. The obtained pellets were supplied to an extruder and extruded to produce an unfoamed sheet. Thereafter, these unfoamed sheets were introduced into a hot air oven adjusted to 220 ° C., and crosslinking and foaming were performed almost simultaneously to produce a flame-retardant resin foam.
In Examples 18 and 19 and Comparative Examples 8 and 10, the components were blended in the proportions shown in Tables 1 to 3, and melted and kneaded at 120 ° C. to obtain resin composition pellets. The obtained pellets were supplied to an extruder and extruded to produce an unfoamed sheet. After that, both surfaces of the non-foamed sheet were irradiated with an electron beam with an irradiation dose of 12 Mrad at an acceleration voltage of 500 V, and then cross-linked. The body was made.

The detail of each component of the resin composition used by Tables 1-3 is as showing below.
<Resin component (A)>
EVA1 (ethylene-vinyl acetate copolymer)
Vinyl acetate content 25%, MFR 2g / 10min
Product name: EVAFLEX EV360, EVA2 (ethylene-vinyl acetate copolymer) manufactured by Mitsui DuPont Polychemical Co., Ltd.
Vinyl acetate content 41%, MFR 2g / 10min
Product name: Evaflex EV40LX, EEA (ethylene-ethyl acrylate copolymer) manufactured by Mitsui DuPont Polychemical Co., Ltd.
Ethyl acrylate content 25%, MFR 0.5g / 10min
Product name: Everflex A714, LLDPE (ethylene-α-olefin copolymer) manufactured by Mitsui DuPont Polychemical Co., Ltd.
MFR 0.5g / 10min
Product name: ENGAGE8180, manufactured by The Dow Dupont Elastomer Co., Ltd.

<Metal hydrate (B)>
Magnesium hydroxide Product name: Kisuma 5B, manufactured by Kyowa Chemical Co., Ltd. (not surface-treated)
Aluminum hydroxide 1
Product name: Heidilite H42S, Showa Denko KK (surface treatment with fatty acid)
Aluminum hydroxide 2
Product name: Heidilite H42M, Showa Denko Co., Ltd. (not surface-treated)

<Flame retardants other than metal hydrates, flame retardant aids>
Halogen-based flame retardant: Decabromodiphenyl ether Product name SAYTEX 102E, manufactured by Albemarle Co., Ltd. Antimony trioxide Product name Antimony trioxide, manufactured by TWINKING STAR

<Red phosphorus (C)>
Product name Novaled 120, manufactured by Rin Chemical Industry Co., Ltd.

<Titanium oxide (D)>
Product name Ti-Pure R-103, manufactured by Furukawa Chemicals

<Pyrolytic foaming agent (E)>
Foaming agent: Azodicarbonamide Product name AC # 1L, manufactured by Eiwa Kasei Co., Ltd.

<Heat stabilizer>
Antioxidant 1: Phenol stabilizer Product name Irganox 1010, manufactured by Ciba Specialty Chemicals Co., Ltd. Antioxidant 2: Phosphite stabilizer Product name ADK STAB PEP-8, manufactured by Asahi Denka Kogyo Co., Ltd.

Crosslinking agent: Dicumyl peroxide Trade name Park mill D, manufactured by Nippon Oil & Fats Co., Ltd. Crosslinking aid: Trimethylolpropane trimethacrylate (TMPT)
Product name Ogmont T200, Shin-Nakamura Chemical Co., Ltd.

  The melt flow rate (MFR) of the above resin was measured as follows (JISK7210). The resin was melted at 190 ° C., extruded through an orifice under a load of 2.16 kgf, and the weight of the resin extruded in 10 minutes was measured.

The obtained non-halogen flame retardant resin foam was measured and evaluated according to the following method. In Tables 1 to 3, it was also described whether the obtained foam contains halogen or antimony trioxide, as is clear from the blended materials. Tables 1 to 3 also describe the total content of vinyl acetate and ethyl acrylate, which are copolymer components of the ethylene-vinyl acetate copolymer and / or ethylene-ethyl acrylate copolymer, in the resin component. did. The table is abbreviated as “VA and EA content”.
1. Foam thickness Measured with a digital caliper.
2. Apparent Density of Foam A test piece having a size of 10 cm × 10 cm was cut out from the obtained foam, and the apparent density was calculated by dividing the mass by the volume. Those with an apparent density of 200 kg / m ³ or less were accepted and those with an apparent density of more than 200 kg / m ³ were rejected.

3. The vertical flame retardancy of the foam was tested in accordance with the UL94 vertical flame test method. Each foam was cut into a size of 125 ± 5 mm in length and 13.0 ± 0.5 mm in width, and five test pieces were prepared for each example and comparative example. Each test piece was supported vertically, a flame of a burner was applied to the lower end of the test piece and kept for 10 seconds (first flame contact), and then the burner flame was separated from the test piece. After that, when the flame disappeared, the burner flame was applied for another 10 seconds (second flame contact) to release the burner flame.
(I) The total of the flaming combustion times of the first and second flame contact (total combustion time (t _t )) of the five test pieces is within 50 seconds, and after the second flame contact The sum of the flammable combustion time and the flameless combustion time (residual time (t _r )) within 30 seconds was defined as V-0.
(Ii) The sum of the flaming combustion times (total combustion time (t _t )) of the first and second flame contact of the five test pieces is within 250 seconds, and after the second flame contact V-1 or V-2 is the sum of the flammable combustion time and the flameless combustion time (residual time (t _r )) within 60 seconds, and V- 1. V-2 was defined as a drip.

4). Generation of Halogen Gas The gas generated by burning the foam was analyzed by ion chromatography to determine whether halogen gas was detected.

実施例１〜１９の発泡体は、適度な見掛け密度を有し、ＵＬ９４垂直難燃試験のＶ−０又はＶ−１レベルである。また、実施例１１、１２、１８及び１９において、金属水和物として、水酸化マグネシウムと表面処理された水酸化アルミニウムが併用されている。実施例１１及び１２では、架橋と発泡をほぼ同時に行う方法で適度な見掛け密度を有し、難燃性に優れた発泡体が得られた。水酸化マグネシウムより水酸化アルミニウムの配合量を多くした場合には、電子線を照射して架橋させた後に加熱し、発泡させる方法により、適度な見掛け密度を有し、難燃性に優れた発泡体が得られている。
これに対して、比較例１では、水酸化マグネシウムの配合量が多すぎて、見掛け密度が大きい発泡体しか得られなかった。比較例２では、酸化チタンの配合量が多いため、同様に、見掛け密度が大きい発泡体しか得られなかった。比較例３では、酸化チタンの配合量が少なすぎて垂直難燃試験に合格しなかった。また比較例４では、赤燐を含まないため、垂直難燃試験に合格しなかった。比較例５〜７では、水酸化マグネシウムの配合量が少なすぎるため、垂直難燃試験に合格しなかった。比較例９は、ハロゲン系難燃剤と三酸化アンチモンを用いているため、水酸化マグネシウムの配合量が少なくてもＶ−０レベルの垂直難燃性を有するが、発泡体燃焼時にハロゲンガスを発生した。比較例１０では、表面処理していない水酸化アルミニウムを用いているため、見掛け密度が大きい発泡体しか得られなかった。
以上説明したように、本発明のノンハロゲン系難燃樹脂発泡体は、燃焼時に有毒なハロゲンガスが全く発生せず、しかも無機物を高充填しているにもかかわらず高発泡倍率で適度な見掛け密度を有することがわかる。とりわけ、本発明のノンハロゲン系難燃樹脂発泡体は、従来の発泡体で困難であった、ＵＬ９４垂直難燃試験においてＶ−１又はＶ−０レベルの高い難燃性を有する。

The foams of Examples 1-19 have a moderate apparent density and are at the V-0 or V-1 level of the UL94 vertical flame retardant test. In Examples 11, 12, 18 and 19, magnesium hydroxide and surface-treated aluminum hydroxide are used in combination as the metal hydrate. In Examples 11 and 12, a foam having an appropriate apparent density and excellent flame retardancy was obtained by a method in which crosslinking and foaming were carried out almost simultaneously. When the amount of aluminum hydroxide is higher than that of magnesium hydroxide, foaming with moderate apparent density and excellent flame retardancy is achieved by heating and foaming after irradiation with an electron beam and crosslinking. The body is obtained.
On the other hand, in Comparative Example 1, the amount of magnesium hydroxide was too large, and only a foam having a large apparent density was obtained. In Comparative Example 2, since the blending amount of titanium oxide was large, only a foam having a large apparent density was obtained. In Comparative Example 3, the amount of titanium oxide was too small to pass the vertical flame retardant test. In Comparative Example 4, red phosphorus was not included, so the vertical flame retardant test was not passed. In Comparative Examples 5-7, since the compounding quantity of magnesium hydroxide was too small, it did not pass the vertical flame retardant test. Since Comparative Example 9 uses a halogen-based flame retardant and antimony trioxide, it has vertical flame retardancy of V-0 level even when the amount of magnesium hydroxide is small, but generates halogen gas when the foam is burned. did. In Comparative Example 10, since aluminum hydroxide that was not surface-treated was used, only a foam having a large apparent density was obtained.
As described above, the non-halogen flame retardant resin foam of the present invention does not generate any toxic halogen gas at the time of combustion, and has an appropriate apparent density at a high expansion ratio despite being highly filled with inorganic substances. It can be seen that In particular, the non-halogen flame retardant resin foam of the present invention has high flame retardancy of V-1 or V-0 level in the UL94 vertical flame retardant test, which was difficult with conventional foams.

Claims (4)

  With respect to 100 parts by mass of the resin component (A) containing the ethylene-vinyl acetate copolymer (A1) and / or the ethylene-ethyl acrylate copolymer (A2), (B) magnesium hydroxide and 151-300 parts by mass of aluminum hydroxide whose surface has been treated, (C) 2-25 parts by mass of red phosphorus, (D) 5-100 parts by mass of titanium oxide, and (E) 10-40 of pyrolytic foaming agent The total content of vinyl acetate and ethyl acrylate, which is a copolymer component of the ethylene-vinyl acetate copolymer (A1) and / or the ethylene-ethyl acrylate copolymer (A2), is contained in parts by mass. A non-halogen flame-retardant resin foam obtained by crosslinking and foaming using a resin composition of 14 to 50% by mass in the resin component (A).   When the compounding amount of the metal hydrate with respect to 100 parts by mass of the resin component (A) is (a) parts by mass and the compounding amount of titanium oxide is (b) parts by mass, a / b is 1.5-60. The non-halogen flame retardant resin foam according to claim 1, wherein (a + b) is 180 or more. ^3. The non-halogen flame-retardant resin foam according to claim 1, wherein the foam has a thickness of 2 to 20 mm and an apparent density of 35 to 150 kg / m ³ .   With respect to 100 parts by mass of the resin component (A) containing the ethylene-vinyl acetate copolymer (A1) and / or the ethylene-ethyl acrylate copolymer (A2), (B) magnesium hydroxide and 151-300 parts by mass of aluminum hydroxide whose surface has been treated, (C) 2-25 parts by mass of red phosphorus, (D) 5-100 parts by mass of titanium oxide, and (E) 10-40 of pyrolytic foaming agent The total content of vinyl acetate and ethyl acrylate, which is a copolymer component of the ethylene-vinyl acetate copolymer (A1) and / or the ethylene-ethyl acrylate copolymer (A2), is contained in parts by mass. A method for producing a non-halogen flame-retardant resin foam, characterized by crosslinking and foaming using a resin composition of 14 to 50% by mass in the resin component (A).