JPH07118435A - Resin foam of flame retardant polyolefin film - Google Patents

Abstract

PURPOSE:To obtain the subject foam free from the generation of corrosive gases in combustion and excellent in flame retardance, softness and foamed appearance by blowing the composition composed of a polyolefin resin, red phosphorus, a thermally expandable graphite and a blowing agent at specific ratios. CONSTITUTION:(A) 100 pts.wt. of a polyolefin resin is compounded with (B) 1-30 pts.wt. of a red phosphorus of preferably <=20mu in particle diameter, (C) 1-30 pts.wt. of a thermally expandable graphite having a dilatation of >=100cc/g at 1000 deg.C and particle diameter of 80-120 mesh and (D) 1-30 pts.wt. of a blowing agent (preferably a decomposable blowing agent, e.g. azodicarbonamide). The objective foamy is obtained by blowing the obtained composition. Further, the component C is obtained e.g. by electrolytic oxidation of scaly graphite in sulfuric acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin resin foam which has good flame retardancy, flexibility and foaming appearance and does not generate corrosive gas during combustion.

[0002]

2. Description of the Related Art Polyolefin resin foams are widely used for footwear soles, core materials, cushioning materials, etc. because they are lightweight, have a soft feel, and are highly elastic. However, since a foam of a polyolefin-based resin easily burns, it cannot be generally used in applications requiring flame retardancy such as building materials.
To make a polyolefin resin foam flame-retardant, a flame-retardant foam is not obtained even if a halogen-based flame retardant or a non-halogen flame retardant that is generally used as a flame retardant is added to a polyolefin resin, It was difficult to obtain a polyolefin resin foam having excellent flame retardancy.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyolefin resin foam which has good flame retardancy, flexibility and foaming appearance and does not generate corrosive gas during combustion.

[0004]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors used non-halogenated red phosphorus and expanded graphite having a specific expandability and a specific particle size as a flame retardant. As a result, they have found that the above problems can be solved, and have completed the present invention.

That is, the present invention relates to a polyolefin resin (1)
1 to 30 parts by weight of red phosphorus (2) to 100 parts by weight, 10
Composition in which 1 to 30 parts by weight of heat-expandable graphite (3) having a degree of expansion at 00 ° C. of 100 cc / g or more and a particle size of 80 to 120 mesh and 1 to 30 parts by weight of a foaming agent (4) are added. The present invention relates to a flame-retardant polyolefin resin foam obtained by foaming a material.

The present invention will be described in detail below.

The polyolefin resin used as the component (1) of the composition in the foam of the present invention means ethylene, propylene, 1-butene, 3-methyl-1-butene, 3-methyl-1-pentene, 4 -Homopolymers of α-olefins such as methyl-1-pentene, copolymers of two or more of these α-olefins, or copolymers of these α-olefins with other copolymerizable unsaturated monomers Is mentioned. Specifically, high density, medium density, low density polyethylene, ethylene and propylene, 1-butene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1- Copolymers of one or more α-olefins such as hexene, 1-octene, 1-nonene, 1-decene, propylene and ethylene, 1-butene, 3-methyl-1-butene, 3-methyl-1- Pentene, 4-methyl-1-pentene, 1-hexene, 1-
At least one α-, such as octene, 1-nonene, 1-decene
Copolymers with olefins, copolymers with ethylene and vinyl esters such as vinyl acetate and vinyl propionate, saponified products of the ethylene and vinyl ester copolymers, methyl and ethyl of ethylene and acrylic acid or methacrylic acid, n
-Copolymers with unsaturated carboxylic acid esters such as butyl and isobutyl, copolymers with ethylene and unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and metal salts thereof, ethylene / vinyl ester / carbon monoxide copolymer Copolymer, ethylene / unsaturated carboxylic acid ester / carbon monoxide copolymer, ethylene / unsaturated carboxylic acid ester / unsaturated carboxylic acid copolymer and metal salts thereof, ethylene / vinyl ester / unsaturated carboxylic acid copolymer and Examples thereof include metal salts thereof, ethylene / methyl acrylate / monoethyl maleate copolymers, ethylene / vinyl acetate / monoethyl maleate copolymers and the like. Furthermore, a modified product of each of the above resins, such as a silane modified product or a carboxylic acid modified product, can also be used. And these resin is used individually or as a mixture of 2 or more types. Of the resins described above, the use of ethylene / vinyl acetate copolymer or low density polyethylene is preferable because a foam having particularly excellent flame retardancy, flexibility and foaming appearance can be obtained.

The red phosphorus used as the component (2) of the composition in the foam of the present invention preferably has a particle size of 20 μm or less from the viewpoint of dispersibility in a resin. Further, red phosphorus surface-treated with a phenol resin, a titanate coupling agent or the like can also be used. The amount of the red phosphorus compounded is 1 to 30 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the polyolefin resin (1). If the amount is less than 1 part by weight, the flame retardancy is poor, and if it exceeds 30 parts by weight, the flexibility of the foam is poor and the cost is increased.

The heat-expandable graphite used as the component (3) of the composition in the foam of the present invention is 1000
The expansion degree at 100C is 100 cc / g or more, and the particle size thereof is 80 to 120 mesh. Here, the expansion degree means the reciprocal of the bulk density, and if the expansion degree is less than 100 cc / g, the flame retardancy of the obtained foam is inferior. Further, when the heat-expandable graphite having a particle size of 80 mesh on is used, voids (spaces formed by chance in the cell material and larger than individual peculiar cells) are generated in the obtained foam, and the foam expands. The appearance of the cut surface when cutting is poor. Further, when the one having a particle size of 120 mesh pass is used, the obtained foam has poor flame retardancy. This heat-expandable graphite (3) is subjected to an oxidation treatment such as electrolytic oxidation of flake graphite in sulfuric acid or oxidation with a mixed acid of two or more kinds selected from phosphoric acid, sulfuric acid, nitric acid, perchloric acid and the like. can get. The blending amount of the heat-expandable graphite is the polyolefin resin (1).
1 to 30 parts by weight, preferably 3 to 2 per 100 parts by weight
0 parts by weight. If the blending amount is less than 1 part by weight, the flame retardancy of the resulting foam will be poor, and if it exceeds 30 parts by weight, the flexibility of the resulting foam will be poor and the cost will increase.

Since the foam of the present invention employs the non-halogen flame retardant of the above-mentioned components (2) and (3) as the flame retardant, the amount of smoke generated at the time of combustion differs from that of the composition containing the halogen flame retardant. There is no problem that a large amount of corrosive gas such as hydrogen halide is generated and people who evacuate in case of fire or damage to equipment and devices lose their escape route due to smoke.

Further, the foaming agent used as the component (4) of the composition in the foam of the present invention is an evaporative foaming agent (physical foaming agent) which is liquid or gaseous at room temperature and volatilizes without chemical change. And a decomposing type foaming agent (chemical foaming agent) that generates gas such as nitrogen, carbon dioxide, and ammonia by chemical decomposition.

Examples of the evaporative blowing agent include aliphatic hydrocarbons such as n-propane, n-pentane, n-hexane, neopentane and isohexane, chlorinated aliphatic hydrocarbons such as methyl chloride and methylene dichloride, and trichloromono. Examples thereof include fluorinated aliphatic hydrocarbons such as fluoromethane and dichlorotetrafluoroethane, which may be used alone or in combination with 2
It is used as a mixture of two or more species. On the other hand, as decomposable foaming agents, inorganic foaming agents such as sodium bicarbonate, ammonium bicarbonate, ammonium carbonate, ammonium nitrite, azide compounds such as calcium azide, N, N'-
Dinitrosopentamethylenetetramine (DPT), N,
Nitroso compounds such as N'-dimethyl-N, N'-dinitrosoterephthalamide (DMDNTA), azo compounds such as azodicarbonamide (ADCA), azobisisobutyronitrile (AZDN), barium azodicarboxylate, benzene Sulfonyl hydrazide (BSH),
p, p'-oxybis (benzenesulfonyl hydrazide) (OBSH), toluenesulfonyl hydrazide (T
SH) or its derivatives such as sulfonyl hydrazides, p
-Toluenesulfonyl semicarbazide (TSC), trihydrazinotriazine, p, p'-oxybisbenzenesulfonyl semicarbazide (OBSC) and the like,
These are used alone or as a mixture of two or more kinds.

Of the above-mentioned foaming agents, a decomposing type foaming agent is preferable because a fine and uniform foaming cell can be obtained. Among the decomposing type foaming agents, azodicarbonamide (ADCA),
Those having a decomposition temperature not lower than the melting point of the polyolefin resin such as p, p′-oxybis (benzenesulfonylhydrazide) (OBSH) and not higher than + 50 ° C. are particularly preferably used.

The blending amount of the foaming agent (4) is 1 to 30 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the polyolefin resin. If the blending amount is less than 1 part by weight, the expansion ratio of the resulting foam will be low and the flexibility will be poor.
If it exceeds 0 parts by weight, the foam moldability is poor.

For the purpose of promoting the decomposition of the foaming agent and lowering the decomposition temperature, oxalic acid, salicylic acid, phthalic acid, benzoic acid, boric acid, carbonic acid, malonic acid, citric acid, fumaric acid, succinic acid, adipic acid, An organic acid such as silicic acid, a foaming aid such as urea, borax, ethanolamine, zinc oxide or lead carbonate may be added to the composition.

A flame retardant other than the components (2) and (3) is added to the composition comprising the components (1) to (4) described above, if necessary, within a range not impairing the effects of the present invention. May be. As the flame retardant other than the components (2) and (3),
For example, inorganic compounds such as antimony oxide, aluminum hydroxide, antimony silicone oxide, zinc borate, tris (chloroethyl) phosphate, tris (monochloropropyl) phosphate, tris (dichloropropyl)
Phosphate, bis (2,3-dibromopropyl) -dichloropropyl phosphate, tris (2,3-dibromopropyl) phosphate, tris (2-bromo-3-)
(Chloropropyl) phosphate, tris (bromocresyl) phosphate, brominated phosphate ester type, halogen-containing condensed organic phosphate ester, bromine-containing / chlorine phosphate ester, chlorine-containing phosphate ester, chlorine-containing phosphorus ester system, ethylenebistris- (2-cyanoethyl) phosphonium bromide, tetraxy (hydroxymethyl) phosphonium chloride, brominated alkyl acid phosphate,
Phosphorus flame retardants such as di- (polyoxyethylene) -hydroxymethylphosphonate, ammonium polyphosphate, low-condensation ammonium phosphate, tetrabromobutane, hexabromobenzene, pentabromoethylbenzene, hexabromobiphenyl, decabromodiphenyl Oxide, pentabromochlorocyclohexane, tetrabromobisphenol A derivative, tetrabromobisphenol S, tris-
(2,3-Dibromopropyl-1) -isocyanurate, 2,2-bis- [4 (2,3-dibromopropoxy) 3,5-dibromophenyl] -propane, brominated acetylene alcohol, brominated epoxy resin, etc. Brominated flame retardants, chlorinated paraffins, chlorinated polyolefins, chlorinated flame retardants such as dimethyl chlorendate, and the like, and these can be added alone or as a mixture of two or more kinds.

In the above-mentioned composition, if necessary, organic / inorganic fillers, organic peroxides, lubricants, antioxidants, light stabilizers, colorants, and ultraviolet absorbers are added as long as the effects of the present invention are not impaired. Additives generally added to polyolefin resins such as agents, antistatic agents, plasticizers, antiblocking agents, nucleating agents, clarifying agents, surfactants and catalyst neutralizing agents may be added.

In order to obtain the foam of the present invention, the above-mentioned composition is foamed, and this foaming is carried out by physical or chemical foaming, and is not particularly limited, and the decomposition type foaming agent, red phosphorus is used. And the graphite obtained by melting and kneading graphite at a temperature not lower than the melting point of the polyolefin resin and not higher than the decomposition temperature of the foaming agent, and heating the sheet obtained at a temperature not lower than the decomposition temperature of the foaming agent to foam at normal pressure, an evaporative foaming agent or decomposition. Includes an extrusion foaming method in which each of the components (1) to (3) containing a mold-type foaming agent is expanded by a pressure change from a high pressure state to a normal pressure by extruding from a die in a molten state, a decomposition-type foaming agent and a cross-linking agent. A sheet obtained by melting and kneading the components of (1) to (3) below the decomposition temperature of the crosslinking agent and the foaming agent is filled in a closed mold and heated under pressure to decompose the crosslinking agent and the foaming agent. Sudden expansion due to pressure change due to pressure release (1) to (3) containing a decomposition-type foaming agent or a dry blend of a polyolefin-based resin pellet impregnated with a decomposition-type foaming agent and components (2) to (3) It is possible to use a conventionally known method such as an injection foaming method in which pellets obtained by melt-kneading at a temperature below the decomposition temperature of the foaming agent are foamed by an injection molding machine.

Components (1) to (1) in the above-mentioned foam production process
The dry blending of (4) can be performed using a ribbon blender, a V blender, a Henschel mixer, or the like. Further, the melt-kneading of the components (1) to (4) can be performed using an extruder, a kneader, a Banbury mixer, a hot roll or the like.

The cross-linking agent used in the above-mentioned foam production process is one which is added to the composition of the present invention as necessary for the purpose of further improving the strength of the foam and increasing the expansion ratio, and is usually Dicumyl peroxide, t-butyl cumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 ,
1,3-bis (t-butylperoxyisopropyl) benzene, 1,1′-bis (t-butylperoxy) 3,3
An organic peroxide having a —O—O— bond in its molecule is used as a compound in which one or two hydrogen atoms of hydrogen peroxide such as 3,5-trimethyl-cyclohexane are replaced with organic radicals.

[0021]

EXAMPLES Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the invention. Parts in Examples and Comparative Examples are parts by weight. The performances in Examples and Comparative Examples were measured by the following methods.

Foam Appearance The cut surface of the foam was visually observed and evaluated according to the following criteria.

◯: No void is observed ×: Void is generated Foam flexibility The flexibility when the foam is pushed by hand was evaluated by touch according to the following criteria.

○: Soft ×: Hard flame-retardant A test piece of 127 × 12.7 × 1.6 (thickness) mm was prepared from the foam by cutting and measured according to the UL94 vertical test method. If it had self-extinguishing property (V0), it was evaluated as practically no problem.

Examples 1 to 3 and Comparative Examples 1 to 3 Ethylene-vinyl acetate copolymer (vinyl acetate content according to JIS K6730; 15% by weight, JIS K6730)
Melt flow rate (hereinafter abbreviated as "MFR"); 1.5 g / 10 min) to 100 parts of red phosphorus (trade name: Novarred 120UF, manufactured by Rin Kagaku Kogyo Co., Ltd.)
And heat-expandable graphite (natural scaly graphite oxidized with sulfuric acid and an oxidizing agent, the expansion degree at 1000 ° C. is 190 cc / g, and the particle size is 80 to 120 mesh), and azodicarboxylic as a foaming agent. Amide-based foaming agent (trade name; Celmic CAP, manufactured by Sankyo Kasei Co., Ltd.) and 1,3-bis- (t-butylperoxyisopropyl) benzene as a cross-linking agent (trade name: Perkadox 14)
/ 40, manufactured by Kayaku Nouri Co., Ltd. in the amounts shown in Table 1 and kneaded with an 8-inch roll having a surface temperature of 100 ° C. to prepare a sheet. Next, add about 340 cc of this kneading sheet to 195
It is put in a mold of × 195 × 10 (thickness) mm, the temperature is 160 ° C., the time is 15 minutes, and the initial pressure is 170 kg.
After cross-linking and foaming under the condition of / cm ² , the pressure was released to obtain a foam.
The results of measuring the appearance and physical properties of the obtained foam are shown in Table 1.
Shown in.

The foam of this example was excellent in foam appearance, flexibility and flame retardancy. On the other hand, the foam of Comparative Example 1 in which the compounding amount of red phosphorus exceeds 30 parts and the foam of Comparative Example 2 in which the compounding amount of heat-expandable graphite exceeds 30 parts are inferior in flexibility, and the compounding amount of the foaming agent is In the resin composition of Comparative Example 3 exceeding 30 parts, the foam scattered and did not form a foam at the time of releasing pressure after heating / pressurizing with a pressing machine.

Comparative Example 4 A kneading sheet was prepared in the same manner as in Example 1 except that red phosphorus was not added, and the same components were used to obtain a foam. The results of measuring the appearance and physical properties of the foam are shown in Table 1. The foam of this comparative example containing no red phosphorus was inferior in flame retardancy.

Comparative Example 5 A kneading sheet was prepared in the same manner as in Example 1 except that the heat-expandable graphite was not added, and the same components were used to obtain a foam. The results of measuring the appearance and physical properties of the foam are shown in Table 1. The foam of this comparative example containing no heat-expandable graphite was inferior in flame retardancy.

Comparative Example 6 Heat-expandable graphite (natural scaly graphite is oxidized with sulfuric acid and an oxidizing agent, and the expansion degree at 1000 ° C. is 1).
The same components as in Example 1 were used, except that a product having a particle size of 80 mesh was used as the product (90 cc / g).
A kneading sheet was prepared in the same manner as in 1. to obtain a foam. The results of measuring the appearance and physical properties of the foam are shown in Table 1. The foam of this comparative example was inferior in foam appearance.

Comparative Example 7 Heat-expandable graphite (natural scaly graphite is oxidized with sulfuric acid and an oxidizing agent, and the expansion degree at 1000 ° C. is 1).
(90 cc / g) and the same components as in Example 1 except that a particle size of 120 mesh was used, and a kneading sheet was prepared in the same manner as in Example 1 to obtain a foam. The results of measuring the appearance and physical properties of the foam are shown in Table 1. The foam of this comparative example was inferior in flame retardancy.

Comparative Example 8 The same components as in Example 1 were used except that ordinary graphite (expansion degree at 1000 ° C. is less than 100 cc / g, particle size; 80 to 120 mesh) was used in place of the heat-expandable graphite. ,
A kneading sheet was prepared in the same manner as in Example 1 to obtain a foam. The results of measuring the appearance and physical properties of the foam are shown in Table 1. The foam of this comparative example was inferior in flame retardancy.

Examples 4 to 5 low density polyethylene (density according to JIS K6760;
0.921 g / cm ³ , MF according to JIS K6760
R: 4 g / 10 minutes) to 100 parts, as an azodicarbonamide-based foaming agent (trade name: Celmic CAP)
-500, manufactured by Sankyo Kasei Co., Ltd., except that Example 1 was used.
The red phosphorus, the heat-expandable graphite and the cross-linking agent used in Example 1 were mixed in the amounts shown in Table 1 and kneaded with an 8-inch roll having a surface temperature of 110 ° C. to prepare a sheet. Using this sheet, a foam was obtained in the same manner as in Example 1. The results of measuring the appearance and physical properties of the foam are shown in Table 1. The foam of this example was excellent in foam appearance, flexibility and flame retardancy.

Comparative Example 9 Decabromodiphenyl ether (trade name; as a flame retardant)
A kneaded sheet was prepared in the same manner as in Example 4 except that 25 parts of a mixture of frame cut 110R, manufactured by Tosoh Corporation / antimony trioxide = 3/1 was blended, and a kneading sheet was produced in the same manner as in Example 4 to obtain a foam. Got The results of measuring the appearance and physical properties of the foam are shown in Table 1. The foam of this comparative example was inferior in flame retardancy.

[0034]

[Table 1]

[0035]

EFFECT OF THE INVENTION The foam of the present invention is excellent in foam appearance, flexibility and flame retardancy, does not generate corrosive gas during combustion, and is suitably used for building materials and the like.

Claims (1)

[Claims] 1. Red phosphorus (2) in an amount of 1 to 30 parts by weight per 100 parts by weight of a polyolefin resin (1), a degree of expansion at 1000 ° C. of 100 cc / g or more, and a particle size of 80.
~ 120 mesh heat expandable graphite (3) 1-30
A flame-retardant polyolefin resin foam obtained by foaming a composition to which 1 part by weight and 1 to 30 parts by weight of a foaming agent (4) are added.