JP2003082145A - Polypropylene resin foamed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polypropylene resin extruded foamed board which can suitably be used for a building thermal insulation material because of having excellent flame retardance. SOLUTION: This polypropylene resin extruded foamed board is obtained by mixing 100 pts.wt. of mixed resins (a) comprising 50-95 pts.wt. of a polypropylene resin (a1) and 50-5 pts.wt. of a polystyrene resin (a2), with 0.1-10.0 pts.wt. of a halogen-flame retardant (b), 0.1-10.0 pts.wt. of a specific nitrogen- containing compound (c), and a foaming agent (d) in an extrudor, and taking out the mixture to a low-pressure zone by applying pressure to it, the obtained board having a density of 10-200 kg/m<3> .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruded foam board made of polypropylene resin. More specifically, the present invention relates to a polypropylene resin extruded foam board having improved flame retardancy, which can be suitably used for, for example, a wall of a building, a structural material such as a floor partition, and a heat insulating material.

[0002]

2. Description of the Related Art A foam made of a thermoplastic resin is generally used for a heat insulating material, a cushioning material, a core material, a food container, etc. because it is lightweight and has a good heat insulating property and a good shock absorbing property against external stress. ing. In particular, a foam made of a polypropylene resin has good chemical resistance, impact resistance and heat resistance, and therefore, it is particularly suitable for use as a cushioning material and the like by taking advantage of its characteristics. However, since polypropylene-based resin is a resin that easily burns, when a foam made of polypropylene-based resin is used in applications such as building materials, it is required to improve flame retardancy. As an attempt to make a foam of a polyolefin resin flame-retardant, for example, Japanese Patent Publication No.
In 3-12004, it is disclosed that chlorinated paraffin, antimony trioxide, etc. are added to a polyolefin resin, but this method uses a thick foam board for foaming after crosslinking the polyolefin resin. It was difficult to manufacture. Further, in this publication, as the polyolefin resin, only polyethylene is described and polypropylene is not described. Further, JP-A-8-208875 discloses that a mixture of neutralized heat-expandable graphite and ammonium polyphosphate is added to a polyolefin-based resin and extrusion foaming is performed. However, the heat-expandable graphite used in the above method is prepared by treating the graphite with a strong oxidant and then performing a neutralization treatment, which complicates the process and makes the polypropylene resin flame-retardant. Requires a large amount of flame retardant,
There is a possibility that characteristics such as impact resistance of the polypropylene resin may be impaired. Thus, at present, a method for producing a polypropylene-based resin foam board having high flame retardancy without extrusion of the characteristics of polypropylene-based resin by extrusion foaming has not yet been found.

[0003]

An object of the present invention is to provide a polypropylene resin extruded foam board having excellent flame retardancy.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a halogen-based flame retardant and a specific nitrogen are added to a resin composition composed of a polypropylene resin and a polystyrene resin. The inventors have found that an extruded foam board having high flame retardancy can be obtained by mixing the contained compound together with a foaming agent in an extruder and extruding it into a low pressure zone, and completed the present invention.

That is, in the present invention, 50 to 95 parts by weight of the polypropylene resin (a1) and 50 parts of the polystyrene resin (a2) are used.
To 100 parts by weight of the mixed resin (a) consisting of 5 parts by weight,
0.1 to 10.0 parts by weight of a halogen-based flame retardant (b), 0.1 to 10.0 parts by weight of a nitrogen-containing compound (c) represented by the following general formula 1 and / or general formula 2, and foaming. The present invention relates to a polypropylene resin extruded foam board having a density of 10 to 200 Kg / m ³ obtained by mixing the agent (d) with an extruder and extruding the mixture into a low pressure zone.

[0006]

[Chemical 3] [Wherein R 1, R 2, and R 3 are hydrogen atoms, an alkyl group having 1 to 8 carbon atoms, an organic group represented by —Y—X (wherein Y is an alkylene group having 1 to 6 carbon atoms, a phenyl group, Cycloalkylene group, X is selected from an epoxy group, a carboxyl group, a hydroxyl group, an amino group, a phenyl group) and a phenyl group, and may be different from each other]

[0007]

[Chemical 4] [Wherein R 4, R 5, and R 6 are hydrogen atoms, an alkyl group having 1 to 8 carbon atoms, an organic group represented by —Y—X (wherein Y is an alkylene group having 1 to 6 carbon atoms, a phenyl group, Cycloalkylene group, X is selected from an epoxy group, a carboxyl group, a hydroxyl group, an amino group, a phenyl group) and a phenyl group, and may be different from each other]

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The polypropylene resin (a1) used in the present invention is a homopolymer of propylene, ethylene, or an α-olefin having 4 or more carbon atoms.
Alternatively, it is a random copolymer or block copolymer of two or more copolymerization components and propylene. The melt flow rate of the polypropylene resin (a1) at 230 ° C. is preferably 5 g / 10 minutes or less, more preferably 0.5 g / 10 min.
g / 10 minutes or less is preferable. Further, the polystyrene-based resin (a2) used in the present invention is preferably a homopolymer of styrene, and a monomer such as α-methylstyrene, acrylonitrile, butadiene, or methylmethacrylate that is copolymerizable with styrene. A copolymer containing styrene as a main component or a mixture thereof may be used. The melt flow rate of the polystyrene resin (a2) at 200 ° C. is preferably 0.5 to 20 g / 10 minutes. further,
In the present invention, a styrene-propylene graft copolymer, if necessary, within a range that does not impair the effects of the present invention,
Styrene-butadiene-styrene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated styrene-isoprene-styrene block copolymer, polyethylene, Resins and rubbers other than the polypropylene resin (a1) and the polystyrene resin (a2) such as poly-1-butene and polybutadiene may be added. As the halogen-based flame retardant (b) used in the present invention, a flame retardant usually used in thermoplastic resins can be used without any particular limitation. For example, hexabromocyclododecane, tris (2,3-dibromopropyl) phosphate, tris (2,3-dibromopropyl) isocyanurate, tetrabromo-vinylcyclohexane, tetrabromocyclooctane, pentabromocyclohexane, hexabromo-2-butene, Tetrabromononane, hexabromobenzene, octabromodiphenyl ether, decabromodiphenyl ether, tribromophenol, tetrabromodihydroxydiphenylmethane, dibromoneopentyl glycol diglycidyl ether, dibromophenylglycidyl ether, tetrabromobisphenol A, tetrabromobisphenol A-di ( 2,3-dibromopropyl ether), tetrabromobisphenol A-di (glycidyl ether), Tiger tetrabromobisphenol S, tetrabromobisphenol S- di (2,3-dibromopropyl ether), ethylene bis tetrabromo phthalimide, brominated polystyrene, include one or more of such. Among these, particularly preferable bromine compounds include hexabromocyclododecane, pentabromocyclohexane, tetrabromocyclooctane, tetrabromobisphenol S-di (2,3-dibromopropyl ether), and the like.

The halogen-based flame retardant (b) is added in an amount of polypropylene resin (a1) and polystyrene resin.
0.1 to 100 parts by weight of mixed resin (a) consisting of (a2)
-10.0 parts by weight is preferable from the viewpoint that flame retardancy is sufficiently exhibited, extrusion foam board formation is not hindered, and it is economical. Furthermore, it is preferably 1.0 to 8.0 parts by weight.

The nitrogen-containing compound used in the present invention
(c) is a compound selected from cyanuric acid, isocyanuric acid, and derivatives thereof represented by the following general formula 1 and / or general formula 2. These compounds are single or 2
A mixture of two or more species can be used.

[0011]

[Chemical 5] [Wherein R 1, R 2, and R 3 are hydrogen atoms, an alkyl group having 1 to 8 carbon atoms, an organic group represented by —Y—X (wherein Y is an alkylene group having 1 to 6 carbon atoms, a phenyl group, Cycloalkylene group, X is selected from an epoxy group, a carboxyl group, a hydroxyl group, an amino group, a phenyl group) and a phenyl group, and may be different from each other]

[0012]

[Chemical 6] [Wherein R 4, R 5, and R 6 are hydrogen atoms, an alkyl group having 1 to 8 carbon atoms, an organic group represented by —Y—X (wherein Y is an alkylene group having 1 to 6 carbon atoms, a phenyl group, A cycloalkylene group, X is selected from an epoxy group, a carboxyl group, a hydroxyl group, an amino group, a phenyl group) and a phenyl group, and may be different from each other.] Specific examples of the nitrogen-containing compound (c) include cyanuric Acid, methyl cyanurate, diethyl cyanurate, trimethyl cyanurate, triethyl cyanurate, isocyanuric acid, methyl isocyanurate, N, N'-diethyl isocyanurate, trismethyl isocyanurate, trisethyl isocyanurate, bis (2-carboxyethyl) ) Isocyanurate, 1,3,5-tris (2-carboxyethyl) isocyanurate, Tris (2 , 3-epoxypropyl) isocyanurate.

The nitrogen-containing compound (c) is preferably a compound which is flame-retardant itself and decomposes or melts at 270 ° C to 400 ° C.

Among the nitrogen-containing compounds (c), particularly preferable nitrogen-containing compounds include isocyanuric acid and bis (2-carboxyethyl) isocyanurate.

The amount of the nitrogen-containing compound (c) added is as follows: polypropylene resin (a1) and polystyrene resin
0.1 to 100 parts by weight of mixed resin (a) consisting of (a2)
-10.0 parts by weight is preferable from the viewpoint that flame retardancy is sufficiently exhibited, extrusion foam board formation is not hindered, and it is economical. More preferably, it is 1.0 to 8.0 parts by weight.
Further, in the present invention, in order to further improve the flame retardance, phosphoric acid ester, phosphate, polyphosphate, phosphorus-based compounds such as red phosphorus, silicon oil, silicone polymer, silicone elastomer, silicon-based such as silica gel. Compound, or antimony trioxide, antimony pentoxide, sodium antimonate, aluminum hydroxide, magnesium hydroxide, calcium oxide, aluminum oxide, magnesium oxide, zinc oxide, titanium oxide, tin oxide, tin oxide hydrate, calcium carbonate, Magnesium carbonate, boron oxide,
Inorganic compounds such as boric acid, zinc borate, barium borate, barium metaborate, carbon black, graphite and expansive graphite may be added. Next, in the present invention, the polypropylene resin (a1) and polystyrene resin (a2), a halogen-based flame retardant (b), and a nitrogen-containing compound (c)
As a method of mixing and foaming the composition consisting of, for example, the volatile foaming agent (d) is pressed into the resin composition at high temperature under high pressure and mixed, cooled to an appropriate foaming temperature, and under atmospheric pressure. Examples include a method of extrusion foaming. The composition is one in which granules or powders of each component are uniformly blended in a blender, which is once melt-blended through a kneading extruder, or a polystyrene resin (a2).
Alternatively, any method may be used in which the flame retardant is melt-blended with the polypropylene resin (a1), and then the remaining resin is dry-blended.

Volatile foaming agent (d) preferred in the present invention
As, for example, propane, butane, isobutane, aliphatic hydrocarbons such as pentane, hexane, heptane, cyclobutane, cyclopentane, alicyclic hydrocarbons such as cyclohexane, chlorodifluoromethane, dichloromethane, dichlorofluoromethane, chloroethane, Examples thereof include halogenated hydrocarbons such as dichlorotrifluoroethane, nitrogen, inorganic gases such as air, water, and the like, or two or more thereof.

The addition amount of the foaming agent (d) is selected depending on the type of the foaming agent (d) and the target foam density, but it is a mixed resin (a) composed of a polypropylene resin (a1) and a polystyrene resin (a2). 1 to 100 parts by weight is preferable with respect to 100 parts by weight.

Further, in order to control the cell diameter, if necessary, a known foaming nucleating agent such as mica, talc, sodium bicarbonate-citric acid mixture, polytetrafluoroethylene, etc. may be used in combination.

There is no particular limitation on the density of the foam, but a foam having a density of 10 to 200 kg / m ³ is usually used for the purpose of building materials.

Further, in the present invention, if necessary, processing aids such as sodium stearate, magnesium stearate, barium stearate, liquid paraffin, olefin wax, stearyl amide compound and the like are added within a range that does not impair the effects of the present invention. Agents, phenolic antioxidants, phosphorus stabilizers, light resistance stabilizers such as benzotriazoles and hindered amines, and other additives such as flame retardants, antistatic agents, coloring agents such as pigments, etc. can be contained. .

The polypropylene-based resin extruded foam board obtained in the present invention is provided with flame retardancy, but the oxygen index measured according to JIS K7201 is 26 or more. It is preferable because it does not burn easily, and because it is out of the designated combustible materials under the Fire Service Law, there are no restrictions on storage and use.

The oxygen index is evaluated by the following procedure. A 150 mm x 6.5 mm x 3 mm test piece cut out from a polypropylene resin extruded foam board from which the skin has been removed was fixed vertically to a support of a candle method combustion tester D type manufactured by Toyo Seiki Seisakusho, and a combustion cylinder. Then, the air flow of a mixed gas consisting of oxygen and nitrogen is left standing for 30 seconds to be stabilized, and then the upper end of the test piece is ignited by using an igniter. Combustion test was performed by changing the mixing ratio of oxygen and nitrogen, and 50
The minimum oxygen concentration required to continue burning over mm is defined as the oxygen index.

The thickness of the polypropylene resin foam board of the present invention is not particularly limited, but is usually 15 to 60 m.
m.

[0024]

EXAMPLES Next, the extruded foam board according to the present invention will be described based on Examples and Comparative Examples, but the present invention is not limited to such Examples.

The evaluation of the extruded foam board was carried out based on the following method. <Evaluation Method of Extruded Foam Board> The density, thickness and oxygen index of the obtained extruded foam board were evaluated by the following methods.

Density: Calculated from the weight and the volume obtained by the submersion method.

Thickness: Measured with a caliper at the center position in the width direction of the foam board.

Oxygen index: According to JIS K7201, a 150 mm × 6.5 mm × 3 mm test piece cut out from a polypropylene resin extruded foam board from which the skin has been removed is used as a candle combustion tester D manufactured by Toyo Seiki Seisakusho KK
The mold is fixed vertically to a mold support, covered with a combustion cylinder, and a mixed gas stream of oxygen and nitrogen is allowed to stand for 30 seconds to be stabilized, and then the upper end of the test piece is ignited by using an igniter. Combustion tests were carried out by changing the mixing ratio of oxygen and nitrogen, and the flame retardancy was evaluated based on the following criteria with the lowest oxygen concentration required to continue burning of 50 mm or more as the oxygen index.

◯: Oxygen index is 26 or more X: oxygen index less than 26

[0030]

Example 1 Ethylene propylene random copolymer (2
Melt flow rate at 30 ° C. 0.4 g / 10 minutes, ethylene content: 3% by weight 60 parts by weight, styrene homopolymer (melt flow rate at 200 ° C .: 1.5 g / 1
0 min) 40 parts by weight, halogen-based flame retardant (b) 4.5 parts by weight of hexabromocyclododecane, nitrogen-containing compound (c) 3 parts by weight of isocyanuric acid, and nucleating agent polytetrafluoroethylene-based 0.07 parts by weight of a lubricant and pentaerythrityl-tetrakis- (3 as a stabilizer
0.2 part by weight of-(3,5-di-t-butyl-4-hydroxyphenyl) propionate) was dry blended with a ribbon blender, and then the mixture was mixed at 50 kg / h.
At 65 ° C. in a first-stage extruder (65 mm) at 200 ° C.
Isobutane as a foaming agent (d) was pressed into 12 parts by weight of 100 parts by weight of the mixed resin (a), and the second stage extruder (90 mm)
Inside the resin is cooled to 143 ° C, slit width 50mm, slit thickness 4.5mm, land 25mm
Was extruded from the rectangular die and passed through a molding die directly connected to the rectangular die to obtain a foam board. The physical properties of the foam are shown in Table 1.

[0031]

Example 2 A foam board was obtained in the same manner as in Example 1 except that 4.5 parts by weight of bis (2-carboxyethyl) isocyanurate was used as the nitrogen-containing compound (c) instead of isocyanuric acid. It was Table 1 shows the physical properties of the obtained foam.

[0032]

Example 3 Instead of hexabromocyclododecane,
A foam board was obtained in the same manner as in Example 1 except that 4.5 parts by weight of tetrabromobisphenol S-di (2,3-dibromopropyl ether) was used as the halogen-based flame retardant (b). Table 1 shows the physical properties of the obtained foam.

[0033]

Example 4 The compounding amount of hexabromocyclododecane was set to 3
A foam board was obtained in the same manner as in Example 1 except that the mixing amounts of the parts by weight and isocyanuric acid were changed to 6 parts by weight, respectively. Table 1 shows the physical properties of the obtained foam.

[0034]

Example 5 Ethylene propylene random copolymer 90
Parts by weight, the ratio is changed to 10 parts by weight of styrene homopolymer,
A foam board was obtained in the same manner as in Example 1 except that the blending amount of hexabromocyclododecane was changed to 6 parts by weight. Table 1 shows the physical properties of the obtained foam.

[0035]

Comparative Example 1 Example 1 except that isocyanuric acid was not added
A foam board was obtained in the same manner as in. Table 1 shows the physical properties of the obtained foam. The foamed board has a low oxygen index and inferior flame retardancy.

[0036]

Comparative Example 2 A foam board was obtained in the same manner as in Example 1 except that hexabromocyclododecane was not added. Table 1 shows the physical properties of the obtained foam. The foamed board has a low oxygen index and inferior flame retardancy.

[0037]

Comparative Example 3 A foam board was obtained in the same manner as in Example 1 except that hexabromocyclododecane and isocyanuric acid were not added. Table 1 shows the physical properties of the obtained foam. The foamed board has a low oxygen index and inferior flame retardancy.

[0038]

Comparative Example 4 A foamed board was obtained in the same manner as in Example 1 except that isocyanuric acid was not added and the amount of hexabromocyclododecane was changed to 20 parts by weight. Table 1 shows the physical properties of the obtained foam. Although it has a high oxygen index and flame retardancy, it is a foam board with a small thickness and a high density.

[0039]

[Table 1]

[0040]

According to the present invention, it is possible to easily provide a polypropylene resin extruded foam board having excellent flame retardancy.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4F074 AA24 AA32 AA98 AD02 AD05                       AD12 AD21 AG10 BA31 BA38                       CA22 DA02 DA18 DA23 DA32                 4J002 BB121 BB141 BC032 BC042                       BC052 BC062 BC072 BP021                       EB076 ED076 EJ056 EU187                       EU196 EU197 EW056 FD136                       FD137 GL00

Claims (2)

[Claims] 1. A halogen-based flame retardant (b) for 100 parts by weight of a mixed resin (a) comprising 50 to 95 parts by weight of a polypropylene resin (a1) and 50 to 5 parts by weight of a polystyrene resin (a2).
0.1 to 10.0 parts by weight, 0.1 to 1 of the nitrogen-containing compound (c) represented by the following general formula 1 and / or general formula 2
0.0 parts by weight and the foaming agent (d) are mixed in an extruder,
Density 10-20 obtained by pressing into the low pressure zone
Polypropylene resin extrusion foam board with 0 kg / m ³ . [Chemical 1] [Wherein R 1, R 2, and R 3 are hydrogen atoms, an alkyl group having 1 to 8 carbon atoms, an organic group represented by —Y—X (wherein Y is an alkylene group having 1 to 6 carbon atoms, a phenyl group, A cycloalkylene group, X is selected from an epoxy group, a carboxyl group, a hydroxyl group, an amino group, a phenyl group) and a phenyl group,
They may be different from each other] [Wherein R 4, R 5, and R 6 are hydrogen atoms, an alkyl group having 1 to 8 carbon atoms, an organic group represented by —Y—X (wherein Y is an alkylene group having 1 to 6 carbon atoms, a phenyl group, A cycloalkylene group, X is selected from an epoxy group, a carboxyl group, a hydroxyl group, an amino group, a phenyl group) and a phenyl group,
They may be different from each other] 2. The polypropylene resin extruded foam board according to claim 1, wherein the nitrogen-containing compound (c) is isocyanuric acid and / or bis (2-carboxyethyl) isocyanurate.