JP2886244B2 - Flame retardant resin composition for foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention has excellent flame retardancy, has a small decrease in mechanical properties, and generates harmful halogen gas even during combustion. The present invention relates to a flame-retardant resin composition for a foam which does not have any.

(Prior Art) In order to make a resin foam based on an olefin resin flame-retardant, an inorganic compound is blended as a flame retardant.

For example, if a metal hydrate such as magnesium hydroxide is blended, when the foam is heated from the outside, it decomposes at its own temperature and releases water of crystallization, lowering the temperature. Flame retardancy is imparted to the foam. Moreover, such a foam does not generate toxic halogen-based gas even during combustion.

(Problems to be Solved by the Invention) In order to impart high flame retardancy to a resin foam using only metal hydrate, it is necessary to mix a large amount of metal hydrate with the base resin.

However, it is very difficult to foam a resin containing a large amount of metal hydrate under normal pressure, and a vacuum foaming treatment is required as it is. Therefore, when foaming is performed under normal pressure, the amount of the metal hydrate must be limited. As a result, the flame retardancy of the foam cannot be sufficiently increased. In addition, when magnesium hydroxide is used in a large amount as a metal hydrate, in addition to the problem that foaming under normal pressure is difficult as described above, the mechanical strength of the foam, particularly the tear strength, tensile strength and compression There is a problem that the recoverability is greatly reduced.

Therefore, in order to solve such problems and obtain a foam having excellent flame retardancy, it is necessary to mix a halogen-based flame retardant together with a metal hydrate as a flame retardant.

However, in this case, there is a new problem that a toxic halogen gas is generated in the human body when the foam is burned.

Therefore, the present invention solves the above problems, has excellent flame retardancy, has a small decrease in mechanical strength, and does not generate toxic halogen gas during combustion. It is intended to provide a conductive resin composition.

(Means and Actions for Solving the Problems) The flame-retardant resin composition for a foam of the present invention comprises 100 parts by weight of an olefin-based resin, 50 to 200 parts by weight of magnesium hydroxide, and 5 to 100 parts by weight of a phosphorus-containing resin. The composition contains 5 to 50 parts by weight of zinc borate and / or antimony trioxide, 0.5 to 5 parts by weight of a lubricant, a foaming agent and a crosslinking agent.

The olefin resin used in the present invention is a base resin of the composition.

Such olefin resins include, for example, high-pressure or low-pressure polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer or ethylene-α-
Olefin copolymers can be mentioned. These are 2
More than one type can be used in combination.

Magnesium hydroxide is a component for imparting flame retardancy to the foam. This magnesium hydroxide can be used as it is or after surface treatment with an appropriate surface treatment agent to enhance dispersibility.

Examples of such surface treatment agents include fatty acids such as maleic acid, oleic acid, and stearic acid; silane coupling agents such as vinyltrimethoxysilane; and titanate-based coupling agents such as isopropyltriisostearoyl titanate. Can be. Further, these surface treatment agents preferably have an average particle size of 0.5 to 10 μm.

The amount of magnesium hydroxide is 10
It is 50 to 200 parts by weight with respect to 0 parts by weight. This amount
When the amount is less than 50 parts by weight, the flame retardancy of the obtained foam decreases. Also, if it exceeds 200 parts by weight, foaming becomes insufficient,
The expected foam performance cannot be obtained. The preferred amount is
80 to 150 parts by weight.

Zinc nitrate or antimony trioxide is a component for imparting flame retardancy to the foam. These can be used in combination.

The compounding amount of zinc nitrate or antimony trioxide is 5 to 50 parts by weight based on 100 parts by weight of the olefin resin. If the amount is less than 5 parts by weight, the flame retardancy of the foam decreases. On the other hand, if it exceeds 100 parts by weight, the foaming becomes insufficient and the production cost increases. The preferred amount is 10 to 30 parts by weight.

The phosphorus-containing resin is a component for imparting flame retardancy to the foam. Such phosphorus-containing resins include those having phosphorus in the main chain and having self-extinguishing properties, for example, the following formula: (Wherein, R represents a monovalent hydrocarbon group which may be the same or different, and n represents a positive number that does not impair the workability of mixing with other components). Can be mentioned. As a preferable example of the nitrogen-phosphorus resin, R in the above formula is (R ′ represents a monovalent hydrocarbon group.) Polyaryloxyphosphazenes.

The compounding amount of the phosphorus-containing resin is 5 to 100 parts by weight based on 100 parts by weight of the olefin-based resin. If the amount is less than 5 parts by weight, the flame retardancy of the foam decreases. Also, 10
If the amount exceeds 0 parts by weight, the foaming becomes insufficient and the production cost increases. The preferred amount is 10 to 50 parts by weight.

The lubricant used in the present invention is a component for improving the moldability of the resin composition by improving the dispersibility of magnesium hydroxide and zinc nitrate or antimony trioxide in the olefin resin, and further improving the foamability. It is.

Examples of such a lubricant include a fatty acid amide compound such as fatty acid amide S (manufactured by Kao Corporation); CF-9150
(Toray Silicone Co., Ltd.).

The amount of the lubricant is 0.5 to 5 parts by weight based on 100 parts by weight of the olefin resin. If the amount is less than 0.5 part by weight, the dispersibility in olefin-based resins such as magnesium hydroxide is reduced. On the other hand, when the amount exceeds 5 parts by weight, the uniform dispersion of the components is hindered. The preferred amount is 1 to
3 parts by weight.

The foaming agent used in the present invention is not particularly limited as long as it generates gas by being thermally decomposed by heating.

Such blowing agents include, for example, azodicarbonamide, N, N-dinitrosopentamethylenetetramine,
4'-oxybis (benzenesulfo) hydrazide can be mentioned. These can be used in combination of two or more.

The blending amount of the foaming agent can be appropriately set depending on the relationship with the desired expansion ratio of the foam. Usually, the amount is preferably 5 to 50 parts by weight based on 100 parts by weight of the olefin resin.

Examples of the crosslinking agent used in the present invention include di-t-butyl peroxide, dicumyl peroxide, t-butyl peroxycumene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and 2,5-dimethyl. -2,5-di (t-butylperoxy) hexyne-3 or 1,1-di- (t-butylperoxy) -3,3,5-trimethylcyclohexane. These can be used in combination of two or more.

Usually, the compounding amount of the crosslinking agent is preferably 0.3 to 3 parts by weight based on 100 parts by weight of the olefin resin.

The resin composition of the present invention may further contain, if necessary, a crosslinking aid, a coloring agent, an antioxidant, an ultraviolet absorber, and the like, in addition to the above components.

Using the resin composition of the present invention, for example, a foam can be produced by the following method.

First, the components are kneaded at a temperature of about 90 to 120 ° C so as to be uniform. Next, it is formed into a predetermined shape using a press or an extruder at a temperature at which the used foaming agent does not decompose.
Thereafter, the foam can be obtained by heating the molded body under normal pressure by a method such as hot air heating, heating in liquid, or heating above liquid.

(Examples) Examples 1 to 5 and Comparative Examples 1 to 5
It kneaded at ℃, and obtained each resin composition of an example and a comparative example.

Each obtained resin composition, press molding at 120 ℃,
A sheet having a thickness of 2 mm was manufactured. The sheet was put into a 220 ° C. hot air oven to produce a foam.

The density, flame retardancy, tear strength, and the presence or absence of halogen gas generation during combustion of each foam thus obtained were measured. The results are shown in Table 1.

The flame retardancy was evaluated by measuring the oxygen index (OI) of each foam. The tear strength was measured in accordance with JISK-667.

(Effect of the Invention) The resin composition of the present invention has excellent flame retardancy because it contains an inorganic flame retardant and a phosphorus-containing resin as constituent components. Further, since the composition contains the phosphorus-containing resin, a decrease in mechanical strength is small even when a large amount of an inorganic flame retardant is blended without blending a halogen-based flame retardant. Further, since it does not contain a halogen-based flame retardant, no toxic halogen gas is generated during combustion. Therefore, the foam obtained from the resin composition of the present invention has excellent flame retardancy and a small decrease in mechanical strength. Further, the foam does not generate a halogen gas even during combustion.

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mitsunori Okada 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (56) References JP-A-62-43436 (JP, A) JP-A Sho 58-129026 (JP, A) JP-A-2-296841 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08J 9/00-9/42 C08L 23/00-23 / 36

Claims (1)

(57) [Claims] (1) 100 parts by weight of an olefin resin, 50 to 200 parts by weight of magnesium hydroxide, 5 to 100 parts by weight of a phosphorus-containing resin,
A flame-retardant resin composition for a foam, comprising 5 to 50 parts by weight of zinc borate and / or antimony trioxide, 0.5 to 5 parts by weight of a lubricant, a foaming agent and a crosslinking agent.