JPH0446965A - Flame-retardant composition - Google Patents

Abstract

PURPOSE:To obtain an excellent flame retardancy especially when catching fire and to reduce the quantity of both harmful gas to be generated and ash to be produced when incinerated to a very small amount or nil by mixing a thermoplastic polymer with a specified compound, e.g. guanidinoacetic acid. CONSTITUTION:This composition contains a thermoplastic polymer (A) and a compound (B) of formula 1 (wherein X is NH or O) in an amount of about 1-50wt.% based on component A. Examples of component B include guanidinoacetic acid, glycosamine, N-amidinoglycine, guanidoacetic acid, etc., when X is NH, and hydantoic acid, ureidoacetic acid, carbamylglycine, etc., when X is O.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is flame retardant yet can be easily incinerated, does not generate harmful gases even when incinerated, and generates extremely little ash. This non-ash flame retardant composition is particularly suitable for use in places where radioactive materials are handled.

(Prior Art) Traditionally, methods for making molded products made of flammable synthetic resins such as polyolefin resins flame retardant have been made using halogen compounds as flame retardants and antimony trioxide as flame retardant aids. A method of blending in combination with hydroxide, a method of blending a water-containing compound such as aluminum hydroxide, magnesium carbonate, etc. are well known. In addition, in order to prevent the generation of harmful gases during combustion, for example, flame-retardant products are made by blending organopolysiloxane and organometallic compounds without blending chlorine-based additives with flammable non-chlorine-based polymers. A composition has also been proposed (see Japanese Patent Publication No. 63-65710).

(Problems to be Solved by the Invention) However, among the above-mentioned conventional technologies, those in which a flammable synthetic resin is blended with a halogen-based compound and antimony trioxide produce harmful substances containing halogens when incinerated after use. This generates a lot of gas, causing pollution, hastening damage to the incinerator, and requires a large amount of money to dispose of the large amount of ash. On the other hand, in the case of the prior art described in Japanese Patent Publication No. 63-65710, even though no harmful gas is generated during incineration, a large amount of ash remains due to the incineration due to organopolysiloxane, organometallic compounds, and the like.

In particular, in places where radioactive materials are handled, such as nuclear power plants and radioactive material laboratories, radioactive materials tend to adhere to floors, walls, ceilings, partitions, etc., and this has a negative impact on the human body, so these must be removed regularly. Therefore, these floors, walls, ceilings, partitions, etc. are covered in advance with films or sheets.

Then, after a certain period of time, it is removed and replaced with a new film, and the old film is incinerated. However, the greater the ash content, the greater the equipment and costs required for its treatment. Therefore, coating films and sheets used especially in such places are required to have a low ash content after incineration.

The present inventor conducted intensive research in view of the conventional technology such as Ugegami, and found that a composition containing a thermoplastic polymer and some specific compounds described below, such as guanidine acetic acid, has flame retardancy. The present invention was completed based on the discovery that the present invention does not cause any problems even when the fuel is present and burned.

(Means for Solving the Problems) The present invention comprises a thermoplastic polymer and a thermoplastic polymer having a general formula of H, N-C-N.
The gist of the invention is a flame-retardant composition characterized by comprising a compound represented by HCH, C0OH I (in the formula, X represents an NH group or an O group).

In the present invention, the term "flame retardant" is used to include those exhibiting self-extinguishing properties.

Thermoplastic polymers used in the present invention include polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polypropylene, polystyrene,
Polymethyl methacrylate, thermoplastic resins such as polyamide, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-ethylene-isoprene-styrene block copolymer, styrene-
Examples include synthetic rubbers such as ethylene-butylene-styrene block copolymer, polyurethane rubber, polyester rubber, styrene-butadiene rubber, nitrile rubber, polybutadiene, polyisobutylene, and polyisoprene.

In the present invention, the flame retardant composition is formed from at least the above thermoplastic polymer and the compound represented by the above general formula, with the latter functioning as a flame retardant.

As for the compound represented by the general formula H2N-(, -NHCH,C0OH (in the formula, X represents an NH group or an O group), specifically, when X is an NH group, guanidoacetic acid, glycocyamine , N-amidinoglycine, guanidoacetic acid, etc., and when X is an O group, hydantoic acid,
Examples include golicoluric acid, ureidoacetic acid, carbamylglycine, etc., and one or more of these may be used in combination.

In the composition of the present invention, the compound represented by the above general formula is used in an amount of 1 to 50% by weight, preferably 5 to 20% by weight, and less than 1% by weight, based on the thermoplastic polymer. In this case, it is difficult to obtain the desired flame retardant effect, and if it exceeds 50%, the physical properties of the molded article may deteriorate or the moldability may deteriorate.

In the present invention, the method of blending the compound represented by the above general formula into a thermoplastic polymer is to add crystals of the above compound or powder obtained by pulverizing the crystals of the compound to powder, chips, or pellets of the thermoplastic polymer. After adding and mixing, this is used as a raw material and molded using a prescribed molding method. - First, this mixture is heated and extruded into a strand or sheet shape, and then this is cut with a cutter or dicer. Pellets or chips and pears,
This can be used as a raw material and molded using a predetermined molding method, or the pellets or chips obtained in this way can be used as a master hatch, mixed with other general thermoplastic resins, etc., and molded using a predetermined molding method. Examples include a method to do so.

When molding a molded article using the thus obtained flame retardant composition of the present invention, the molding temperature is preferably lower than the melting point or decomposition point of the compound, and when molded at a temperature higher than the melting point, The thermoplastic polymer decomposes and aggregates, making it impossible to obtain the desired physical properties such as flame retardancy and strength.

Molding methods for molding a molded article using the flame retardant composition of the present invention include extrusion molding, injection molding, compression molding, blow molding, and foam molding, in which raw materials are heated and melted. In addition to the molding method, there are also methods for dissolving or dispersing a thermoplastic polymer and the above compound in an organic solvent, or dissolving the above compound in an emulsion of thermoplastic resin, etc. on the surface of a thermoplastic resin molded product, etc. It is also possible to adopt a method such as coating.

It is optional to add softeners, fillers, pigments, antioxidants, ultraviolet absorbers, etc. to the flame retardant composition of the present invention, if necessary.

Further, halogenated flame retardants such as chlorinated paraffin, chlorinated polyethylene, and bromine compounds can also be used in small amounts within a range that does not impede the expected effects of the present invention. Heat theory: Using halogen-based flame retardants will generate harmful gases, but
There is no problem as long as the amount of harmful gas generated is extremely small.

(Function) The flame retardant composition of the present invention comprises a thermoplastic polymer and a general formula of H,N-C-NHCI (, COOH (wherein, X represents an NH group or 0 group). Since it contains a compound, when it is burned,
The presence of the specific compound represented by the above general formula provides an extinguishing effect at the initial stage of combustion (particularly at the time of ignition) and imparts flame retardancy.

On the other hand, in the case of incineration after use, although it shows a flame retardant effect at the initial stage when it is ignited in the incinerator, it continues to receive strong firepower in the incinerator, and as combustion progresses, the above-mentioned general The compound represented by the formula ultimately decomposes into carbon dioxide gas, nitrogen gas, and water, and all of it scatters, so it loses flame retardancy and is burned due to the inherent flammability of thermoplastic polymers. and leaves almost no residue.

(Example) Examples of the present invention will be described in detail below.

External link ↓ Mix 20% by weight of guanidinoacetic acid crystals with 100 meshes of powder of ethylene-vinyl acetate copolymer (vinyl acetate content: 20%), and apply this to the surface of a 12μ thick polyester film. It was sprayed at a rate of 200 g/rrf on
Melt the vinyl acetate copolymer and immediately apply a layer of 2.
A 5μ low density polyethylene film was pressed using a pressure roll.

Next, this sheet was cut into test pieces with a diameter of 15 mm and a length of 100 m1, which were hung vertically and ignited, and immediately extinguished when removed from the flame, demonstrating self-extinguishing properties.

This is Elle! LL Example 1 except that guanidinoacetic acid crystals were not mixed.
A test piece was prepared in the same manner as above and a combustion test was conducted, and it continued to burn until the end.

1 application 1- Ethylene-vinyl acetate copolymer (vinyl acetate content 10
%) of pellets, hydantoic acid crystalline powder 1
0% by weight was mixed and kneaded with two rolls heated to 120°C to form a sheet, which was then sandwiched between two mirror-finished stainless steel plates, and then placed in a heated press at 120°C to form a sheet. A film with a thickness of 100 μm was obtained, and this was used as a test piece in the same manner as in Example 1.

Next, this test piece was hung vertically and ignited, and when removed from the flame, it immediately went out, indicating self-extinguishing properties.

Example 2 except that hydantoic acid crystals were not mixed.
A test piece was prepared in the same manner as above and a combustion test was conducted, and it continued to burn until the end.

(Effects of the Invention) The present invention provides a thermoplastic resin containing a thermoplastic resin and a compound in which the general two is H,N-(, -NHCHtCOOH (in the formula, X represents an NH group or a 0 group). Therefore, if you burn this,
It has a great flame retardant effect especially when ignited.

In addition, during incineration, only a small amount of harmful gas is generated, or no harmful gas is generated, there is no damage to the incinerator, and large amounts of flame retardants that leave ash content, which are conventionally used, are not used, so ash content is not generated. The amount is extremely small and processing is very easy.

As a result, floors, walls, especially in areas where radioactive materials are handled,
If used for surface coating films such as ceilings, partitions, shoe dust removal mats, packaging materials, containers, etc., the ash content is very low and disposal is easy when incinerated after use.

Claims (1)

[Claims] 1. Consisting of a thermoplastic polymer and a compound whose general formula is represented by ▲A mathematical formula, a chemical formula, a table, etc.▼ (wherein, X represents an NH group or an O group) A flame retardant composition characterized by: