GB2029419A - Fire-retardant Putty-like Compositions Comprising a Polymer and Metal Oxide - Google Patents

Abstract

A composition, for filling the spaces in bores, penetrating walls and floors of buildings and having electric wires and cables extending therethrough or for filling the clearances at the joints of interior finishing materials of buildings, comprises by weight (a) 100 parts of a curable polychloroprene in a liquid state at 25 DEG C (b) 200 to 700 parts of a hydrated metallic oxide or hydroxide (e.g. hydrated alumina or magnesia), and (c) 20 to 100 parts of a heat- resistant fibrous material (e.g. glass, asbestos, carbon, phenolic resin, polyimide or polyamide-imide fibres). The components (b) and (c) together comprise at least 250 parts per 100 parts of the component (a). The composition will not soften, sag or drip in molten drops even when subjected to the high-temperature conditions of a fire, and gives a tough residual product retaining the original shape when burned and ashed, effectively preventing the spread of fire and assuring outstanding smoketightness.

Description

SPECIFICATION Fire-Retardant Putty-Like Compositions Comprising a Polymer and Metal Oxide This invention relates to fire-retardant putty-like compositions for filling the spaces in bores penetrating walls and floors of buildings and having electric wires and cables extending therethrough or for filling the clearances at the joints of interior finishing materials of buildings.

Various fire-retardant putty-like compositions of this type have heretofore been proposed. These compositions must have such properties that when a fire breaks out in a section of a building, the composition, exposed to a high temperature in the initial stage of the fire, will not sag due to softening and deformation per se or fall in molten drops, without permitting flames and smoke to spread to an adjacent section through a space which would otherwise be formed. Additionally, the putty-like composition must remain in shape free of large deformation or dripping even if heat and wind pressure build up in the fire section due to fierce flames and heavy smoke amidst of the fire.It is further desired that even when the composition has been burned out, carbonized and eventually ashed, the residual ashed product has toughness without bcoming brittle and falling, thus completely preventing the spread of fire to the adjacent section to minimize the damage.

Published Unexamined Japanese Patent Application 122895/1977 discloses a composition containing soybean oil as a binder and consisting mainly of an inorganic filler such as hydrated alumina and an inorganic fiber such as asbestos. The composition softens and deforms with a rise in temperature in the event of a fire, is not satisfactory in non-sagging properties and fails to fully prevent the spread of fire. Published Unexamined Japanese Patent Applications 341 50/1 978 and 125552/1977 disclose compositions containing liquid chloroprene as a binder and consisting predominently of an inorganic filler such as hydrated alumina, and glass fiber or like inorganic fiber of an organic fiber.Although having good non-sagging or non-dripping properties, the compositions burn when subjscted to a fierce fire involving a heavy smoke and high wind pressure, giving a brittle ash residue which cracks and progressively breaks down into falling fragments to form a hole where the composition has been applied. Thus the compositions are unable to completely prevent the spread of fire.

While the putty-like compositions of this invention comprise known materials which are individually employed in the prior art references mentioned above, the materials are used in specified combination in specific proportions as will be described later, so that the present compositions exhibit outstanding performance, have excellent non-sagging and non-dripping properties under the severe conditions of fires and retain the original shape, or a shape near to the original even when burned to an ashed state because the ash residue has exceedingly high toughness which has never been afforded by the conventional putty-like compositions. The present compositions assure outstanding smoketightness and effectively prevent the spread of fire. The compositions are also easy to handle, especially for filling spaces.

The main object of the present invention is to overcome the foregoing drawbacks of the conventional compositions and to provide novel putty-like compositions which have suitable plasticity, and airtightness for filling various spaces, joint clearances, etc. in buildings and which retain nonsagging and non-dripping properties even when subjected to severe conditions in the event of a fire, the present composition, when burned and ashed, giving a residual product having high toughness and retaining the original shape or a shape near to the original.

The fire-retardant putty-like compositions of this invention comprise (a) 100 parts by weight of a curable polychloroprene in a liquid state at room temperature (25 C), (b) 200 to 700 parts by weight of a hydrated metallic oxide or hydroxide, and (c) 20 to 100 parts by weight of a heat-resistant (to 2500C) fibrous material, the compositions containing the hydrated metallic oxide or hydroxide (b) and the heat-resistant fibrous material (c) in a combined amount of at least 250 parts by weight per 100 parts by weight of the polychloroprene (a).

The polychloroprene in a liquid state at room temperature which is used as component (a) of the compositions of the invention is used as a binder, and is curable at room temperature (250C) or higher temperature.

Examples of such polychloroprenes are (i) chloroprene homopolymer, (ii) copolymers of chloroprene and at least one monomer which is copolymerizable with-chloroprene, including vinyl compounds such as styrene, methacrylic acid, methyl methacrylate or acrylonitrile and conjugated dienes such as 1,3-butadiene, isoprene or 2,3-dichloro-1 ,3-butadiene and (iii) chloroprene-sulfur copolymers, the amount of the comonomer being up to 100 parts by weight, preferably 5 to 40 parts, per 100 parts by weight of the chloroprene. Exemplary of useful end groups of these polychloroprenes are an active halogen group, hydroxyl group, carboxyl group, thiol group, alkylxanthate group, or like groups being able to cause a condensation or addition reaction.

The liquid polychloroprenes used in the present invention are usually used together with a curing agent described below. although the agent is not necessarily needed in the case where such a polychloroprene, for example, those having alkylxanthate end groups or carboxyl end groups is used which is curable at high temperatures without the curing agent.Examples of useful curing agents are lead peroxide and like metallic peroxides; tolylenediisocyanate and like diisocyanates; tetraethylenepentamine, aminoethylpiperadine, 4-aminomethylpiperidine, N-aminopropylpipecolin, N,N-dimethylpropane-1 ,3-diamine, methyliminobis-propylamine, ketimine, methacrylate-amine adduct, epoxy-amine adduct and like amines; t-butylhydro peroxide, 2,4-dichlorodibenzoyl peroxide, dicumyl peroxide and like organic peroxides; zinc oxide, magnesium oxide, lead monoxide, red lead and like metallic oxides; sulfur; n-butylaldehydeaniiine and like aldehydeamines;N,N'-diphenylthiourea, N,N'-diethylthiourea and like thioureas; di-orthotolylguanidine, di-orthotolylguanidine salt of dicatechol borate and like guanidines; sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate and like dithiocarbamates; and zinc butylxanthate and like xanthates. One or, if necessary, two or more suitable curing agents selected from the above are used according to the end group of the polychloroprene.

The curing agents are used in an amount about 0.5 to about 20 parts by weight per 100 parts by weight of the liquid polychloroprene.

Preferable among the liquid polychloroprenes exemplified above are those having a viscosity of 5,000 to 500,000 cps, especially about 10,000 to about 300,000 cps, at room temperature (250C).

With respect to the end group, preferable are those having an alkylxanthate group in which the alkyl portion has 2 to about 10 carbon atoms, such as ethyl, propyl or butyl. It is also desirable to use those having a hydroxyl end group conjointly with a diisocyanate such as tolylenediisocyanate serving as a curing agent. It is more desirable to use a liquid polychloroprene having at least one kind of the alkylxanthate end groups as admixed with a liquid polychloroprene having at least one hydroxyl end group in an amount of up to about 100 parts by weight per 100 parts by weight of the former.

According to this invention, the liquid polychloroprenes given above are usable, with or without any of the curing agents mentioned above when so desired. Preferable polychloroprenes are those having curing properties as determined by the following test method.

Test method: 100 parts by weight of the component (a) is admixed with 400 parts by weight of Al203.3H20 (mean particle size: 3.5,us) and 30 parts by weight of glass fiber (mean diameter: 1 3 pm, mean length; 6 mm) and the mixture is kneaded into a putty-like composition, which is then heated at 2500C for 30 minutes. The component (a) is acceptable when the composition, after the heating, is up to about 1, preferably up to about 0.5 in cone penetration value evaluated in accordance with JIS A 5752-1966 (mm/1 50 g, 5 sec, at 200C).

The hydrated metallic oxide or hydroxide of metal serving as the component (b) of the present compositions is in the form of a fire-retardant or nonflammable powder preferably having a mean particle size by number of up to about 100 ,um, preferably up to about 80 ym, and having a heat loss of at least about 8% by weight, most preferably, at least about 20% by weight obtained by the following formula: A-B Heat loss (%)= xl 100 A where A: initial weight of sample B: constant weight of sample after heating at a temperature of 400+20 C.

Examples of useful hydrated metallic oxides are hydrated aluminas, represented by the formula Al203.nH2O (n being 0.5-about 6), such as Al2O2.+H20, Al203.H20, Al203.2H20 and Ai203.3H20(Al(OH)3) and hydrated magnesias such as Mg(OH)2.

It is preferable to use a hydrated metallic oxide comprising at least two portions which differ in particle size, or to conjointly use at least two kinds of hydrated metallic oxides which differ in particle size. Stated more specifically, the component (b) comprises at least two portions one of which has a mean particle size of 10 to 100 ,um, preferably 10 to 80 um, the other portion being up to 10 ,um in mean particle size.

The hydrated metallic oxides serving as the component (b) are used in an amount of 200 to 700 parts by weight, preferably 250 to 450 parts by weight, per 100 parts by weight of the component (a).

With less than 200 parts by weight of the component (b) present, the putty-like composition has greatly increased flowability, is prone to deformation when applied even at room temperature, is liable to soften and drop when subjected to the heat of fires and gives a brittle residue when ashed. With use of more than 700 parts by weight of the component (b), the ingredients (a), (b) and (c) will have reduced compatibility when they are mixed, while the resulting composition is not satisfactorily applicable to spaces, bores or the like and affords low airtightness even at room temperature if filled in place.

When the component (b) comprises at least two portions of different particle sizes, the portion up to 10 ,um in mean particle size is used in an amount of 10 to 500 parts by weight per 100 parts by weight of the other portion with a mean particle size of 10 to 100,us.

According to this invention it is advantageous to use the component (b) in combination with particles, smaller than 10 ym, of at least one of clay, zinc borate, bentonite, talc, diatomaceous earth, calcium carbonate and mica in an amount of up to 80% by weight, preferably up to 50% by weight, based on the component (b). The composition will then afford a residual product of enhanced toughness when ashed. Among the above-mentioned materials, clay, zinc borate and bentonite are especially advantageous to use.

The heat-resistant fibrous materials useful as the component (c) of the present compositions are inorganic fibers, and organic polymeric fibers which preferably will not thermally deform at temperatures of lower than about 2500C. Such fibers are up to about 100 ym, preferably 0.5 to 50 ym, in mean diameter (by number) and up to about 30 mm, preferably about 1 to about 20 mm, in mean length (by number).

Examples of useful inorganic fibers are glass fiber, asbestos fiber, carbon fiber, etc. Examples of suitable organic polymeric fibers are phenolic resin fibers, polyimide fiber, polyamide-imide fiber, etc.

Among these fibers, glass fiber and asbestos fiber are preferable. A mixture of glass fiber and asbestos fiber is more preferable.

The heat-resistant fibers serving as the component (c) are used in an amount of20 to 100 parts by weight, preferably 20 to 60 parts by weight, per 100 parts by weight of the component (a). With less than 20 parts by weight of the component (c), the putty-like composition, when exposed to the high temperature of a fire, is liable to soften and sag, and also fails to give a tough ashed product. If used in an amount of more than 100 parts by weight, the component (c) will be less compatible with the other ingredients when formulated into a putty-like composition, while the composition is not satisfactorily applicable and provides impaired airtightness at room temperature if used.

When the heat-resistant fibrous material (c) comprises a mixture of glass fiber and asbestos fiber, it is suitable to use 10 to 300 parts by weight of asbestos fiber per 100 parts by weight of glass fiber.

As described above the fire-retardant putty-like compositions of the present invention consist essentially of 100 parts by weight of the component (a), about 200 to about 700 parts by weight of the component (b) and about 20 to about 100 parts by weight of the component (c). It is also critical that the compositions contain the component (b) and the component (c) in a combined amount of at least about 250 parts by weight per 100 parts by weight of the component (a). If the combined amount of the components (b) and (c) is less than about 250 parts by weight, the composition is unable to exhibit high fire retardancy and non-sagging and non-dripping properties in the event of a fire and to yield a tough ashed product.

The fire-retardant putty-like compositions of this invention, when comprising the components (a), (b) and (c) in the proportions specified above, have outstanding fire retardancy, will not sag or drip even if exposed to a high temperature and high wind pressure due to the intense flame and smoke of fires but rather gain hardness with the lapse of time, and afford a tough ashed product if burned and ashed.

The present compositions are therefore exceedingly superior to any of the conventional puttylike compositions in assuring high smoketightness and. preventing the spread of fire. Such remarkable effects are not achievable if any one of the components (a), (b) and (c) is used in a proportion outside the specified range.

The present compositions, which consist essentially of the components (a), (b) and (c), may further incorporate flame retardants, plasticizers, and silane coupling agents or titanate coupling agents, such as given below: when so desired.

Flame Retardants: Suitable flame retardants are those heretofore known for use with rubbers and plastics. Examples are: (i) inorganic flame retardants such as antimony trioxide, antimony oxide, molybdenum trioxide, ammonium polyphosphate, zirconium oxide, etc., and (ii) organic flame retardants such as chlorinated paraffin, decabromodiphenyl ether and like halogen-containing organic compounds, tris(aziridinyl)phosphine oxide, phosphonyl amide and like phosphorus-containing organic compounds, bromo cresyl phosphate, tetrakis(hydroxymethyl)phosphonium chloride and like phosphorus- and halogen- containing organic compounds, etc.

These flame retardants are useful for imparting improved flame retardancy to the putty-like composition during the rise of temperature in the initial stage of a fire. The above-mentioned flame retardants are used in an amount of up to about 100 parts by weight per 100 parts by weight of the component (a).

Plasticizers: Plasticizers usually used for polyvinylchloride are usable Examples are diisobutyl phthalate, dioctyl phthalate and like phthalic acid derivatives, diisooctyl sebacate and like sebacic acid derivatives, tricresyl phosphate and like phosphoric acid derivatives. Other examples are process oil, linseed oil, soybean oil and like oils, liquid urethane resin, liquid epoxy resin, liquid polybutene resins and like liquid synthetic resins.

Use of such plasticizers renders the resulting composition easily applicable. When the composition is used, for example, for filling the space in a bore around a cable extending through the bore and sheathed as with polyvinylchloride, the plasticizer in the sheath can be held in equilibrium with the plasticizer in the composition at room temperature and prevented from migrating into the composition. This inhibits the hardening of the cable sheath, and hence is desirable. The plasticizers nevertheless tend to impair the non-sagging or non-dripping properties of the composition at high temperatures, so that it is preferable to use the plasticizers in an amount of only up to 50 parts by weight, more preferably up to 30 parts by weight, per 100 parts by weight of the component (a).

Silane Coupling Agents: Useful silane coupling agents are those represented by the formula Y(CnH2n)SlX3 wherein n is zero or an integer of 1 to 6, X is chlorine, alkoxy or acetoxy, and Y is chlorine, vinyl, methacryloxy, cyclic epoxy, glycidoxy, mercapto, amino, diamino or ureido, the organic groups exemplary 6f X and Y having about 2 to about 30 carbon atoms;Examples of such silane coupling agents are y-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyl-tris(p-methoxyethoxy)silane, y- methacryloxypropyltrimethoxysilane, p-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, y- glycidoxypropyltrimethoxysilane, y-mercaptopropyltrimethoxysilane, y-a minopropyltriethoxysilane, N p-(aminoethyl)-p-a minopropyltrimethoxysilane, y-ureidopropyltriethoxysilane, etc.

Titanate Coupling Agents: Useful titanate coupling agents are represented by one of the following formulae: (RO) ,--Tii--((--O--X-R2-Y),

wherein RO is C16 alkoxy, n is an integer of 1 or 4, m is an integer of 2 or 3, X is carboxyl, phenyl, ethylene, phosphate, pyrophosphate, phosphite or sulfonyl, R2 is C1--20 alkyl, and Y is hydrogen; allyl, vinyl or amino-imino. Examples are isopropyltriisostearoyltitanate, diisostearoyl ethylene titanate, titanium diacrylate oxyacetate, etc.

The silane coupling agents or titanate coupling agents give the component (b) or (c) improved affinity for the component (a) and are effective for preparing suitable putty-like compositions. Up to 30 parts by weight, preferably 2 to 10 parts by weight, of such agents are used per 100 parts by weight of the component (a).

Also, the components (a), (b) and (c) can be used conjointly with antioxidants, pigments, carbon black, stabilizers, etc which are usually used for rubbers and plastics. Suitably these additives are used in an amount of up to about 20 parts by weight per 100 parts by weight of the component (a).

The fire-retardant putty-like compositions of this invention initially have a plasticity such as to have a cone penetration value (mm/1 50 g, 5 sec, at 200C) of about 2 to about 40, preferably 4 to about 15, as determined according to JIS A 5752-1966. When having a cone penetration value within the abovementioned range, the putty-like compositions have suitable softness of filling various spaces, joint clearances, etc.

The fire-retardant putty-like compositions of the invention can be prepared by mixing the foregoing ingredients with rolls usually used for mixing rubbers and plastics. To effect dispersion of the ingredients, especially the heat-resistant fiber, namely the component (c), in the composition with improved uniformity, the ingredients are preferably mixed together while being subjected to high-shear friction with use of a kneader or the like.

The features of the fire-retardant putty-like compositions of this invention will be described below in greater detail with reference to examples.

Examples 1-13 and Comparison Examples 1-6 The compositions listed in Table 1 were prepared with use of 2-liter experimental kneader and tested for mixing workability, airtightness at room temperature, fire retardancy, shape retentivity against heat and toughness of ashed product by the methods to be described later. The properties of the compositions were evaluated according to the criteria given below. The results are shown in Table 2. The compositions of Examples 1 and 4, and Comparison Example 3 were filled in simulated cable bores and subjected to a flame test under conditions similar to an actual fire as will be described below to observe the burning process of the compositions. Table 3 shows the results.

The above properties were determined by the following test methods and evaluated according to the criteria given below.

Mixing Workability The ingredients of each composition in specified amounts were placed into a 2-liter test kneader equipped with agitator blades and mixed together at room temperature to 800C for 40 minutes. The resulting mixture was observed with the unaided eye and touched with fingertips to evaluate the homogeneity thereof according to the three criteria of: excellent, good and poor.

Airtightness An iron pipe, 300 mm in inside diameter and 600 mm in length, was filled at its one end with the composition to a thickness of 100 mm. While exposing the outer surface of the composition layer to the atmospheric pressure at 800 C, air was forced into the pipe from the other end at pressure of 0.8 kg/cm2 gauge for 5 minutes. If the leakage of air through the composition layer was not larger than 5 liters/min, the composition was evaluated as acceptable.

Fire Retardancy The oxygen index of the composition was determined in accordance with JIS K 7201-1976 to evaluate the fire retardancy based on the following criteria: Not smaller than 80 in oxygen index excellent 60 to less than 80 in oxygen index good Less than 60 in oxygen index poor Shape retentivity against heat: The composition was shaped into a pillar, 3 cmx3 cmx7 cm, which was then allowed to stand in its upright position within an oven at 2500C for 30 minutes and thereafter withdrawn from the oven.

The resulting variation in the height of the pillar was measured to evaluate the shape retentivity based on the variation and according to the following criteria: Less than 5% in variation excellent 5% to less than 10% in variation good Not less than 10% in variation, or overturned or cracked pillar poor Toughness of Ashed Product: The composition was shaped into a cube, 3 cmx3 cmx3 cm, which was then heated in an electric furnace at 1 ,0000C for 3 hours to a completely ashed state, thereafter withdrawn and allowed to cool.The ashed residue was checked for appearance and touched with fingertips to evaluate the toughness according to the following criteria: Uncollapsible with a strong pressing touch excellent Slightly collapsible with a strong pressing touch good Easily collapsible with a light touch poor Flame test The following flame test was conducted for the putty-like compositions of Examples 1 and 4, and Comparison Example 3 with use of bore penetrating cables simulating those in actual buildings to observe the burning process of the compositions as applied to the penetrating cable portions.

A rectangular bore, 45 cmx 12 cm, was formed in the center of a concrete board 1 m x 1 m x 0 cm. Ten 600 V polyvinylchloride-sheathed polyvinylchloride-insulated cables, 34 mm in sheath outside diameter and 1.6 m in length, were passed through the bore arranged side by side at right angles to the concrete board, with equal lengths of the cables projecting from opposite sides of the board. One of the above-mentioned compositions was filled in the space within the bore around the cables to prepare a specimen. The lower side only of the specimen including the cable portions projecting therefrom was assembled into a vertical heating furnace measuring 1 mxl mix 1.5 m and was sealed off. The interior of the furnace was heated with propane gas with its flame in direct contact with the bored portion of the concrete board on its lower side.The specimen was heated for 2 hours in conformity with the heating curve (room temperature to 1,01 00C, max.) provided in JIS A 1304-1975 and approximately representing the rise of temperature in actual fires. The same procedure as above was repeated with use of the other two compositions. The results are given in Table 3.

Table 1 Examples Nos. Comparison Examples Nos.

Material 1 2 3 4 5 6 7 8 9 10 11 12 13 1 2 3 4 5 6 Polychloroprene1 100 70 50 100 100 100 - 70 80 100 - 100 100 100 100 100 - 100 Polychloroprene2 - 30 50 - - - 100 30 - - 100 - - - - - 100 - 100 Polychloroprene3 - - - - - - - - 20 - - - - - - - - - Zinc oxide - - - - - - 10 - - - 10 - - - - - 10 - Tolylenediisocyanate - - - - - - 3 - - - 3 - - - - - 3 - Aluminium hydroxide 60 m* 50 100 100 100 100 100 100 100 100 - 30 - - 50 200 100 100 50 100 Aluminium bydroxide 25 m* 50 150 150 150 100 150 150 200 100 - - - - - 300 100 150 100 150 Aluminium hydroxide 35 m* 100 150 - - 100 - 150 200 100 300 - - - 130 300 100 50 50 150 Aluminium hydroxide 10 m* 100 - - - - - - - - - - - - - - 100 - - Magnesium hydroxide 10 m* - - - - - 150 - - - - - 300 250 - - - - - Clay 30 m* - - 150 - - - - - - - - - 100 - - - - - Zinc borate 30 m* - - - 150 - - - - - - - - - - - - - - Bentonite 10 m* - - - - 30 - - - - - - - - - - - - - Glass fiber4 30 20 15 30 30 30 30 20 30 30 60 30 30 30 30 5 15 15 30 Asbestos fiber5 - 10 10 10 10 10 10 - - - - - - 10 - 5 - 5 10 Phenolic filber6 - - - - - - - - 10 - - - - - - - - - Dioctylphthalate - 30 30 30 - 30 - 30 - - - - - - 30 - - - 30 Antlmony trioxide - 10 - - - 10 - - 10 - - - - - - - - - Chlorinated paraffin7 - - - - - - - - 30 - - - - - - - - - γ-Chloropropyltrimethoxysilane - - 10 - - 10 - 10 - - - - - - - - - - Notes for Table 1 1, Viscosity at 25 C; 100,000 c.p.s., End group; Alkylxanthate group 2, Viscosity at 25 C; 57,000 c.p.s., End group; Hydroxyl group 3, Viscosity at 25 C; 300,000 c.p.s., End group; Carboxyl group 4, Diameter; 13 m, Length; 6 mm 5, Diameter; 0.07 m, Length; 13 mm 6, diameter; 14 m, Length; 6 mm 7, Chlorine Content; 70 w% *, Mena particle size Table 2 Examples No. Comparison Examples No.

1 2 3 4 5 6 7 8 9 10 11 12 13 1 2 3 4 5 6 Mixing Workability: E E E E E E E G E E G G G G P E E G E Airtightness: A A A A A A A A A A A A A U U A A U A Fire retardancy: E E E E E E E E E E E E E P E E E G E Shape retentivity against heat: E E E E E E E E E G E G E P P P G P P Toughness of ashed product: E E E E E E E E E G G G E P P P P P P E: Excellent, G:Good, P:Poor, A:Acceptable, U:Unacceptable, Table 3 Burning process Examples 1 and 4 No smoke leaked through the bore to the upper side of the specimen outside the furnace even two hours after the start of heating. The cable sheaths on the upper side remained free of burning although slightly thermally expanded. No portion of the composition in the bore-dropped.Inside the furnace, the composition was found to have been ashed as held in place without falling, and maintaining the original shape thus very effectively preventing the spread of fire.

Comp. Ex. 3 One hour after the start of heating, the composition burned and ashed on the inner side of the furnace, began to release part of the ashed product. Ashed portions thereafter dropped in an increasing amount, permitting marked outflow of smoke through the bore to the upper side. The cable sheaths burned in the vicinity of the bore on the upper side of the specimen outside the furnace.

As will be apparent from the above examples, the fire-retardant putty-like compositions of this invention can be prepared with good mixing workability, are usable with extreme ease because of suitable softness, retain high airtightness at room temperature, will not soften, sag or drop unlike conventional compositions even when exposed to the high temperature of a fire, and give a hard, compact and tough residue even if ashed to very effectively prevent the spread of fire.

Of these outstanding properties, the present compositions are distinct from the conventional compositions in that they will not become softened ahd they form a tough residue when burned and ashed. Thus these are excellent features of the compositions.

Claims (16)

Claims

1. A fire-retardant putty-like composition comprising (a) 100 parts by weight of a curable homo or copolymer of chloroprene in a liquid state at room temperature, (b) 200 to 700 Farts by weight of a hydrated metallic oxide or hydroxide, and (c) 20 to 100 parts by weight of a fibrous material which is heat-resistant, the composition containing the hydrated metallic oxide or hydroxide (b) and the heatresistant fibrous material (c) in a combined amount of at least 250 parts by weight per 100 parts by weight of the polychloroprene (a).

2. A composition as claimed in Claim 1 wherein the hydrated metallic oxide (b) is a hydrated alumina.

3. A composition as claimed in Claim 1, wherein the hydrated metallic oxide (b) is a hydrated magnesia.

4. A composition as claimed in Claim 2, wherein the hydrated alumina comprises 100 parts by weight of a portion 10 to 100 ym in mean particle size by number and 10 to 500 parts by weight of another portion less than 10 ,:::m in mean particle size.

5. A composition as claimed in any one of Claims 1 to 4, wherein the heat-resistant fibrous material (c) comprises glass fibers and/or asbestos fibers.

6. A composition as claimed in Claim 5, wherein the heat-resistant fibrous material (c) comprises glass fiber and asbestos fiber in an amount of 10 to 30 parts by weight of asbestos fiber per 100 parts by weight of the glass fiber.

7. A composition as claimed in any of Claims 1 to 6, wherein the liquid polychloroprene (a) has a viscosity of 5,000 to 500,000 centipoises at 250C and an alkylxanthate end group in which the alkyl portion has 2 to 10 carbon atoms.

8. A composition as claimed in any one of Claims 1 to 6, wherein the liquid polychloroprene (a) has a viscosity of 5,000 to 500,000 centipoises at 250C and comprises a mixture of a polychloroprene having an alkylxanthate end group in which the alkyl portion has 2 to 10 carbon atoms and a polychloroprene having a hydroxyl end group.

9. A composition as claimed in any one of Claims 1 to 6, wherein the liquid polychloroprene (a) has a viscosity of 5,000 to 500,000 centipoises at 250C and a hydroxyl end group and contains 0.5 to 20 parts by weight of a curing agent per 100 parts by weight of the polychloroprene.

10. A composition as claimed in any preceding claim, further comprising at least one material less than 10 u, in mean particle size and selected from clay, zinc borate, bentonite, talc, diatomaceous earth, calcium carbonate and mica, in an amount of up to 80% by weight of the component (b).

11. A composition as claimed in any preceding claim, further comprises up to 1 00 parts by weight of a flame retardant per 100 parts by weight of the component (a).

12. A composition as claimed in any preceding claim, further comprising up to 50 parts by weight of a plasticizer per 100 parts by weight of the component (a).

13. A composition as claimed in any preceding claim, further comprising up to 30 parts by weight of a silane coupling agent or a titanate coupling agent per 100 parts by weight of the component (a).

14. A composition as claimed in any preceding claim, which has a plasticity such that it has cone penetration value (mm/1 50 g, 5 sec, at 200 C) of 2 to 40 as determined according to JIS A 5752/1966.

1 5. A composition as claimed in any preceding claim, wherein the heat-resistant fibrous material (c) does not become thermally deformed at temperatures of up to 2500C.

16. A composition as claimed in any preceding claim, wherein the fibres of the material (c) are up to 100 microns in mean diameter (by number) and up to 30 millimetres in mean length (by number).

1 7. A fire-retardant composition as claimed in Claim 1, substantially as hereinbefore described with reference to any of Example Nos. 1 to 12.