NO771960L - SMOKE, SOFTENED POLYVINYL CHLORIDE COMPOSITIONS - Google Patents

Description

In the following, low-emission, plasticized polyvinyl halide polymers with 2-30 parts of zinc oxide added as a smoke suppressant are described.

Zinc oxide has previously been used with polyvinyl chloride resins as a stabilizer (U.S. Patent 3,446,765), as a pigment (U.S. Patent 2,682,484), and as a stabilizer for propellant auxiliaries (U.S. Patent 3,041,193).

Synthetic materials that are subjected to forced combustion give off smoke and toxic gases that are dangerous in the event of a fire because they reduce the chance of escape, cause damage, reduce the survival rate and make firefighting more difficult. Recent statistics show that around half of the dbdfalls in fires are caused by dust and not heat or real combustion, which emphasizes the need for the development of synthetic organic materials with as minimal dust formation during fire as possible. This applies in particular to areas of use such as clothing ifLy, boats, motorhomes and houses, and for mobiles and the like.

During forced combustion, it is known that polyvinyl halide compositions emit large amounts of black ash and compositions containing plasticizers or plasticizers such as di-octyl phthalate emit even more ash than unplasticized resins. Flame retardants such as oxides of tin, lead, magnesium, manganese, tellurium, titanium, copper, chromium, aluminium, vanadium and tungsten are of no value as smoke retardants in polyvinyl halides. Antimony oxide, which is widely used as a flame retardant in polyvinyl halide preparations, can often increase the emission of smoke during forced combustion.

As one aspect of the invention, plasticized polyvinyl halide containing 2-30 parts by weight of zinc oxide is thus provided. As another aspect, polyvinyl halides are provided which are processed with a mixture of plasticizers, an antimony compound as a flame retardant and 2-30 parts by weight of zinc oxide. The preferred mixture of plasticizers is a mixture of alkyl trimellitate and alkyl phthalate with antimony trioxide as the preferred antimony compound. Another feature of the invention consists in adding calcium carbonate or magnesium oxide as synergistic fillers.

According to the invention, compositions are therefore provided with a reduced tendency to emit smoke during combustion - a very desirable safety feature. The invention will therefore contribute to increasing the fire safety of building materials.

According to the practice of the invention, 2-30 parts by weight of zinc oxide are used as a smoke inhibitor in plasticized polyvinyl halide.

Polyvinyl halide resins that can be used according to the invention are homopolymers, copolymers and polymer mixtures. Examples of applicable polyvinyl halide resins are: 1. Homopolymers such as polyvinyl chloride, polyvinyl bromide, polyvinyl fluoride, polyvinylidene chloride, polydichlorostyrene etc., 2. Copolymers such as vinyl chloride-vinyl acetate, vinyl chloride-vinyl alcohol, vinylidene chloride-vinyl chloride, vinyl chloride-diethyl maleate, vinyl chloride esters of unsaturated alcohols and unsaturated acids beer. and 3. Mixtures such as polyvinyl chloride and polydichlorostyrene, polyvinyl chloride and vinyl acetate-vinyl chloride copolymer and polyvinyl chloride, polyvinylidene chloride and a copolymer of vinyl chloride-diethyl maleate, and the like.

The plastics can be treated with zinc oxide flame retardant in any suitable way. In some cases, the noise inhibition can be achieved by treating one or more surfaces of a plastic object with an additive-containing plastic composition so that the treated surface is coated with the added composition. In a similar way, textiles of all types can be coated with a thin skin or layer of plastic containing zinc oxide addition.

Suitable plasticizers Jbr the above resin types, especially polyvinyl chloride, are generally used in amounts of 30 - 100 parts by weight per 100 parts by weight polyvinyl halide and can be high-boiling esters such as. bis(2-ethylhexyl) adipate, bis(2-ethylhexyl) azelate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, tri-n-butyl citrate, acetyl tri-n-butyl citrate, epoxidized soybean oil, 2-ethylhexyl epoxy tallate, diethylene glycol dipelar -gonate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, bis(2-ethylhexyl) isophthalate, butyl oleate, tris(2-ethylhexyl) phosphate, tributoxyethyl phosphate, cresyl diphenyl phosphate, tri- cresyl phosphate, 2-ethylhexyl diphenyl phosphate, butyl octyl phthalate, di-n-octyl phthalate, diisooctyl phthalate, bis(2-ethylhexyl) phthalate, n-octyl-n-decyl phthalate, isooctyl -isodecyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diphenyl phthalate, isodecyl benzyl phthalate, adipic acid polyester (mol weight 2200), azelaic acid polyester (mol weight 1500), sebacic acid polyester (mol weight 800), methyl -ricinoleate, n-butyl-acetyl ricinoleate, bis(2-ethylhexyl)-sebacate, butyl-acetoxystearate, alkyl sulfonic acid ester of phenol and cresol and tris(2-ethylhexyl)-trimellitate.

Other suitable plasticizers include chlorinated biphenyl (54% chlorine), hydrogenated terphenyls, polyalkylnaphthalenes, chlorinated paraffin (24 - 70% chlorine), [N-cyclohexyl-p-toluenesulfonamide and copolymers of a conjugated diolefin with less than 7 C- atoms such as butadiene with a copolymerizable monomer such as acrylonitrile or methyl isopropenyl ketone.

For minimal cracking, it has been found that a particularly effective plasticizer or plasticizer is a mixture of phthalate plasticizer and trimellitate plasticizer. A mixture of these two plasticizers in the phthalate/trimellitate weight ratio of approx. 6/1 to 1/1 gives a synergistic effect combined with zinc oxide as flame retardant and antimony trioxide as flame retardant.

In general, improved flame suppression can be achieved with

to add to the relevant mixtures metal compounds where the metal is antimony, arsenic or bismuth in an amount of 1-30 percent by weight of the polymer mass. Antimony oxide is preferred in that connection. However, many other antimony compounds are use-only. Suitable antimony compounds are antimony sulphides, salts

of alkali metals in group I of the periodic table, antimony salts of organic acids and their pentavalent derivatives and esters of antimonic acids and their pentavalent derivatives. It is appropriate to use sodium antimonite or potassium antimonite when needed

to use alkali metal salts of antimony as mentioned above. U.S. patent 2,996,528 describes suitable antimony salts of organic acids and their pentavalent derivatives. Compounds in this class include antimony butyrate, antimony valerate, antimony caproate, antimony heptylate, antimony caprylate, antimony pelargonate, antimony caprate, antimoncinnamate, antimonanisate and their pentavalent dihalgenide derivatives. Likewise, esters of antimony acids and their pentavalent derivatives are described in U.S. Pat. patent 2,993,924, for example tris(n-octyl)antimonite, tris(2-[e1;ylhexyl)antimonite, tribenzyl-antimonite, tris (beta-chloroethyl)antimonite, tris(beta-chloropropyl)antimonite, tris(beta-chlorobutyl)antimonite )antimonite and their pentavalent dihalide derivatives. Further suitable organic antimony compounds are cyclic antimonites such as trimethylolpropane antimonite, pentaerythritol antimonite and glycerol antimonite. The corresponding arsenic and bismuth compounds can also be used, especially oxides of arsenic and bismuth.

Other processing aids can be used in polyvinyl halide compositions according to the invention, e.g. a. light and heat stabilizers, waxes, pigments, propellants and other flame retardants and fillers such as carbon dioxide, silicon oxide, baryte, clay, wood flour, magnesium oxide, calcium carbonate etc. When magnesium oxide or calcium carbonate are used as fillers, there is a synergistic reduction of scum formation.

Prior art in the field shows that there is usually a direct relationship between the achievable smoke suppression and the amount of smoke suppressant used, with a greater amount of smoke suppressant usually providing greater smoke suppression when all other

factors are constant. In some cases, there is a practical upper limit to the amount of smoke suppressant. medium. This upper limit is based on secondary factors such as price, mixing difficulties or possible deterioration of desired properties of the plastic. In the present special case, it has unexpectedly been found that the expected direct relationship between noise attenuation and the amount of noise-inhibiting agent does not exist. In the case of zinc oxide plus a mixture of phthalate plasticizer and trimellitate plasticizer at a total content of plasticizer of about 70 pph (parts per hundred), the rby release drops rapidly when the amount of zinc oxide increases to approx. 7 parts

per 100 parts of polyvinyl chloride and from there, the formation of bubbles increases unexpectedly when the amount of zinc oxide increases from 10 - 30 parts per 100 parts polyvinyl chloride. As the plasticizer content increases, so does the optimum concentration of zinc oxide. The preferred amount of zinc oxide is therefore from 3-30 parts per hundred parts polyvinyl halide and the best quantity for minimal smoke formation is 2 - 10 parts per 100 parts polyvinyl halide when the plasticizer content is 30 - 50 parts, and is 5 - 12 parts zinc oxide when the plasticizer content is 50 - 100 parts.

The composition according to the invention can be used for all purposes where plasticized polyvinyl halides are used, including coated textiles, wire, wire and cable insulation and sleeve production, wall coverings etc. Examples of suitable fiber substrates for coated textiles are cotton textiles, rayon textiles, felt, paper, polyester textiles and mixtures of these. The textile can be coated by calendering, by stitching, by plastisol coating, by roller coating or on other

ways known in the art.

When carrying out the invention in practice, the zinc oxide flash suppressor, the antimony compound as a flame retardant, fillers and other auxiliary substances can be mixed into the resin in suitable mixing equipment available on site.

In the examples below, all compositions were prepared as follows, where nothing else is mentioned: The components were first mixed by hand and then for 10 minutes in a double-roll differential mixer with electric heating which maintained a temperature of 150°C. The homogeneous mixture was pressed in a 30 ton hydraulic press for 10 minutes at 160°C under full pressure. A mold of 7.5 x 15 cm x 0.5 mm was used. To test the energy release for the different compositions, test pieces were cut approx. 7.5 x 7.5 cm x 0.5 mm from the four die-cast plates above. Each sample was placed on aluminum foil cut to the same length to enable overlapping of the sample on all four sides. The wrapped sample was placed in a holder and burned in an "Aminco NBS" type dust chamber according to the given specifications and according to "NBS Technical Note 708 (1971). The amount of dust was measured in a light multiplier. Specific optical density was calculated and corrected for soot that was on the lens after the experiment. One measures the dilution of a light beam by dust that accumulates in a closed space during combustion. The results are expressed as specific optical density derived from a geometric factor and the measured optical density (absorption). This is the single measurement most characteristic of the "rby concentration". The photometric scale used for measuring the rby according to this method is of a similar type to the optical density scale for the human eye .

Compositions without zinc oxide give a corrected maximum specific optical density in the range of 400 or more. In comparison, 10 parts zinc oxide reduces this number to below 200. In the NBS experiment, a lower number will indicate less noise. It is noted that most figures for maximum specific optical density for a composition are a mean value of measurements with two or more test pieces of each composition. In general, two compositions are considered to have different noise-emitting properties if the difference in maximum specific optical density is greater than 10.

Other details relating to the reduction of the formation of bubbles can be seen in the following examples, where all compositions are based on weight per 100 parts polyvinyl chloride resin. All compositions contained 1.8 parts barium-cadmium-zinc stabilizer, 2.7 parts epoxidized soybean oil and 0.2 parts stearic acid where nothing else is noted.

Example 1

A composition containing 100 parts polyvinyl chloride ("Marvinol 22" from Uniroyal, Inc.), 70 parts by weight dioctyl phthalate as a plasticizer ("DOP"), 15 parts by weight calcium carbonate as a filler, 10 parts by weight antimony trioxide (Sb 2 O 2 ) and 10 parts by weight zinc oxide was mixed by hand and rolled in a double roller assembly for 10 minutes. The composition was pressed to approx. 0.75 mm thickness as previously described. Two samples of 7.5 cm square were cut out of the plate and subjected to tests for crack formation in the "Aminco NBS" crack chamber according to the fire test.

The above procedure was repeated, except that zinc oxide was omitted.

Average maximum specific optical density for the two compositions was:

Example 2

The procedure from example 1 was repeated, but different plasticizers were used. Compositions and cloud formation are summarized in the following table 1.

In the table, the plasticizers are indicated by brand, which is as follows:

Phthalate protection

"Santicizer 711" = mixed (Cy-C-^) alkyl phthalate "PX-316" = mixed alkyl phthalate, higher percent linear component than "Santicizer 711"

The phosphate type

"Santicizer 141" = 2-ethylhexyl diphenyl phosphate "Santicizer 148" = isodecyl diphenyl phosphate Trimellitate type

"Santicizer 79TM" = mixed (Cy-Cg) alkyl trimellitate.

The results in Table I clearly show that addn

of 10 parts by weight of zinc oxide dramatically reduces the amount of rust developed for the preparations that contained antimony trioxide file lambda damper, regardless of the plasticizer.

Example 3

The procedure from example 2 was repeated with several fillers to show that, although there are differences in terms of the absolute amount of rbyk emitted by a particular composition, depending on the filler and the amount of filler, the zinc oxide works as a rbyk inhibitor in all cases. Maximum noise attenuation was achieved when the filler was calcium carbonate. Composition and results appear in table II.

Example 4

The procedure from Example 1 was repeated to find the effect of antimony trioxide (813203) on the vapor formation for polyvinyl chloride compositions. With "mixed alkyl phthalate plasticizer ("PX-316") as described in Example 2 and the filler combination used in these compositions, a synergistic effect was found between zinc oxide and antimony trioxide in suppressing smoke formation.

Compositions and results are shown in Table 3.

Example' 5

The procedure from example 1 was repeated to show the relationship between the zinc oxide concentration and the smoke suppression. It will be seen that the effect of zinc oxide on the reduction of smoke formation is complicated by the fact that initially there is a reduction of smoke formation with a decreasing amount of zinc oxide and then quite unexpectedly, increased smoke formation occurs above the optimal addition, namely approx. 5-12 parts by weight per 100 parts by weight polyvinyl chloride for a mixture containing 70 pph plasticizer. Compositions and results appear in table IV.

Example , 6 I

The example shows that various other zinc compounds are either ineffective as smoke retardants for poly-vinyl chloride's breast etches. or significantly worse than zinc oxide.

The trial plates were produced as in example 1 from the following basic composition:

The results for the various zinc compounds examined were:

Example 7

The procedure from example 1 was repeated to show the synergistic effect of a mixture of a phthalate plasticizer and trimellitate plasticizer on smoke formation for a composition that contained an optimal amount of zinc oxide as a smoke inhibitor and antimony trioxide as a flame retardant. The observed synergistic effect occurs at a weight ratio between phthalate plasticizer and trimellitate plasticizer of approx. 6/1

to 1/1.

Example 8

Coated textiles were produced by mixing a coating composition on a double roller assembly as in example 1 and calendering the mass on 85 g/m polyester-cotton knitted textile in a known manner. A coating thickness of 0.3 mm was used at a temperature of 150°C.

The following compositions were coated on the polyester-cotton cloth and gave the following number of repetitions:

Example 9

The example shows that the optimum amount of zinc oxide, as is also apparent from example 5, increases when the amount of plasticizer increases in the plasticized polyvinyl chloride composition. The results appear in table VI.

Claims (8)

1. Compositions with reduced rby emissions during combustion consisting of polyvinyl halide, a stabilizer and a plasticizer in an amount of 30 - 100 parts by weight per 100 parts by weight of polyvinyl halide, with 2-30 parts by weight of zinc oxide added as a smoke inhibitor. 2. Composition as stated in claim 1, characterized in that the polyvinyl halide is polyvinyl chloride or copolymers thereof. 3. Composition as stated in claim 1, take care. r-i <!> ~s ert in that the plasticizer is added in a quantity of 30 - 50 parts per 100 parts by weight polyvinyl halide and the zinc oxide in an amount of 2 - 10 parts by weight. 4. Composition as stated in claim 1, characterized in that the plasticizer constitutes 50 - 100 parts by weight per 100 parts by weight of polyvinyl halide and the zinc oxide 5 - 12 parts by weight. 5. Composition as stated in claim 1, characterized in that the plasticizer is phthalates, phosphates, trimellitates or mixtures thereof. 6. Composition as stated in claim 1, characterized in that it also contains up to 30 parts by weight of antimony oxide (Sb^O-^). 7. Composition as stated in claim 1, characterized in that it additionally contains up to 60 parts by weight of filler selected from calcium carbonate and magnesium oxide. 8. Composition as stated in claim 1, characterized in that the plasticizer is a mixture of dialkyl phthalate and alkyl trimellitate.