CA2042223A1 - Flame retardant thermoplastic compositions - Google Patents
Flame retardant thermoplastic compositionsInfo
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- CA2042223A1 CA2042223A1 CA 2042223 CA2042223A CA2042223A1 CA 2042223 A1 CA2042223 A1 CA 2042223A1 CA 2042223 CA2042223 CA 2042223 CA 2042223 A CA2042223 A CA 2042223A CA 2042223 A1 CA2042223 A1 CA 2042223A1
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Abstract
PATENTS
60SI-1279/MAM/8973o Abstract of the Disclosure A thermoplastic composition having improved flame resistant properties is provided, consisting essentially of:
A. about 30 to about 60 parts by weight of a thermoplastic;
B. about 40 to about 70 parts by weight of aluminum trihydrate, the sum of (A) and (B) being 100 parts;
C. a silicone oil; and D. a silicone resin which is soluble in the silicone of component C, the ratio of (C) to (D) being from about 2:1 to about 2.5:1, and the sum of (C) and (D) being from about 4 to about 12 parts per 100 parts of (A) plus (B).
A method for improving the flame resistance of a thermoplastic composition consisting essentially of components A and B of the composition set forth above, and articles produced therefrom, are also provided.
60SI-1279/MAM/8973o Abstract of the Disclosure A thermoplastic composition having improved flame resistant properties is provided, consisting essentially of:
A. about 30 to about 60 parts by weight of a thermoplastic;
B. about 40 to about 70 parts by weight of aluminum trihydrate, the sum of (A) and (B) being 100 parts;
C. a silicone oil; and D. a silicone resin which is soluble in the silicone of component C, the ratio of (C) to (D) being from about 2:1 to about 2.5:1, and the sum of (C) and (D) being from about 4 to about 12 parts per 100 parts of (A) plus (B).
A method for improving the flame resistance of a thermoplastic composition consisting essentially of components A and B of the composition set forth above, and articles produced therefrom, are also provided.
Description
~0~223 Prakash K. Pawar Backqround of the Invention The present invention relates to thermoplastic compositions. More particularly, the present invention relates to thermoplastic compositions containing silicone-based additives which impart unexpectedly improved flame retardant properties to the thermoplastic compositions.
Aluminum trihydra~e (ATH) is used extensively in the plastics industry as a flame retardant filler in thermoplastic resin and elastomer compositions. ATH-filled copolymers of thermoplastic resins and elastomers are economical but lack good fire retardancy and good physical properties.
Efforts have been made in the past to increase the flame resistance of thermoplastic compositions containing aluminum trihydrate. Reference is made, for example, to U.S. Patent Nos. 4,387,176 (Frye); 4,496,680 (Ashby); and 4,536,529 (Frye et al.).
In U.S. Patent No. 4,387,176 (Frye), there is disclosed a flame retardant thermoplastic composition, comprising a thermoplastic polymer, a silicone fluid or gum, a Group IIA
metal organic salt, a silicone resin, and, optionally, aluminum trihydrate. This flame retardant composition is most effective with the addition of a halogen.
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The Frye invention is based on the discovery that "efficient flame retardant plastics can be provided by combining in the correct proportions certain metal soaps (e.g., magnesium stearate) with a mixture of certain silicone resins such as a polytriorganosilyl silicate and a polydiorganosiloxane polymer." (Frye, column 2, lines 4-8). It is stated in Frye that the invention therein "differs from the prior art in several respects, notably in that it requires the use of a combination of polyorganosiloxane silicone and a silicone resin, thereby achieving a synergistic flame retardant effect which is not taught by the prior art."
In U.S. Patent No. 4,496,680 (Ashby), a nylon composition is disclosed which is rendered substantially flame-resistant when combined with an additive composition comprising diphenylsilanediol, low molec~lar weight phenyl substituted siloxane diol, or mixture thereof; a Group IIA metal carboxylic acid salt; aluminum trihydrate; an organic halide; and, optionally, a silicone resin such as that disclosed in U.S.
Patent No. 4,387,176 to Frye, discussed above.
In U.S. Patent No. 4,5369529 (Frye et al.), there is disclosed a flame retardant composition, containing a thermoplastic polymer, a silicone fluid, metal soap precursors, a silicone resin, and, optionally, alumina trihydrate.
The Frye et al. invention is based on the discovery that efficient flame retardant thermoplastics can be made by mixing in the correct proportions during compounding certain metal soap precursors, such as stearic acid and a reactive magnesium . . . . . .
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Aluminum trihydra~e (ATH) is used extensively in the plastics industry as a flame retardant filler in thermoplastic resin and elastomer compositions. ATH-filled copolymers of thermoplastic resins and elastomers are economical but lack good fire retardancy and good physical properties.
Efforts have been made in the past to increase the flame resistance of thermoplastic compositions containing aluminum trihydrate. Reference is made, for example, to U.S. Patent Nos. 4,387,176 (Frye); 4,496,680 (Ashby); and 4,536,529 (Frye et al.).
In U.S. Patent No. 4,387,176 (Frye), there is disclosed a flame retardant thermoplastic composition, comprising a thermoplastic polymer, a silicone fluid or gum, a Group IIA
metal organic salt, a silicone resin, and, optionally, aluminum trihydrate. This flame retardant composition is most effective with the addition of a halogen.
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PATENTS
The Frye invention is based on the discovery that "efficient flame retardant plastics can be provided by combining in the correct proportions certain metal soaps (e.g., magnesium stearate) with a mixture of certain silicone resins such as a polytriorganosilyl silicate and a polydiorganosiloxane polymer." (Frye, column 2, lines 4-8). It is stated in Frye that the invention therein "differs from the prior art in several respects, notably in that it requires the use of a combination of polyorganosiloxane silicone and a silicone resin, thereby achieving a synergistic flame retardant effect which is not taught by the prior art."
In U.S. Patent No. 4,496,680 (Ashby), a nylon composition is disclosed which is rendered substantially flame-resistant when combined with an additive composition comprising diphenylsilanediol, low molec~lar weight phenyl substituted siloxane diol, or mixture thereof; a Group IIA metal carboxylic acid salt; aluminum trihydrate; an organic halide; and, optionally, a silicone resin such as that disclosed in U.S.
Patent No. 4,387,176 to Frye, discussed above.
In U.S. Patent No. 4,5369529 (Frye et al.), there is disclosed a flame retardant composition, containing a thermoplastic polymer, a silicone fluid, metal soap precursors, a silicone resin, and, optionally, alumina trihydrate.
The Frye et al. invention is based on the discovery that efficient flame retardant thermoplastics can be made by mixing in the correct proportions during compounding certain metal soap precursors, such as stearic acid and a reactive magnesium . . . . . .
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2~2223 PATENTS
compound, which are precursors to magnesium stearate, certain silicone fluids and silicone resins, and adding the mixture to a thermoplastic (Frye et al., column 1, lines ~6-55). The Frye et al. additives result in less reduction in mechanical properties than conventional flame retardants and improve impact resistance, gloss, and processability.
Another patent, U.S. Patent No. 4,487,858 (Lovgren et al.), claims a propylene/polydimethylsiloxane/MQ resin blend containing aluminum trihydrate, talc, and a cross-linking 10agent, but teaches at column 6, lines 35-41 therein that the blend may also contain "Group IIA metal organic compounds or salts, such as magnesium stearate, calcium stearate, barium stearate, etc., which enhance the flame retardance of the thermoplastic/silicone fluid blend."
15The patents discussed above all teach that the presence of a Group IIA metal organic salt in addition to a silicone fluid and silicone resin is required to improve the flame resistance of the thermoplastic composition. The presence of a Group IIA
metal organic salt increases the melt flow properties of the thermoplastic composition. However, in some applications, such as sheet extrusion, it is desirable to use a thermoplastic composition having lower melt flow properties.
Thus, an object of the present invention is to provide an ATH-filled thermoplastic composition having improved flame retardancy and reduced melt flow.
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Another object of the present in~ention is to provide an ATH-filled thermoplastic composition having improved flame retardancy, reduced melt flow, and good or acceptable physical properties.
These objects are achieved in the present invention.
Summary of the Invention The present invention is based on the discovery that the flame retardancy and certain physical properties of thermoplastic compositions can be improved without the use of a Group IIA metal carboxylic acid salt by adding to the thermoplastic critical amounts of the silicone fluid and silicone resin taught in the patents discussed above.
In one aspect, the present invention provides a thermoplastic composition having improved flame resistant properties, consisting essentially of:
A. about 30 to about 60 parts by weight of a thermoplastic;
B. about 40 to about 70 parts by weight of aluminum trihydrate, the sum of (A) and (B) being 100 parts;
C. a silicone oil; and D. a silicone resin which is soluble in the silicone of component C, the ratio of (C) to (D) being from about 2:1 to about 2.5:1, and the sum of (C) and (D) being from about ~ to about 12 parts per 100 parts of (A) plus !3) .
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605I-1279/MAMi8973O
In another aspect, the present invention is directed to a method for improving the flame resistance of a thermoplastic composition consisting essentially of components A and B of the composition set forth above, wherein the method consists essentially of the step of adding to the thermoplastic composition components C and D in the amounts indicated.
The present invention is further directed to articles of manufacture comprising a substrate coated with the thermoplastic composition of this invention.
In addition to improved flame resistance, the compositions of this invention have improved low temperature impact strength and anti-dripping properties, and reduced melt flow.
The compositions of this invention are useful in the construction, building, and wire and cable insulation industries.
Brief Description of the Drawings Figure 1 is a graph illustrating the effect on the melt flow index of a 40 parts ethylene ethyl acrylate/60 parts aluminum trihydrate copolymer ("40 EEA/60 ATH") of the silicone oil and silicone resin combination (i.e., "Silicone") and Silicone/magnesium stearate.
Figure 2 is a graph illustrating the effect of Silicone and Silicone/magnesium stearate on the limiting oxygen index of 40 EEA/60 ATH.
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~42223 Figure 3 is a graph illustrating the effect of Silicone and Silicone/magnesium stearate on the flammability of 40 EEA/60 ATH.
Figure 4 is a graph illustrating the effect of Silicone and Silicone/magnesium stearate on the impact strength of 40 EEA/60 ATH at -20C.
Figure 5 is a graph illustrating the effect of Silicone and Silicone/magnesium stearate on the impact strength of 40 EFA/60 ATH at -50C.
Figure 6 is a graph illustrating the effect of Silicone and Silicone/magnesium stearate on the tensile strength of 40 EEA/60 ATH.
Figure 7 is a graph illustrating the effect of Sil;cone and Silicone/magnesium stearate on the tensile modulus of 40 EEA/60 15 A'rH.
Figure 8 is a graph illustrating the effect of Silicone and Silicone/magnesium stgearate on the tensile elongation of 40 EEA/60 ATH.
Detailed DescriDtion of the Invention As mentioned previously herein, the .present invention is based on the discovery that the flame resistance of an ATH-filled thermoplastic composition can be improved without - . .. :, . . .
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20~223 PATENTS
the use of a Group IIA metal carboxylic acid salt, by adding to the thermoplastic composition critical amounts of a silicone oil and silicone resin.
The present invention is directed to a thermoplastic composition having improved flame retardancy and consisting essentially of (A) a thermoplastic polymer, (B) aluminum trihydrate, and critical amounts of (C) a silicone oil, and (O) a silicone resin.
Thermoplastic polymers suitable as Component (A) of the composition of this invention include, for example, polyolefins such as : polyethylenes such as low density polyethylene (LDPE) and high density polyethylene (HOPE); polypropylene, polybutylene, etc. and copolymers of these; polystyrene, polycarbonate such as Lexan brand and thermoplastic polyesters such as ValoxR resin, both manufactured by the General Electric Company, and other polymers such as polyamides (e.g. Nylon 66, Nylon 12, etc.), polycaprolactams, ionomers, polyurethanes, co- and ter-polymers of acrylonitrile, butadiene and styrene; as well as acrylic polymers9 acetal resin, ethylene-vinyl acetate, polymethylpentene, flexible polyvinylGhloride, polyphenylene oxide, polyphenylene oxide-polystyrene blends or copolymers such as NorylR polymer (manufactured by General Electric); Monsanto Santoprene and Uniroyal TPR thermoplastic polyesters. The thermoplastic polymers suitable for use in this ;nvention will hereinafter be collectively referred to as "thermoplastics". Those skilled in the art will be able to adapt and optimize the flame retardant compositions of the present invention to a wide variety of , ;
: .
2~2223 PAT~NT5 60SI-1279/MAMi89730 thermoplastic formulations including engineering plastics. It is not intended that the above listing be all inclusive, and the present invention should not be so limited.
The composition of this invention contains about 30 tc about 60, preferably about 30 to about 40, and most preferably about 40, parts by weight of a thermoplastic polymer, i.e., co~ponent (A).
Component (B) of the composition of this invention is aluminum trihydrate, which imparts flame retardance properties to thermoplastic compositions by dehydrating when exposed to heat of the combustion process.
Generally7 the aluminum trihydrate may be present in the composition of this invention in amounts ranging from about 40 to about 70, preferably about 60 to about 70, and most preferably about 60, parts by weight.
The sum of components (A) and (B) in the composition of this invention is 100 parts.
Component (C) of the composition of this invention is a silicone oil. The term "silicone oil" as used herein is generic for a wide range of polysiloxane materials which can be advantageously utilized in the composition of the present invention. For purposes of the present specification it is intended that the expression "silicone oil" be construed as including those effective silicone materials as described by MacLaury et al. in U.S. Patent No. 4,273,691, which is hereby : ~L ~ :
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60SI-l279/MAMi8973O
9_ incorporated by reference. Typically effective silicone materials will be those silicone fluids or gums which are organopolysiloxane polymers comprised of chemically combined siloxy units typically selected from the group consisting of R3SiOo 5, R2SiO, ~lSiOl 5, RlR2SiOo 5, RRlSiO, (Rl)2SiO, RSiOl 5 and SiO2 units and mixtures thereof wherein each R represents independently a saturated or unsaturated monovalent hydrocarbon radical, Rl represents a radical such as R or a radical selected from the group consisting of a hydrogen atom, hydroxyl, alkoxy, aryl, vinyl, or allyl radicals etc~ and wherein said organopolysiloxane has a viscosity of approximately 600 to 300,000,000 centipoise at 25C. A preferred silicone material is a polydimethylsiloxane having a viscosity of approximately 90,000 to 150,000 centipoise at 25C. Such effective silicone materials will be collectively referred to as either silicones or silicone oils and are to be distinguished from the class of materials referred to as silicone resins. Such silicone oils are readily available under a wide variety of brand and grade designations.
Component (D) is a silicone resin, which is soluble in the above described silicone oil (i.e. fluid or gum) and which is effective for imparting improved flame retardancy to the composition of the present invention. Among the preferred silicone resins are MQ silicone resins. The expression "MQ
silicone resin" refers to the fact that such resins are typically comprised primarily of monofunctional M units of the formula R3SiOo 5 and tetrafunctional Q units of the average 204~223 PATENTS
formula SiO2 having a specified ratio of M to Q units. A
notable effective silicone resin for use in the present invention is polytrimethylsilylsilicate which can have a ratio of, approximately, 0.3 to 4.0 M units per Q unit. A
particularly effective formulation might preferably contain a ratio of, approximately, 0.6 to 2 M units per Q units. An example of a commercially available MQ silicone resin is General Electric SR545 (60% MQ resin solids in toluene). A
preferred method of utilizing such an MQ resin solution is to mix it with the silicone oil component and thereafter remove the solvent. The solvent can be removed by well known methods, e.g. by distillation at moderate temperatures.
Component (C) and (0) are present in the composition of this invention in a ratio of from about 2:1 to about 2.5:1 and preferably about 2.3:1. The sum of Components (C) and (0) in the composition of this invention ranges from about 4 to about 12, preferably from about 5 to ab~ut 10, and most preferably from about 5 to about 7, parts per 100 parts of (A) plus (B).
It is critical that components (C) and (D) be present in the composition of this invention in the range of ratios and amounts indicated above. At ratios and amounts outside the parameters recited above, flame retardancy and other proDerties ~ill suffer.
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60SI-1279/MAM/8973u It is contemplated that other silicone oil soluble forms of solid silicone resins may be effective for use in the flame retardant compositions of the present invention. Indeed, MT
and TQ silicone resins (where T represents trifunctional RSiOl 5 units) may also be effective as well as mixtures and copolymers of each of the resins mentioned. These silicone resins are well known materials and are readily available. A
criteria for suitability is that such effective silicone resinous materials be soluble or dispersible in the silicone oil base.
Additionally it is to be noted that although the thermoplastic composition specifies the silicone oil (essentially D functional) and silicone resin (M, D, T, or Q
functional) as discrete ingredients to be admixed, it is intended that the present invention encompass reaction products of such materials which may be equally effective as flame retardant additives. It is also foreseeable that a copo1ymer containing requisite M, D, T, or Q functionality may be utilized in place of discrete silicone-oit and silicone resin constituents.
The composition of the present invention may further contain various fillers such as talc, clay, calcium carbonate, fumed silica, wollastonite and the like. Other suitable ~illers will be obvious to those s~illed in the art.
In the practice of the invention, the flame retardant compositions can be made by mixing together the thermoplastic polymer with the silicone oil and the silicone resin by means , .
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60SI-1279/MAM/~9730 of any conventional melt compounding apparatus, such as a Banbury mixer, twin screw extruder, or two-roll rubber mill. A
twin scre~ extruder is expected to give the most reproducible product. Exa~ples of suitable blending techniques are S described in U.S. Patent No. 4,487,858 (Lovgren et al.), which is incorporated by reference herein.
Order of addition of the particular constituents does not appear to be critical; however, those skilled in the art will be able to optimize the flame retardant comDositions contemplated herein without undue experimentation. Preferably, the silicone resin and the silicone polymer are premixed so as to form a homogeneous mixture prior to blending with the thermoplastic/ATH composition within the extruder.
The thermoplastic and aluminum trihydrate are typically preblended as well, prior to the addition thereto of the silicone blend. The thermoplasticfAT~I composition, silicone resin and silicone oil are typically blended at a temperature within the range of from about 100 to 200C, the preferred blending temperature falling within the range of about 120 to 160C.
The flame retardant composition of the present invention can be extruded onto an electrical conductor and in particular instances, crosslinked depending on whether a peroxide curing agent is present. Of cou~se, there are numerous other applications where the flame retardant compositions of the present invention may be used to great advantage. The , ~ : ' 2~2~3 PATENTS
compositions of this invention are easily processed into end use products such as wire and cable extrusions, and sheet extrusions for a variety of construction products.
In order that those skilled in the art may better understand the practice of the present invention, the following examples are given by way of illustration and not by way of limitation.
Experimental In the examples, tables, and figures below, the term "SFR
100" refers to a blend containing by weight 54 parts of a silanol- terminated polydimethylsiloxane having a viscosity of about 120,000 and 46 parts of a 60% solution of MQ resin in toluene or xylene. The term "LDPE" refers to low density polyethylene which is composed of the copolymer ethylene ethyl acrylate, made by Un~on Carbide Company under the tradename "DPDA-1682", and the term "phr" refers to parts per hundred.
Those skilled in the art will appreciate that there are several methods for testing and comparing relative flame retardancy of thermoplastics. Among the most well known are limiting oxygen index and horizontal and vertical burn tests.
Underwriters' Laboratories Bulletin UL-94 describes a "Burning Test for Classifying Materials", hereinafter referred to as "UL-94". In accordance with this test procedure, materials are rated V-0, V-I, or V-II based on the results of testing five specimens, which are evaluated according to the 25 following criteria:
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605I-1279/MAM/897io V-0: Average flaming and/or glowing after removal of the igniting flame shall not exceed 5 seconds, and no individual specimen shall drip particles which ignite absorbant cotton or burn longer than 10 seconds.
V-I: Average flaming and/or glowing after removal of the igniting flame shall not exceed 25 seconds, and no individual specimens shall drip particles which ignite absorbant cotton or burn longer than 30 seconds.
V~ Average flaming and/or glowing after removal of the igniting flame shall not exceed 25 seconds (with no individual burn greater than 30 seconds) and the specimens drip flaming particles which ignite absorbant cotton.
The vertical burn tests conducted in connection with the following examples essentially follow the test procedures described in UL-94.
Example 1 illustrates the preparation of a composition within the scope of this invention.
ExamDle 1 .
A mixture of thermoplastic (e.g., ethylene ethyl acrylate based Low Density Polyethylene (i.e., LDPE), made by Union Carbide Company under the tradename "DPDA-6182") and aluminum trihydrate was prepared at d LDPE to ATH ratio of 40:60, and subjected to compounding on a Banbury compounding machine. ~he ~. . ..................... .. . .
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2~2223 PATENTS
mixture was melt fluxed at 160C for 5 minutes. Then, silicone fluid was introduced at 5 phr (parts per 100 parts of 40:60 LDPE:ATH composition and the resulting mixture was compounded for 5 minutes. After 10 minutes of total cycle time, the material was removed and broken into small pieces which were then subsequently ground into small pellets for injection molding ASTM specimens.
Examples 2 through 9 Using the general procedure described in Example 1, eight samples were prepared having the compositions set forth in Table 1 below. The effects of SFR 100 with and without magnesium stearate on various properties, including flammability of the base resin (i.e., 40 parts Low Density Polyethylene (LDPE) and 60 parts aluminum trihydrate (ATH)), were determined. The level of SFR 100 used was in the range of 5 to 15%. The ratio of SFR 100 to magnesium stearate (where applicable) was maintained at 2:1 as was the case in U.S.
Patent No. 4,387,176 (Frye), discussed previously herein).
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60SI-1279/MAMi89730 Table 1 Example ~ LOPE /~ ATH ~ SFR 100 (phr) Mag~ Stearate ~phr)
compound, which are precursors to magnesium stearate, certain silicone fluids and silicone resins, and adding the mixture to a thermoplastic (Frye et al., column 1, lines ~6-55). The Frye et al. additives result in less reduction in mechanical properties than conventional flame retardants and improve impact resistance, gloss, and processability.
Another patent, U.S. Patent No. 4,487,858 (Lovgren et al.), claims a propylene/polydimethylsiloxane/MQ resin blend containing aluminum trihydrate, talc, and a cross-linking 10agent, but teaches at column 6, lines 35-41 therein that the blend may also contain "Group IIA metal organic compounds or salts, such as magnesium stearate, calcium stearate, barium stearate, etc., which enhance the flame retardance of the thermoplastic/silicone fluid blend."
15The patents discussed above all teach that the presence of a Group IIA metal organic salt in addition to a silicone fluid and silicone resin is required to improve the flame resistance of the thermoplastic composition. The presence of a Group IIA
metal organic salt increases the melt flow properties of the thermoplastic composition. However, in some applications, such as sheet extrusion, it is desirable to use a thermoplastic composition having lower melt flow properties.
Thus, an object of the present invention is to provide an ATH-filled thermoplastic composition having improved flame retardancy and reduced melt flow.
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2~2~23 PATENTS
Another object of the present in~ention is to provide an ATH-filled thermoplastic composition having improved flame retardancy, reduced melt flow, and good or acceptable physical properties.
These objects are achieved in the present invention.
Summary of the Invention The present invention is based on the discovery that the flame retardancy and certain physical properties of thermoplastic compositions can be improved without the use of a Group IIA metal carboxylic acid salt by adding to the thermoplastic critical amounts of the silicone fluid and silicone resin taught in the patents discussed above.
In one aspect, the present invention provides a thermoplastic composition having improved flame resistant properties, consisting essentially of:
A. about 30 to about 60 parts by weight of a thermoplastic;
B. about 40 to about 70 parts by weight of aluminum trihydrate, the sum of (A) and (B) being 100 parts;
C. a silicone oil; and D. a silicone resin which is soluble in the silicone of component C, the ratio of (C) to (D) being from about 2:1 to about 2.5:1, and the sum of (C) and (D) being from about ~ to about 12 parts per 100 parts of (A) plus !3) .
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605I-1279/MAMi8973O
In another aspect, the present invention is directed to a method for improving the flame resistance of a thermoplastic composition consisting essentially of components A and B of the composition set forth above, wherein the method consists essentially of the step of adding to the thermoplastic composition components C and D in the amounts indicated.
The present invention is further directed to articles of manufacture comprising a substrate coated with the thermoplastic composition of this invention.
In addition to improved flame resistance, the compositions of this invention have improved low temperature impact strength and anti-dripping properties, and reduced melt flow.
The compositions of this invention are useful in the construction, building, and wire and cable insulation industries.
Brief Description of the Drawings Figure 1 is a graph illustrating the effect on the melt flow index of a 40 parts ethylene ethyl acrylate/60 parts aluminum trihydrate copolymer ("40 EEA/60 ATH") of the silicone oil and silicone resin combination (i.e., "Silicone") and Silicone/magnesium stearate.
Figure 2 is a graph illustrating the effect of Silicone and Silicone/magnesium stearate on the limiting oxygen index of 40 EEA/60 ATH.
. ~....'. -:, .. . .
~42223 Figure 3 is a graph illustrating the effect of Silicone and Silicone/magnesium stearate on the flammability of 40 EEA/60 ATH.
Figure 4 is a graph illustrating the effect of Silicone and Silicone/magnesium stearate on the impact strength of 40 EEA/60 ATH at -20C.
Figure 5 is a graph illustrating the effect of Silicone and Silicone/magnesium stearate on the impact strength of 40 EFA/60 ATH at -50C.
Figure 6 is a graph illustrating the effect of Silicone and Silicone/magnesium stearate on the tensile strength of 40 EEA/60 ATH.
Figure 7 is a graph illustrating the effect of Sil;cone and Silicone/magnesium stearate on the tensile modulus of 40 EEA/60 15 A'rH.
Figure 8 is a graph illustrating the effect of Silicone and Silicone/magnesium stgearate on the tensile elongation of 40 EEA/60 ATH.
Detailed DescriDtion of the Invention As mentioned previously herein, the .present invention is based on the discovery that the flame resistance of an ATH-filled thermoplastic composition can be improved without - . .. :, . . .
,. ; ~ . :-, , ~ : ~. . , ~ " , . ~ ~r.
20~223 PATENTS
the use of a Group IIA metal carboxylic acid salt, by adding to the thermoplastic composition critical amounts of a silicone oil and silicone resin.
The present invention is directed to a thermoplastic composition having improved flame retardancy and consisting essentially of (A) a thermoplastic polymer, (B) aluminum trihydrate, and critical amounts of (C) a silicone oil, and (O) a silicone resin.
Thermoplastic polymers suitable as Component (A) of the composition of this invention include, for example, polyolefins such as : polyethylenes such as low density polyethylene (LDPE) and high density polyethylene (HOPE); polypropylene, polybutylene, etc. and copolymers of these; polystyrene, polycarbonate such as Lexan brand and thermoplastic polyesters such as ValoxR resin, both manufactured by the General Electric Company, and other polymers such as polyamides (e.g. Nylon 66, Nylon 12, etc.), polycaprolactams, ionomers, polyurethanes, co- and ter-polymers of acrylonitrile, butadiene and styrene; as well as acrylic polymers9 acetal resin, ethylene-vinyl acetate, polymethylpentene, flexible polyvinylGhloride, polyphenylene oxide, polyphenylene oxide-polystyrene blends or copolymers such as NorylR polymer (manufactured by General Electric); Monsanto Santoprene and Uniroyal TPR thermoplastic polyesters. The thermoplastic polymers suitable for use in this ;nvention will hereinafter be collectively referred to as "thermoplastics". Those skilled in the art will be able to adapt and optimize the flame retardant compositions of the present invention to a wide variety of , ;
: .
2~2223 PAT~NT5 60SI-1279/MAMi89730 thermoplastic formulations including engineering plastics. It is not intended that the above listing be all inclusive, and the present invention should not be so limited.
The composition of this invention contains about 30 tc about 60, preferably about 30 to about 40, and most preferably about 40, parts by weight of a thermoplastic polymer, i.e., co~ponent (A).
Component (B) of the composition of this invention is aluminum trihydrate, which imparts flame retardance properties to thermoplastic compositions by dehydrating when exposed to heat of the combustion process.
Generally7 the aluminum trihydrate may be present in the composition of this invention in amounts ranging from about 40 to about 70, preferably about 60 to about 70, and most preferably about 60, parts by weight.
The sum of components (A) and (B) in the composition of this invention is 100 parts.
Component (C) of the composition of this invention is a silicone oil. The term "silicone oil" as used herein is generic for a wide range of polysiloxane materials which can be advantageously utilized in the composition of the present invention. For purposes of the present specification it is intended that the expression "silicone oil" be construed as including those effective silicone materials as described by MacLaury et al. in U.S. Patent No. 4,273,691, which is hereby : ~L ~ :
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.
.
~2223 PATENTS
60SI-l279/MAMi8973O
9_ incorporated by reference. Typically effective silicone materials will be those silicone fluids or gums which are organopolysiloxane polymers comprised of chemically combined siloxy units typically selected from the group consisting of R3SiOo 5, R2SiO, ~lSiOl 5, RlR2SiOo 5, RRlSiO, (Rl)2SiO, RSiOl 5 and SiO2 units and mixtures thereof wherein each R represents independently a saturated or unsaturated monovalent hydrocarbon radical, Rl represents a radical such as R or a radical selected from the group consisting of a hydrogen atom, hydroxyl, alkoxy, aryl, vinyl, or allyl radicals etc~ and wherein said organopolysiloxane has a viscosity of approximately 600 to 300,000,000 centipoise at 25C. A preferred silicone material is a polydimethylsiloxane having a viscosity of approximately 90,000 to 150,000 centipoise at 25C. Such effective silicone materials will be collectively referred to as either silicones or silicone oils and are to be distinguished from the class of materials referred to as silicone resins. Such silicone oils are readily available under a wide variety of brand and grade designations.
Component (D) is a silicone resin, which is soluble in the above described silicone oil (i.e. fluid or gum) and which is effective for imparting improved flame retardancy to the composition of the present invention. Among the preferred silicone resins are MQ silicone resins. The expression "MQ
silicone resin" refers to the fact that such resins are typically comprised primarily of monofunctional M units of the formula R3SiOo 5 and tetrafunctional Q units of the average 204~223 PATENTS
formula SiO2 having a specified ratio of M to Q units. A
notable effective silicone resin for use in the present invention is polytrimethylsilylsilicate which can have a ratio of, approximately, 0.3 to 4.0 M units per Q unit. A
particularly effective formulation might preferably contain a ratio of, approximately, 0.6 to 2 M units per Q units. An example of a commercially available MQ silicone resin is General Electric SR545 (60% MQ resin solids in toluene). A
preferred method of utilizing such an MQ resin solution is to mix it with the silicone oil component and thereafter remove the solvent. The solvent can be removed by well known methods, e.g. by distillation at moderate temperatures.
Component (C) and (0) are present in the composition of this invention in a ratio of from about 2:1 to about 2.5:1 and preferably about 2.3:1. The sum of Components (C) and (0) in the composition of this invention ranges from about 4 to about 12, preferably from about 5 to ab~ut 10, and most preferably from about 5 to about 7, parts per 100 parts of (A) plus (B).
It is critical that components (C) and (D) be present in the composition of this invention in the range of ratios and amounts indicated above. At ratios and amounts outside the parameters recited above, flame retardancy and other proDerties ~ill suffer.
. . . . ...
: ~ ;. . .
~ ,:
2~2223 PATENTS
60SI-1279/MAM/8973u It is contemplated that other silicone oil soluble forms of solid silicone resins may be effective for use in the flame retardant compositions of the present invention. Indeed, MT
and TQ silicone resins (where T represents trifunctional RSiOl 5 units) may also be effective as well as mixtures and copolymers of each of the resins mentioned. These silicone resins are well known materials and are readily available. A
criteria for suitability is that such effective silicone resinous materials be soluble or dispersible in the silicone oil base.
Additionally it is to be noted that although the thermoplastic composition specifies the silicone oil (essentially D functional) and silicone resin (M, D, T, or Q
functional) as discrete ingredients to be admixed, it is intended that the present invention encompass reaction products of such materials which may be equally effective as flame retardant additives. It is also foreseeable that a copo1ymer containing requisite M, D, T, or Q functionality may be utilized in place of discrete silicone-oit and silicone resin constituents.
The composition of the present invention may further contain various fillers such as talc, clay, calcium carbonate, fumed silica, wollastonite and the like. Other suitable ~illers will be obvious to those s~illed in the art.
In the practice of the invention, the flame retardant compositions can be made by mixing together the thermoplastic polymer with the silicone oil and the silicone resin by means , .
.
-, :
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60SI-1279/MAM/~9730 of any conventional melt compounding apparatus, such as a Banbury mixer, twin screw extruder, or two-roll rubber mill. A
twin scre~ extruder is expected to give the most reproducible product. Exa~ples of suitable blending techniques are S described in U.S. Patent No. 4,487,858 (Lovgren et al.), which is incorporated by reference herein.
Order of addition of the particular constituents does not appear to be critical; however, those skilled in the art will be able to optimize the flame retardant comDositions contemplated herein without undue experimentation. Preferably, the silicone resin and the silicone polymer are premixed so as to form a homogeneous mixture prior to blending with the thermoplastic/ATH composition within the extruder.
The thermoplastic and aluminum trihydrate are typically preblended as well, prior to the addition thereto of the silicone blend. The thermoplasticfAT~I composition, silicone resin and silicone oil are typically blended at a temperature within the range of from about 100 to 200C, the preferred blending temperature falling within the range of about 120 to 160C.
The flame retardant composition of the present invention can be extruded onto an electrical conductor and in particular instances, crosslinked depending on whether a peroxide curing agent is present. Of cou~se, there are numerous other applications where the flame retardant compositions of the present invention may be used to great advantage. The , ~ : ' 2~2~3 PATENTS
compositions of this invention are easily processed into end use products such as wire and cable extrusions, and sheet extrusions for a variety of construction products.
In order that those skilled in the art may better understand the practice of the present invention, the following examples are given by way of illustration and not by way of limitation.
Experimental In the examples, tables, and figures below, the term "SFR
100" refers to a blend containing by weight 54 parts of a silanol- terminated polydimethylsiloxane having a viscosity of about 120,000 and 46 parts of a 60% solution of MQ resin in toluene or xylene. The term "LDPE" refers to low density polyethylene which is composed of the copolymer ethylene ethyl acrylate, made by Un~on Carbide Company under the tradename "DPDA-1682", and the term "phr" refers to parts per hundred.
Those skilled in the art will appreciate that there are several methods for testing and comparing relative flame retardancy of thermoplastics. Among the most well known are limiting oxygen index and horizontal and vertical burn tests.
Underwriters' Laboratories Bulletin UL-94 describes a "Burning Test for Classifying Materials", hereinafter referred to as "UL-94". In accordance with this test procedure, materials are rated V-0, V-I, or V-II based on the results of testing five specimens, which are evaluated according to the 25 following criteria:
.
,,, ~
~42223 PATENTS
605I-1279/MAM/897io V-0: Average flaming and/or glowing after removal of the igniting flame shall not exceed 5 seconds, and no individual specimen shall drip particles which ignite absorbant cotton or burn longer than 10 seconds.
V-I: Average flaming and/or glowing after removal of the igniting flame shall not exceed 25 seconds, and no individual specimens shall drip particles which ignite absorbant cotton or burn longer than 30 seconds.
V~ Average flaming and/or glowing after removal of the igniting flame shall not exceed 25 seconds (with no individual burn greater than 30 seconds) and the specimens drip flaming particles which ignite absorbant cotton.
The vertical burn tests conducted in connection with the following examples essentially follow the test procedures described in UL-94.
Example 1 illustrates the preparation of a composition within the scope of this invention.
ExamDle 1 .
A mixture of thermoplastic (e.g., ethylene ethyl acrylate based Low Density Polyethylene (i.e., LDPE), made by Union Carbide Company under the tradename "DPDA-6182") and aluminum trihydrate was prepared at d LDPE to ATH ratio of 40:60, and subjected to compounding on a Banbury compounding machine. ~he ~. . ..................... .. . .
~: .
.,, ::
~,. .
2~2223 PATENTS
mixture was melt fluxed at 160C for 5 minutes. Then, silicone fluid was introduced at 5 phr (parts per 100 parts of 40:60 LDPE:ATH composition and the resulting mixture was compounded for 5 minutes. After 10 minutes of total cycle time, the material was removed and broken into small pieces which were then subsequently ground into small pellets for injection molding ASTM specimens.
Examples 2 through 9 Using the general procedure described in Example 1, eight samples were prepared having the compositions set forth in Table 1 below. The effects of SFR 100 with and without magnesium stearate on various properties, including flammability of the base resin (i.e., 40 parts Low Density Polyethylene (LDPE) and 60 parts aluminum trihydrate (ATH)), were determined. The level of SFR 100 used was in the range of 5 to 15%. The ratio of SFR 100 to magnesium stearate (where applicable) was maintained at 2:1 as was the case in U.S.
Patent No. 4,387,176 (Frye), discussed previously herein).
' 2~22~
PATENTS
60SI-1279/MAMi89730 Table 1 Example ~ LOPE /~ ATH ~ SFR 100 (phr) Mag~ Stearate ~phr)
3 40 60 -- --
4 40 60 5 --S 40 60 S 2.5 7 40 60 10 5.0 g 40 60 lS 7.5 Table 2 lists the physical properties of the blends prepared in Examples 2 through 9. In Table 2, the term "MFI" refers to melt flow index; L.O.I. refers to limiting oxygen index;
"UL94" refers to the test described previously herein; "T.
Str." refers to tensile strength, T. Modulus refers to tensile modulus; "~ E" refers to percent of elongation; and "F. Mod."
refers to flexural modulus.
, , . ,- ,. ~ , .
,, :, . - , . . .
2~2223 PATENTS
60SI-lZ79/MAM789730 Table 2 __ EXAMPLE l\~lFi L 0.1.UL a~ ï .S.r. r.Ma~ oc Iz~d NO. (c) ~ 8re~ @ -2~G .@ -~C
(~rn/1 Om) (~' ) (s2r) (psi) - (Psl) (ps~ lbJin) ~flb/in) 2 1 2.3Z -- -- 1 o~ 4260 2a 57Q / 5.2~ a.s~
3 t .7Z2C.5 20~ 20500 7 i 1(:~1ag8 7.81 3.52 4 a.31 2'i.5 23.~ ~6ZS i3060 ~ A3330 8.C4 7.6 i _. . 828 ~7 30 ~3 _ c 33 l 7720 . SO ~0 ~ Z0 l ~r4~ 8 .8 6 0.3 28.0 1~.3 1243 t3855 3a 81939 5 51 S
7 5 9~127.8 23.8 32a t; t73 65 g8770 8 8 7.28 8 0.4 2~.8. tg.~ 770 ~3/-4 ~o ~ 80 ~.25 5 62 g ~.a4 27.3 16.5 730 ~060 ~!o 3,2C23 o. ' i 5 .. ...... . . .
2~42223 PATENTS
Examples 10 through 20 Eleven compositions were prepared having the compositions indicated in Table 3 so as to illustrate the effect of SFR 100 and Silicone/magnesium stearate on the melt flow properties of neat propylene (i.e., ATH is not present).
Table 3 Comwsitions (%l Melt Index (a) Example # Polypropylene SFR 100 Mag. Stearate (gms/min) 100.0 ~ 7.0 11 97.5 2.5 -- 11.83 12 96.25 2.5 1.25 10.62 o - 12.0 14 92.5 5.0 2.5 13.14 92.5 7.5 -- 14.0 16 88.75 7.5 3.75 16.21 17 90.0 10.0 -- 14.75 1~ 85.0 10.0 5.0 21.6 19 80.0 20.0 -- 20.36 70.0 30.0 -- 52.5 (a) Melt Index = Flow rate @ 44 psi (Load of 2.164 kgs) and at 230C, with Capillary Die Dimensions:
- Die I.D. = 0.0825"
- Oie Length ~ 0.315"
, , ; - ~ .
.
:,:
2~2~23 PATENTS
_19_ As can be seen from Tables 1 and 2 above and Figures 1-8, the physical properties of the "40 LDPE/60 ATH" resin (also referred to herein as "LDPE/ATH resin")/SFR 100 blend shows some unique trends, which are discussed as follows.
The flammability performance of this blend is unique. The ATH-LDPE resin itself has poor flame ~esistance as indicated in Figures 2, 3 and 4. Aluminum trihydrate at 60~ does not improve flame resistance of polyethylene. However~ the addition of SFR 100 or silicone/magnesium stearate at various concentrations improves the Limiting Oxygen Index and Flame Out Time (UL 94 test). The oxygen index seems to be independent of the addition of magnesium stearate (Fig. 2), but flame out times appear to decrease at low concentrations (i.e. less than
"UL94" refers to the test described previously herein; "T.
Str." refers to tensile strength, T. Modulus refers to tensile modulus; "~ E" refers to percent of elongation; and "F. Mod."
refers to flexural modulus.
, , . ,- ,. ~ , .
,, :, . - , . . .
2~2223 PATENTS
60SI-lZ79/MAM789730 Table 2 __ EXAMPLE l\~lFi L 0.1.UL a~ ï .S.r. r.Ma~ oc Iz~d NO. (c) ~ 8re~ @ -2~G .@ -~C
(~rn/1 Om) (~' ) (s2r) (psi) - (Psl) (ps~ lbJin) ~flb/in) 2 1 2.3Z -- -- 1 o~ 4260 2a 57Q / 5.2~ a.s~
3 t .7Z2C.5 20~ 20500 7 i 1(:~1ag8 7.81 3.52 4 a.31 2'i.5 23.~ ~6ZS i3060 ~ A3330 8.C4 7.6 i _. . 828 ~7 30 ~3 _ c 33 l 7720 . SO ~0 ~ Z0 l ~r4~ 8 .8 6 0.3 28.0 1~.3 1243 t3855 3a 81939 5 51 S
7 5 9~127.8 23.8 32a t; t73 65 g8770 8 8 7.28 8 0.4 2~.8. tg.~ 770 ~3/-4 ~o ~ 80 ~.25 5 62 g ~.a4 27.3 16.5 730 ~060 ~!o 3,2C23 o. ' i 5 .. ...... . . .
2~42223 PATENTS
Examples 10 through 20 Eleven compositions were prepared having the compositions indicated in Table 3 so as to illustrate the effect of SFR 100 and Silicone/magnesium stearate on the melt flow properties of neat propylene (i.e., ATH is not present).
Table 3 Comwsitions (%l Melt Index (a) Example # Polypropylene SFR 100 Mag. Stearate (gms/min) 100.0 ~ 7.0 11 97.5 2.5 -- 11.83 12 96.25 2.5 1.25 10.62 o - 12.0 14 92.5 5.0 2.5 13.14 92.5 7.5 -- 14.0 16 88.75 7.5 3.75 16.21 17 90.0 10.0 -- 14.75 1~ 85.0 10.0 5.0 21.6 19 80.0 20.0 -- 20.36 70.0 30.0 -- 52.5 (a) Melt Index = Flow rate @ 44 psi (Load of 2.164 kgs) and at 230C, with Capillary Die Dimensions:
- Die I.D. = 0.0825"
- Oie Length ~ 0.315"
, , ; - ~ .
.
:,:
2~2~23 PATENTS
_19_ As can be seen from Tables 1 and 2 above and Figures 1-8, the physical properties of the "40 LDPE/60 ATH" resin (also referred to herein as "LDPE/ATH resin")/SFR 100 blend shows some unique trends, which are discussed as follows.
The flammability performance of this blend is unique. The ATH-LDPE resin itself has poor flame ~esistance as indicated in Figures 2, 3 and 4. Aluminum trihydrate at 60~ does not improve flame resistance of polyethylene. However~ the addition of SFR 100 or silicone/magnesium stearate at various concentrations improves the Limiting Oxygen Index and Flame Out Time (UL 94 test). The oxygen index seems to be independent of the addition of magnesium stearate (Fig. 2), but flame out times appear to decrease at low concentrations (i.e. less than
5%, fig. 3) of the magnesium stearate.
Thus, the data shown in Tables l and 2 and Figures 1-~
indicates that, in general, Group IIA metal salts are unnecessary to impart improved flame resistant properties to highly filled copolymers- of polyethy~e~e containing aluminum trihydrate and, in critical amounts, SFR 100.
Table 2 and Figures 5 to 8 show the impact of SFR 100 and silicone/magnesium stearate on various physical properties of the LOPE/ATH resin. The low temperature impact strength is pronounced in the samples with SFR 100 alone. Tensile Elongation and Modulus seem to be unaffected by the additional presence nf magnesium stearate (Figures 7 and 8).
:
20~22~3 PATENTS
Overall, the evidence presented in the tables and figures above indicates that in ATH-filled thermoplastic compositions, the presence of critical amounts of SFR 100 alone, i.e., without magnesium stearate, will improve the flame resistance of the thermoplastic composition and many of the properties studied.
Modifications and variations of the present invention are possible in light of the above teachings. It should therefore be understood that changes may be made in the particular embodiments of the invention described which are within the full intended scope of the invention as defined by the appended claims.
~ .
Thus, the data shown in Tables l and 2 and Figures 1-~
indicates that, in general, Group IIA metal salts are unnecessary to impart improved flame resistant properties to highly filled copolymers- of polyethy~e~e containing aluminum trihydrate and, in critical amounts, SFR 100.
Table 2 and Figures 5 to 8 show the impact of SFR 100 and silicone/magnesium stearate on various physical properties of the LOPE/ATH resin. The low temperature impact strength is pronounced in the samples with SFR 100 alone. Tensile Elongation and Modulus seem to be unaffected by the additional presence nf magnesium stearate (Figures 7 and 8).
:
20~22~3 PATENTS
Overall, the evidence presented in the tables and figures above indicates that in ATH-filled thermoplastic compositions, the presence of critical amounts of SFR 100 alone, i.e., without magnesium stearate, will improve the flame resistance of the thermoplastic composition and many of the properties studied.
Modifications and variations of the present invention are possible in light of the above teachings. It should therefore be understood that changes may be made in the particular embodiments of the invention described which are within the full intended scope of the invention as defined by the appended claims.
~ .
Claims (18)
60SI-1279/MAM/8973o What is claimed is:
1. A flame retardant composition consisting essentially of by weight:
A. about 30 to about 60 parts by weight of a thermoplastic;
B. about 40 to about 70 parts by weight of aluminum trihydrate, the sum of (A) and (B) being 100 parts;
C. a silicone oil; and D. a silicone resin which is soluble in the silicone of component C, the ratio of (C) to (D) being from about 2:1 to about 2.5:1, and the sum of (C) and (D) being from about 4 to about 12 parts per 100 parts of (A) plus (B).
A. about 30 to about 60 parts by weight of a thermoplastic;
B. about 40 to about 70 parts by weight of aluminum trihydrate, the sum of (A) and (B) being 100 parts;
C. a silicone oil; and D. a silicone resin which is soluble in the silicone of component C, the ratio of (C) to (D) being from about 2:1 to about 2.5:1, and the sum of (C) and (D) being from about 4 to about 12 parts per 100 parts of (A) plus (B).
2. A composition according to claim 1 wherein the sum of components (C) and (D) is from about 5 to about 10 parts per 100 parts of (A) plus (B).
3. A composition according to claim 2 wherein the sum of components (C) and (D) is from about 5 to about 7 parts per 100 parts of (A) plus (B).
4. A composition according to claim 1 wherein the ratio of component (C) to component (D) is about 2.3:1.
PATENTS
60SI-1279/MAM/8973o
PATENTS
60SI-1279/MAM/8973o
5. A composition according to Claim 1 wherein said silicone resin is an MQ silicone resin comprised of monofunctional M
units of the average formula R3SiO0.5 and tetrafunctional Q
units of the average formula SiO2, and having an average ratio of, approximately 0.3 to 4.0 M units per Q unit.
units of the average formula R3SiO0.5 and tetrafunctional Q
units of the average formula SiO2, and having an average ratio of, approximately 0.3 to 4.0 M units per Q unit.
6. A composition according to Claim 1 wherein said thermoplastic is selected from the group consisting of polypropylene, polyethy- lene, polycarbonate, polystyrene, acrylonitrile-butadiene- styrene terpolymer, polyphenylene oxide-polystyrene blends, acrylic polymer, polyurethane and polyamides.
7. A composition according to claim 1 wherein the silicone oil is an organopolysiloxane comprised of chemically combined siloxy units selected from the group consisting of R3SiO0.5, R2SiO, RSiO1.5, , RR1SiO, , and SiO2 units and mixtures thereof wherein each R represents independently a saturated or unsaturated monovalent hydrocarbon radical, R1 represents independently a saturated or unsaturated monovalent hydrocarbon radical or a radical selected from the group consisting of a hydrogen atom, hydroxyl, alkoxy, aryl, vinyl, or allyl radicals and wherein said organopolysiloxane has a viscosity of approximately 600 to 300,000,000 centipoise at 25°C.
8. A composition as in Claim 7 wherein the silicone oil is an essentially linear polydimethylsiloxane copolymer having a viscosity of 90,000 to 150,000 centipoise at 25°C.
PATENTS
60SI-1279/MAM/8973o
PATENTS
60SI-1279/MAM/8973o
9. A composition according to Claim 1 wherein the thermoplastic is present in an amount of about 30 to about 40 parts by weight.
10. A composition according to Claim 9 wherein the thermoplastic is present in an amount of about 40 parts by weight.
11. A composition according to Claim 1 wherein the aluminum trihydrate is present in an amount of about 60 to about 70 parts by weight.
12. A composition according to Claim 11 wherein the aluminum trihydrate is present in an amount of about 60 parts by weight.
13. A thermoplastic composition having improved flame resistant properties, consisting essentially of:
A. about 40 parts by weight of thermoplastic;
B. about 60 parts by weight of aluminum trihydrate;
C. a silicone oil; and D. a silicone resin which is soluble in the silicone of Component B, the ratio of (C) to (D) being about 2.3:1, and the sum of (C) and (D) being from about 5 to about 7 parts per 100 parts of (A) plus (B).
A. about 40 parts by weight of thermoplastic;
B. about 60 parts by weight of aluminum trihydrate;
C. a silicone oil; and D. a silicone resin which is soluble in the silicone of Component B, the ratio of (C) to (D) being about 2.3:1, and the sum of (C) and (D) being from about 5 to about 7 parts per 100 parts of (A) plus (B).
PATENTS
60SI-1279/MAM/8973o
60SI-1279/MAM/8973o
15. A method for improving the flame resistance of a thermoplastic composition consisting essentially of (A) about 30 to about 60 percent by weight of thermoplastic and (B) about 40 to about 70 percent by weight of aluminum trihydrate, the method consisting essentially of the step of mixing the thermoplastic composition with (C) a silicone oil; and (D) a silicone resin which is soluble in the silicone of Component C, the ratio of (C) to (D) being from about 2:1 to about 2.5:1, and the sum of (C) and (D) being from about 4 to about 12 parts per 100 parts of (A) plus (B).
16. An article of manufacture comprising a substrate coated with the flame retardant composition of claim 1.
17. An article according to claim 16 wherein the substrate is an electrical conductor.
18. The invention as defined in any of the preceding claims including any further features of novelty disclosed.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US54478090A | 1990-06-27 | 1990-06-27 | |
| US544,780 | 1990-06-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2042223A1 true CA2042223A1 (en) | 1991-12-28 |
Family
ID=24173569
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2042223 Abandoned CA2042223A1 (en) | 1990-06-27 | 1991-05-09 | Flame retardant thermoplastic compositions |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH0778171B2 (en) |
| CA (1) | CA2042223A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6326425B1 (en) | 1998-11-17 | 2001-12-04 | Shin-Etsu Chemical Co., Ltd. | Flame retardant resin compositions |
| US6534576B2 (en) | 2000-01-20 | 2003-03-18 | Dow Corning Toray Silicone Co., Ltd. | Flame retardant organic resin composition |
| US20120238702A1 (en) * | 2011-03-16 | 2012-09-20 | Siemens Medical Instruments Pte. Ltd. | Hydrophobic abs plastics material for casings |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3891272B2 (en) | 2002-03-05 | 2007-03-14 | 信越化学工業株式会社 | Flame retardant resin composition and molded product thereof |
-
1991
- 1991-05-09 CA CA 2042223 patent/CA2042223A1/en not_active Abandoned
- 1991-06-24 JP JP17779191A patent/JPH0778171B2/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6326425B1 (en) | 1998-11-17 | 2001-12-04 | Shin-Etsu Chemical Co., Ltd. | Flame retardant resin compositions |
| US6509421B2 (en) | 1998-11-17 | 2003-01-21 | Shin-Etsu Chemical Co., Ltd. | Flame retardant resin compositions |
| US6534576B2 (en) | 2000-01-20 | 2003-03-18 | Dow Corning Toray Silicone Co., Ltd. | Flame retardant organic resin composition |
| US20120238702A1 (en) * | 2011-03-16 | 2012-09-20 | Siemens Medical Instruments Pte. Ltd. | Hydrophobic abs plastics material for casings |
| US8611568B2 (en) * | 2011-03-16 | 2013-12-17 | Siemens Medical Instruments Pte. Ltd. | Hydrophobic ABS plastics material for casings |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0778171B2 (en) | 1995-08-23 |
| JPH04226159A (en) | 1992-08-14 |
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