JP2002504611A - Flame retardant polymer blend - Google Patents

Abstract

  (57) [Summary] Antimony-free combinations of phosphate ester flame retardants (especially aryl diphosphates) and organoclays are synergistic with polymer blends, especially polyphenylene ether-polystyrene blends and blends of polycarbonates with styrene copolymers such as ABS copolymers. Imparts flame retardancy. Polyphenylene ether-polystyrene blends without fluorocarbon additives are preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL BACKGROUND OF THE INVENTION

The present invention relates to polymer blends, and more specifically to blends having flame retardancy.

[0002] Improving the flame retardancy of polymers has long been one of the goals of polymer compounders. Flame retardancy is typically underwriters laboratories
es UL-94 test (ASTM D3801). In this test, the polymer that gave the desired V-0 rating was a flame that did not burn for more than 10 seconds after the test flame was applied to the test piece, and that 10 test flames were applied to each of the five test pieces. The time during which the test piece raises the flame and burns does not exceed 50 seconds, that is, the "extinguish time" of the sample is 50 seconds or less.

[0003] Various types of compounds may be used as flame retardant additives. Such compounds include halogenated compounds, especially brominated compounds, which often need to be used in combination with antimony compounds such as antimony trioxide and phosphate compounds. Such additives are often used in combination with an anti-drip agent such as a fluorocarbon polymer.

[0004] In some cases, it may be desirable to use only phosphate ester-based compounds. But,
Often such compounds must be present in large amounts to provide the required flame retardancy. For example, commercial blends of polyphenylene ether and olefin polymers often require phosphate ester-based compounds in an amount greater than 20 phr (parts by weight per 100 parts by weight of resin). In the case of a blend of a polycarbonate and an alkenyl aromatic copolymer (for example, a copolymer of styrene, acrylonitrile and butadiene), the amount of the phosphoric ester compound usually exceeds 5 phr.

[0005] The use of organoclays with flame retardant additives has been disclosed. Usually,
The additives used are halogen-based.

[0006] For example, US Pat. No. 4,582,866 discloses a copolyester elastomer containing a bromine compound and antimony trioxide as a flame retardant improver, wherein a clay modified with a quaternary ammonium salt is used as an anti-drip agent. Have been. GB 1114174 discloses polymers such as polyamide, polystyrene and olefin polymers, flame retardant additives (which may be halogen-based or phosphate-based), and organophilic cations as anti-drip agents. Blends with modified clays are disclosed. According to EP-132,228, polyesters can be made flame-retardant by the action of halogenated compounds in combination with antimony or phosphorus compounds and organically modified layered silicates. A similar blend using this modified clay as a "drip inhibitor" is disclosed in European Patent Application No. 239986.

[0007] Applicant's pending US patent application Ser. No. 08 / 950,092 discloses a combination of polyester, a halogenated flame retardant, an organoclay, antimony oxide and a fluorocarbon polymer. It is stated that this combination of additives allows to reduce the use of halogenated flame retardants and antimony oxide.

[0008] The above prior art does not seem to suggest a measure for improving flame retardancy applicable to various polymer blends. Furthermore, they have no relevance to the use of a phosphate ester-based flame retardant alone, and there is no description of a potential synergist.

[0009]

SUMMARY OF THE INVENTION

The present invention is based on the discovery that organoclays can be used as synergists for phosphate-based flame retardant additives in polymer blends, thereby significantly reducing the additive concentration in the blend. . The function of the organoclay is not merely as an anti-drip agent, but can actually form a synergistic combination with the phosphate ester flame retardant to reduce the use of the phosphate ester flame retardant. It has also been found that for certain blends of the present invention, the presence of the fluorocarbon polymer is unnecessary, and such a polymer is even disadvantageous because it can impair the flame retardancy of the blend.

The present invention includes a composition comprising the following components (A) to (D) and optionally a reaction product thereof, and containing no antimony compound. (A) a major amount of the first thermoplastic resin; (B) a small amount of the second thermoplastic resin in the range of about 3-45% by weight, based on Component A and Component B; (D) one or more organoclays, provided that the proportions of component C and component D are such that the UL-94 test yields a V-0 rating or averages It is an effective amount to reduce the quenching time by 10% or more.

[0011]

[Preferred Embodiment]

Whether or not the components of the composition of the present invention cause a chemical interaction to form another substance has not been ascertained and is not critical to the present invention. Accordingly, the present invention relates to the above composition, regardless of whether a chemical interaction has occurred. In other words, the present invention encompasses both compositions comprising the above components and compositions comprising their reaction products.

[0012] Component A and component B are a first thermoplastic resin and a second thermoplastic resin. These resins have different structural units. For example, if component A is a homopolymer, component B may be a copolymer containing the same structural unit as component A together with another structural unit. However, in most cases, component A and component B contain completely different structural units.

The chemical structure of the resin constituting component A and component B is not important as long as the above conditions are satisfied. Both addition polymers and condensation polymers are included. Exemplary thermoplastic resins are olefin polymers, such as polyethylene and polypropylene; Polymers of saturated carboxylic acids and their functional derivatives; alkenyl aromatic polymers such as polystyrene; diene polymers such as polybutadiene and polyisoprene; nylon-6
Polyamide such as poly (ethylene terephthalate) and poly (butylene terephthalate); polycarbonate such as bisphenol A polycarbonate; and poly (2,6-dimethyl-1,4-phenylene ether) and copoly (2 , 6-dimethyl-1,4-phenylene ether)-(2,
Polyarylene ethers such as 3,6-trimethyl-1,4-phenylene ether). Both homopolymers and copolymers are included, and the latter may be a random copolymer, a block copolymer, or a graft copolymer. For example, suitable polysrenes include homopolymers and copolymers. The latter includes high impact polystyrene (HI
PS), which is a type of rubber modified polystyrene in the sense of including blends and grafts, where the rubber is polybutadiene or about 70-98% styrene and 2-30% diene monomer. It is a rubber-like copolymer consisting of

The blend of component A and component B may be compatible, incompatible, or chemically or physically compatibilized by known methods. It is often preferred that component B is an auxiliary of component A (eg, an impact modifier or a second component of an industrial polymer blend).

For many applications, preferred polymer blends are blends of polyphenylene ether, especially homopolystyrene and blends of homostyrene and copolystyrene, including copolymers of diene rubber and styrene (eg, high impact polystyrene), and There are blends of polycarbonate. In some polycarbonate blends, component B is composed of one or more types of copolystyrene. In particular, component B is one or more types of copolymers of aliphatic diene, nitrile and styrene (for example, acrylonitrile-butadiene-styrene or ABS copolymer). There is something consisting of. The copolystyrene blended with the polycarbonate is often a mixture of an ABS copolymer and a styrene-acrylonitrile copolymer.

The component C may be a phosphate-based organic compound that imparts flame retardancy. "
The “phosphate ester type” means an organic compound containing one or more phosphate ester (PO ₄ ) groups.

Suitable phosphoric ester compounds also include triaryl monophosphates such as tricresyl phosphate. However, a preferred phosphate compound is an aryl diphosphate. Aryl diphosphates include compounds of the formula:

(A ¹ O) ₂ P (O) O [A ² OP (O) (OA ¹ ) O] _n A ¹ wherein each A ¹ is independently a monovalent C _6-20 aromatic group. And each A ² is a divalent C _6-20 aromatic group, and n is 0 to 5, preferably 1. The aromatic group may be a hydrocarbon or a substituted hydrocarbon group, but is preferably a hydrocarbon group. The term “aromatic” includes monocyclic, including alkylaromatic groups such as methylphenyl, dimethylphenyl, 2,2-bis (4-phenylene) propane (ie, groups derived from bisphenol A). And polycyclic fused rings and polycyclic bonded ring groups.

Specific examples of suitable aryl diphosphates include hydroquinone bis (diphenyl phosphate), resorcinol bis (diphenyl phosphate), bisphenol A bis (diphenyl phosphate) and resorcinol bis (di-2,6-
Xylyl phosphate). Preferred diphosphates are generally resorcinol bis (diphenyl phosphate) and bisphenol A bis (diphenyl phosphate).

Component C is the only flame retardant in the composition of the present invention. Therefore, there are no halogenated flame retardants.

Component D is one or more organoclays. "Organoclay" as used herein
Is a layered clay (usually a silicate clay) derived from a layered mineral, in which organic groups have been chemically incorporated by ion exchange (particularly cation exchange) with organic ions and / or onium compounds. Things. Exemplary organic ions are monoammonium and polyammonium cations such as trimethyldodecylammonium and N, N'-didodecylimidazolium.

Exemplary layered minerals are kaolinite and montmorillonite. Minerals of the illite group, such as hydromica, fengite, branmarite, glauconite, celadonite, may also be used. Frequently, preferred layered minerals include what are referred to as 2: 1 layered silicate minerals, including muscovite, vermiculite, saponite, hectorite, and montmorillonite, the latter being often the most preferred. Although layered minerals can be synthesized, layered minerals are mostly naturally occurring and are commercially available. For a detailed description of suitable layered minerals see US Pat. No. 5,553,0052.
And the disclosure of which is incorporated herein by reference.

[0023] Among the organoclays that can be used, specific examples of suitable organoclays that are commercially available or that can be easily prepared are cation-exchanged with dimethyldi (hydrogenated tallow) ammonium ion, commercially available from Southern Clay Products. CLAYTONE HY which is montmorillonite, and dodecylammonium, trimethyldodecylammonium, N, N'-didodecylimidazolium, N
Montmorillonite which has been cation-exchanged with an ion such as N, N'-ditetradecylbenzimidazolium or methylbis (hydroxyethyl) (hydrogenated tallow) ammonium.

The compositions of the present invention may include conventional additives for polymer blends of the type described above, provided that no antimony compound is used as an additive. Suitable additives include anti-drip agents, stabilizers, fillers, pigments, dyes, antistatic agents, crystallization aids and mold release agents. These are well known in the art and will not be dealt with in detail herein.

In a composition wherein component A is a polyphenylene ether, especially a component B which is a polymer of one or more ethylenically unsaturated monomers and in which the amount of component C is relatively low, the fluorocarbon polymer is It is often preferred not to use it as an anti-drip agent. Thus, a preferred embodiment of the present invention is a polyphenylene ether blend containing less than 20 parts by weight of component C per 100 parts by weight of components A and B in total (phr) and no fluorocarbon polymer. The presence of the fluorocarbon polymer in such a blend impairs flame retardancy, exemplified by either or both the UL-94 test rating and flame out time.

The proportions of each component in the compositions of the present invention can vary over a wide range. Component A
Is present in a majority amount based on the total amount of the components A and B, and the component B is present in about 3% of the total amount.
４５45% by weight, preferably about 5-40% by weight.

[0027] Component C and component D are present in an amount effective to produce a V-0 rating in the UL-94 test or reduce the average flame out time by more than 10%. The amounts are as follows: Component A and Component B
Varies depending on the type of

When component A is a polyphenylene ether, especially when component B is an addition polymer of one or more ethylenically unsaturated monomers, the proportion of component C is usually from 10 to
It is 25 phr, preferably 15 to 20 phr. The ratio is 20 phr
Above D, it is often not necessary to use component D to obtain satisfactory flame retardancy. Below 15 phr, even with the use of component C and component D, it may not be possible to achieve the desired balance between flame retardancy and other properties.

In the case of polycarbonate blends, especially in the case of blends with addition polymers of ethylenically unsaturated monomers, the proportion of component C is usually about 5 to 15 phr, preferably 7 to 15 phr.
１１11 phr. If the amount is small, little or no flame retardancy is obtained even in the presence of the component D, and it is not necessary to increase the amount, and the effect of the component D may be impaired.

It is generally effective to use from 0.08 to 0.6 phr of component D, with higher amounts having no effect, but rather reducing flame retardancy or the presence of polycarbonate in the blend. If so, the polycarbonate may be deteriorated. Even within this range, slight variations in the effect are observed, especially when the amount of component C is near the limit. However, an effective amount can be easily determined by those skilled in the art by a simple experiment.

Fluorocarbon polymer, often polytetrafluoroethylene (PTFE)
In blends where is used as an anti-drip agent, the polymer is generally from about 0.1 to 0
. Used in the range of 5 phr.

The compositions of the present invention may be manufactured by conventional blending techniques for thermoplastics. Such techniques include solution blending and melt blending. Melt blending, especially by a method suitable for continuous operation such as extrusion, is often preferred.

The present invention is illustrated by the following examples. All parts and percentages are on a weight basis. The molecular weight is the weight average molecular weight and was measured by gel permeation chromatography. Intrinsic viscosity was measured at 25 ° C. in chloroform. UL-94 test is 1/16
Performed on inch (1.6 mm) specimens.

[0034]

【Example】

Example 1 64.32 parts of poly (2,6-dimethyl-1,4-phenylene ether) having an intrinsic viscosity of 0.46 dl / g; HIPS (molecular weight 210000-250,000, rubber content 10.3%, melt flow index 2. 2 to 3.1 g / 10 minutes) 35.
68 parts; 5.49 phr of conventional additives including stabilizer, impact modifier and release agent; 50
0.15 phr of a 50% poly (tetrafluoroethylene) and 50% styrene-acrylonitrile copolymer (72% styrene units) blend (“PTFE blend”)
And 5.32 phr, 10.63 phr, 15.95 phr and 21.26 p;
A series of experiments were performed with a blend of hr and various proportions of resorcinol bis (diphenyl phosphate). These blends were made by mixing the components in a Henschel mixer and extruding in a counter-rotating 20 mm twin screw extruder at a temperature in the range of 120-232 ° C. The UL-94 test required 21.26 phr diphosphate to achieve a V-0 rating.

A similar blend containing 21.26 phr of diphosphate was made with and without PTFE and organoclay (CLAYTONE HY). UL
-94 test results and the average extinction time (FOT) for 5 sets of 5 test specimens each
) Are shown in Table 1.

[0036]

[Table 1]

A comparison of Blends 2 and 4 with Blends 1 and 3 shows that at this level of diphosphate, the presence of the PTFE blend improves FOT. The presence of organoclay has no adverse effect in the presence of PTFE (blends 2 and 4) and has a beneficial effect in the absence of PTFE (blends 1 and 3).

Example 2 A blend similar to Example 1 was prepared and tested except that it contained 15.95 phr diphosphate. Table 2 shows the results.

[0039]

[Table 2]

At this level of diphosphate (less than 20 phr), the presence of PTFE impairs the flame retardancy of the blend. This is for blends 5 and 7 and blends 6 and 8
It is clear from the comparison with. The presence of the organoclay significantly reduces FOT, with or without PTFE (compare Blends 7 and 8 with Blends 5 and 6).

Example 3 A blend similar to that of Example 1 was prepared and evaluated except that it contained bisphenol A bis (diphenyl phosphate) in an amount of 25.80 phr. Table 3 shows the results.

[0042]

[Table 3]

Also in this case, the effect obtained by the presence of the organoclay is apparent. PTF
The presence of E has virtually no effect on flame retardancy.

Example 4 A blend similar to Example 3 was prepared and tested, except that it contained 19.35 phr of bisphenol A bis (diphenyl phosphate). Table 4 shows the results.

[0045]

[Table 4]

Again, it is clear that flame retardancy is improved by the presence of the organoclay, and that at this level of diphosphate, the presence of PTFE impairs flame retardancy.

Example 5 Using the blending method of Example 1, 81.7% of a linear bisphenol A polycarbonate resin having an intrinsic viscosity of 0.50 dl / g; (1) a discontinuous elastomer phase (polybutadiene having an average particle size of about 300 nm) Hard thermoplastic phase (polystyrene 75 pb
45.5% of a commercially available emulsion-grafted ABS graft copolymer containing a copolymer of w and acrylonitrile (25 pbw) and (2) a styrene-acrylonitrile copolymer having a molecular weight of about 90,000 (SAN, 75 parts of styrene / 25 parts of acrylonitrile) 54 .5%
A blend comprising about 18.3% of an addition copolymer mixture with 9.5 phr of resorcinol bis (diphenyl phosphate); and 0.4 phr of a PTFE blend. Although there was a slight difference in the amount ratio between the polycarbonate and the addition polymer in these blends, it is unlikely that the difference would have any effect on the properties studied. Table 5 shows the results.

[0048]

[Table 5]

The results in Table 5 show that at this level of diphosphate, only 0.1 phr organoclay improves flame retardancy.

Example 6 A blend similar to Example 5 was prepared and tested except that it contained about 82% polycarbonate, 18% addition polymer and 7.5 phr diphosphate. Table 6 shows the results.

[0051]

[Table 6]

At this level of diphosphate, 0.1 to 0.25 phr of organoclay has the desired improvement in flame retardancy.

Example 7 Approximately 82.4% polycarbonate, 17.6% addition polymer and 6.0 phr
A blend similar to that of Example 5 was prepared and tested, except that it contained a diphosphate of Table 7 shows the results.

[0054]

[Table 7]

At this level of diphosphate, flame retardancy is improved without the organoclay.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kouri, Farid Foad United States, 12065, New York, Clifton Park, Tamarack Lane, No. 6 (72) Inventor Campbell, John Robert United States, 12065, New York State, Clifton Park, Pepper Hallow, No. 41 F term (reference) FD136 FD137

Claims (19)

[Claims] 1. A composition comprising the following components (A) to (D) and optionally their reaction products and free of antimony compounds. (A) a major amount of the first thermoplastic resin; (B) a small amount of the second thermoplastic resin in the range of about 3-45% by weight, based on Component A and Component B; (D) one or more organoclays, provided that the proportions of component C and component D are such that the UL-94 test yields a V-0 rating or averages It is an effective amount to reduce the quenching time by 10% or more. 2. The composition of claim 1, wherein component C is one or more aryl diphosphates. 3. The composition according to claim 2, wherein the proportion of component B is about 5 to 40% of the sum of component A and component B. 4. The amount of component D is from 0.1 to 100 parts by weight of the total of component A and component B.
3. The composition of claim 2, wherein the composition is in the range of 08 to 0.6 parts by weight. 5. The composition according to claim 4, wherein component C is resorcinol bis (diphenyl phosphate). 6. Component C is bisphenol A bis (diphenyl phosphate)
The composition according to claim 4, which is: 7. The composition of claim 4, wherein component D is montmorillonite into which the organic moiety has been introduced by cation exchange. 8. The composition according to claim 4, wherein component A is a polyphenylene ether. 9. The composition according to claim 8, wherein component A is poly (2,6-dimethyl-1,4-phenylene ether). 10. The amount of the component C is 2 per 100 parts by weight of the total of the components A and B.
9. The composition of claim 8, wherein the composition is less than 0 parts by weight. 11. The composition of claim 10, wherein said composition does not comprise a fluorocarbon polymer. 12. The composition according to claim 11, wherein component B is a polymer of one or more ethylenically unsaturated monomers. 13. The composition according to claim 12, wherein component B is homopolystyrene or copolystyrene. 14. The composition of claim 13, wherein component B is high impact polystyrene. 15. The composition according to claim 2, wherein component A is a polycarbonate. 16. The composition of claim 15, wherein component A is bisphenol A polycarbonate. 17. The composition of claim 15, comprising one or more fluorocarbon polymers in an anti-drip amount. 18. The composition of claim 17, wherein component B comprises one or more ABS copolymers.
A composition as described. 19. The composition of claim 18, wherein component B is a mixture of one or more ABS copolymers and one or more styrene-acrylonitrile copolymers.