KR20070017382A - Pelletized brominated anionic styrenic polymers and their preparation and use - Google Patents

Abstract

Despite the fragility of the granules without additives of brominated anionic styrenic polymers, the bromine content is at least about 50% by weight and preferably at least about 70% by weight (preferably at least about 75%) of the pellets using certain mechanical methods. It is desirable to yield pellets of pure brominated anionic styrene-based polymers that remain on this standard US 40 sieve and up to about 30 wt% (preferably about 25 wt% or less) remain on the standard US 5 sieve. I found it possible. In a preferred embodiment, such pelletized anionic styrenic polymers are brominated anionic polystyrenes having a bromine content in the range of at least about 67% by weight, for example from about 67 to about 71% by weight. Also preferred are pelletized brominated anionic styrenic polymers having a melt flow index (ASTM D 1238-99) at 220 ° C., 2.16 kg, of at least 4 g / 10 minutes, preferably at least 5 g / 10 minutes. Another embodiment of the invention is a process for the preparation of pelletized pure brominated anionic styrenic polymers, comprising:

A) forming strands of molten pure brominated anionic styrenic polymer;

B) cooling the strands on the porous conveyor belt and forcing the air flow downwards to break the strands into pellets; And

C) The pellets are dropped in a granulator that removes particulates from the pellets.

Description

Pelletized brominated anionic styrenic polymers and their preparation and use {PELLETIZED BROMINATED ANIONIC STYRENIC POLYMERS AND THEIR PREPARATION AND USE}

Brominated anionic styrenic polymers are excellent flame retardants. Very preferred methods for preparing such polymeric flame retardants are described in US Pat. No. 5,677,390; 5,686,538; 5,686,538; 5,767,203; 5,767,203; 5,852,131; 5,852,131; No. 5,916,978; And 6,207,765.

The properties of brominated anionic styrenic polymers, such as brominated anionic polystyrenes, tend to form a significant amount of small particles and powder when attempting to pellet the product. In pellet formation, it was found that if not bound together by an external crosslinker or the like, it tends to break and return to fine particles and fine powder, typically referred to as "particulates". Because of this property, various conventional pelletization procedures are inherently unsuitable for the production of brominated anionic styrenic polymers free of particulates. As can be readily appreciated, the presence of particulates in this type of product is not only disadvantageous to the appearance of the pelletized product, but moreover is not desired by the consumer.

In order to effectively use brominated anionic styrenic polymers as flame retardants in certain thermoplastic polymers, the use of crosslinking agents or other foreign materials to maintain the present state of the flame retardant in pelletized form is also considered to be undesired by the consumer. Therefore, there is a need for a process for producing pure pelletized brominated anionic styrene-based polymers that do not form undesirable amounts of particulates during manufacture and packaging.

Summary of the Invention

According to the present invention, brominated anionic styrenic polymers can now be prepared and packaged in pure pelletized form, essentially free of particulates. Furthermore, a preferred embodiment of the present invention enables an economic basis since the advantageous results produce only relatively small amounts of particulates during operation. In fact, in the preferred method of the present invention, a small amount of dry fine particles that can be formed can be recycled during operation without high cost or difficulty.

Therefore, according to one embodiment, the present invention has a bromine content of at least about 50% by weight, and at least about 70% by weight (preferably at least about 75% by weight) of the pellets remain in the standard US No. 40 sieve, about 30 Pellets of pure brominated anionic styrene-based polymers, up to% by weight (preferably up to about 25% by weight) remain in the standard US 5 sieve. In a preferred embodiment, such pelletized anionic styrenic polymers are brominated anionic polystyrenes having a bromine content in the range of at least about 67% by weight, for example from about 67 to about 71% by weight. Also preferred is pelletization, wherein the melt flow index (ASTM D 1238-99) at 220 ° C., 2.16 kg is at least about 4 g / 10 minutes, and more preferably at least about 5 g / 10 minutes at 220 ° C., 2.16 kg. Brominated anionic styrenic polymers. When handled properly, the pellets in the manufacture and packaging are substantially free of particulates, ie particles which have passed through the standard US No. 40 sieve.

Another embodiment of the present invention is a process for preparing a pelletized pure brominated anionic styrenic polymer comprising:

A) forming strands of molten pure brominated anionic styrenic polymer;

B) cooling the strands on the porous conveyor belt and forcing the air flow downwards to break the strands into pellets; And

C) The pellet is dropped in a classifier that removes particulates from the pellets.

The term "pure" means that no external components such as binders (e.g., waxes or other polymeric or oligomeric materials), inorganic salts, etc., are added to the brominated anionic styrenic polymer prior to or during the method of making the pellets. it means. Instead, brominated anionic styrenic polymers contain only residual impurities remaining in the brominated polymer after manufacture.

These and other embodiments of the invention will be even more apparent from the following detailed description, drawings and claims.

1 is a schematic front view of a mechanical system found to be effective for producing the pelletized brominated anionic styrenic polymer of the present invention according to the method of the present invention.

FIG. 2 is a schematic plan view of the system of FIG. 1 with components 10 and 12 removed for simplicity.

Bromination Anionic Styrene series  polymer

The polymer which is converted into pelletized form according to the invention comprises one or more combinations of brominated anionic styrenic polymers, i.e., styrene-based homopolymers made of one or more anionic brominated or (ii) ) At least one anionic copolymer of two or more styrenic monomers brominated, or (iii) both (i) and (ii). The bromine content of such polymers should be at least about 50% by weight. The bromine content of the preferred brominated anionic styrene-based polymers, in particular brominated anionic polystyrene, is at least about 60% by weight, and more preferably the bromine content of the brominated anionic styrene-based polymers, particularly brominated anionic polystyrene, is at least about 64% by weight. Particularly preferred brominated anionic styrene-based polymers, especially brominated anionic polystyrenes, have a bromine content in the range of about 67 to about 69% by weight. The bromine content of brominated anionic styrenic polymers, such as brominated anionic polystyrene, will rarely exceed about 71% by weight. Typically the melt flow index of brominated anionic styrenic polymers is at least about 3 g / 10 min, preferably at least about 4 g / 10 min, more, by ASTM D1238-99 test procedure performed at 220 ° C., 2.16 kg. Preferably at least about 5 g / 10 minutes. Typically, this melt flow index will range from about 3 to about 40 g / 10 minutes, preferably from about 4 to about 35 g / 10 minutes. The melt flow index of the most preferred brominated anionic styrenic polymers used in the practice of the present invention is in the range of about 5 to about 30 g / 10 minutes under the above test conditions. In this regard, the polymer may not be “melted” in the sense of reaching a melting point temperature that suddenly begins to transform from solid to liquid. Rather, they are amorphous components that tend to soften gradually as the temperature increases upon heating, so they tend to become more flexible gradually and can be dispersed with other materials using conventional mixing or blending procedures. Tend to take on characteristics.

In all embodiments of the present invention, the most preferred brominated anionic styrenic polymers used to form pellets of the present invention are pure brominated anionic polystyrene.

The brominated anionic styrene-based polymer for forming the pelletized brominated anionic styrene-based polymer according to the present invention is at least one of an anionic homopolymer and / or an anionic copolymer of at least one vinyl aromatic monomer. Preferred vinyl aromatic monomers have the formula:

H ₂ C = CR-Ar

[Wherein R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and Ar is an aromatic group having 6 to 10 carbon atoms (including an alkyl-ring substituted aromatic group). Examples of such monomers are styrene, alpha -methylstyrene, ortho -methylstyrene, meta -methylstyrene, para -methylstyrene, para -ethylstyrene, isopropenyltoluene, vinylnaphthalene, isopropenyl naphthalene, vinylbiphenyl, vinyl Anthracene, dimethylstyrene, and tert-butylstyrene. Polystyrene is the preferred reactant. When brominated anionic styrenic polymers are prepared by bromination of an anionic copolymer of two or more vinyl aromatic monomers, styrene is one of the monomers and styrene is at least 50 wt.%, Preferably at least about 80 wt. It is preferred to include vinyl aromatic monomers. As used herein, the terms “brominated anionic styrenic polymer” and “brominated anionic polystyrene” are distinguished (oligomer or polymer) from oligomers or polymers prepared by oligomerization or polymerization of one or more brominated styrene-based monomers. Properties are considerably different from brominated anionic polystyrene in many respects), pre-existing anionic styrenic polymers, such as anionic polystyrenes or styrenes and anionic copolymers of one or more other vinyl aromatic monomers. Reference is made to the brominated anionic polymer being. In addition, the terms "vinylaromatic" and "styrene-based" in connection with monomer (s) or polymer (s) are used interchangeably herein.

The aromatic pendant component of the anionic styrenic polymer may be alkyl substituted or substituted by bromine or chlorine atoms, but in most cases will not be so substituted. Typically, the anionic styrenic polymers used to prepare the brominated anionic styrenic polymers used in the practice of the present invention have a weight average molecular weight (M _w ) in the range of about 2000 to about 50,000, and the degree of polydispersity Will range from 1 to about 10. Preferred brominated anionic styrenic polymers used in the practice of the present invention have a weight average molecular weight (M _w ) in the range of about 3000 to about 10,000, polydispersities in the range of 1 to about 4, most preferably they From anionic styrenic polymers ranging from about 3500 to about 4500 and 1 to about 4, respectively. Both M _w and polydispersity values were based on the gel permeation chromatography (GPC) technique described herein.

Methods of making anionic styrenic polymers such as anionic polystyrene are known in the art and reported in the literature. For example, US Pat. No. 3,812,088, the disclosure of which is incorporated herein by reference; No. 4,200,713; No. 4,442,273; No. 4,883,846; No. 5,391,655; 5,717,040; 5,717,040; And 5,902,865. Particularly preferred methods are described in co-owned US Pat. No. 6,657,028, issued December 2, 2003, the method specification of which is incorporated herein by reference.

Bromination methods that can be used in the preparation of brominated anionic styrenic polymers are described in US Pat. No. 5,677,390, the disclosure of which is incorporated herein by reference; 5,686,538; 5,686,538; 5,767,203; 5,767,203; 5,852,131; 5,852,131; No. 5,916,978; And 6,207,765.

Typical properties of preferred brominated anionic polystyrenes for use in making the pellets of the present invention include:

Appearance / Form-White Powder

Bromine content-67-71 wt%

Melt flow index (220 ° C., 2.16 kg)-4 to 35 g / 10 min

Tg (℃)-162

Specific gravity (@ 23 ℃)-2.2

TGA (TA instrument model 2950, 10 ° C./min, under N ₂ ):

1% weight loss, ℃-342

5% weight loss, ℃-360

10% weight loss, ℃-368

50% weight loss, ℃-393

90% weight loss, ℃-423

If necessary or deemed desirable, any reliable interpretation procedure as reported in the literature can be used to determine this analysis or property. In any case where you are unsure or controversial, we recommend the following:

1) Bromine Content-Since brominated anionic styrenic polymers have a good or satisfactory solubility in a solvent such as tetrahydrofuran (THF), determination of the total bromine content for brominated anionic styrenic polymers is conventional X It is easily performed using in-line fluorescence technology. The sample analyzed is a diluted sample called 0.1 ± 0.05 g brominated anionic polystyrene in 60 mL THF. The XRF spectrometer can be a Phillips PW1480 spectrometer. A standardized solution of bromobenzene in THF is used as the assay standard.

2) Melt Flow Index—To determine the melt flow index of brominated anionic styrenic polymers, use the procedures and test equipment of ASTM Test Method D1238-99. The extruded plasticizer is operated at 220 ° C. and 2.16 kg applied pressure. The sample used for the test consisted of 14-16 g brominated anionic polystyrene.

3) Weight average molecular weight and polydispersity-M _w value of the anionic styrenic polymer was used as a Waters Model 510 HPLC pump and, as a detector, a Waters refractive index detector, Model 410 and Precision Detector light scattering detector, Model PD2000, or equivalent equipment. Obtained by GPC. The columns are Waters, μStyragel, 500 mm 3, 10,000 mm 3 and 100,000 mm 3. The automatic sampler is Shimadzu, Model Sil 9A. Polystyrene standards (M _w = 185,000) are routinely used to verify the accuracy of light scattering data. The solvent used is tetrahydrofuran, HPLC grade. The test procedure used involves dissolving 0.015 to 0.020 g of sample in 10 mL of THF. An aliquot of the solution is filtered and 50 μl is injected into the column. The separation is analyzed using the software provided by the Precision Detector for the PD 2000 light scattering detector. The instrument is converted to a weight average molecular weight and further converted to a number average molecular weight to provide a result. Therefore, to obtain a value for polydispersity, the value for the weight average molecular weight is divided by the value for the number average molecular weight.

Pellet  Produce

As indicated above, the pelletized brominated anionic styrenic polymers of the present invention can be prepared by a process comprising:

A) forming strands of molten pure brominated anionic styrenic polymer;

B) cooling the strands on a moving porous conveyor belt while forcing air flow downwards such that at least a portion of the strands break into pellets; And

C) leaving the pellets on the conveyor belt and dropping them in a granulator, optionally causing some further cleavage to the pellets, where the granulator removes particulates from the pellets formed in B) and optionally C).

In carrying out step A) above, various commercially available machines can be used successfully to form strands of molten or softened brominated anionic styrenic polymers. For example, co-rotating twin-screw extruders such as those available from Buss Ko-Kneader (Coperion GmbH) or Coperion GmbH, Berstoff, Century, Leistritz, or JSW Japan Steel Works can be used. If the brominated anionic styrenic polymer does not melt, the machine is operated at a suitable temperature profile to at least greatly soften. The temperature profile used will therefore vary somewhat depending on the substrate of the brominated anionic styrenic polymer being treated. Therefore, in the case of the brominated anionic polystyrene, such as SAYTEX ^® HP 3010 has the same properties as described above, it was found that the preferred temperature profile of 220 to 240 ℃.

In step B), the extrudate from the machine is passed through a die plate and allowed to drop the resulting continuous strands on a moving porous conveyor belt. The conveyor belt system is provided with vacuum equipment under a porous layer that continuously blows air over the strands on the belt and down through the device in the belt itself. On the conveyor belt is placed a water jetting machine for cooling the hot polymer strands, and at the bottom an air blower that applies sufficient force to the cooling strands, typically causing at least a portion of the strands to break up on the belt. The remaining undivided strands, if any, undergo fragmentation if left on the conveyor belt, typically because of the gravity acting on the unsupported strands that have recently been made from the end of the belt.

In step C), any previous contents of the conveyor belt, which may have recently been made from the contents of the belt and the ends of the conveyor belt, are dropped into a granulator that separates the pellets and particulates respectively. This fall onto the splitter can also cause some splitting to occur. The granulator may comprise, for example, an essentially horizontally arranged sieve which causes it to oscillate back and forth in the longitudinal direction. Particularly suitable machines of this type are vibration mills such as those sold by The Witte Company, Inc.

In a typical operation of step A), the conveyor belt used was about 14 feet (ca. 4.27 meters) long and operated at a speed in the range of about 100 to about 200 ft / min (ca. 60.96 meters / minute). The applied air and water used for spraying the strands is typically at ambient room temperature, but can be heated if desired to reduce heat shock. The dropping distance from the end of the conveyor belt to the screen of the granulator ranged from about 18 to about 36 inches (ca. 45.7 to ca. 91.4 cm).

In a suitably performed pelletization process of the invention, the product has a particle or dust that passes through the standard US No. 40 sieve of about 5% by weight or less, preferably about 3% by weight or less, more preferably about 1% by weight or less It should be possible to manufacture with. Therefore, the method of the present invention is very effective; Only small amounts of these particulates are collected and are preferably recycled to step A) during the entire pelletization operation.

The above exemplary operation of the present invention can be further recognized with reference to the drawings. Referring now to the preferred system as schematically depicted in FIGS. 1 and 2, the same numerals describe the same parts and the brominated anionic styrene-based polymer in powder form, preferably Saytex HP-3010 polymer in powder form (Albemarle The brominated anionic polystyrene powder having the same properties as that of the Corporation) is injected from the hopper 10 into the powder injector 12 and through the funnel 14 into the kneader 15 . The polymer is passed from the kneader 15 into the crosshead extruder 16 . The kneader-extruder combination heats and forms a melt of the brominated anionic styrenic polymer, the melt being discharged through the die 18, on which a strand of polymer, typically a continuous strand, moves on the conveyor belt 20 . Extruded. In the system depicted, the belt 20 has a distal end of the upper portion of the belt typically about 18 to 36 inches (ca. 45.7 to ca. 91.4 cm) above the oscillating granulator 30 . It is tilted. The spraying system, generally designated 33 , forms and dispenses a spray or spray of water over the hot polymer strand on the top of the belt 20 that moves in the direction indicated by the arrow 35 . Then the cooled strands are carried down the belt 20, air knife 37, 37 for cutting or splitting at least a portion of the strands into pellets by. Vacuum inlet of the underside of belt 20, air knife 37, in proximity to the location of 37 is conventional (not shown), the vacuum manifold system to fall the remaining water and particles from the bottom of the belt 20 ( 39) , (39) . The resulting pellet exits the upper outer end of the belt 20 and falls under the influence of gravity over the operating top surface of the granulator 30, which may be a vibratory granulator as schematically depicted in FIG. The impact of the drop can cause the formation of additional pellets through the break up of the larger pieces falling from the belt 20 . The pellets in the system depicted in FIGS. 1 and 2 are therefore mainly formed in the area extending from the air knives 37 , 37 and comprising the granulator 30 . Transfer devices such as segmented conveyors or bucket-type elevators arranged to receive and transport the pellets forward and upward at a suitable height for injecting the pellets into suitable large packaging containers 50 , such as Supersack or Gaylord containers ( 40) Above, the fine particles are separated and collected by a granulator 30 which continuously conveys the pellets remaining after separation. A small amount of pellet cleavage, which is typically not inevitable, may occur in this packaging step, but if this occurs, the height falling from the conveying device to the packaging container can be reduced to minimize.

It will be readily appreciated that the system as depicted in FIGS. 1 and 2 can be suitably modified to achieve the formation of pelletized pure brominated anionic styrenic polymer (ie essentially free of particulates). For example, a kneader such as Buss Ko-Kneader and the associated crosshead extruder may be replaced with a suitable twin screw extruder, for example any twin screw or single screw extruder having a length / diameter (L / D) ratio of 20/1 or greater. Can be. It is also possible to replace the strand die, the conveyor, and the vibratory granulator with a pelletizer facing the die-side or an eccentric pelletizer.

Of the present invention Pellet

According to the present invention, the pelletized brominated anionic styrenic polymer, if any, is formed and packaged with little or no fine particles or dust. Generally speaking, the pellets of the present invention have a bromine content of at least about 50% by weight (preferably at least about 60% by weight), and at least about 70% by weight of the pellets (preferably at least about 75% by weight) are standard US Pat. It consists of pure brominated anionic styrenic polymer, which remains on the hose body and up to about 30% by weight (preferably up to about 25% by weight) remains on the standard US No. 5 sieve. In a more preferred embodiment, the bromine content of the pellets is at least about 64% by weight, and particularly preferred brominated anionic styrenic polymers have a bromine content in the range of about 67 to about 69% by weight. The brominated content of the pelletized brominated anionic styrenic polymers of the present invention, such as brominated anionic polystyrenes, will rarely exceed about 71% by weight and therefore particularly preferred is in the range of about 67 to about 71% by weight of the present invention. Pelletized brominated anionic styrenic polymers. Also preferred are pelletized brominated anionic styrene-based polymers having a melt flow index (ASTM D 1238-99) of at least about 4, preferably at least about 5.

Particularly preferred pellets of the present invention have a bromine content in the range of about 67 to about 71 weight percent, more preferably in the range of about 67 to about 69 weight percent bromine and at least about 80 weight percent of the pellet (more preferably about 85 weight percent). At least% by weight, most preferably at least about 90% by weight) remains on the standard US 40 body and is at most about 20% by weight (more preferably at most about 15% by weight, most preferably at most about 10% by weight) ) Is formed from a brominated anionic styrenic polymer, which remains on the standard US No. 5 sieve. In all cases, the preferred brominated anionic styrene-based polymer in all of the pelletized products is brominated anionic polystyrene.

Another feature of the preferred pellets of the present invention is that when poured into a 20 mL cylindrical clear plastic cap bottle, essentially no visible perceptible dust or powder remains on the inner wall of the bottle.

As flame retardant Pellet  Usage

The pellets of the present invention can be used as flame retardants in various kinds of thermoplastic polymers. Among these polymers, thermoplastic polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polycyclohexylene terephthalate, and the like; Thermoplastic polyamides such as nylon 6, nylon 6,6, nylon 6,12, and the like; Polycarbonates; Polyphenylene oxides such as poly (2,6-dimethylphenylene oxide); Polysulfones; Polystyrene or other styrenic homopolymers; Copolymers of two or more styrene-based monomers such as styrene, vinyltoluene, ethyl styrene, tert-butyl styrene, α-methyl styrene, vinyl naphthalene, and the like; Rubber-modified vinylaromatic homopolymers or copolymers (eg, high impact polystyrene); Acrylate or methacrylate polymers such as ethylene-methylacrylate, ethylene-ethylacrylate, ethylene-butylacrylate, poly (methylmethacrylate), and the like; Ethylene-vinylacetate copolymers; Acrylonitrile-based copolymers and terpolymers such as acrylonitrile-butadiene-styrene (ABS) and styrene-acrylonitrile (SAN), and the like; Polyolefins such as polyethylene, polypropylene, poly- (1-butene), and copolymers of ethylene with one or more higher vinyl olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene ; And blends, alloys, or composites of different polymers, such as blends of poly (2,6-dimethylphenylene oxide) and polystyrene, blends of polycarbonate and polystyrene, and similar blends. Additional polymers that may be flame retardant in combination with the pelletized flame retardant additive of the present invention include rubbery block copolymers such as styrene-ethylene-ethylene-styrene, styrene-ethylene-propylene-styrene, styrene-ethylene-butylene-styrene , Etc; Polyurethane; Epoxy resins; Phenolic resins; Elastomers such as natural rubber, butyl rubber, GRS, GRN, EPDM, and the like; Polysiloxanes; Etc. are included. In addition, the polymer may be crosslinked by chemical means or spinning where appropriate. Numerous flame retardant-free polymers suitable for use in the practice of the present invention can be obtained from many commercial sources.

A preferred group of substrate polymers that can be effectively flame retarded using the pellets of the present invention is polyester. Thermoplastic polyesters, often referred to as polyalkylene terephthalates, are reaction products of aromatic dicarboxylic acids or reactive derivatives thereof, such as methyl esters or anhydrides, and aliphatic, cycloaliphatic, or araliphatic diols, and such reactions Mixture of products. Examples of such thermoplastic polyesters include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, and related copolyesters and blends (one or more thermoplastic polyesters and one or more other thermoplastic polymers). Such as polycarbonates, especially combinations of aromatic polycarbonates).

Preferred thermoplastic polyesters comprise at least 80% by weight, preferably at least 90% by weight of terephthalic acid relative to the dicarboxylic acid component, and at least 80% by weight, preferably at least 90% by weight ethylene glycol and / or 1, based on the diol component, It contains 4-butanediol units.

In addition to terephthalic acid units, the preferred thermoplastic polyesters and other aromatic or cycloaliphatic C ₈ of less than 20 mol%, preferably 10 mol% _-14 dicarboxylic acids or aliphatic C _{4 -12} dicarboxylic acid units, e. For example, it contains a unit of phthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-diphenyl dicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, or cyclohexane diacetic acid. can do.

In addition to ethylene glycol and 1,4-butanediol units, the preferred thermoplastic polyester is 20 mol% or less, preferably other aliphatic C ₃ of less than 10 mol% _-12 diol or cycloaliphatic C _{6 -12} diol, for example, 1 , 3-propanediol, 2-ethylpropane-1,3-diol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 3-ethylpentane-2 , 4-diol, 2-methylpentane-2,4-diol, 2,2,3-trimethylpentane-1,3-diol, 2-ethylhexane-1,3-diol, 2,2-diethylpropane- 1,3-diol, 2,5-hexanediol, 2,2-bis (4-hydroxycyclohexyl) propane, 2,4-dihydro-1,1,3,3-tetramethylcyclobutane, 2, It may contain a unit of 2-bis [4- (2-hydroxyethoxy) phenyl] propane or 2,2-bis [4-hydroxypropoxy) phenyl] propane.

Polyalkylene terephthalates may be branched by incorporation of relatively small amounts of tri or tetrahydric alcohols or tribasic or tetrabasic carboxylic acids. In this regard, see, for example, US Pat. No. 3,692,744. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethylol ethane and propane and pentaerythritol.

Particularly preferred thermoplastic polyesters are those produced solely from terephthalic acid or reactive derivatives thereof such as dialkyl esters, and ethylene glycol and / or 1,4-butane diol, and mixtures of such polyalkylene terephthalates. Preferred polyalkylene terephthalate mixtures contain 1 to 50% by weight polyethylene terephthalate and 99 to 50% by weight polybutylene terephthalate. Particularly preferred mixtures contain 1 to 30% by weight polyethylene terephthalate and 99 to 70% by weight polybutylene terephthalate.

Polyalkylene terephthalates which are preferably used generally have an inherent viscosity as measured at 25 ° C. in phenol / o-dichlorobenzene (1: 1 parts by weight) using a Ubbelohde viscometer, from 0.4 to 1.5 dl / g, It is preferably 0.5 to 1.3 dl / g, more preferably 0.55 to 1.2 dl / g. Most preferred are polyethylene terephthalate and polybutylene terephthalate in the above inherent viscosity range, and mixtures thereof. As is well known, producers of polyethylene terephthalate engineering resins from raw PET (typically 0.55-0.70 IV) or PET recovered from industrial scraps, polyester film scraps, bottles and, in rare cases, polyester fiber scraps. Mix the product.

Further thermoplastic polyesters that may be used in the practice of the present invention include, for example, polyetheresters, polyester-polycarbonate blends or alloys, polyester-ABS blends or alloys, polyester-MBS blends or alloys, And impact-modified thermoplastic polyesters.

Polyalkylene terephthalates can be prepared by known methods. For example, Encyclopedia of Polymer Science and Technology , Vol. 11, pages 62-128, John Wiley & Sons, Inc., copyright 1969; And Kirk-Othmer, Encyclopedia of Chemical Technology , 4th Ed., Vol. 19, pages 609-653, John Wiley & Sons, Inc., copyright 1996.

Another group of preferred thermoplastic polymers that can be effectively flame retardant using the pellets of the present invention are polyamides, sometimes referred to as nylon polymers. Such polyamide matrix polymers can be any amorphous and / or some crystalline, predominantly aliphatic / cycloaliphatic or partially aromatic thermoplastic polyamides. Typically such materials are diamines whose structure is predominantly or wholly aliphatic or cycloaliphatic, or whose structure is partially or wholly aromatic, and whose structure is predominantly or wholly aliphatic or cycloaliphatic, or whose structure is partially or wholly aromatic From polycarboxylic acids or lactams by polycondensation and / or polymerization processes. Typical amines used to form polyamides include hexamethylenediamine, tetramethylenediamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, diaminodicyclohexylmethane (isomer), diaminodicyclohexyl Diamines such as propane (isomer) and isophoronediamine (isomer), and xylenediamine. Also used as source material are aminocarboxylic acids such as ε-aminocaproic acid, or ω-aminocarboxylic acids such as ω-aminolauric acid and ω-aminoundecanoic acid. Typically, the carboxylic acids used are aliphatic or mixed aliphatic-aromatic dicarboxylic acids having less than 50% by weight aromatic components, such as adipic acid, 2,2,4- and 2,4,4-trimethyladip Acids, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, cyclohexanedicarboxylic acid, hexahydroterephthalic acid, isophthalic acid and terephthalic acid.

Copolyamides from most known monomers can also be used.

Exemplary polyamides that may be used in the practice of the present invention are nylon 6, nylon 6,6, nylon 6,9, nylon 6,10, nylon 6,12, nylon 11, nylon 12, nylon 12,12, nylon 6 / Polyamides such as 6,6 copolymers, and high temperature nylons such as nylon 4,6, and partially aromatic nylons (e.g., Ixef polyarylamide PA MXD6 from Solvay, Zytel HTN from DuPont, and Amodel polyarylamides from Solvay) to be. Other polyamides that may be used include Mitsui Chemicals, Inc. Arlen modified polyamide 6T, Genestar PA9T polyamide resin from Kuraray Company, Stanyl polyamide 46 from DSM, Vydyne polyamide 6/66 copolymer from Monsanto, Polyamide 612 (Vestamid D from Creanova), and similar polyamides do. Among the various nylon polymers, nylon 6 and nylon 6,6 are preferred matrix polymers.

The invention also relates to thermoplastic blends or alloys of one or more polyamides, for example polyamide-polyolefin blends or alloys, polyamide-ionomer blends or alloys, polyamide-ABS blends or alloys, polyamide-EPDM blends or alloys, It is applicable to polyamide-polyphenylene oxide blends or alloys, or impact-modified polyamides.

Methods of making polyamide polymers are known and described in the literature. For example, Encyclopedia of Polymer Science and Technology , Vol. 10, pages 460-482, John Wiley & Sons, Inc., copyright 1969; And Kirk-Othmer, Encyclopedia of Chemical Technology , 4th Ed., Vol. 19, pages 559-584, John Wiley & Sons, Inc., copyright 1996.

The following examples illustrate the practice and advantages of the present invention. This embodiment is not intended to limit the comprehensive scope of the invention.

Example  One

Excellent results that can be achieved according to the invention are shown in the operation using the system as schematically depicted in FIGS. 1 and 2. In this system, the following equipment was used:

a) The extruder system was a 140 mm Buss Ko-Kneader (15) with an L / D of 11/1 (but can be 7.1 or more ) fitted to the crosshead extruder 16 . The screw profile of the kneader included kneading components.

b) The die 18 was a 20-hole die with a hole of 4 mm in diameter.

c) The conveyor belt 20 was a Scheer-Bay conveyor with 14 feet (ca. 4.3 meters) long, 15 inches (ca. 38.1 cm) wide, and 3-inch (ca. 7.6 cm) diameter rollers. The sieve belt is tilted upwards at an angle of about 12 °.

d) The granulator 30 was a Witte model 200 granulator.

The vertical distance between the end of the belt 20 to the top of the granulator 30 was about 24 inches (ca. 61 cm), and the vertical distance from the end of the conveying device 40 to the bottom of the conveying container 50. The distance, when empty, was about 60 inches (ca. 152 cm).

The operating conditions in the system are as follows:

The extruder system was operated at the barrel and at a melt temperature of 220-240 ° C. During operation, a 6 to 8 inch mercury vacuum (ca. 0.21 to 0.28 kg / sq cm) was applied to both the kneader and the crosshead extruder. The conveyor moved at a speed of 150 to 175 ft / min (ca. 45.7 to ca. 53.3 meters / minute). Water spray was injected at a rate of about 1 gallon per minute (ca. 3.79 liters per minute). The air knife was operated at a pressure of 10-25 psig and placed about 5 inches (ca. 12.7 cm) above the surface of the conveyor belt. The vacuum applied under the conveyor belt was about 2200 square feet per minute (ca. 62.3 square feet per minute) and was run across the belt with the opening of each individual applicator with an area of 45 square inches (ca. 114.3 cm 2). The vacuum was applied directly to the near surface of the conveyor belt by means of two vacuum applicators placed.

Periodically for a four hour operating period, samples of brominated anionic polystyrene pellets prepared from the system were recovered, sieved and, in some cases, melt index measurements. In the sieving operation, a 100 gram sample was placed in a pile of three components, the upper part of the standard US No. 5 sieve, the lower component of the standard US No. 40 sieve, and the bottom component of the collection pan for particulates. After placing the sample on the upper sieve, the entire pile was hit 10 times by hand with the same force as possible. The contents of the three components were then weighed to calculate the weight percent value of pellets remaining on the No. 5 sieve, on the No. 40 sieve, and in the collection pan for the particulates.

In melt flow measurement, pellet samples were used in the standardization method.

Table 1 summarizes the data obtained in the above operation.

Example  2

Same equipment as in Example 1, except that the Buss Ko-Kneader and crosshead extruder were replaced by a 90 mm twin screw extruder, model ZSK-90, co-rotating interlock extruder manufactured by Werner Pfleiderer. , Operating conditions, and sample evaluation were used. The extruder was operated at a speed of 1200 lbs / hr (ca. 543 kg / hour) with a temperature profile of 220-240 ° C. In this operation, samples were taken periodically for an operating time of 4 hours. Table 2 summarizes the results of the above operation.

Within the three sigma statistical limits, the results presented in Tables 1 and 2 with respect to the percentage remaining on sieves 5 and 40 show that the remaining percentage for sieve 5 is from 0 to 16% by weight, whereas 40 It shows 83 to 100% by weight remained on the body. Based on the same statistics, 0 to 2% by weight of particulates will pass through No. 40 sieve. Therefore, it was found statistically that the method yielded the desired product yield in the range of 98 to 100%.

Except as otherwise expressly specified, when the article “a” or “an” is used herein, and as used, it is not intended to be limiting and is not intended to be construed in the description of a single element mentioned by the article. It should not be construed as limited. Rather, the article “a” or “an”, as used herein, and as used herein, is intended to include one or more such elements unless the text indicates otherwise expressly.

Each and all patents and documents mentioned in any part of this specification are incorporated herein by reference, as mentioned herein.

The invention is subject to variations that can be considered within the scope and spirit of the claims. Therefore, the specification is not intended to be limiting, and the invention should not be construed as limited to the specific illustrations set forth herein above. Rather, what is intended to be included are those mentioned in the claims and their equivalents permitted by law.

Claims (32)

Pure brominated anionic styrene system with a bromine content of at least about 50% by weight, at least about 70% by weight of the pellets remaining on the standard US No. 40 sieve, and up to about 30% by weight remaining on the standard US No. 5 sieve. Pellets of polymer. The pellet of claim 1 wherein the bromine content is at least about 60% by weight. The pellet of claim 1 wherein the bromine content is at least about 64% by weight. The pellet of claim 1 wherein the bromine content is in the range of about 67 to about 71 weight percent. The pellet of claim 1 wherein the bromine content is in the range of about 67 to about 69 weight percent. The pellet according to any one of claims 1 to 5, wherein the melt flow index is at least 4.5. 7. The pellet of claim 6 wherein the melt flow index is at least 5.5. The pellet according to any one of claims 1 to 5, wherein at least about 75% by weight of the pellets remain on the standard US No. 40 sieve and up to about 25% by weight are left on the standard US No. 5 sieve. The pellet according to any one of claims 1 to 5, wherein at least about 80% by weight of the pellets remain on the standard US No. 40 sieve and up to about 20% by weight remain on the standard US No. 5 sieve. The pellet according to any one of claims 1 to 5, wherein at least about 85% by weight of the pellets remain on the standard US No. 40 sieve and up to about 15% by weight are left on the standard US No. 5 sieve. The pellet according to any one of claims 1 to 5, wherein at least about 90% by weight of the pellets remains on the standard US No. 40 sieve and up to about 10% by weight is left on the standard US No. 5 sieve. The method according to claim 1, wherein at least about 75% by weight of the pellets remain on the standard US No. 40 sieve and up to about 25% by weight remain on the standard US No. 5 sieve and the pellets Pellets with a melt flow index of 4.5 or greater. The method according to any one of claims 1 to 5, wherein at least about 80% by weight of the pellets remain on the standard US No. 40 sieve and up to about 20% by weight remain on the standard US No. 5 sieve and the pellets Pellets with a melt flow index of 4.5 or greater. The method according to any one of claims 1 to 5, wherein at least about 85% by weight of the pellets remain on the standard US No. 40 sieve and up to about 15% by weight remain on the standard US No. 5 sieve and the pellets Pellets with a melt flow index of 4.5 or greater. The method according to claim 1, wherein at least about 90% by weight of the pellets remain on the standard US No. 40 sieve and up to about 10% by weight remain on the standard US No. 5 sieve and the pellets Pellets with a melt flow index of 4.5 or greater. The method according to claim 1, wherein at least about 75% by weight of the pellets remain on the standard US No. 40 sieve and up to about 25% by weight remain on the standard US No. 5 sieve and the pellets Pellets with a melt flow index of 5.5 or greater. The method according to any one of claims 1 to 5, wherein at least about 80% by weight of the pellets remain on the standard US No. 40 sieve and up to about 20% by weight remain on the standard US No. 5 sieve and the pellets Pellets with a melt flow index of 5.5 or greater. The method according to any one of claims 1 to 5, wherein at least about 85% by weight of the pellets remain on the standard US No. 40 sieve and up to about 15% by weight remain on the standard US No. 5 sieve and the pellets Pellets with a melt flow index of 5.5 or greater. The method according to claim 1, wherein at least about 90% by weight of the pellets remain on the standard US No. 40 sieve and up to about 10% by weight remain on the standard US No. 5 sieve and the pellets Pellets with a melt flow index of 5.5 or greater. Of brominated anionic polystyrene with a bromine content of at least about 50% by weight, at least about 70% by weight of the pellets remaining on the standard US No. 40 sieve, and up to about 30% by weight being left on the standard US No. 5 sieve. Pellets. The method of claim 20 wherein at least about 80% by weight of the pellets remain on the standard US No. 40 sieve, up to about 20% by weight is left on the standard US No. 5 sieve and the bromine content is at least about 60% by weight. And pellets having a melt flow index of said polystyrene of at least 4.5. 21. The method of claim 20, wherein at least about 90% by weight of the pellets remains on a standard US No. 40 sieve, up to about 10% by weight is left on a standard US No. 5 sieve and the bromine content is about 67 to about 71 weights. Pellets having a range of% and a melt flow index of said polystyrene of 5.5 or greater. Process for preparing pelletized pure brominated anionic styrenic polymer comprising the following method: A) forming strands of molten pure brominated anionic styrenic polymer; B) cooling the strands on the porous conveyor belt and forcing the air flow downwards to break the strands into pellets; And C) The pellets are dropped in a granulator that removes particulates from the pellets. 24. The process of claim 23 wherein the pure brominated anionic styrenic polymer used in step A) is pure brominated anionic polystyrene. The method of claim 23, wherein the particulates that pass through the standard US 40 sieve produce up to about 2 wt%. 26. The method of any one of claims 23-25, wherein the melt flow index of the polymer used is at least about 4.5. 26. The method of any one of claims 23-25, wherein the melt flow index of the polymer used is at least about 5.5. 26. The process according to any one of claims 23 to 25 wherein the bromine content of the polymer used is at least 50% by weight. 26. The process according to any one of claims 23 to 25, wherein the bromine content of the polymer used is at least 60% by weight. 26. The process of any one of claims 23-25, wherein the bromine content of the polymer used is in the range of about 67 to about 71 weight percent. The process according to claim 23, wherein the bromine content of the polymer used is at least 60% by weight and the melt flow index is about 4.5. 26. The process of any one of claims 23-25, wherein the bromine content of the polymer used is in the range of about 67 to about 71 weight percent and the melt flow index is about 5.5.

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