KR20010031091A - Injection-molded articles made from long chain branched syndiotactic monovinylidene aromatic polymers - Google Patents

Abstract

The present invention relates to an injection molded article made from a composition comprising a syndiotactic monovinylidene aromatic polymer having a long chain branched chain. Long chain branched chains can be prepared during the polymerization reaction by polymerizing in the presence of small amounts of bifunctional monomers.

Description

Injection-molded articles made from syndiotactic monovinylidene aromatic polymers with long chain branching {Injection-molded articles made from long chain branched syndiotactic monovinylidene aromatic polymers}

The present invention relates to syndiotactic monovinylidene aromatic polymers and injection molded articles prepared therefrom.

Syndiotactic monovinylidene aromatic polymers such as syndiotactic polystyrene (SPS) are useful polymers having high melting point and high crystallization rate and good heat and chemical resistance. However, in some applications, such as in electronic connectors and injection molded parts for automotive parts, the melt flow rate or crystallization rate is insufficient for injection molding to obtain the desired properties.

Syndiotactic copolymers with good heat and chemical resistance have also been developed. In U.S. Patent No. 5,202,402 to Funaki et al., A bifunctional monomer was used to form a syndiotactic copolymer with styrene, but an injection molded article is produced because the polymer crosslinks completely at high temperatures to form a thermoset. Melting was not possible.

Injection molded articles are linear syndiotactic as described in U.S. Patent Nos. 5,034,441, 5,326,813, 5,444,126 and 5,418,275, European Patent No. 312976976 and European Patent Nos. 733675 and 736364. It is made from a monovinylidene aromatic polymer. However, the melt flow rate and crystallization rate of linear syndiotactic monovinylidene aromatic polymers are often too low to produce injection molded articles, particularly thin injection molded articles having the desired properties such as low molding stress, sufficient and uniform crystallinity. .

Therefore, it is advantageous to obtain an injection molded article from a syndiotactic monovinylidene aromatic polymer having good heat resistance and chemical resistance, high melt flow rate and high crystallization rate.

The present invention relates to an injection molded article made from a composition comprising a syndiotactic monovinylidene aromatic polymer having a long chain branched chain. Long chain branched chains can be prepared during the polymerization reaction by polymerizing in the presence of small amounts of bifunctional monomers.

Compared to injection molded articles made of linear syndiotactic monovinylidene aromatic polymers, the injection molded articles of the present invention have low molding stress, low filling pressure, and mechanical properties such as improved heat resistance and high temperature creep resistance. It is more uniform and has a higher degree of crystallinity.

In one embodiment, the invention is an injection molded article made from a composition comprising a syndiotactic monovinylidene aromatic (LCB-SVA) polymer having a long chain branched chain.

As used herein, the term "syndiotactic" refers to a stereoregular of at least 90% syndiotactic, preferably at least 95% syndiotactic, of racemic triads measured by 13C nuclear magnetic resonance spectroscopy. The polymer which has a structure is shown.

Syndiotactic monovinylidene aromatic polymers are homopolymers and copolymers of vinyl aromatic monomers in which the chemical structure of the monomer contains both unsaturated and aromatic residues. Preferred vinyl aromatic monomers are compounds of the formula H ₂ C═CR-Ar, wherein R is nitrogen or an alkyl group having 1 to 4 carbon atoms, and Ar is an aromatic radical having 6 to 10 carbon atoms. Examples of such vinyl aromatic monomers include styrene, α-methylstyrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, vinyl toluene, para-t-butylstyrene and vinyl naphthalene; Bromo-substituted styrenes, in particular p-vinyltoluene and ring brominated or ibrominated styrenes. Styrene bromide is particularly useful for producing flammable syndiotactic monovinylidene aromatic polymers. Flammable LCB-SVA polymers can also be prepared by brominating LCB-SVA polymers. Representative syndiotactic copolymers include styrene-p-methylstyrene, styrene-pt-butylstyrene and styrene-toluene copolymers. Syndiotactic monovinylidene aromatic polymers and monomers prepared therefrom are already described, for example, in US Pat. No. 4,680,353, US Pat. No. 4,959,435, US Pat. No. 4,950,724 and US Pat. No. 4,774,301. Known in the art. Syndiotactic polystyrene is a recently preferred syndiotactic monovinylidene aromatic polymer.

Long chain branching can be achieved by polymerizing vinyl aromatic monomers in the presence of small amounts of multifunctional monomers under conditions sufficient to produce syndiotactic monovinylidene aromatic polymers. Multifunctional monomers are compounds that have at least one olefinic functional group capable of reacting with a vinyl aromatic monomer under polymerization conditions. Typically, the multifunctional monomer is a compound of formula I containing 2 to 4 olefinic functional groups.

In Formula I,

R is a group having 2 to 20 carbon atoms, including a vinyl group or a terminal vinyl group, wherein the group having 2 to 20 carbon atoms may be alkyl, alkenyl, cycloalkyl or aromatic, and the cycloalkyl group may be 5 or more carbon atoms And aromatic groups contain at least 6 carbon atoms),

n is an integer of 1 to 3,

Provided that the R groups are in the meta or para position based on the vinyl group of the formula (I), and when n is 1 or more, R may be the same or different.

Preferred R is a vinyl group.

Preferably, the multifunctional monomer contains two terminal vinyl groups where n is one. Typically, such monomers include difunctional vinyl aromatic monomers such as divinyl benzene or di-styryl-ethane.

The amount of the multifunctional monomer depends on the weight average molecular weight (Mw) of the polymer to be produced, but is usually 10 to 1000 ppm, preferably 50 to 800 ppm, more preferably 75 to 650 ppm, based on the amount of the vinyl aromatic monomer, Most preferably, it is 100-500 ppm.

The multifunctional monomer can be introduced into the polymerization reaction by any method that can react the polyfunctional monomer with a vinyl aromatic monomer during the polymerization reaction to produce an LCB-SVA polymer. For example, the polyfunctional monomer may be dissolved in the vinyl aromatic monomer prior to the polymerization reaction or separately introduced into the polymerization reactor before or during the polymerization reaction. In addition, the multifunctional monomer can be dissolved in an inert solvent used in a polymerization reaction such as toluene or ethyl benzene.

As long as the multifunctional monomer is further present during the polymerization, any polymerization process that produces syndiotactic monovinylidene aromatic polymers can be used to prepare the LCB-SVA polymers of the present invention. Conventional polymerization processes for syndiotactic monovinylidene aromatic polymers are well known in the art and include US Pat. No. 4,680,353, US Pat. No. 5,066,741, US Pat. No. 5,206,197 and US Pat. No. 5,294,685. It is described in

Typically, the weight average molecular weight (Mw) of the LCB-SVA polymer is 50,000 to 3,000,000, preferably 100,000 to 1,000,000, more preferably 125,000 to 500,000, most preferably 150,000 to 350,000.

The side chain syndiotactic monovinylidene aromatic polymer contains syndiotactic monovinylidene aromatic polymer chain extensions bonded to the polymer backbone. Syndiotactic monovinylidene aromatic polymers having a long chain branched chain typically contain chain extensions of at least 10, preferably at least 100, more preferably at least 300, and most preferably at least 500 monomer repeat units. do.

Typically, injection molded articles of the present invention are made from a composition of LCB-SVA polymers in the absence of other polymers. However, injection molded articles can be prepared from compositions comprising other components including LCB-SVA and other polymers. The amount of LCB-SVA polymer contained in the composition for injection molding depends on the end use, and in some cases advantages can be obtained even in small amounts. In general, at least 5%, usually at least 20%, preferably at least 40%, more preferably at least 70% and most preferably at least 100% by weight of the LCB-SVA polymer is used for the production of injection molded articles. Used in the composition. Other polymers that can be used in such compositions include straight chain SPS, polystyrene, polyphenylene oxide, polyolefins such as polypropylene, polyethylene, poly (4-methylpentene), ethylene-propylene polymers, ethylene-butene-propylene Copolymers, nylons such as nylon-6, nylon-6,6; Polyesters such as poly (ethylene terephthalate), poly (butylene terephthalate); And copolymers or blends thereof. Other materials or maleated polymers including antioxidants, impact modifiers, tonicity agents, coupling agents (e.g., maleic anhydride modified polyphenylene oxide or maleic anhydride modified syndiotactic monovinylidene aromatic polymers ), An additive comprising a flame retardant comprising a binder that enhances the wet strength of the base fabric, a brominated polystyrene, a brominated syndiotactic monovinylidene aromatic polymer, a brominated aromatic compound, anddimonium trioxide, and polytetrafluoroethylene. It may be added to the SVA polymer composition or an injection molded article prepared therefrom.

Impact modifiers that can be used in LCB-SVA polymer compositions include block copolymers or graft copolymers of vinyl aromatic monomers with butadiene or isoprene monomers, substantially random interpolymers of α-olefin monomers and vinyl aromatic monomers, and polyolefin elastomers. do. The term "interpolymer" as used herein preferably denotes a polymer prepared by the polymerization of two or more different monomers. Thus, the term general interpolymer includes copolymers commonly used to refer to polymers made from two different monomers and polymers made from two or more different monomers.

In the present invention, polymers or interpolymers are described as containing or containing specific monomers, which means that these polymers or interpolymers contain or contain units polymerized from such monomers. For example, when the monomer is ethylene CH ₂ = CH ₂ , the derivatives of these units incorporated into the polymer are -CH ₂ -CH _2- .

Substantially random interpolymers of α-olefins and vinyl aromatic monomers contained in the vinyl aromatic monomer interpolymers include the vinyl aromatic monomers described above as monomers useful for preparing syndiotactic monovinylidene aromatic polymers.

Aliphatic α-olefin monomers contained in the interpolymer include aliphatic and cycloaliphatic α-olefins having 2 to 18 carbon atoms, preferably α-olefins having 2 to 8 carbon atoms. Most preferably, the aliphatic α-olefins are preferably ethylene or propylene, with one or more other α-olefins having 3 to 8 carbon atoms (eg ethylene and propylene, ethylene and octene, or ethylene and propylene and octene) Preferably ethylene.

The interpolymer is preferably a pseudo-random straight chain interpolymer or a substantially straight interpolymer, comprising aliphatic α-olefins and vinyl aromatic monomers, more preferably straight chain interpolymers. These pseudo-random straight chain interpolymers are described in EP-A 0,416,815.

Substantially random interpolymers are prepared by conventional grafting, hydrogenation, functionalization, or other reactions well known to those skilled in the art, as long as their impact or ductility modification is substantially unaffected. Can be modified. The polymer can be easily sulfonated or chlorinated to yield derivatives functionalized according to existing methods.

Pseudo-random interpolymers can be prepared as described in EP-A 0,416,815. Preferred operating conditions for this polymerization reaction are atmospheric pressures to 3000 atm and temperatures of 30 to 200 ° C.

Examples of suitable catalysts and methods for preparing the pseudo-random interpolymers are described in EP-A 416,815, EP-A 468,651, EP-A 514,828, EP-A 520,732, WO 93 /. 23412, U.S. Pat. US Pat. No. 5,064,802, US Pat. No. 5,132,380, and US Pat. No. 5,189,192.

Elastomeric polyolefin impact modifiers may be any elastomeric polyolefin as described in US Pat. No. 5,460,818. Elastomeric polyolefins include all polymers comprising one or more C _2-20 α-olefins in polymerized form having a Tg of less than 25 ° C., preferably less than 0 ° C. Examples of polymer types in which the elastomeric polyolefins of the invention are selected are homopolymers and copolymers of α-olefins, for example ethylene / propylene, ethylene / 1-butene, ethylene / 1-hexene or ethylene / 1-octene Copolymers and terpolymers of ethylene, propylene and comonomers (eg hexadiene or ethylidenenorbornene). Graft derivatives of the foregoing elastomers, such as polystyrene-, maleic anhydride-, polymethylmethacrylate- or styrene / methyl methacrylate copolymer-grafted elastomeric polyolefins, may also be used.

The LCB-SVA polymer composition may also contain an inorganic reinforcing agent. Suitable reinforcing agents include inorganic, glass, ceramic, polymeric or carbon reinforcing filters such as glass fibers, mica, talc, carbon fibers, wollastonite, graphite, silica, magnesium carbonate, alumina, metal fibers, kaolin, silicon carbide, and glass Flakes are included. Such materials may be present in the form of fibers with a ratio of length to diameter (L / D) of 5 or greater. Preferred particle diameters are from 0.1 μm to 1 mm. Preferred reinforcing agents are glass fibers, glass roving or chopped glass fibers having a length of 0.1 to 10 mm and an L / D of 5 to 100. Three such suitable glass fibers are sold under the trade names OCF-187A or 497 (O Owens Corning Fiberglass) or 3540 (PPG). Suitable fillers include nonpolymeric materials that lower the linear coefficient of thermal expansion of the resulting material, provide coloring or dyeing to it, reduce the flame transfer properties of the composition, or change the physical properties of the composition. Suitable fillers include mica, talc, chalk, titanium dioxide, clay, alumina, silica, glass microspheres, wollastonite, calcium carbonate, magnesium sulfate, barium sulfate, calcium oxysulfate, tin oxide, metal powder, glass powder and various pigments do. Preferred fillers are present in particulate form with an L / D of less than 5. The amount of reinforcing agent or filler used is preferably 10 to 50 parts by weight. Preferred fillers are talc with a number average diameter of less than 1 micron, such as MP 10-52 (Mineral Technologies), and wollastonite having a number average diameter of less than 5 micron, such as Jilin 2000 (GLS).

Reinforcing agents can include a surface coating of a sizing agent, or similar coatings that can improve the adhesion between the reinforcing agent and the remaining components, in particular the matrix of the composition, among other actions. Suitable adjuvants may contain amine, aminosilane, epoxy and aminophosphine functional groups and may contain up to 30 non-hydrogen atoms. Preference is given to aminosilane coupling agents and C _1-4 alkoxy substituted derivatives thereof, in particular 3-aminopropyltrimethoxysilane.

LCB-SVA polymer compositions also contain stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, ethylene bis stearamide, pentaerythritol tetrastearate, organic phosphates, mineral oil, trimellitate, polyethylene glycol, silicone Oil, epoxidized soybean oil, tricresyl phosphate, polyethylene glycol dimethyl ether, dioctyl adipate, di-n-butylphthalate, butylene glycol montanate (Wax OP), pentaerythritol tetramonttanate (TPET 141), aluminum Other additives, including lubricants such as monostearate, aluminum distearate, montanic acid wax, montanic acid ester wax, polar polyethylene wax, and nonpolar polyethylene wax. Other additives include polyarylene ethers as described in US Pat. No. 3,306,874, US Pat. No. 3,306,875, US Pat. No. 3,257,357, and US Pat. No. 3,257,358. Preferred polyarylene ethers are poly (2,6-dimethyl-1,4-phenylene) ethers. Polyphenylene ethers are typically prepared by oxidative coupling reactions of the corresponding bisphenol compounds. Preferred polyarylene ethers are polar group functionalized polyethylene ethers which are known compound groups prepared by contacting a polar group-containing reactant with a polyarylene ether. The reaction is usually carried out at elevated temperatures, preferably in a melt of polyarylene ether, under conditions that allow the incorporation of the functionalizing agent uniformly. Suitable temperatures are 150 to 300 ° C.

Suitable polar groups include acid anhydrides, acid halides, acid amides, sulfones, oxazolines, epoxides, isocyanates and amino groups. Preferred polar group-containing reactants are compounds with reactive unsaturated groups having up to 20 carbon atoms, for example ethylenically unsaturated groups or aliphatic ring unsaturated groups, together with the desired polar group functional groups. Particularly preferred polar group-containing reactants are dicarboxylic acid anhydrides, most preferably maleic anhydride. Typically, the amount of polar group functionalizing agent is from 0.01 to 20% by weight, preferably from 0.5 to 15% by weight and most preferably from 1 to 10% by weight, based on the weight of the polyarylene ether. The reaction may optionally be carried out in the presence of a free radical generator such as an organic peroxide or hydrogen peroxide reagent. Methods of preparing polar group functionalized polyarylene ethers are already described in US Pat. No. 3,375,228, US Pat. No. 4,771,096, and US Pat. No. 4,654,405.

Polar group modified polyarylene ethers advantageously act as compatibilizers to improve the adhesion between the reinforcing agent and the syndiotactic monovinylidene aromatic polymer. Thus, it is particularly preferred to use fillers or reinforcing agents when they are additionally used. The amount of polyarylene ether used in the resin blend of the present invention is advantageously 0.1 to 50 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of glass and polyarylene ether.

The polar group modified polyarylene ether may be in the form of a coating applied to the outer surface of the reinforcement to impart additional miscibility between the reinforcement and the polymer matrix. The polar group modified polyarylene ether used in this way can be incorporated into the blend with an additional amount of polyarylene ether or polar group modified polyarylene ether. The surface coating is suitably applied to the reinforcement by contacting it with a solution or emulsion of polar group functionalized polyarylene ether. Solvents suitable for use in dissolving polar group functionalized polyarylene ethers to form solutions or for preparing emulsions of water-in-oil or oil-in-water type include methylene chloride, trichloromethane, trichloroethylene and trichloroethane. Preferably, the concentration of polar group functionalized polyarylene ether in the solution or emulsion is 0.1 to 20% by weight, preferably 0.5 to 5% by weight. After applying the reinforcing agent using a solution or emulsion, the liquid excipient is removed, for example, by evaporation, hernia or vacuum drying. The resulting surface coating preferably accounts for 0.001 to 10% by weight of the unreinforcement weight.

Other additives useful in LCB-SVA polymer compositions include nucleating agents that can shorten the time required to initiate crystallization of syndiotactic monovinylidene aromatic polymer when cooled from the melt. The nucleating agent further increases the crystallinity of the molding resin and distributes the crystallinity more uniformly under various molding conditions. High crystallinity is desirable to achieve increased chemical resistance and improved heat resistance performance. In addition, it is also possible to change the crystal form. Examples of suitable nucleating agents for use herein include magnesium aluminum hydroxide monolayer, calcium carbonate, mica, wollastonite, titanium dioxide, silica, sodium sulfate, lithium chloride, sodium benzoate, aluminum benzoate, talc and metal salts, especially organic acids or phosphates Aluminum salt or sodium salt of phonic acid. Particularly preferred compounds are the aluminum and sodium salts of benzoic acid and C _1-10 alkyl substituted benzoic acid derivatives. Most preferred nucleating agent is aluminum tris (p-tert-butyl) benzoate. The amount of nucleating agent used should be an amount sufficient to initiate nucleation and crystallization in the syndiotactic vinyl aromatic polymer in a reduced time compared to a composition that does not contain such nucleating agent. The preferred amount is 0.5 to 5 parts by weight.

Irganox ^{TM (IRGANOX) 1010, 555,} 1425 and 1076, said the force ^{TM (IRGAFOS) 168, CGL-} 415 and ribs noksil ^TM (GALVINOXYL) (manufactured; Ciba Geigy Corporation), senokseu ^TM (SEENOX) 412S (manufactured by ; Witco), ultra Knox ^TM (ULTRANOX) 626 and 815 (manufactured; GE Specialty Chemicals), marks (mARK) PEP ^TM 36 (manufactured; Adeka Argus), fried light (AGERITE) ^TM white, MA and DPPD, methyl jimeyiteu, bar Knox ^TM (VANOX) MT1 and 12 (manufactured; RT Vanderbilt), Now garde ^TM (NAUGARD) 445 and XL-1 (manufactured; Uniroyal Chemical), a cyano Knox ^TM (CYANOX) STDP and 2777 (manufactured; American Cyanamide), a notek ^TM 201 (vitamin E) (manufactured; Roche), miksim (MIXXIM) CD-12 and CD-16 (manufactured; Fairmount), eta Knox ^{TM (Ethanox) 398, DHT-} 4a, sage Tex ^TM (SAYTEX) 8010 , 120, BT93, and 102 (manufactured; Ethyl), No. star Knox ^TM (Hostanox) PAR 24, 03 and ZnCS1 (manufactured; Hoechst Celanese), benzoate, cesium, sodium, pH stops ^TM (SANDOSTAB) PEPQ (manufactured; Sandoz) , t- Butyl hydroquinone and Santo Bar ^TM (SANTOVAR) A (manufactured; Monsanto), phenothiazine, pyridoxine, copper stearate, cobalt stearate, molybdenum densem (MOLYBDENUM TENCEM) (manufactured; Mooney Chemicals), ruthenium (III) Acetylacetonate, boric acid, citric acid, MARK 6000 (manufactured by Adeka Argus), antimony oxide, 2,6-di-t-butyl-4-methylphenol, stearyl-β- (3,5-di -Tert-butyl-4-hydroxyphenol) propionate, triethylene glycol-bis-3- (tert-butyl-4-hydroxy-5-methylphenyl) propionate, tris (2,4 Antioxidants, pigments and flame retardants, including -tert-butylphenyl) phosphite and 4,4'-butylidenebis (3-methyl-6-tert-butylphenyl-di-tridecyl) -phosphite; Trisnonyl phenyl phosphite, carbon black, PYROCHEK PB68 (Ferro Corporation), decabromodiphenyl oxide, anti-sticking agents such as alumina, silica, aluminosilicate, calcium carbonate, calcium phosphate and silicon Fine particles made of a resin; Light stabilizers such as hindered amine compounds or benzotriazole compounds; Plasticizers such as organopolysiloxanes or mineral oils; Other additives, including blowing agents, extrusion aids, stabilizers, such as bis (2,4-di-tert-butyl phenyl) pentaerythritol and trisnonyl phenyl phosphite, may be included in the compositions of the present invention. It may be.

The injection molded articles of the present invention are a number of methods including direct injection molding, gas assisted injection molding, co-injection molding, reciprocating screw injection molding, multi-station reciprocating screw injection molding, multi-station screw / RAM injection molding and blow molding. It can manufacture by.

Typically, the injection molded article of the present invention has a thickness of about 0.1 to 10 mm, more preferably 0.5 to 5 mm.

The injection molded articles of the present invention can also be applied or laminated with other materials to add additional properties to the injection molded articles.

Injection molded articles of the present invention can be used in electronic connectors, electrical connectors, electrical members, automotive hood bottom components, lighting components, automotive air induction components, automotive coolant system components, and battery compartments.

The following examples are provided to illustrate the invention. The examples are not intended to limit the scope of the invention and should not be so interpreted. Unless otherwise stated, amounts are parts by weight or weight percent.

Example

Preparation of LCB-SVA

All reactions are carried out in anhydrous boxes under inert atmosphere. Reagents, toluene and styrene monomers are purified and handled using standard inert atmospheric techniques. Di-styryl-ethane (DSE) is prepared according to the methods described in W. H. Li et al. J. Polymer Sci., Part A, Polymer Chem., 32 (1994) 2023.

10% methylalumoxane solution in toluene, 1M triisobutylaluminum in toluene and 0.03M pentamethylcyclopentadienyl-titanium trimethoxide solution in toluene at a ratio of 75: 25: 1 in a volumetric flask in a dry box. And mixed with a catalyst solution with a final concentration of 0.003M based on titanium.

4.54 mg of styrene is charged into four ampoules. A 1% solution of di-styryl-ethane (DSE) in toluene is added in the amounts shown below (ppm). The ampoule is then sealed and allowed to equilibrate for 10 minutes at a polymerization temperature of 70 ° C. The polymerization reaction is initiated by the addition of a catalyst solution having a molar ratio of styrene to titanium of 175,000: 1. After 1 hour excess methanol is added to stop the polymerization reaction. The polymer is separated, dried and the molecular weight is determined by hot size exclusion chromatography.

The results are as follows:

DSE (ppm) % Conversion Mn Mw Mz Mw / Mn 0 82 98,700 345,000 684,600 3.50 200 86 67,500 496,900 1,126,100 7.36 400 85 125,800 662,400 1,768,000 5.27 800 79 104,900 659,300 1,703,700 6.28

A significant increase in Mz of di-styryl-ethane is a measure of the long chain branching degree in the SPS polymer.

Large-scale reactions are carried out in a 5 "Teledyne kneader-mixer described in US Pat. No. 5,254,647. A 1.3 weight percent di-styryl-ethane solution in toluene is added to the styrene monomer in the amounts shown in Table 1. And was fed to the reactor at a rate of 17.5 kg / hour so that the residence time averaged 18 minutes .. The polymerization reaction was carried out at 55 to 67.5 ° C. Methylaluminoxane, triisobutylaluminum and octahydrofluorenyl titanium trimethock The catalyst solution consisting of the side catalyst is fed to the reactor so that the molar ratio of styrene to titanium is from 80,000: 1 to 100,000: 1 The product obtained is a fine white powder with a conversion of 36 to 50%. After quenching by adding excess methanol, the sample is dried in a nitrogen-depleted 220 ° C., 5 mm Hg vacuum oven for 2 hours. Mass average molecular weight (Mw) is determined by hot size exclusion chromatography The results are shown in Table 1.

Sample ppm DSE Mw Mn Mz Mw / Mn One 400 294,900 82,100 1,151,900 3.59 2 400 334,800 86,500 1,377,300 3.87 3 250 420,000 92,300 2,418,300 4.55 4 250 368,900 71,600 1,962,000 5.15

A significant increase in Mz of di-styryl-ethane is a measure of the long chain branching degree. The sample in powder form described above is converted to pellets using a 0.5 "single screw extruder. The molecular weight of the pellets is summarized below:

Sample Mw Mn Mz Mw / Mn One 279,900 75,000 1,137,400 3.73 2 304,900 82,000 1,161,100 3.72 3 313,000 74,900 1,294,900 4.18 4 301,000 65,000 1,204,900 4.63

Melt strength is determined according to the method described in the literature (see SK Goyal, Plastics Engineering, 51, (2), 25, 1995), plunger speed of 1 in / min, winder speed of 50 ft / min and test conditions of 279 ° C. Measure using Melt flow rate is measured using a load of 1.2 kg and test conditions of 300 ° C. according to ASTM method D1238. A straight chain SPS polymer with a Mw of 300,000 is used as a control sample. The results are summarized below:

Sample Melt strength (g) MFR (g / 10 min) One 4.0 19.1 2 5.4 14.1 3 5.5 15.5 4 4.5 17.1 Control sample 1.9 3.6

LCB-SPS samples have higher melt strength and melt flow rates compared to straight chain SPS control samples.

Example 1

Preparation of LCB-SPS and Injection Molded Products Prepared therefrom

The polymerization reaction is carried out in a 5 "teledyne kneader-mixer with an average residence time of 18 minutes and then in a 500 liter tank reactor for an average residence time of 10 hours. The operation of these devices is described in US Pat. No. 5,254,647. The styrene monomer is mixed with 250 ppm of a 3.3% solution of di-styryl-ethane in toluene and fed to the reactor at a rate of 17.5 kg / hour The polymerization reaction is carried out at 55 ° C. In addition, methylalumine A catalyst solution consisting of oxane, triisobutylaluminum, and octahydrofluorenyltitanium trimethoxide is fed to the reactor so that the molar ratio of styrene to titanium is 80,000: 1. After the polymerization reaction, the polymer is hermetically degassed as described above. Pelletize The molecular weight of the polymer is determined by hot size exclusion chromatography and the results are shown below:

Mw Mn Mz Mz + 1 Mw / Mn 313,900 86,100 1,227,500 2,729,300 3.65

A straight chain SPS polymer with a Mw of 300,000 is used as a control sample.

LCB-SPS and control polymers are formulated with 30% glass fibers, antioxidants, nucleators and release agents. The composition is extruded on a 40 mm co-rotating twin screw extruder using the following conditions:

Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 die ℃ 280 280 280 290 290 290 300 315

The resulting pellets are injection molded into standard tensile bar specimens using a 100 ton injection molding machine. The set point of the instrument used to shape the tension bar is as follows:

Cycle time 80 sec Cooling time 38 seconds Injection speed 22mm / min Holding pressure 250 psi Holding pressure time 16 seconds Screw speed 40 Barrel Temperature: Supply Area Barrel Area Nozzle 45 ℃ 310, 310, 310 ℃ 315 ℃ Mold temperature 95 ℃

The heat distortion temperature (461 ° F.) of the glass-filled LCB-SPS composition is higher than the heat deformation temperature (373 ° F.) of the corresponding glass-filled straight chain SPS composition.

Other lots of LCB-SPS polymers are also prepared in the same manner as described above. The molecular weight of the polymer is determined via hot size exclusion chromatography and the results are shown below:

Mw Mn Mz Mz + 1 Mw / Mn 366,200 86,300 1,635,100 3,552,000 4.24

A straight chain SPS polymer with a Mw of 300,000 is used as a control sample.

LCB-SPS and control polymers are formulated with 30% glass fibers, antioxidants, nucleators, mold release agents and flame retardant packaging. The compound is extruded on a 40 mm co-rotating twin screw extruder using the same conditions as described above. The resulting pellets are injection molded into standard tensile bar specimens by a 100 ton injection molding machine using the same injection molding conditions as described above.

The formulated pellets are then melted and the viscosity is measured using the capillary method.

LCB-SPS (300,000 Mw) Straight Chain SPS (300,000 Mw) Shear rate in seconds ^-1 Viscosity (cps) Shear rate in seconds ^-1 Viscosity (cps) 300 ℃ 81.92 7712 100.9 9200 252.5 3515 293.9 4055 869.6 1481 950.7 1701 2695 653.4 2780 752.4 9339 258.1 9029 323.9 320 ℃ 84.08 5949 99.68 7502 253.7 2655 295.2 3217 851 1186 970.6 1323 2568 553.5 2876 580.9 8617 230.1 9465 236.7

Glass-filled, flammable LCB-SPS compositions have a viscosity of 12-20% lower over a shear rate of 100 to 10000 sec ⁻¹ than the corresponding straight chain SPS compound.

Flexural creep is measured using a Rheometrics RSA II solids analyzer equipped with a hot oven in anhydrous N ₂ environment. Samples are prepared from injection molded bars having a width of 12.7 mm, a thickness of 3.2 mm and a length of at least 60 mm. A three point flexure fixture with a constant 48 mm distance between points is used. Set the oven to 250 ° C. and equilibrate for 10 minutes. The sample is subjected to a pressure of 1.58 × 10 ⁶ Pa by applying 1 g of compressive force. Creep strain that occurs during the run is measured 500 times over 600 seconds.

LCB-SPS Straight chain SPS Creep after 10 minutes at 250 ° C Creep after 10 minutes at 250 ° C 0.39% 0.45%

LCB-SPS compositions also have improved resistance to creep at elevated temperatures.

Claims (14)

An injection molded article made from a composition comprising a syndiotactic monovinylidene aromatic polymer having a long chain branched chain. The injection molded article according to claim 1, wherein the composition further comprises 10 to 50% by weight of glass fibers based on its total weight. The injection molded article according to claim 2, wherein the composition further comprises a brominated flame retardant and antimony trioxide. The injection molded article according to claim 2, wherein the composition further comprises an impact modifier. The method of claim 4, wherein the impact modifier is selected from the group consisting of block copolymers or graft copolymers of vinyl aromatic monomers with butadiene or isoprene monomers; substantially random interpolymers of α-monomers with vinyl aromatic monomers; Or injection moldings which are polyolefin elastomers. The impact modifier of claim 5, wherein the impact modifier is a styrene-butadiene-styrene copolymer, a styrene-isoprene-styrene copolymer, a styrene-ethylene / butadiene-styrene copolymer, a styrene-ethylene / propylene-styrene copolymer, a styrene-butadiene airborne Injection molding selected from the group consisting of copolymers, styrene-isoprene copolymers, butadiene-styrene-butadiene copolymers, isoprene-styrene-isoprene copolymers, hydrogenated products thereof, ethylene-styrene copolymers and ethylene-octene copolymers. The injection molded article of claim 1, wherein the composition further comprises a lubricant. The method of claim 7, wherein the lubricant is stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, ethylene bis stearamide, pentaerythritol tetrastearate, organic phosphate, mineral oil, trimellitate, polyethylene glycol, Silicone oil, epoxidized soybean oil, tricresyl phosphate, polyethylene glycol dimethyl ether, dioctyl adipate, di-n-butyl phthalate, butylene glycol montanate (Wax OP), pentaerythritol tetramontanate (TPET 141), Injection moldings selected from the group consisting of aluminum monostearate, aluminum distearate, montanic acid wax, montanic acid ester wax, polar polyethylene wax and nonpolar polyethylene wax. The injection molded article of claim 1, wherein the composition further comprises a polyarylene ether. 10. The injection molded article according to claim 9, wherein the polyarylene ether is a polar group functionalized polyarylene ether. The injection molded article of claim 1, wherein the composition further comprises a nucleating agent. The nucleating agent according to claim 11, wherein the nucleating agent is an aluminum magnesium hydroxide monolayer, calcium carbonate, mica, wollastonite, titanium dioxide, silica, sodium sulfate, lithium chloride, sodium benzoate, aluminum benzoate, talc, organic acids and aluminum salts of phosphonic acid and sodium Injection molded article selected from the group consisting of salts. The injection molded article of claim 1, wherein the composition further comprises an antioxidant. The injection molded article according to claim 1, wherein the composition further comprises a flame retardant.