JPH09511276A - Free-radical grafting of monomers onto polypropylene resin - Google Patents

Abstract

  (57) [Summary] (i) A polypropylene resin is mixed with an allyl epoxy compound, a styrene compound and a peroxide as an initiator, and (ii) the above mixture is grafted onto the polypropylene resin with an allyl epoxy compound and a styrene compound to a desired degree. Heating to a temperature above the melting point of the polypropylene resin and the decomposition temperature of the peroxide, under continuous mixing conditions, until (iii) the resulting composition is cooled and ground. , A method for grafting free radicals of monomers onto a polypropylene resin. The graft polypropylene composition obtained by the above method contains glycidyl methacrylate in an amount of 0 to 10% by weight and styrene in an amount of 0 to 10% by weight, calculated on the polypropylene resin. The grafted polypropylene composition may be used as a compatibilizer in the production of polymer blends, as a polymer adhesion promoter and in articles requiring improved printability.

Description

Detailed Description of the Invention Free-radical grafting of monomers onto polypropylene resin Technical field   The present invention relates to a method of grafting free radicals of monomers onto a polypropylene resin. Book The invention is particularly directed to two different monomers, preferably an acrylic polymer, on a polypropylene polymer. Method for simultaneously grafting rill epoxy compound and styrenic compound and method It relates to substances obtained by the method. background   In order to produce a composition with improved properties, certain compounds on the polymer backbone are It is known to modify polypropylene resin by grafting .   European Patent No. 0.280.454 has at least two different types on a molten hydrocarbon polymer. A method of grafting a monomer is disclosed. In the examples, the polymer Is a homopolymer of propylene, high density polyethylene or linear low density polyethylene. And the monomer is styrene or maleic anhydride. Different from the method of the present invention Therefore, the above method does not involve the presence of an initiator for the grafting reaction and does not oxidize the polymer. Performed using the extruder under extrusion conditions, in the substantial absence of inhibitors .   U.S. Pat.No. 5,079,295 is polyphenylene ether resin, modified propylene polymerization It relates to a thermoplastic composition comprising a body and a rubbery substance. polypropylene Graph of monomer mainly composed of styrene and unsaturated carboxylic acid or its derivative I am making it. A number of grafting methods have been described. In the example, 100 Parts by weight polypropylene to 1 part maleic anhydride (MAH), 1 part styrene and 1 part Part of the peroxide is mixed in a mixer and then extruded at 220 ° C. In another aspect, A dispersion of polypropylene, styrene and MAH in water at 120 ° C in an autoclave. Reacting. In yet another embodiment, the MAH of the dispersion is glycidyl methacrylate. Or glycidyl acrylate.   Norway (NO) patent application No. 924786 uses organic peroxides as free radical generators. Obtained by kneading the molten mixture, preferably in an inert atmosphere, Polypropylene grafted with glycidyl acrylate or glycidyl methacrylate It relates to a ropylene composition.   In the grafting method, the high molecular weight raw material polypropylene resin is It should retain its mechanical and mechanical properties. Smell of polypropylene graft method When only one type of monomer such as monomeric allyl epoxy compound is used, Has poor grafting efficiency and scission at the β-position. Due to heavy polymer degradation and simultaneous single weight of added monomer. Accompany. Due to the decomposition of polypropylene, polypropylene having a reduced molecular weight is obtained. The composition produced inevitably results in articles produced from this composition being raw materials. Will have poorer properties than the properties of articles made from polypropylene resin . It is safe to the intermediate polymeric radicals generated during the grafting process. When grafting is performed in the presence of a compound having a stabilizing effect, the problem of chain breakage is Will be avoided. Therefore, the composition exhibits its high molecular weight and high value of physical properties. Will hold. SUMMARY OF THE INVENTION   Now, surprisingly, the free-radical initiation group of the monomer on the polypropylene polymer chain is Degradation of polypropylene polymer by β-dissociation in rafts was carried out using the above graft. It was found that the reduction can be significantly reduced when carried out in the presence of a thylene compound. Was. That is, in the presence of the styrenic compound, in the molten polypropylene resin, Monomeric allyl epoxide without significant degradation of the polypropylene polymer itself. The xy compound may be grafted.   Therefore, according to the present invention, 0.2 to 100 g / 10 min, preferably 0.2 to 50 g / 10 min. Has Routflow index (measured at 230 ° C / 2.16kg according to ASTM D 1238) Free radical grafting of monomers onto polypropylene resin In the method of   (i) The polypropylene resin is represented by the formula: (In the formula, R is H or C_1-4Alkyl; R₁Is-(CH₂) n-, -C (O) O- (CH₂) n-or -(CH₂) n-O-; n is an integer of 1 to 4); formula: (Where R₂Is H, OH, CH_ThreeOr allylic)), and Mixed with peroxide as an initiator;   (ii) Polypropylene of an allyl epoxy compound and a styrene compound is added to the above mixture. Resin under continuous mixing conditions until the desired degree of grafting onto the resin is achieved. Heating to a temperature higher than the melting point of the polypropylene resin and the decomposition temperature of the peroxide, Incidentally   (iii) cooling the obtained composition and pulverizing the composition, A method for grafting free radicals of monomers onto a polypropylene resin is provided.   According to the invention, further, a grafted polypropylene obtained by the above method A composition is provided.   The composition of the present invention is used as a compatibilizer in the production of polymer blends as a polymer contacting agent. It can be used as an adhesion promoter and in articles requiring improved printability. Detailed Description of the Invention   The object of the present invention is to provide a method for grafting free radicals of monomers onto polypropylene resin. This method achieves a substantial degree of polypropylene due to chain scission. Carried out under conditions that give improved levels of grafting without degradation of You. This means that grafting an allyl epoxy compound in the presence of a styrenic compound Achieved when done.   The polypropylene resin that can be used in the method of the present invention is polypropylene homopolymer. And copolymers of propylene with ethylene and / or butadiene, in particular 150,000 Weight average molecular weight of ~ 500,000 and measured according to ASTM D 1238 at 230 ° C and 2.16 kg load. The melt flow index of 0.2 to 100 g / 10 min, preferably 0.2 to 50 g / 10 min. It has a resin. The copolymer is up to 20% by weight, preferably 2 to 12% by weight. It may contain len.   The monomeric allyl epoxy compounds to be grafted onto the polymer chain are polar or It must contain a functional substituent. The monomer preferably has the formula: (In the formula, R is H or C_1-4Alkyl; R₁Is-(CH₂) n-, -C (O) O- (CH₂) n-or -(CH₂) n-O-; n is an integer of 1 to 4) Selected from the group consisting of R is preferably H or CH_ThreeAnd more preferably CH_Three It is. R₁Is preferably -C (0) O- (CH₂) n-. Therefore, the most preferred compound The product is glycidyl methacrylate.   Suitable styrenic compounds have the formula: (Where R₂Is H, OH, CH_ThreeOr allylic). . R₂Is preferably H, and therefore the most preferred styrenic compound is styrene. It is. Styrene-based compounds are grafted by delocalization It is presumed to stabilize the free radical species present therein. Has a conjugated unsaturated double bond However, other compounds than those mentioned above, such as quinones, can give similar results.   To initiate the grafting, free radicals known to those skilled in the Group-generating peroxide compounds can be used. In particular, the following peroxide initiators are acceptable: Was found to give the following results: 2,5-bis (tert-butylperoxy) Si) -2,5, -Dimethylhexane (“DHBP”), bis (tert-butylperoxyisopro) Pill) benzene [“Perkadox-14”] and 2,5-bis (tert- Butylperoxy) -2,5, -dimethyl-3-hexyne [“Trigonox-145” (“Trig onox-145 ”)].   Polypropylene resin, initiator and graft monomer, melting point of polypropylene resin And intimate mixing at temperatures above both the decomposition temperature of the peroxide and the decomposition temperature of the peroxide is It is a prerequisite for achieving the desired degree of grafting in the method. Required Gu Raft conditions can be achieved by both batch and continuous methods.   In the batch-type grafting method, any conventional type equipped with a continuous stirrer is used. A suitable internal batch mixer may be used, such as a Haake mixer.   Polypropylene resin with styrene compound, allyl epoxy compound and initiator Both are preheated and operated at a mixing speed of 10 to 200 rpm and a temperature of 150 to 200 ° C. Introduce to the opportunity. Generally, acceptable grafting takes less than 15 minutes at the above temperatures. Achieved.   Grafting is preferably carried out in a continuous process, for which purpose an extruder is used. Can be used. The grafting conditions are well known to those skilled in the art and are suitable for the type of extruder used. To combine. The most important features of this method are proper mixing of the polymer melt and uniform temperature. And that the residence time is sufficient to achieve completion of the grafting reaction. . Twin screw disc with co-rotating intermeshing screws Liu extruders, eg ZSK Werner & Pfleiderer extrusion It is preferred to use a machine.   In both batch and continuous grafting methods, the ingredients are Can be fed to the mixer in any number of ways. The order of addition of the components is not critical. For continuous extrusion In some cases, it is possible to premix the ingredients, which may be any conventional Mixer and methods known to those skilled in the art.   To obtain the optimum degree of grafting, add 100 parts by weight of polypropylene resin to 10 parts. Mix with up to 10 parts by weight of styrenic compounds and up to 10 parts by weight of allyl epoxy compounds I do. The actual weight of the styrenic compound and the allyl epoxy compound is Obviously, it will vary with the particular type of compound used, and therefore The invention is not limited to the use of specific amounts of graft compound. Open The initiator is usually added in an amount up to 0,25% by weight of the raw material polypropylene resin, Higher amounts may also be used.   The problem associated with grafting is that the reactants can be mixed with oxygen from the ambient air. Is there. Oxygen spontaneously reacts with the radicals produced, and the chain of the polymer. It produces an oxi-radica which is a particularly active reactant in chain scission. Follow The grafting method is preferably an inert atmosphere, most preferably a nitrogen atmosphere. Done.   The polymer chain scission and molecular weight of the composition of the present invention is the use of a comonomer system as described above. Can be controlled by. When the graft reaction occurs, the styrenic compound undergoes chain transfer. Will act as an agent. If the grafting is performed under the conditions as described above, For the decomposition of polypropylene main chain by β-cleavage, a chain transfer agent compound can be used. Significantly lower than that which can be achieved with conventional grafting methods Would.   In certain aspects of the invention, such as those illustrated by the examples, a predetermined constant The grafting efficiency of glycidyl methacrylate was When the concentration of styrene is increased, the efficiency of incorporation of styrene (incorporation e fficiency) is virtually constant. If styrenic monomer is present, the Grafting level of sidylmethacrylate is the same as when styrenic monomer is not present. Compared with this, it is more than doubled.   The composition obtained by the method of the present invention is 0-10% by weight, preferably 2-5% by weight % Glycidyl methacrylate and 0-10% by weight, preferably 2-5% by weight Of styrene; the above weights are based on the raw, neat polyp It was calculated based on ropylene resin.   Styrene compounds also act as comonomer, reacting with allyl epoxy compounds Gives a random copolymer. Therefore, side chains grafted to the polypropylene backbone Is a random copolymer of the above two monomers. Bulky of the above copolymer The benzene group is the monomer that polymerizes the reaction site in the reaction mixture. Shows a sterical effect that makes it more accessible. , A larger amount of glycidyl methacrylate is copolymerized and made into polypropylene resin It can be grafted. As the amount of glycidyl methacrylate contained increases, the porosity The number of polar groups in the polypropylene composition increases, increasing its compatibilizing effect. S The ethylene compound acts as a comonomer in the copolymerization reaction, and at the same time, the above copolymerization Has the effect of combination in that it also acts as a chain transfer agent compound in the reaction . The polymer composition obtained by the grafting method of the present invention has a polymer grafted on the polymer. Ratio of rill epoxy compound and styrenic compound to those obtained by other known methods Compared to other methods, the content of polypropylene chain is higher than that of polypropylene chain. Will be substantially lower than.   The polymer composition obtained by the method of the present invention is particularly suitable for polymer blends of various types. It is suitable as a compatibilizing precursor in. Typical in such blends The amount used is from 0.1 to 15% by weight, preferably from 1 to 15% by weight, based on the weight of the final blend. It is 5% by weight.   The graft polypropylene composition of the present invention comprises a polymer adhesion promoter (p It can also be used as an olymer adhesion promotor) and used in the coating method. Is done. Furthermore, since the polarity of the grafted polypropylene composition is increased, the The paintability of articles made from the product will be improved.   In the following, the invention will be illustrated and described in more detail by way of examples. The invention is not limited to these examples.Example     Batch graft method   Polypropylene resin, styrene monomer, glycidyl methacrylate (GMA) and And the peroxide were introduced into a conventional closed Haake mixer equipped with a stirrer. Mixer The unit was operated at a constant speed of 64 rpm during the grafting process. Sample of thermal graft polymer It was removed and cooled in air at ambient temperature or in liquid nitrogen.     Continuous grafting method   ZSK Warner with 1230 mm length, L / D = 42 co-rotating mating screws & Frederer Twin-screw extruder continuously guides polypropylene composition Rafted. The screw speed was 150 rpm in all of the illustrated examples. . The polypropylene raw material premixed with the styrene monomer, GMA and the initiator was The propylene raw material was fed to the extruder at a constant rate of 3.5 kg / hour. The temperature distribution of the extruder is It was as follows.   Polypropylene polymer extruded as strands, cooled with water and then pelletized Turned intoAnalysis of grafted polypropylene composition   Dissolve a sample of the recovered polypropylene composition in hot xylene and then dilute it in hot solution. Precipitation was achieved by adding large amounts of ambient temperature acetone. Precipitate in vacuum at 50 ° C And dried for 8 hours. Styrene and / or grafted on polypropylene resin Measured the amount of GMA by IR spectrum analysis. Weight and number of each polymer sample Average molecular weights, Mw and Mn, respectively, are measured by size exclusion chromatography (size ex It was measured by clusion chromatography (SEC).   The experimental data and the results obtained are shown in Tables 1-4. In the raw reaction mixture The concentrations of styrene, glycidyl methacrylate and peroxide are [styrene N]_i, [GMA]_iAnd [peroxide]_iOn the other hand, on polypropylene resin The amounts of styrene and glycidyl methacrylate grafted were [ Chiren]_gAnd [GMA]_gIt is represented by Of the GMA and styrene shown in the table Grafting efficiency depends on the amount of each of the above compounds grafted on the polymer resin It is% of the total amount of the above compounds introduced into the reaction mixture. Shown in the table The molecular weight distribution MWD was calculated as MWD = Mw / Mn.   In the following examples, all the amounts shown by weight are all unless otherwise specified. It is based on a non-grafted polypropylene raw material resin.Grafting experiments in a discontinuous Haake mixer Comparative example A   Polypropylene resin in powder form rotating at 64 rpm and heated to 200 ° C Introduced into the mixer. After mixing and reacting at 200 ° C for 15 minutes, collect the thermal sample. , Cooled in air at ambient temperature. Table 1 shows the measured molecular weight and calculated molecular weight distribution. It is shown.Comparative Example B   Polypropylene powder premixed with 0.22 wt% "DHBP" peroxide at ambient temperature Was introduced into the mixer. The mixing and sampling conditions were the same as in Comparative Example A. The molecular weight and molecular weight distribution of the obtained sample are shown in Table 1.Comparative Examples C, D, E and F   0.22 wt% "DHBP" peroxide and 0.58, 1.49, 4.44 and 7.48 wt respectively Polypropylene powder pre-mixed with styrene in a quantity of% at ambient temperature into the mixer Introduced. The mixing and sampling conditions were the same as in Comparative Example A. Polypropylene set The amount of grafted styrene in the product is shown in Table 1.Comparative Example G   Preserve at ambient temperature with 0.24 wt% "DHBP" peroxide and 5.84 wt% GMA monomer The mixed polypropylene powder was introduced into the mixer. Mixing and sampling conditions Was the same as Comparative Example A. Molecular weight of the obtained polypropylene composition, molecular weight fraction The amount of fabric and grafted GMA is shown in Table 2.Example 1-4   0.24 wt% "DHBP" peroxide, 5.8-6.1 wt% GMA and 2.18 each. , 3.50, 4.40 and 6.53% by weight of monomeric styrene polypremixed at ambient temperature Propylene powder was introduced into the mixer. Therefore, [GMA]_iAgainst [styrene]_i The ratio is 0.5 to 1.5 on a molar basis. The mixing and sampling conditions were the same as in Comparative Example G. It was the same. The results obtained are shown in Table 2.Comparative Example H   Polypropylene premixed with 5.82 wt% GMA and 8.73 wt% styrene at ambient temperature The ropylene powder was introduced into the mixer. Mixing and sampling conditions are compared Identical to Example G. Molecular weight of the obtained polypropylene composition, molecular weight distribution and The amounts of GMA and styrene grafted are shown in Table 3.Example 5-8   5.82 wt% GMA, 8.73 wt% styrene and 0-0.44 wt% "Percadock Mixer with polypropylene powder premixed with Su-14 "peroxide at ambient temperature Was introduced. The mixing and sampling conditions were the same as in Comparative Example H. The obtained polyp Molecular weight, molecular weight distribution of ropylene composition and amount of grafted GMA and styrene Are shown in Table 3.Continuous grafting under extrusion conditions Examples 9 and 10   0.30% by weight of "Percadox-14" peroxide and the amount of GMA shown in Table 4 and unit weight Polypropylene powder premixed with body styrene at ambient temperature, on a molar basis, [ styrene]_i/ [GMA]_i = 1.40 introduced into the extruder while maintaining a constant ratio . The extrusion conditions were as described above. The composition was obtained by collecting the sample with an extruder die. The amount of grafted GMA and styrene of the product was measured. The results obtained are shown in Table 4. Have been.

────────────────────────────────────────────────── ─── Continuation of front page    (81) Designated countries EP (AT, BE, CH, DE, DK, ES, FR, GB, GR, IE, IT, LU, M C, NL, PT, SE), OA (BF, BJ, CF, CG , CI, CM, GA, GN, ML, MR, NE, SN, TD, TG), AP (KE, MW, SD), AM, AT, AU, BB, BG, BR, BY, CA, CH, CN, C Z, DE, DK, ES, FI, GB, GE, HU, JP , KE, KG, KP, KR, KZ, LK, LT, LU, LV, MD, MG, MN, MW, NL, NO, NZ, P L, PT, RO, RU, SD, SE, SI, SK, TJ , TT, UA, US, UZ, VN (72) Inventor Rambla, Moran             France F-67200 Strasbourg             Le, Lyuda Grosmer, 21

Claims (1)

What is claimed is: 1. In a method of free radical grafting of a monomer onto a polypropylene resin having a melt flow index of 0.2 to 100 g / 10 minutes (230 ° C / 2.16 kg), (i) formula: (Wherein, R is H or C _1-4 alkyl; R ₁ is _{- (CH 2) n -,} - C (O) O- (CH 2) n- or - (CH ₂₎ a nO- N is an integer of 1 to 4); (Wherein R ₂ is H, 0H, CH ₃ or allyl); and a peroxide as an initiator; and (ii) the above mixture is mixed with an allyl epoxy compound and a styrenic compound. Heating to a temperature above the melting point of the polypropylene resin and the decomposition temperature of said peroxide under continuous mixing conditions until the desired degree of grafting of the compound onto the polypropylene resin is achieved, then (iii) A method of grafting free radicals of a monomer onto a polypropylene resin, the method comprising the steps of cooling and crushing the composition. 2. The method according to claim 1, wherein the melting and mixing of the reactants are carried out in an inert atmosphere, preferably a nitrogen atmosphere. 3. The method according to claim 1 or 2, wherein the grafting step is carried out in an internal mixer under continuous stirring conditions. 4. The method according to claim 1 or 2, wherein the grafting step is performed in an extruder. 5. Grafting is carried out under conditions in which the styrenic compound acts both as a chain transfer agent compound and as a copolymerizable monomer, whereby the β-dissociation of the polypropylene polymer is achieved with pure polypropylene resin alone. 5. A method according to any of claims 1 to 4, which is lower than that obtained when processed. 6. The method according to claim 1, wherein the allyl epoxy compound is glycidyl methacrylate. 7. The method according to claim 1, wherein the styrenic compound is styrene. 8. A graft polypropylene composition obtained by the method according to claim 1. 9. A composition according to claim 8 containing glycidyl methacrylate in an amount of 0-10% by weight and styrene in an amount of 0-10% by weight, calculated on the polypropylene resin. Ten. Use of the composition obtainable by the method according to any of claims 1 to 9 as a compatibilizer in the production of polymer blends, as a polymer adhesion promoter and in articles requiring improved printability. .