DD266358A1 - PROCESS FOR PREPARING POLAR-MODIFIED POLYPROPYLENE - Google Patents

Abstract

By radical modification of isotactic polypropylene (PP) having a mean molecular weight Mw between 50,000 and 250,000 in a first stage by treating the PP with oxygen (O2) or air or other inert gas containing O2 mixtures under a pressure between 0, 3 and 1.5 MPa in the presence of organic peroxidic and / or diazo-containing initiators having a mass fraction based on the PP of 0.1 to 10% at temperatures between 40 and 80C until a hydroperoxide mass fraction between 1.010 3 and 1.010 1% and - After relaxation to atmospheric pressure, nitrogen sparge and Abkuehlung the reaction mixture to a temperature between 10 and 40C, is added in the acrylic acid with a PP based mass fraction of 3 to 12%, - in a 2nd stage with heating to a graft polymerization between 60 and 100C by carboxylation of the in situ hydroperoxidated PP until a Ca rboxyl group bulk content between 0.3 and 8.0%, polar modified PP for direct use is prepared as a self-adherent polymer coating material for metallic surfaces or for use as a chemical coupler in thermoplastic-glass fiber composites.

Description

The invention relates to a process for the preparation of polymodified polypropylene for direct use as a self-adhesive Polymerbesohiohtungsmaterial on metallic surfaces or as a chemical coupler in thermoplastic-fiber composites by Radikalisohe carboxylation of in situ by treatment of isotactic polypropylene (PP) with average molecular weights H between 50,000 and

250000 duroh oxygen-containing media or gas mixtures in the presence of organic peroxidisoher and / or diazogruppenhaltiger initiators - hydroperoxldiertem polypropylene.

Characteristic of the known solutions without solutions

For the production of polarmodifiziertem PP, which causes the "chemical coupling" of hydrophilic functional groups having glass fiber material to the PP matrix or the adhesion via the polar functional groups to the metallic surfaces, various methods of direct grafting oarboxylgruppenhaltigen compounds on the PP RUokgratbotte known, in particular the less effective radiation grafting (US 3290415, 3347692), technologies in the PP soymilk (DE 2242324, 2426972, EP 0082704) and suspension grafting - usually with the addition of nonpolar solvents or comonomers for swelling of the crystalline PP (DE 2640059, EP 0041214).

While the grafting in the melt, generally directly as an additional operation in the extruder, makes high demands on the material properties of the respective extruder parts, the suspension grafting processes require a high technological and thus economic expense.

In addition to the direct graft polymerization processes, indirect radical grafting technologies are known, which are generally characterized by grafting the monomers onto hydroperoxidized PP prepared in situ (It. P. 867340). In a first stage, the PP with air, oxygen or Οκοη - usually using organic peroxidisoher initiators - treated at higher DrUoken (Oxidiorungsstufe), and in the second stage, the oarboxylgruppenhaltige monomers, optionally after addition of a second initiator, at higher temperatures , z. B. zwisohen 180 and 220 ⁰ C decomposes (grafting in the soymel), grafted (carboxylation stage).

On dleae Weiae unsaturated Carbunuüuren, such as acrylic acid and methacrylic acid, in the PP soybean (in the extruder) can be selectively grafted (EP 0109532). The disadvantage of this Carboxyllerungsverfahren is in addition to a high teohnisoh-teohnologlsohen effort in the twofold molecular degradation of the PP, since both by the hydroperoxidation and the high grafting temperatures, the meohanisohen PP starting values are lowered.

A wirtsohaftliohes method is the modification of PP below 100 ⁰ C in aqueous suspension or in the Pulverphane, said first means of air under Druok the PP hydroporoxidiert (Beati, E. and et al, Makrom Chem 61 (1963), 104....; Natta, G., Beati, E. et al., Chim. E Ind. (Mlla.no) 50 (1968), 851) and the oxidized PP is graft-modified in a separate step using gaseous dienes or even vinyl chloride ( It. P. 867340, DD 137112).

This double-phase gas phase grafting (Pegafaro, M. and Beati, E., Chim. E Ind. (Mllano) 56 (1974) 9, 595-599) leads to products with improved impact resistance, but a use as "ohemisher coupler" in PP It is not possible to use GF or as a pressure-sensitive adhesive on metallic surfaces since, using butadiene as the grafting monomer, the PP backbone chain is not provided with functional hydrophilic groups and the VC / PP grafting products become insoluble after processing Have adhesive strength and thermal stability.

Ub 3 Si

Object of the invention

The object of the invention is to produce in a wirtsohaftliohe way polarmodifiziertes polypropylene with a higher, based on an overall improved adhesive strength ^ use value.

Explanation of the essence of the invention

The invention has for its object to provide a process for the preparation of polarmodifiziertem PP with einfaohen teohnisoh-teohnologischen agents and measures for use as ohemisoher coupler in glass fiber reinforced thermoplastics to improve the meohanisohen Kennwertniveaus dos composite or as a self-adhesive polymeric Besohiohtungsmaterial rlt increased adhesion to metallic surfaces duroh radical-selective carboxylation of in situ-by means of treatment of isotactic polypropylene (PP) nlt average molecular weights M zvisehen 50,000 and 250000 duroh oxygen, optionally ozone-containing media or gas mixtures in the presence of organic peroxidlsoher and / or diazoguppenhaltlger initiators - hydroperoxidiertem polypropylene.

According to the invention in a first stage oxygen (Op) or air or other Inertgasanteile containing Op mixtures under a Druok between 0.3 and 1.5 MPa duroh in dry powdery and / or granular and / or flookiger, sohuppiger or blättohenförmiger form and present with a mass fraction of 0.1 to 10% of the (the) Inltiator (s) containing PP at a temperature zwisohen 40 and 80 ⁰ C until reaching a hydroperoxide Massenantells zwisohen 1,0'10 and ^J 1, 0 * 10 % passed , and - after relaxation on Normaldruok, Stick- 'stoffspUlung u.id cooling of the reaction mixture on

Mb 358

a temperature zwisohen 10 and 40 ⁰ C, with a time related to the submitted PP mass fraction zwisohen in Aorylsäure 3 and 12% is added, - in a 2nd stage is under heating to a graft polymerization zwisohen 60 and 100 ⁰ C to a carboxyl group Mass fraction zwisohen 0.3 and 8.0 % polymerized.

Apart from isotactic propylene homopolymers, it is also possible to use propylene copolymers having a slight mass fraction between 0.5 and 5.0% of copolymerized comonomers, in particular ethylene and butene units, as PP to be modified.

The presented PP has an average molecular weight

4 5 and 2.5 * 10

1.0 * 10 ⁵ and 2.0 * 10 ⁵ , and is about the relationship

4 5 M between 5.0 * 10 and 2.5 * 10, preferably doubling

By measurements of the relative viscosity pw ~] of 0.1 JJigen solutions in decalin at 135 ⁰ C determined.

The PP is in powder form within a Teilohengrößenberelohes zwisohen 20 and 1000 μπι (mass fraction of 9f> to 100 Ti), preferably between 63 and 800 μπι (mass fraction of 85 to 100 %) , and with a middle Teilohendurohmesser (C value) between 200 and 450 μιτι and / or as granules with a Teilohendurohmesser zwisohen 1.0 and 5.0 mm, preferably zwisohen 1.5 and 4.0 mm, and / or as Flooken, Sohuppen or Blättohen (English: flakes) with a Length expansion zwisohen 0.1 and 0.8 mm (mass fraction of 75 to 100 %) , preferably between 0.2 and 0.7 mm (MasHenanteil of 70 to 100%) used.

Mh 354

Ali criterion for the aue Mostly isotaktisohen structural units constructed PP chains is the min in a boiling heptane for "twice for 30. Remaining Lösungsmasserüokstand, referred to as the isotacticity index. The Isotaxleindloes of the to be modified PP are zwisohen 50 and 100%, preferably zwlsohen 90 and 99 %>

The PP used is generally by known antioxidants and / or UV stabilizers such. As substituted phenenes or benzene and / or Benzotriaoenderivate pre-stabilized.

As peroxidisoho initiators, the known diacyl peroxides, v / ie dilauroyl and dibenzoyl peroxide (DLPO, DBPO), and Dialkylperoxidioarbonat «(DIPP, DEHP). and diazo compounds such as 2,2'-azo-bis-butobutyronitrile) (AIBN).

As PP oxidizing agents in the 1st stage (hydroperoxidation), apart from oxygen (Op), above all compressed air (0.3-1.5 MPa), but also other 0p-Iriertgaa gemisohe, in particular Og with the UbLLohen mass fractions gaseous impurities (in total 1 to 2% Np ₁ COp, noble gases) used.

The first stage is carried out to a leroxidmassengehalt Γ-ΟΟΗ] zwisohen between 0.001 and 0.1%, preferably zwisohen 0.005 and 0.05%.

Analytical [-OOHJ determination of hydropoxylated PP samples (in toluene / Eisesslg) Naoh addition of a defined saturated KJ solution and titration with sodium thiosulfate solution (1 % strength as indicator). Naoh completion of the 1st stage, the reaction vessel is purged with nitrogen several times, to a temperature nwisohen 10 and 40 ⁰ C, preferably zwisohen 20 and 35 ⁰ O, cooled and acrylic acid (AS) was added, the d dispersed d dispersed on the preoxidized PP becomes.

Wed 35'S

The SiOH subsequent 2, grafting is under Aufholzen to a temperature T _p zwiachen 60 and 100 ⁰ C, which is generally the final stage of grafting with a constant T _p, to an AS-mass conversion awisohen 30 and 95% durohgefMhrt.

The graft product is duroh an extraction -

♦ treatment of the product with methanol at room temperature to remove the unreacted AS and the PAS homopolymer,

♦ Extract the residue with xylene to remove the ungrafted ΡΓ as well

♦ Treatment of the residue in xylene with excess inethanolisoher KOH (defined amount) and Rücküoktitration with methanolisoher HCl to determine the Γ-COOH] - mass fraction -

characterized.

A exemplary embodiment

A temperature-controlled horizontal stainless steel reactor, equipped with a wall-mounted stirrer and Druok and Temperaturmeßeinriohtungen, are 100 Massontelle (MT) powdery PP with the following characteristics (PP-1):

Dioxane 0.91 g / om ³

H 159000

average particle size _OQQ (C value) ^{288 μΐη}

Mass fraction of particle size Q ₂ η zwisohen 0.2 and 0.8 mm

Mass fraction of particle size 5 3 7 between 20 and 63 μm

Isotaxy index 92.2 %

Sohm index MFI ¹ ^ ° ^C 9.6 g / 10 min.

(TGL 44) ^{Hy N}

Tensile strength (50 mm / min) _{w M} / 2

ISO rod (TGL 14070) ^id ' ^m

Tear thinning 250 %

Bend modulus of elasticity (TGL 14067) 1400 N / mm ²

Mass fraction of antioxidant 0.005 %

0otadeoyl-3-propionate (3.5-di-tert-butyl-4-hydroxyphenyl)

submitted together with 1 MT DIP and diluted at room temperature. Compressed air is subsequently Aufreohterhaltung of emotion aufgedrüokt, the reactor heated to a temperature of 70 ⁰ C, and under a constant Luftdruok of 1.0 MPa over a Gesamtzeitraurr. 6 hours of the oxidation process is done. The targeted hydroperoxydation is carried out to a (-0Og content of 250 mg / kg PP and up to a lowered H value of 35770. Danaoh is discharged from the reactor.

clamped, purged with nitrogen and cooled.

NaOH to achieve an internal reactor temperature of 30 ⁰ C 10 MT AS are added, and after dispersion in the reaction mass, the reactor is heated within 4 hours to a polymerization temperature (T _p ) of 80 ⁰ C and "postpolymerized" at a constant Tp total nooh for 1 hour.

The reaction is terminated by a nitrogen purge with simultaneous cooling to room temperature.

From the Wandansatzfroion reactor a total product amount of 109.2 MT is discharged with the following characteristic characteristics:

MFI 9 ° _N 7 ^ g / 10 min.

Extraction values (in% by mass) PAS content 8.42 %

extracted AS 0.8 %

Graft yield 90.5 %

(Maesenanteil grafted AS for the total polymerize AS)

C-COOHJ content 5.26 %

By varying the PP modification conditions in the case of the transformation of different PP-RUokgratpolymorcr in the 1st stage, the degree of hydroperoxidation About the treatment by Druokluft (time, Druok, temperature or Aufheisreglme) and various initiators in different concentrations (DIPP, DEHP, DLPO, AIBN) and in the second stage the degree of carboxylation is set via the amount of AA and the grafting temperature regime selected over the given polymerization time.

Table 1 lists the most important parameters for the two-stage graft polymerization process and the most important characteristics of the oarboxylated PP products obtained.

In addition to the o. A. For example, two other RUokgratpolymers (ΡΡ-Ί) were used, two more PPs to be modified (PP-2, PP-3) (see Table 2).

Table 1: Credits of the preparation (hydroperoxidation and carboxylation) ur.c Characterization of the polarmodified PP products

Backbone PP 100 MT 1 . Step (. hydroperoxidation; Temp. CC) j Time ¹ ^ (h) Oxication product _: _ ι M ^! W Ser. No. PP-1 Init. Air / 0 ₂ pressure (MPa) 70 6 [-OCKj-go. (n: g / K9 PP) 35770 1 PP-1 1 DIP? 1.0 air 70 3 250 36420 2 PP-2 2 DIP 1.0 air 60 6 256 62900 3 PP-2 1.5 DIP? 1.05 air 70 6 159 28 ~ "0 4 PP-3 2 DEHP 1.0 air 40-80 3.1 324 55900 5 RP-1 1 DIP 0.9 air 40-80 3.1 144 90700 6 PP-1 2 AIBN 1.0 air 75 3.1 105 63500 7 PP-1 1 DLPO / 1 DIP 1.0 air 75 6 157 30400 8th PP-3 2 DIP 0.7 air 40-80 3.1 305 59500 9 PP-3 2 AIBN 1.0 air 70 6 148 448C0 10 PP-1 1.5 DIP 1.0 air / 0 2 170 265 ^ 0 11 PP-3 0.7 DEHP 0.7 0 | ^} ': -0-60 2 348 27000 12 0.7 DIP 1.0 ojp 330

1) 1 Number of figures: Total reaction time (heating up and reaction period) 2 Numbers: 1st value - Heating up time of room temp. on RK.-Temp.

2nd value - reaction time at constant end temp. (Tp)

2) Impurities: 0.8% Np / 0.2 % C0 ₂ / 0.1 % noble gas

Continuation Table 1:

Ser. No. 2nd stage (Carboxylation) Time ¹ J (h) PAS-go. (50 graft 190 "C ^ÄF1 21 N (g / 10 ¹ ) 1 AS (MT) T ¹ Pm Cc) 4.1 8.42 Graft yield (55) 7.5 2 10 30-80 4.1 9.05 90.5 5.9 10 30-90 3.1 5.15 92.5 2.55 6 30-80 4 / 1.5 9.02 86.0 7.62 .) 10 30-85 4.1 9.05 91.8 3.64 6 10 30-90 4.1 8.35 88.5 0.5 7 10 30-90 3.2 10.6 92.0 2.9 8th 12 30-85 3.1 7.2 85.6 9.0 9 8th 30-85 4.1 8.1 89.5 4.1 10 10 30-80 3.2 8.52 89.2 4.8 11 10 30-80 3.1 7.5 90.3 7.7 12 8th 30-85 3.1 7.5 92.8 8.2 8th 30-80 94.1

1) 1 Number of figures: Total reaction time (heat-up plus 2 numbers: 1st value - Heat-up time after clearing

2nd value - reaction time at const

Reaction period3) to RK.-Temp. (T end temp. (Tp _1n )

Table 2:

Kenn fourth

PP-2

PP-3

av. Particle size (C value)

Mass fraction d. Part height size between 0.2 and 0.8 now

Isotactic indox r190 ⁰ C

MFI

49 N

Tensile strength (50 mm / min.), ISO bar

Elongation at break Bend modulus of elasticity

Mass fraction of antioxidant

148000

288.8 μπ) (flaky)

%

95.4 %

5.8 g / 10 min.

N / mm ²

% N / mm ²

0.01%

126000

438.7 um (flaky)

96 %

94.9 %

5.2 g / 10 min.

35 N / mm ²

280 % 1550 N / mm ²

0.05 %

The polar modified PP products of the invention are preferably glass fiber reinforced. Thermoplastic molding compounds in an amount between 5 and 15 %, based on the total molding composition, in order to improve the msohanisohen characteristics added. Compared to comparable non-coupler thermoplastic GF compositions, the corresponding coupler-modified injection molded products have an improved toughness / strength level.

In addition, the graft polymerization products according to the invention are suitable for use as self-adhesive polymer topcoat, especially on metallic surfaces.

Claims (1)

46635 * 13 Invention claim h Method of making polar modified polypropylene for direct use as a self-adherent polymer overcoating material on metallic surfaces or as an ohmic coupler in thermoplastic-glass fiber composites by radical polymerization of in situ by treatment of isotactic polypropylene (PP) with average molecular weights 500 between 50,000 and 50,000 250000 duroh oxygen-containing media bzv /. Gas mixtures in the presence of organic peroxidisoher and / or diazogruppenhaltiger initiators - hydroperoxidiertem polypropylene, characterized in that in a 1st stage oxygen (Op) or air or other Inertgasanteile Op Gemlsohe under a Druok zwisohen 0.3 and 1.5 MPa duroh the present in trookener powdery and / or granular and / or flaky, sohuppiger or Blattohenförmiger form and with a mass fraction of 0.1 to 10 % of the (the) initiator (s) containing PP at a temperature zwisohen ^ O and 80 ⁰ C. until a hydroperoxide mass fraction is reached -3 - 1 1, 0Ί0 ^J and 1.0 * 10 % are passed - after relaxation to normal distillation, nitrogen purge and cooling of the reaction mixture to a temperature zwisohen 10 and h0 ⁰ C, in the case of acrylic acid with a mass fraction based on the PP presented zwisohen 3 and 12 % - is heated in a second stage with heating to a graft polymerization temperature between 60 and 100 ⁰ C to a carboxyl group mass fraction zwisohon 0.3 and 8.0 % is polymerized.