DD296947A5 - INTERLOCK POLYAMIDE SHAPES - Google Patents

Abstract

Schlagzaehe polyamide molding compositions are prepared by addition of 3 to 40 parts by mass of grafting of a, b-ethylenically unsaturated mono- or dicarboxylic acids or their anhydrides, other carboxyl-free comonomers on ethylene-vinyl acetate copolymers having a proportion by weight of Vinylacetateinheiten between 5 and 25 % (EVAC-5/25) and MFI (190C, 21.0N) melt index between 0.1 and 20 g / 10 min. At temperatures between 40 and 100C with the exclusion of aqueous and organic dispersing, dissolving or disintegrating agents carboxylated * which has a carboxyl group mass fraction between 0.3 and * preferably between 1 and 3%, and a gel mass fraction between 20 and 90%, preferably between 35 and 75%, to 60 to 95 parts by weight of a partially crystalline polyamide, preferably PA 6 or PA 6.6 or PA 6.6 / 6 or PA 6 / PA 6.6 mixtures. {Polyamide molding compounds; Polycapronamide (poly-e-caprolactam); Poly (hexamethylene adipamide); polyolefinic impact modifier; graft-carboxylated ethylene-vinyl acetate copolymer; Trockenphasenpfropfung; Carboxyl mass fraction}

Description

Field of application of the invention

The invention relates to impact polyamide (PA) molding compositions based on mixtures of 60 to 97 parts by mass of a partially crystalline polyamide, preferably polycypronamide (PA6) or poly (hexamethylene-adipamtd) (PA6.6) or their mixed polycondensates PA6 6/6 or PA6 / PA6 6 mixtures, with a relative solution viscosity η _Γί ι between 1.5 and 3.5 (according to TGL 20055/01) and 3 to 40 parts by mass of a carooxylated ethylene-vinyl acetate copolymer of the mass composition 5 to 25% vinyl acetate units (VAO / 95 to 75% ethylene units as impact modifier, which, due to their improved mechanical-physical and thermal and processing properties can be used for a variety of recruitment as engineering plastics

Characteristic of the known technical solutions

Polyamides (PA) have been widely used in engineering materials (G Blinne and E Pnebe, Kunststoffe 1987, 10, S 983-993).

In terms of quantity, the semi-crystalline PA6 and PA6 6 occupy a top position. Due to their high brittleness in the dry (spray-fresh) state, they are subjected to targeted water treatment, the so-called conditioning, or in order to limit the drastic decrease in strength, steepness and shrinkage associated with increasing water absorption the Dirnensionsstabilitat the injection-molded parts - conveniently equipped by the addition of suitable elastomers (high) impact (B.Brassat u W. Nielinger, Kunststoffe 7111981] 3, S 172-177, P Loheu J.Arndt, Kunststoffe78 [1988] 1, S 49-52 , G.BIinne, HG Dorstu C Plachetta, Kunststoffe 1978 [1988] 7, S 612-616) Apart from a substantially lower glass transition temperature Tg than the polyamides, the elastomeric modifiers must adhere well within the polymer composite

Due to their tensile elastic behavior and a low glass transition temperature, especially (poly) olefinic elastomers are weather-resistant (double bond-free) modifiers, either by directly grafted or grafted (grafted) carboxyl (hydroxyl, carboxyl, dicarboxylic anhydride carboxylate or ester group-containing) comonomer units in the main or side chain (graft) or additionally by added components with polar comonomer units, such as ζ B α-olefin-FDi-lCarboxylsauretenhydridl copolymers, a sufficient or increased adhesion to the PA matrix is mediated suitable

(S Cartasegnau W Heider, Gum Fibers Kunststoffe 41, 1988), p. 3, pp. 110-119, ibid., P. 5, pp. 224-226). The use of EVAC with proportions of copolymerized vinyl acetate (VAC) units is known as an elasticizing modifier 5 and about 60% and Tg-Wersn below 0 ° C and with different melt index (degree of crosslinking) (LD Orazio and Mitarb, J Mater Sei 21 [1986], S 983, ibid 22 [1987], S 429, EP 228229.00 83463,

Also in its hydrolyzed form (EVAI) - for the intended use as a reactive elasticizing component compared to the matrix material with a generally high degree of saponification "set" (DE 3624577, DE 3637446 FR 2586027, JA 62 13449) - EVAC is used in PA molding compositions

As an additional component in a mostly lower concentration to present elasticizing EVAC, which essentially serves to improve the compatibility or adhesion between hard and soft polymer phase, α-olefin-dicarboxylic acid anhydride copolymers (DD 228286,228287,228288,228289, 228290, DD 206784, DD 244141, DD 161134, 161135, 161136, DD 248368) and also α-olefin maleic anhydride half ester copolymers (DD 228289) are incorporated into the melt blend. With regard to chemical or physical constitution of the Elastrfizierkomponente EVAC this can be present in saponified (DD 109884, DD 120657, DD 228288) or - by treatment with sodium alcoholate - in crosslinked form (DD 228286, DD 248 368)

Furthermore, oxidized polyolefin (waxes) (DD 228288, DD120657, DD 234684) can be added as mixing and processing aids

Overall, although the EVAC Modiftzierung brings a toughening improvement, but the impact resistance - both for the value at room temperature and for values at temperatures below freezing - only moderately higher use requirements corresponds, which also by adding ethylene (or propylene ) / Maleic acid (or itaconic anhydride) copolymers can not be achieved to a sufficient extent (DD 161136, DD 248368) Also known is the improvement of the (notched) impact strengths in a broader temperature range based on the sole addition of olefin (ethylene and / or propylene) / a, ß-ethylenically unsaturated (s) (di) carboxylic acid (anhydnd) co- or terpolymers in PA molding compositions (DE 2245957, DE 3444096, DE 3604308, DE 3604376, US 4172859, US 4346194, US 4478978, EP 234819, FR 2580656, GB 998439, JA 5991148, JA 6215258)

Analogously, in partially pigmented PA molding compositions, "carboxylated" EVAI or EVAC products, such as EVAI-methacrylic acid and EVAI-glycidyl methacrylate terpolymers (US 4595730), an EVAC-acrylic acid terpolymer (LD Orazio, J. Mat Sei 22 (1987) , S 429) and Terpolymensate based on ethylene-acrylate-Maleinsaureanhydric or methacrylic acid (DE 3711730, WO 88/03543, WO 86/06397, US 4174358)

Also, melt blends of styrene-acrylic acid (maleic anhydride) copolymers (St / AS [MSA] -CP), EVAC-AS (MSA) terpolymers and PA6 or PA6 6 are known (DE 3604348, DE 3604376).

A series of co- and terpolymenates can be neutralized by metal ions for various purposes (US 3845163, US 4172859, US 4412040, US 4478978). The co-or terpolymerization of a mixture of an olefin (mixture), carboxyl monomer and optionally another third or fourth ethylenically unsaturated compound (methacrylate, acrylate, VAC and other vinyl monomers) polymer products obtained directly in a polymerization stage can be used as impact modifiers without further addition of an hsftverbessernden component In contrast, by an additional graft polymerization of unsaturated carboxylic acids or anhydrides α, β- unsaturated dicarboxylic acids, such as MSA, to an olefinic backbone polymer PA impact modifiers having the same or similar gross composition but - due to a targeted side-chain Carboxylgruppenausrustung - are obtained with a higher adhesive strength (E P.266221.US 4602058; DE 2420942, JA 6296551, JA 62138228, JA 62243646, E P 82704, DE 3545033)

As backbone polyolefins find especially isotactic polypropylenes (EP 235876, WO 88/02387, WO 88/06174, JA 6259652, JA 6259653) and ethylene-α-olefin (preferably propylene) co- or terpolymers, in particular EPM and EPDM , Use (E.P. 235876, EP 266221, JA 62177065, JA 62179546, JA 6243456)

The Kombinatton from the two product classes, carboxyl-containing Olefmcopolymeren and carboxylated polyolefinic graft copolymers is known (JA 6211761, JA 6279260)

In general, the application of the carboxyl groups or acid anhydride groups to the olefinic backbone polymer takes place by melt grafting in a kneader or extruder, without specifically referring to the use of EVAC as the grafting base (backbone) or of the melt-grafted (carboxylated) EVAC products as impact coefficients for PA (EP 286734, EP 235876, EP 82704, EP 266221, WO 88/06174, JA 6384/64)

Object of the invention

The aim of the invention is the production of molding compositions equipped by means of carboxylated EVAC products with improved impact strength based on semicrystalline polyamides as matrix polymers

Explanation of the essence of the invention

The invention has the object of impact polyamide molding compositions on the basis of mixtures of 60 to 97 parts by mass of a teilknbstinen polyamide, preferably PA 6, PA6 6, PA 6 6'6 or PA6 / PA6 6 mixtures, with a relative solution viscosity η , _β | between 1.5 and 3.5 and 3 to 40 parts by mass of a by grafting of α, β-ethylenically unsaturated mono- or dicarboxylic acids or their anhydrides, including their mixtures with each other and with carboxyl group-free comonomers, at temperatures between 40 and 100 ⁰ C - under Exclusion of aqueous or organic dispersants, solvents or diluents - to ethylene-vinyl acetate copolymers with a vinyl acetate content by mass of between 5 and 25% (EVAC -5 / 25) and a melt index MFI (190 ⁰ C, 21.2N) between 0 , 1 and 20g / 10 min. Of carboxylated (co) peroxide product obtained, which, because of their improved level of properties, are used as engineering thermoplastic material for a wide range of applications and applications. According to the invention the object is achieved in that a (co-graft carboxylated EVAC -5 / 25 with a carboxyl group mass fraction between 0.3 and 8% and a gel mass fraction of between 20 and 90% of the molding composition is added is preferred as a good "sticking Adding impact modifier (co-graft carboxylated EVAC-5/25 having a carboxyl group mass fraction of 1.0 to 3.0% and a gel mass fraction of between 35 and 75% of the molding composition The melt mixture of the two molding material main constituents under defined temperature and shear conditions ( Melting kneaders, ES or DS extruders) granules obtained by processing can be increased from high to high impact for a broader temperature range, especially by means of extensive use of injection molding technology, depending on the quantitative proportion and the type (carboxyl group concentration and grafted total monomer mass) of the modifier Field of application adapted who The (co) graft polymer products acting as impact modifiers are further prepared by free-radical grafting or cografting of AS, MSA, optionally with addition of another vinyl monomer without carboxyl or dicarboxylic anhydride group, such as styrene (St) and its derivatives / homologues ( Meth) acrylates or (meth) acrylonitrile (AN), on EVAC-5/25 (average particle diameter between 0.05 to 0.5 mm) in the dry phase, ie excluding liquid solvents, dispersants and diluents, including the polymer melt itself

Preferred free-radical organic initiators are known diacyl peroxides and dialkyl peroxides having 10-hour half lives (10 hours HWT, measured in 0.1 m Benzenlosung) between 40 and 75 ° C and in a total of about 10 to 40% based on the submitted total monomer mass concentration used As extremely effective impact modifiers have been found.

P [EVAC-5/25 g-AS]

PIEVAC-5/25-g msal,

PIEVAC - 5/25 - g - (As-co-MSA)],

P [EVAC -5 / 25-g- (AS-co St) I

P (EVAC -5 / 25-g- (AS / MSA / St)]

The modifiers with the abovementioned (inventive) carboxyl group concentrations within the "to be set" characteristic values for the so-called gel mass fraction (m _c .), Which is to be understood as a percentage of solution pressure under defined conditions (2g product weight in 100ml xylene after 12 hours treatment under reflux) , between 30 and 80%, as well as melt indices MFI (19O ⁰ C, 212N pad weight, TGL 25244) within the range of virtually "not measurable" (nm) to about 30 g / 10 min

The relative to the total amount of graft product carboxyl group mass fraction ([-COOHl) is by an alkaline titration using appropriate normal solutions (KOH, HCl back-titration) -grafted maleic anhydride (MSA) is under these conditions in hydrolyzed form before-mediated

Exemplary embodiments

In a twin-screw extruder T ₁ /. ./T ₆ = 220/220/210/210/210/220 ⁰ C and a screw speed of 150 rpm, a molding compound (granules) based on compositions of 60-95 MT PA 6 (relative viscosity r) _re i = 2.3, MFI [240 ⁰ C and 49 N applied weight] = 45.5 g / 10 min) or PA 6 6 (n _Re, = 2.8, MFI = 32,6g / 10min) with the (in Table 2 Lfd Nr Vgl 01 u 02) mechanical-physical and thermal characteristics and

15-40MT Carboxylated EVAC -15 or EVAC-18 (with the product parameters given in Tab 1), which are then applied to a Kuasy 150/50 injection molding machine (tool heated shutter, temperature profile 220 / 23O / 24O / 240 ° C, mold temperature 80 ⁰ C, injection pressure · 44MPa) to ISO Prufkorpern in the dimensions 80 mm χ 10 mm χ 4mm be processed

For comparison with the used according to the invention listed in Tab 1 modifiers (Lfd No. 1 to 6), the following known or comparison modifiers are used

• unmodified EVAC _ ^ - 18_

(VAC content 18.2%, M _n / M _w 29200/177000, MFU19O ° C, 21,2N] 1.87 g / 1 Omin, density 0,937g / cm ³⁾ (See paragraph 7)

• unidentified EVA-15

(VAC content 16.3%, LVIN / M _w 13000/141000, MFI [190 ° C, 21,2N] 3.6 g / 10 min, density: 0,934g / cm ³⁾ (. See # 8) "unmodified EVAC -35

(VAC-content 35%, MFI [190 ° C, 21,2NJ 2.8 g / 10 min, density of 0,949g / cm ³⁾ (see point 9)

Using 0.3% MSA or 2.5% MSA or 0.5% AS / 0.5 styrene (St) as graft monomers, di-tert-butyl peroxide as initiator and EVAC-35 (35% VAC),

as Ruckgratpolymer in the melt (165-200 ¹ C in the DS-extruder) hotmelt prepared (co-) graft products (See point 10 to 12)

Table 1

Carboxylated EVA modifiers used, including comparative modifiers using various EVA backbone polymers (EVAC-15 EVAC-15 -EVAC-18, -EVAC-35) and dilauroyl peroxide (DLPO) as an initiator for the powder phase grafting (Lfd # 1-6)

Mooifikator production Graft Mono Template (MT) Init MSA St / AN IMT) Modifier key data (-COOH) (%) MFI (190 ° C, 212 N) YTD 100 MTEVAC AS 1.7 _ 1-0 'pm (%) 55.3 (G / 10min) 3.3 2.5 _ 1.0 cc) 2.81 71.3 10.2 1 EVAC 15 5.0 - - 1.0 70 4.31 65.2 η m 2 EVAC 15 2.5 - - 0.5 70 1.87 38.2 η m 31 EVAC 18 2.5 2.5 - 1.0 70 1.21 52.0 3.6 32 EVAC 18 _ - 5,0St 1.0 70 1.64 66.5 0.6 4 EVAC 18 5.0 _ 3,3AN 1.0 70 2.52 30.2 5.4 5 EVAC 18 1.7 _ _ _ 70 1.06 0.2 7.8 6 EVAC 18 _ _ _ _ 70 _ 0.3 22.5 Compare 7 EVAC 18 _ _ _ _ 0.0 25.3 See Fig. 8 EVAC 15 _ 2.5 - 0.2 _ _ 0.0 2.8 Compare 9 EVAC 35 - 0.3 - 0.02 _ 2.50 0.0 8.8 See 10 EVAC-35 - - 0,5St 0.05 165 0.22 0.1 12.8 See 11 EVAC 35 0.5 200 0.19 6.7 See 12 EVAC 35 190

The specimens are regarding

- Schlagbiege- and Charpy impact strength a "and a _k at +23 and -20 ⁰ C (TGL 14068 / a _n · 23 ° C all test specimens -100% without breakage.)

- tensile strength o _s

(50 mm / mm; TGL14070)

Bend strength and flexural modulus o _b 1.5 and E _b (TGL 14067)

- Heat resistance according to Vicat WFB (TGL 17274, method B)

- Ball compression hardness (30sec penetration time) HK ₃₀ - (TGL 20924) tested

On the basis of the test ken η values given in Table 2, and above all by comparison with the (known) comparative molding compositions, it is apparent that the notch impact strengths (especially ak (-2o -) values) are increased above average for the molding compositions according to the invention a much lower Eb drop, as well as ensuring the high Vicat heat distortion resistance

These statements relate primarily to the PA6 molding compounds with "styrene" or "acrylnrtril" -free carboxylated EVAC -15 / 18 modifiers

Table 2

Characteristics of the impact-modified PA6 and PA6.6 molding compounds

(Processing throughput in DSE: 5.0kg / h, screw speed 150rpm, except lfd no.6.2 and6 3: 200rpm)

No Proportion of midifcator a _n (-20 ° C) ²¹ a _k (kJ / m ² ) (+23 ° C) characteristics ^σ Μ, 5 Eb (MPa) WFB on 100 MT PA form (kJ / m ² ) (-20 ⁰ C) (MPa) (MPa) ( ⁰ C) mass ¹¹ (MT) 5.5 (MPa) 124 (Code no. Tab 1) 100% o B 2.6 4.7 77 2197 132 174 Cf. 01 - (pure PA 6) 100% ο Β 2.3 7.4 83 79 2290 100 185 Compare 0 2 - (PurePA6 6) 90% / 55 3.4 12.6 85 59 1567 70 182 Compare 1 1 10EVAC-15 (Cf. 8) 100% o B 3.3 11.5 60 42 1132 80 132 Compare 1 2 30EVAC-15 (Cf. 8) 90% / 72 4.6 11.1 42 51 1365 65 166 Compare 1 3 20EVAC-18 (Cf. 7) * 100% o B 3.0 9.5 48 41 1118 76 130 Compare 1 4 30EVAC-18 (Cf. 7) 80% / 68 2.7 11.6 43 47 1285 78 161 Compare 1 5 20EVAC-15 (Vgl.7) 100% ο Β 3.2 10.3 49 49 1320 73 166 Compare 2 20Propfpr (Cf. 11) 80% / 65 2.8 8.9 52 50 1185 80 141 Compare 3 1 30Propfpr (Cf. 12) * 90% / 70 3.0 29.5 46 50 1360 110 168 Compare 3 2. 20Propfpr (See 10) 100% o.B 11.5 48.9 51 71 1882 92 182 51 10Propfpr. (31) 100% o B 19.3 64.1 65 54 1568 79 180 5.2 20Propfpr (3 1) 100% o B 25.6 26.6 52 45 1327 88 153 53 30Propfpr. (31) 100% o B. 8.9 8.8 43 50 1515 116 172 54 20Propfpr (3 2) 80% / 74 4.4 17.0 49 70 1957 109 198 61 5Propfpr (2) 100% ο Β 6.7 16.3 71 69 1858 92 178 62 lOPropfpr (2) 100% o B. 7.0 22.6 65 50 1421 72 183 63 20Propfpr (2) 100% ο Β 7.4 8.9 52 42 1163 107 145 64 30Propfpr (2) 40% / 36 3.5 29.8 42 69 1895 92 159 71 lOPropfpr. (5) 80% / 65 3.0 41.5 69 60 1704 69 128 72 20Propfpr (5) 60% / 49 3.9 36.2 59 51 1435 92 130 73 20Propfpr (5) 100% o B 15.2 38.5 51 58 1645 80 176 81 20Propfpr. (4) 100% ο Β 16.5 13.6 54 51 1420 87 155 82 30Propfpr (4) 80% / 62 4.6 6.8 47 49 1410 91 173 91 20Propfpr (1) 15% / 32 2.5 17.5 50 51 1620 85 180 92 lOPropfpr (1) ^# 40% / 43 3.5 13.1 53 39 1355 72 162 93 30Propfpr (D * 40% / 43 2.6 11.5 46 34 1155 78 136 10 1 20 grafts (6) 30% / 35 2.4 39 37 1220 140 102 20Propfpr (6) * 40

1 Marking * indicates that PA 6 6 has been used as the matrix polymer (otherwise PA 6 is always used)

2% value indicates the proportion of non-boned test bars without break (o B), for the number of break test bars1 in addition to the% value, the corresponding numerical value is given

Claims (2)

1. Schlagzahe polyamide molding compositions based on mixtures of 60 to 97 parts by mass of a partially crystalline polyamide, preferably PA 6 or PA 6.6 or PA 6 6/6 or PA ö / PA ^ mixtures, with a relative solution viscosity between 1.5 and 3.5 and 3 to 40 parts by mass of a by grafting of α, β-ethylenically unsaturated mono- or dicarboxylic acids or their anhydrides, including their mixtures untereinancer and with other carboxyl-free comonomers, at temperatures between 40 and 100 ⁰ C-excluding aqueous or organic dispersing, solvent or diluent - on ethylene-vinyl acetate copolymers having a vinyl acetate content by masses of between 5 and 25% (EVAC -5 / 25) and a melt index MFI (190 ⁰ C, 21.0N) between 0.1 and 20g / 10min obtained carboxylated (co-) graft product, characterized in that a (co) graft carboxylated EVAC -5/25 with a Cat boxylgruppen mass fraction between 0.3 and 8% and a Gel- Mass fraction is added between 20 and 90% of the molding composition 2. Schlagzahe polyamide molding compositions according to claim 1, characterized in that a (co-) graft carboxylated EVAC -5/25 having a carboxyl group mass fraction between 1.0 and 3.0% and a gel mass fraction between 35 and 75% of Form mass is added.