DD258242A1 - METHOD FOR PRODUCING THERMOPLAST / FUEL COMPOUNDS WITH IMPROVED MECHANICAL PROPERTIES - Google Patents

Abstract

The invention relates to a process for the production of thermoplastic / filler composites with improved properties and good flow behavior during injection molding. This is achieved by adding a filler having a length / diameter ratio of 1 to 20 to the thermoplastic and 0.01 to 6% by weight of a maleamic acid, bismaleamic acid or a hydrogen maleate or fumarate of diols to the thermoplastic / filler mixture.

Description

η = 1 - 13

X = CH ₂ , Y-CO-CH = CH ·

Y = 0, NH

be added.

2. The method according to claim 1, characterized in that 0.1 to 1.5Ma .-% of the modifier are added.

3. The method according to claim 1 and 2, characterized in that the thermoplastic / filler composite of 40 to 80 wt .-% polyethylene and / or polypropylene and / or ethylene-propylene copolymer and 20 to 60 wt .-% inorganic finely dispersed Filler exists.

4. The method according to claim 1 to 3, characterized in that 0.001 to 2, preferably 0.01 to 0.5Ma .-% of an organic peroxide, are added.

5. The method according to claim 1 to4, characterized in that 0.005 to 1 wt .-% of a stabilizer are added.

6. The method according to claim 1 to 5, characterized in that. Only a part of the matrix required for composite formation with the modifier and / or the peroxide and / or the stabilizer is .Vormodified.

7. The method according to claim 1 to 6, characterized in that 60 to 20 wt .-% kaolin with a length to diameter ratio of 3 to 5 or chalk with a ratio of «1 are added as filler.

Field of application of the invention

The invention relates to a process for the preparation of thermoplastic / filler composites based on polyolefins with improved mechanical properties, in which the thermoplastic / filler mixture is modified before or during compounding with other substances. The thermoplastic / filler composites are used as molding compounds for the injection molding of molded parts.

Characteristic of the known state of the art

In order to improve certain physico-mechanical properties and thus for better suitability for certain application purposes, finely dispersed mineral fillers are added to thermoplastics. The addition of modifiers improves the material properties, which deteriorate as a result of the incorporation of the filler. A wealth of modifiers have been described that either encase the filler or cause property improvements through physical effects. The known solutions usually achieve only a partial improvement of the mechanical properties of thermoplastic / filler composites. A significant increase in all property levels with justifiable modification effort is hardly achieved so far. Thus, unsaturated fatty acids are used for filler modification (DE-PS 958830 and US-PS 4420341). In US-PS 4328041 the modification of thermoplastic / filler composites (eg PE / chalk) with Alkenylbemsteinsäureanhydrid (about 0.4Ma .-%) and in FR-PS 7931 219 and EP-PS 032076 with Alkenylbemsteinsäureimiden described , With maleic anhydride and peroxide initiator PE / kaolin composites for property improvement are modified (US-PS 3956230 and 4071494). It is also known that unsaturated di- and tricarboxylic acids, their anhydrides and various derivatives (eg esters) (maleic acid, fumaric acid, maleic anhydride, maleimides, maleic and fumaric dibutyl, itaconic anhydride, citric anhydride, crotonic acid, angelic acid, etc., usually with peroxide ) can be used as modifiers (US Pat. No. 4,476,273). In addition, the use of acrylic and methacrylic acid and of compounds of the large class of esters of both acids is known (DE-AS 2262 126, DE-OS 2330022 and 2523434, US-PS 3926873,3969313, GB-PS 1416340). The modification of polyolefin / mica compounds with 0.01 to 7% by mass of a maleamic acid or bismaleamic acid is known, it being possible for the maleamic acid to have a silane group, without addition of peroxide (EP-PS 069937). The modification increases the tensile stress and the bending modulus of elasticity of the composite; however, with constant impact strength, the level of elongation in the tensile test certainly decreases.

- ζ - «go Purpose of the invention

The object of the invention is to produce mineral-filled thermoplastic molding compositions having improved mechanical properties and good flowability suitable for the injection molding of technical moldings.

Explanation of the essence of the invention

The object of the invention is to add more suitable modifiers to thermoplastics. According to the invention the object is achieved in that a thermoplastic filler with a length-diameter ratio of 1 to 20 and the thermoplastic / filler mixture 0.01 to 6Ma .-% maleamic acid, bismaleamic or hydrogen maleate or fumarate of diols of the general structural formula

HOOC-CH = CH-CO (CH-Y ₂ ) _n -, X-COOH

η = 1 - 13

X = CH ₂ , Y-CO-CH = CH Y = O, NH

be added.

The modifier is obtained according to generally known synthetic instructions from maleic acid, maleic anhydride or fumaric acid and an amino acid, a diol or a diamine.

This monomeric modifier capable of radical grafting reactions is added to the thermoplastic / filler mixture in amounts of 0.01 to 6% by weight, preferably 0.1 to 1.5% by weight. It does not matter whether all three components are premixed before thermoplastic processing on one of the usual machines (Brabender Plasticorder, rolling mill, single or twin screw extruder) below the melting point of the modifier, a continuous addition of the individual components via a metering in the extruder, or with the modifier premodification of filler or matrix polymer is carried out at temperatures above the melting point of the modifier.

The modifying effect can be easily enhanced by the addition of 0.001 to 2 mass%, preferably 0.01 to 0.50 mass%, of an organic peroxide adapted to the processing temperatures. Optionally, small amounts of a stabilizer can be added.

The thermoplastic / filler composite advantageously consists of 40 to 80% by weight of polyethylene and / or polypropylene and / or ethylene-propylene copolymer and 20 to 60% by mass of inorganic finely dispersed fillers. Carbonates or silicates, in particular chalk with a length-diameter ratio of = 1 or kaolin with a ratio of 3 to 5, are added as fillers.

Surprising was a good dispersion of the filler in the composite by the specified modifier without drop in tensile strength.

embodiments

The invention will be explained in more detail below with reference to several examples.

Comparative Example 1

PEHD powder with a flowability of 24 g (10 min) (MFI 49 N, 190 ° C) is processed via a twin-screw extruder at 190 ⁰ C, granulated and injected via an injection molding machine to test specimens (80 χ 10 χ 4) / mm ³ .

Comparative Example 2

60% by weight of PEHD powder and 40% by weight of chalk (at least 97.8% of CaCO ₃ , specific surface area about 1.7 m ² × g ^-1 density 2.5 to 2.6 g.cm ^-3 , Particle size distribution 100% <32 pm.89% <5μητι, 70% <3 pm.32% <1 pm, length-diameter ratio = 1) are mixed for 30 min in a high-speed mixer (750min ~ ¹ ) at about 25 ° C Composite mixture is further processed as in Comparative Example 1.

Comparative Example 3

60% by mass of PEHD powder and 40% by mass of kaolin (at least 81% kaolinite, specific surface area> 10 m ² · g ~ \ density 2.6 to 2.7 g cm ³ , particle size distribution 100% <80 pm.96%) 20 pm.87% <10 pm. 69% <5 pm, length Z diameter ratio from 5 to 5) are mixed according to Comparative Example 2 and processed as in Comparative Example 1.

Comparative Example 4

40% by weight of PEHD powder and 60% by weight of chalk are mixed as in Comparative Example 2 and further processed as in Comparative Example 1.

Comparative Example 5

40Ma .-% PEHD powder and 60Ma .-% kaolin are mixed as in Comparative Example 2 and further processed as in Comparative Example 1.

Comparative Example 6

PP granules (isotactic) with a flowability of 10 g / (10 min) (MFI 49N, 190 ⁰ C) is processed via a twin-screw extruder at 220 ° C, granulated and sprayed over a spray machine as in Comparative Example 1 to test specimens.

Comparative Example 7

40% by weight of PP granules and 60% by weight of chalk are mixed in the same way as in Comparative Example 2 and then further extruded and sprayed as in Comparative Example 6.

example 1

In a high speed mixer (750 min ^"1) be at about 25 ⁰ C maleamic 60 parts by mass of HDPE powder, 39.08 parts by mass of chalk, 0.8 parts by mass of N- (5-carboxypentyl), and 0, 12 parts by mass of tert-butyl perbenzoate (50% in dibutyl phthalate) for 30 minutes This composite mixture is processed at 190 ° C. by means of a twin-screw extruder, granulated and injected via an injection molding machine into test specimens (80 × 10 × 4) / mm ^3. A comparison The values from Comparative Example 2 illustrate a significant increase in the level of the material properties. For example, a _{n increases} to> 345%, a to 195%, Oh to 130% and ε _Η to 265% with a consistently high bending E level.

Based on the unfilled plastic (Comparative Example 1), the rigidity and the tensile strength increase at approximately the same level in the impact strengths and the elongation.

Example 2

As in Example 1, 60 parts by mass PEHD powder, 39.54 parts by weight of kaolin, 0.4 parts by mass of Ν, Ν'-hexamethylene-bismaleamidsäure and 0.06 parts by mass tert. Butyl perbenzoate mixed, granulated and sprayed into test specimens. The comparison with the values of Comparative Example 3 shows an increase in impact strength and tensile strength with constant flexural properties.

Example 3

As in Example 1, 40 parts by mass of PEHD powder, 59.85 parts by weight of chalk, 0.06 part of tetramethylene bis (hydrogen maleate) and 0.09 parts of tert. Butyl perbenzoate mixed, granulated and sprayed. A comparison with the values from Comparative Example 4 shows an increase of a _n to more than 675%, from a 1 to 285%, from σ ₁ to 150% and from ₁ to 500% at the same high ov values.

Example 4 ~

As in Example 1, 40 parts by mass of PEHD powder, 51.31 parts by weight of kaolin, 0.06 part of N- (5-carboxypentyl) maleamic acid and 0.09 part of tert. Butyl perbenzoate mixed, extruded and sprayed. The significant property improvement of the modified composite can be seen by looking at the values from Comparative Example 5. Thus, a _{n increase} to 245%, a _k to 230% and σ _Η to 120% with constant flexural strength and elongation.

Example 5

As in Example 1, 60 parts by mass of PEHD powder, 39.60 parts by mass of chalk and 0.4 part by mass of N- (5-carboxypentyl) maleamic acid mixed, extruded several times, granulated and sprayed into test specimens. The comparison of the values to those of Comparative Example 1 also show here a significant increase in the level of impact, bending and tensile properties.

Example 6

60% by weight of chalk, unmodified and with tetramethylene bis (hydrogen maleate) and peroxide (2,5-dimethyl-2,5-di-tert-butyl peroxyhexane) modified PP granules are mixed in such a ratio that, based on the composite, 0.067 Ma .-% tetramethylene bis (hydrogen maleate) and 0.010 wt .-% peroxide are used. The processing is carried out on a twin-screw extruder at 220 ⁰ C. Anschließend'werden as in Example 1 test specimens injection molded. Compared to the unmodified 40/60 PP / chalk composite (Comparative Example 7), all certain material properties are significantly increased in their level. Thus a _{n increases} to 205% a _k to 165%, σι, 1.5 to 145%, σ _Η to 165% and ε _Η to 160%. The 60% by weight chalk filled PP material also has very good properties compared to pure PP. Thus, the 40/60 thermoplastic / filler composite compared to the unfilled polypropylene (Comparative Example 6) has a higher rigidity with the same high level of tensile strength and only small losses in impact resistance behavior.

table Shock notch bending bending train strain shape bending impact- tension elastic festig ε _Η ⁵¹ Dimensions zähigikeit bending zitäts- ness toughness (MPa) module Oh ⁵ ' (kJ · m ~ ² )] a _k ²¹ C 4) tb (kJ · m " ² ) (GPa) (MPa) (%) > 100 5.5 19 0.85 21 14 Comparative Example 1 29 3.3 27 1.7 19 4.9 Comparative Example 2 22 2.9 35 3.0 24 6.7 Comparative Example 3 6.5 2.1 32 * 3.2 19 2.2 Comparative Example 4 7.4 2.2 39 * 4.6 21 2.1 Comparative Example 5 > 100 4.7 36 1.4 32 14 Comparative Example 6 30 2.2 41 4.5 20 2.6 Comparative Example 7

shape blow notch bending bending train strain Dimensions bending impact- tension elastic festig ε _Η ⁵⁾ toughness bending O _bl .5 ³⁾ zitäts- ness a ^1! toughness (MPa) module σ _Η ⁵⁾ (kJ · rrr ² ) a _k ² > E _b ⁴ > (kJ · rrr ² ) (GPa) (MPa) (%) example 1 > 100 6.4 27 1.4 25 13 Example 2 42 3.6 39 2.9 29 8.0 Example 3 44 6.0 38 2.6 29 11 Example 4 18 5.1 52 5.1 25 2.3 Example 5 > 100 5.6 28 1.7 24 11 Example 6 61 3.6 59 4.3 33 4.1

1) impact test according to TGL 14068 (according to Charpy)

2) notched-bar impact test according to TGL 14068 (according to Charpy)

3) Bending test according to TGL 14067, bending stress at limit deflection f _b = 1.5

4) Bending test according to TGL 14067

5) Tensile test to TGL 14070, maximum force F _H

All test methods were carried out on a standard small scale (80 × 10 -4) / mm ³ according to TGL 14067.

Claims (1)

1. A process for the preparation of thermoplastic / filler composites with improved mechanical properties, in which a thermoplastic / FüMstoff composite is modified with other materials, characterized in that a thermoplastic, a filler having a length to diameter ratio of 1 to 20 and 0.01 to 6% by weight of maleamic acid, bismaleamic acid or hydrogen maleate or fumarate of diols of the general structural formula, from the thermoplastic / filler mixture HOOC-CH = CH-CO-Y (CH ₂ ) _n _ ₁ X-COOH