DD251761A1 - COATING THERMOPLASTIC MOLDING BASED ON POLYVINYL CHLORIDE - Google Patents

Abstract

The invention relates to the production of impact-resistant thermoplastic molding compositions with increased rigidity based on PVC modified with inorganic fillers and a VC-EVA graft copolymer. The molding compositions according to the invention have an increased impact strength while at the same time improving the rigidity in comparison with the prior art molding compositions based on PVC / VC-EVA graft copolymer. The processing width is increased because the impact strength is moderately slightly dependent on the processing temperature. The molding compositions according to the invention are prepared by mixing PVC in the presence of conventional thermal stabilizers and processing aids with inorganic fillers in an amount between 5 and 50% by weight, based on the total mixture, and a VC-EVA graft copolymer in such an amount that the EVA content of the total mixture is between 0.5 and 12 mass%, with the vinyl acetate content of the copolymer used for grafting being between 2 and 39 mass%. The mixture thus obtained is suitable for the production of moldings and semi-finished products by known processes.

Description

Field of application of the invention

The invention relates to impact-resistant thermoplastic molding compositions with increased rigidity on the basis of polyvinyl chloride (PVC) and / or copolymers of vinyl chloride (VC), an inorganic filler and a graft copolymer of VC on ethylene-vinyl acetate copolymers (EVA copolymers) as modifiers for Toughening included. The molding compositions of the invention are suitable for the production of moldings and semi-finished products by known methods, such as extrusion, calendering, etc.

Characteristic of the known technical solution

It is known to produce impact-resistant thermoplastic molding compositions by adding modifiers with elasticizing effect to rigid PVC mixtures. Thus, it is known to use VC-EVA graft copolymers as impact modifiers for PVC molding compositions (DD 158908). These molding compositions have the disadvantage that they have a reduced modulus of elasticity and their impact strength is highly dependent on the processing temperature and is lost at elevated processing temperature.

It is also known to add inorganic fillers with EVA copolymers or EVA graft copolymers to impact-modified rigid PVC molding compositions. Thus, in order to increase the dimensional stability of extrusion strands, various chalks or kaolin are used. However, only small amounts of inorganic fillers are used (5, preferably 2 to 3 parts by weight) and the mechanical properties of the extrudates, such as impact resistance and stiffness are not improved (DD 82832).

According to US Pat. No. 4,377,051, blends with increased impact strength are obtained from PVC and an EVA copolymer premixed with a finely divided inert inorganic filler. For this purpose, however, EVA copolymers with high vinyl acetate content (> 40%) and finely divided inorganic fillers (0.01 to 3 / xm) are required.

Further, PVC with increased impact resistance can be obtained by adding a mineral filler impregnated with 1 to 10% of a C8 to C22 fatty acid and an EVA copolymer. Disadvantage of this method is that the increased impact resistance can be achieved only with combined use of fatty acid / EVA copolymer and only after previous impregnation of the filler with fatty acid and EVA copolymers and when using very finely divided filler (<400nm) (CS 197006 and CS 205243).

Object of the invention

The object of the invention is to develop filled thermoplastic molding compositions having increased toughness and stiffness while improving processability.

Explanation of the essence of the invention

The technical problem to be solved by the invention is based on the object of producing impact-resistant thermoplastic molding compositions with increased stiffness on the basis of mixtures of PVC or copolymers of the VC and VC-EVA graft copolymers which comprise an inorganic filler as a co-modifier, wherein the amount of VC-EVA graft copolymer modifier is reduced and which have an increased processing latitude in terms of processing temperature.

Features of the invention

The object is achieved in that PVC mixed in the presence of conventional thermal stabilizers and processing aids with a VC-EVA graft copolymer and an inorganic filler and the mixture is then processed on a processing machine, wherein the amount of inorganic filler between 5 and 50 Ma. %, based on the total mixture, and the VC-EVA graft copolymer is added in such an amount that the BVA content of the total mixture is between 0.5 and 12% by mass.

Suitable VC-EVA graft copolymers are those having an EVA content between 95 and 5% by mass and a vinyl acetate content of the grafted EVA copolymer between 2 and 39% by mass. As inorganic fillers, u.a. various calcium carbonates, e.g. As chalk, calcite and precipitated products, kaolin, lime and anhydrite used. It is an advantage of the molding compositions according to the invention that their impact strength is relatively slightly dependent on the processing temperature and is maintained even at higher processing temperatures at which the prior art molding compounds of PVC and VC-EVA graft copolymer lose their impact strength, resulting in an increased processing latitude results.

Another advantage is that for the preparation of the molding compositions according to the invention relatively coarse and non-prepregged fillers used and both toughness and rigidity can be improved simultaneously.

embodiments

1. On a rolling mill mixtures of suspension PVC, lead stearate as a stabilizer, VC-EVA graft copolymer having an EVA content of 85 Ma. -% and a vinyl acetate content of EVA used for grafting of 13 Ma (η u modified and modified superficial s) .-% and chalk with different grain size distribution at 18O ⁰ CfUr processed for 10 minutes. Subsequently, the rolled sheets are pressed at a temperature of 190 ⁰ C to plates for mechanical testing (composition of the mixtures and mechanical characteristics see Table 1)

2. For comparison, as in Example 1, mixtures of suspension PVC having a K value of 58, lead stearate and VC-EVA graft copolymers are processed to give plates which are subjected to mechanical testing (composition of the blends and mechanical properties see Table 2).

3. Analogously to Example 1, mixtures of suspension PVC, lead stearate, VC-EVA graft copolymer and precipitation lime, anhydrite, kaolin or calcite are processed into plates for mechanical testing (for composition of the mixtures and mechanical properties, see Table 3).

4. Analogously to Example 1, a mixture of PVC, lead stearate, VC-EVA graft copolymer and a chalk corresponding to No. 6 / Table 1 is processed at different roller temperature (composition of the mixture and mechanical properties see Table 4)

Table 2

No. PVC Pb stearate VC-EVA graft ^a K,., 2) Erei ²¹ ig] [G] copolymer at RT • at RT [G] 1 200.0 2.00 1.00 1.00 2 194.0 2.00 6.0 1.37 0.90 3 188.0 2.00 12.0 1.97 0.77 4 180.0 2.00 19.2 4.32 0.71

Table 1

No, tg] PVC lead VC-EVA graft [G] chalk At <2.5 / atm modifi ^a K ", 2) Erel ^21st 91 cation stearate copolymer Comber part. [M%] ¹¹ 91 none at RT at RT 148 K- 40.0 91 none 118 Ig] tg] 70.0 <10 / 91 none 3.92 1.06 178 value 1.60 12.0 10.0 99 none none 2.50 1.25 1 178.2 58 1.30 12.0 19.4 99 51 2.96 3.00 0.93 2 158 58 1.90 12.0 30.0 99 91 Stearic. 1.49 1.17 3 154 58 1.86 2.4 40.0 99 91 none 0.98 4 151 58 1.70 12.0 40.0 81 91 none 2.11 1.32 5 151 58 1.60 6.0 40.0 93 91 none 1.68 1.24 6 151 58 1.60 9.0 40.0 99 none 3.13 1.19 7 136 52 1.60 9.0 44.8 99 4.07 1.21 8th 63 1.60 9.0 99 4.75 0.82 9 70 1.55 19.2 99 10 58

Table 3

PVC

[G]

174.0 174.0 164.0 154.0

stearate

[g] 1.80 1.80 1.70 1.60

VC-EVA graft kind filler Kornverteil. [M%] ^1! <ΙΟμ, ΓΠ ^a K ", 2) Erel ^21st 57 copolymer amount <40μ.ιη 69 at RT at RT kaolin 99 42 [G] lime [G] 98 16.5 1.52 1.23 6.0 calcite 20.0 97 1.65 1.05 6.0 anhydrite 20.0 97.5 1.50 1.02 6.0 30.0 1.42 1.24 6.0 40.0

Table 4 PVC Ig] Lead stearate Ig] VC-EVA graft copolymer [g] Chalk Ig] Walzentemp. [ ⁰ C] 3Κ,., 2) at RT Erel ²¹ at RT No. 148.0 148.0 148.0 1.60 1.60 1.60 12.0 12.0 12.0 40.0 40.0 40.0 160 170 180 3.47 3.24 3.00 1.07 1.05 1.06 1 2 3

¹¹ Determination with the aid of sedation analysis according to Dallendörfer-Langhammer.

ate ,,,, E _n , Relative impact strength, relative modulus of elasticity ax "e ₀ Impact strength / modulus of elasticity of PVC according to No. 1 / Table aκ ,, Bending strength / modulus of elasticity of each sample

Claims (3)

1. Impact-resistant thermoplastic molding compositions with increased rigidity on the basis of polyvinyl chloride and / or copolymers of vinyl chloride and a VC-ethylene-vinyl acetate graft copolymer, characterized in that the molding compositions ais comodifier an inorganic filler with a particle fraction of <40 / xm of at least 95th % is added in an amount between 5 and 50% by weight, based on the total mixture, and the total EVA content is between 0.5 and 12% by mass. 2. Molding compositions according to item 1, characterized in that as inorganic filler preferably calcium carbonates (eg chalk, calcite and precipitated calcium carbonates), anhydrite,   Lime and kaolin are used. 3. Molding compositions according to item 1, characterized in that a VC-EVA graft copolymer having an EVA content of between 95 and 5% by weight is used and the vinyl acetate content of the grafted EVA copolymer is between 2 and 39% by mass. lies.