DD246768A1 - METHOD FOR PRODUCING HIGH-POROUS POLYVINYL CHLORIDE FOR HARD-PROOF PROCESSING - Google Patents

Abstract

High porosity PVC with apparent densities (SD) 0.4 g / cm3 (according to TGL 14 074), average particle diameters (d) between 0.25 and 1.0 mm and good melting behavior is achieved by free-radical polymerization of vinyl chloride (VC) in aqueous monomergesaturated, a water-soluble peroxidisulfate in an amount between 10 3 and 10 1 mol / l and a metal (III) salt in an amount between 10 5 and 510 3 mol / l prepared solution by in the emulsifier and suspension stabilizer-free phase in the temperature range between 320 K and 350 K, the VC vapor pressure p is kept below the corresponding monomer vapor pressure ps and the consumed monomer is continuously replenished until a PVC solids content in the range between 5 and 30 wt .-%. As metal (III) salts, the chlorides, sulfates and nitrates of aluminum, cerium and lanthanum are particularly suitable. The values for SD and d can be specifically adjusted via the initiator and impurity concentrations. The resulting VC homopolymers have no pericellular membranes and are due to their property levels - after appropriate addition of known blowing agents and other conventional processing aids - particularly suitable for hard foam processing.

Description

Features of the invention

The object is achieved in that the polymerization of a metal (III) salt, such as the corresponding

Chlorides, sulfates and nitrates of aluminum, cerium and lanthanum, in a concentration of 10 -5 to ⁵ 10 ^-3 mol / l and up to a PVC solids content of 5 to 30%, based on the total (water plus polymer) Dimensions,

is polymerized.

The peroxidisulfate initiator concentrations are generally between 10 ^-3 mol / l and 10 ^-1 mol / l.

As 1Vallall (III) salts are particularly Al ₂ (SO ₄ I ₃ · 18 H ₂ O, LaCl ₃ · 7 H ₂ O and Ce (NO ₃ J ₂ 6 H ₂ O (crystallization products of water) is used, wherein the mentioned salt concentrations on the pure anhydrous metal (III) -Sulfate, -Chloride

or nitrates.

Via the initiator and metal (III) salt concentration (total ionic strength), the most important polymer characteristics, such as bulk density (SD), average polymer particle diameter (wet-sieving C value) or the distribution width (depending on the degree of VC conversion or PVC solids content) are determined ( F value of the wet sieving) and of the Fikentscher K value (KW.).

The resulting PVC products, generally stabilized with a known tin compound in the usual concentrations of 0.5 to 4.0%, become, due to their large grain diameters and very high porosity, for optimum distribution of a conventional propellant and subsequent foaming for the preparation used by rigid PVC foam.

embodiment

In an autoclave equipped with an anchor stirrer (generally constant speed of 400 rpm) and pressure and temperature measuring devices, 800 parts by mass (MT) of water are charged together with the amount of aluminum sulfate indicated in Table 1. After the pressure test carried out with nitrogen, the headspace of the autoclave is purged with VC and then heated to a polymerization temperature (T _Pm ) of 333K and a VC pressure ρ of 0.9 MPa (corresponding to p / p _s -0.88) is set.

Thereafter, the dissolved in water initiator (K ₂ S ₂ O ₈ in amounts shown in Table 1) is pressed through a Meßbürette in the reactor.

The VC consumed by the polymerization is continuously recharged while maintaining T _Pm and ρ constant. When establishing the desired solids content (FG), the VC Nachfuhr is interrupted, the reactor is expanded and the product obtained by PVC-S-Aufarbeitungstechnologie isolated. The conversion rate was always between 80 and 100%. Table 1 lists the polymerization conditions, including recipe, and PVC characteristics (SD, HC, thermostability TS and wet screening).

The achieved polymerization rates v _Br (polymer weight per unit time) are comparable to those of known emulsion and suspension polymerization. The polymerization temperature (T _Pm has (333 + 5) K and the relative pressure p / p _s (0.85 + 0.5) in the examples, wherein the size of the fluctuation width of the more or less accurate continuous replenishment of consumed The TS determination is carried out at 453 K by the stabilimeter method on a cast film prepared from 5 g of PVC, which is dissolved together with 1 drop of a modified dibutyltin maleate in 20 ml of cyclohexanone at room temperature, poured as a clear solution on a glass substrate and after drying in a vacuum oven has been removed at room temperature as a film.

Table 1

polymerization

PVC characteristics

K2S2U8

(minor)

Me (III) salt (mol / l,)

Phasenverh. v _Br

VCges./Wasser

(Ma.-Shares (MT / min) (%

SD

(g / cm ³

K-W. TS wet sieving

> 0.5 mm C-W. F-W. (min) (%) (mm)

Al ₂ (SO ₄ J ₃

1 0.001 0.00005 1 / 5.6 0.3 13.3 0.14 60 30 18 0.32 3.3 2 0.005 0.00005 1 / 4.2 0.6 16.4 0.23 53.5 20 37 0.29 4.0 3 0.01 0.00005 1 / 2.8 0.75 14.6 0.37 46.2 15 45 0.40 7.0 4 0.02 0.00005 1 / 4.2 0.7 18.5 0.26 42 15 31 0.28 4.7 5 0.001 0.0001 1 / 8.9 0.2 8.0 0.08 62 30 50 0.38 4.0 6 0.005 0.0001 1 / 5.8 0.7 13.9 0.20 52 20 44 0.36 4.4 7 0.005 0.0001 1 / 4.3 0.6 18.0 0.25 49 15 19 0.29 2.8 8th 0.01 0.0001 1 / 2.9 0.8 25.3 0.39 47 25 37 0.26 5.6 9 0.005 0.0005 1 / 5.8 0.43 13.5 0.15 57 30 50 0.49 4.0 10 0.01 0.0005 1 / 5.4 0.40 12.6 0, ί6 56 25 70 1.23 8.5 11 0.02 0.0005 1 / 4.0 0.55 19.3 0.34 46 25 72 0.82 8.0 12 0.03 0.0005 1 / 3.4 0.66 22.4 0.38 42 15 58 0.55 6.8 13 0.04 0.0005 1 / 3.4 0.55 23.6 0.40 40 15 59 0.77 4.6 14 0.03 0.001 1 / 3.3 0.69 22.6 0.27 52 25 45 0.44 5.1 15 0.04 0.001 1 / 3.2 0.61 20.1 0.36 44 20 56 0.61 6.5

Continuation Table 1

K ₂ S ₂ O ₈ polymerization Phasenverh. V _B r FG SD K-W. PVC characteristics > 0 wet screening F-W. No. Me (III) salt VC ges./Wasser TS (%) , 5 mm C-W. (minor) (Ma. Shares (MT / min) (%) (g / cm ³ 34 (Mm) 4.3 0.05 (minor) 1 / 3.2 0.72 23.2 0.33 44 (Min) 83 0.31 16 0.01 0.001 1 / 5.7 0.38 13.6 0.15 48 20 28 8.2 17 0.02 0.0015 1 / 5.9 0.38 11.8 0.19 44 25 68 0.81 6.3 18 0.03 0.0015 1 / 5.9 0.32 13.1 0.18 44 15 42 0.77 4.5 19 0.04 0.0015 1 / 3.4 0.67 23.0 0.29 42 25 44 0.42 7.0 20 0.05 0.0015 1 / 5.8 0.62 19.4 0.30 40 15 0.55 21 0.0015 15 44 3.8 0.001 Ce (NOs) ₂ 1 / 9.0 0.25 10.2 0.12 62.6 39 0.36 3.5 22 0.001 0.00005 1 / 5.6 0.31 12.5 0.22 57.0 30 60 0.39 5.1 23 0.005 0.0005 1 / 3.8 0.35 15.8 0.23 56.2 25 38 0.30 5.3 24 0.005 0.0001 1 / 3.5 0.40 14.3 0.28 51.8 25 41 0.44 4.4 25 0.01 0.0005 1 / 3.8 0.48 15.5 0.31 50.5 20 29 0.41 6.1 26 0.01 0.0005 1 / 5.5 0.65 16.8 0.33 48.0 20 35 0.38 6.3 27 0.02 0.001 1 / 7.2 0.45 12.3 0.25 46.2 15 48 0.50 3.8 28 0.03 0.001 1 / 5.8 0.56 20.2 0.38 42.0 20 50 0.61 4.1 29 0.04 0.0005 1 / 3.4 0.75 16.1 0.31 40.3 15 0.38 30 0.0015 20 38 4.4 0.001 LaCI ₃ 1 / 5.6 0.45 13.5 0.25 58.1 48 0.50 4.1 31 0.005 0.0001 1 / 5.8 0.45 15.6 0.26 54.1 25 51 0.38 5.8 32 0.01 0.0005 1 / 3.3 0.62 21.8 0.35 49.1 30 33 0.67 3.8 33 0.02 0.0001 1 / 3.4 0.58 20.2 0.31 46.0 15 44 0.35 6.5 34 0.04 0.0010 1 / 5.8 0.55 15.3 0.28 42.1 20 0.51 35 0.0015 25

Claims (1)

Invention claim: A process for the preparation of highly porous polyvinyl chloride for rigid foam processing based on the radical polymerization of vinyl chloride in aqueous monomer-containing, a water-soluble initiator, such as potassium or ammonium peroxydisulfate, in an amount between 1CT ³ and 10 ~ ^Ί mol / l containing phase excluding Emulsifiers and suspension stabilizers at monomer pressures ρ below the respective monomer saturation vapor pressure p _s corresponding to p / p _s between 0.5 and 0.95 in the temperature range between 320K and 350K, characterized in that the polymerization of a metal (III) salt, such as the corresponding chlorides , sulfates, and nitrates of aluminum, cerium and lanthanum, added in a concentration of 10 ^-5 to 5 × 10 ^-3 mol / l and up to a PVC solids content 5 to 30%, based on the total (water plus polymer) - Mass, polymerized. Field of application of the invention The invention relates to a process for the preparation of highly porous polyvinyl chloride (PVC) for rigid foam processing on the bass of the radical polymerization of vinyl chloride (VC) in aqueous monomer-saturated, a water-soluble initiator such as potassium or ammonium peroxydisulfate, in an amount between 10 ^-3 and 10 ^-1 mol / l-containing phase with the exclusion of emulsifiers and suspension stabilizers at monomer pressures ρ below the respective monomer saturation vapor pressure p _s corresponding to p / p _s between 0.5 and 0.95 in the temperature range between 320 K and 350 K. Characteristic of the known technical solutions It is known to polymerize VC and VC comonomer mixtures while maintaining p / p <1 and using suspension stabilizers and / or emulsifiers and monomer or water-soluble initiators or redox systems in the usual temperature range between 320K and 350K in aqueous phase (GB A916280, GBA967895, GBA1413135, GBA1413173, GBA1215775). As a specific variant, in particular with respect to a number of important processing and performance polymer characteristics (high porosity and ease of digestibility), the VC polymerization below p _s in aqueous monomer-saturated solution of a water-soluble peroxidisulfate or redox system, without PVC or other polymer template and in the absence of suspension stabilizers and emulsifiers (hereinafter referred to as surfactants) or in the presence of severely limited surfactant concentrations which do not ensure stabilization of the monomer droplets have been developed (DD 142805, DD 150210, DD150207, DD154101, DD 216470A1, DD211454). The VC homo- and copolymers obtained in this way are characterized by a high purity due to the exclusion of surfactants and other impurities, porosity, sufficient to high yield strength and heat stabilization within a broad Fikentscher K value range. Due to bulk densities in general> 0.4g / cm ³ (according to TGL 14074), the average particle diameters <0.2mm (according to TGL20645, wet sieving) usual for PVC, these products are suitable for hard foam processing without expensive formulation and technological measures (incorporation of the Propellant) can not be used. Object of the invention The aim of the invention is, without increased technological and formulation overhead, highly porous PVC with bulk densities <0.4 g / cm ³ (according to TGL 14074) and average particle diameters in the range between 0.25 and 1.0 mm (according to TGL 20645) for hard foam processing manufacture. Explanation of the essence of the invention
The technical task The invention has for its object to provide a process for the preparation of highly porous PVC for rigid foam processing based on the radical VC polymerization in aqueous surfactant-free monomer-saturated and a water-soluble initiator, such as potassium or ammonium peroxydisulfate phase while maintaining a relative pressure p / p _s between 0.5 and 0.95 in the temperature range between 320K and 350K to develop.