DE2227887A1 - Vinylchloride suspension copolymer - in presence of a methyloxazoline/propyloxazoline copolymer as stabiliser - Google Patents

Abstract

In copolymsg. vinylchloride with =50 wt.% comonomer e.g. VAc in aq. suspension and in presence of a suspension stabiliser (I) and an oil-sol. catalyst, the (I) is a copolymer or methyl-DELTA 2-oxazoline, employed at 0.1-3.0% based on wt. of monomers. Reaction is started with 40-60 wt.% vinylchloride and (almost) all the comonomer, the remainder of the vinylchloride being subsequently continuously added under constant press. Used in mfre. of lacquers, coatings, the prods. have improved solubility in org. solvents with reduced tendency to clouding. Emulsifier need not be removed.

Description

Process for the preparation of vinyl chloride copolymers in aqueous Suspension of the present invention is a method of manufacture vcln vinyl chloride copolymers with a comonomer content of up to 50 percent by weight Polymerization in aqueous suspension in a counter-host to suspension stabilizers and monomer-soluble catalysts, said comonomers and 40 to 60, with advantage 45 to 55 percent by weight of the eyinzupolyrnerivierenden vinyl chloride and the remaining vinyl chloride is metered in continuously at constant pressure.

An important aim of the process according to the invention is to produce suspension copolymers of vinyl chloride with improved solubility behavior in organic solvents to provide.

Copolymers of vinyl chloride are known to be produced by solution, emulsion or to produce suspension polymerization.

When performing the solution polymerization, it must be taken into account that that the solvent used often affects the properties of the polymers formed adversely affected; In addition, the process is expensive because of the large amount of solvent need to be recovered.

Emulsion polymerization produces products with emulsifier compounds, which are used for many purposes, for example as raw materials for paints and coating agents, disturb significantly. Due to their emulsifier content, the products generally show strength Solvent retention and often produce cloudy solutions in those commonly used organic solvents such as lipophatic esters and ketones. In the preparation of C '-) coatings and lacquers therefore result in inhomogeneities, speckled surfaces and uneven coatings.

The removal of the emulsifier contents is complex and difficult, however.

When using suspension polymers for the production of paints and overlaying, the emulsifier hardening and the problems arising therefrom are eliminated; However, organic solvents only result in cloudy, gel-containing solutions, so that an aftertreatment with aldehydes, ketones or acidic acids is necessary is to get to soluble end products (see. DT-PS 929 643 Example 1 and 2, last lines in each case).

With the semi-continuous described in DT-PS 1 105 177 Processes for the production of vinyl chloride-vinyl acetate copolymers do arise Polymers which are dissolved in organic solvents without any aftertreatment can; however, the solutions contain specks and tend to be cloudy, like the The results of the comparative tests are shown in the table below.

These disadvantages of the prior art are overcome with the invention Procedure overcome.

In the process according to the invention for the preparation of vinyl chloride copolymers with up to 50 percent by weight comonomer content by polymerization in aqueous suspension, in the presence of suspension stabilizers and oil-soluble Catalysts in which all or almost all of the comonomer and 40 to 60, preferably 45 to 55 percent by weight of the vinyl chloride to be polymerized in front of and. the remaining vinyl chloride is continuously metered in at constant pressure, 0.1 to 3.0 percent by weight, based on monomers, are used as suspension stabilizers, a copolymer of methyl- # ²-oxazoline and propyl- # ²-oxazoline used.

The suspension stabilizer is preferably used in amounts of 0.1 up to 0.5, in particular 0.1 to 0.2 percent by weight, based on monomers, use.

The copolymers used as suspension stabilizers exist from 90 to 50, preferably 80 to 70 mol percent methyl - / \ 2-oxazoline units and 10 to 50, preferably 20 to 30, mole percent propyl- # ²-oxazoline units. Your K-value is 20 to 50, preferably 40 to 45.

In a preferred embodiment, the comonomer is vinyl acetate, in particular in amounts of 10 to 20 percent by weight, based on total monomers present, used.

The products according to the invention yield in organic Solvents surprisingly clear solutions with few specks, from which homogeneous low-speck films are obtained.

The following comonomers can be used: vinylidene chloride, vinyl esters such as vinyl acetate, vinyl alkyl ethers such as n-butyl vinyl ether, maleic acid esters such as, for example dibutyl taleate.

The comonomer can be used in amounts up to 50 percent by weight, based on d @ s entire copolymers are polymerized. For the manufacture of paint raw materials 10 to 20 parts by weight of comonomer, in particular vinyl acetate, are preferred, used.

The polymerization is customary depending on the desired K value a temperature of 40 to 80 ° C, preferably 60 to 70 ° C carried out.

Care should be taken to avoid caking on the wall during polymerization ensure that the reaction temperature is below the flocculation point of the suspension stabilizer lies. (The flocculation point is the temperature at which the suspending agent flocculates from a 0.5 percent aqueous solution.) To products with those for paint raw materials desired γ-values of 40 to 45, is in the present case Polymerization to maintain a temperature of 70 to 60 ° C, however, by application can be lowered by controllers to 65 to 55 ° C.

The usual regulators in vinyl chloride polymerization can be used Use compounds such as trichlorethylene, carbon tetrachloride and other non-polymerizable halogenated hydrocarbons, in the usual ways Quantities of approx.

0.05 to 5.0 with Vorte] 3.0 to 4.0 percent by weight, based on Monomers. The phase ratio of water to monomers can be varied within wide limits can be varied and is usually between 1.5: 1 and 5: 1, advantageously it is 1.5 to 2.0.

The usual oil-soluble redical catalysts are used as catalysts to be used such as dialkyl or diacyl peroxides or azo compounds. Examples are Lauroyl peroxide, benzoyl peroxide, di-alkyl peroxydicarbonate, tert-butyl perpivalate, Acetylcyclohexylsulfonyl peroxide, azodiisobutyronitrile. Mixtures of catalyst with smaller and larger half-lives of the decay are used to advantage.

Since the flocculation point of the suspension stabilizer, regardless of The K value, which falls with increasing propyl- # ²-oxazoline proportions, can be used to produce varnish only those copolymers of methyl- # ²- and propyl- # ²-oxazolines with good success use as suspension stabilizers that contain up to approx. 30 mole percent propyl- # ²-oxazoline contain.

For polymerizations at lower temperatures, for example at approx. 50 ° C, the suspending agent in question can contain up to 50 mol percent Propyl ²-oxazoline fractions are used with advantage.

Products with K values, such as they are currently not desired for paint raw materials; working in the present however, the suspending agents to be used according to the invention are quite general the surprising advantage that equally good results when using smaller amounts of suspending agents compared to those of the prior art.

Homopolymers of vinyl chloride in Presence of the suspension stabilizers to be used according to the invention, otherwise usual process conditions n of suspension polymerization.

The suspension stabilizers to be used according to the invention are obtained in a known manner by cationic polymerization, as for example in DT-PS 1 263 300 is described.

Their K values are (according to composition) between 20 and 50, preferably between 40 and 45.

These K values correspond to reduced viscosities, measured in 0.5 % m-cresol solution from 0.2 to 1.0.

The following examples serve to further explain the inventive concept Process and the technical progress achieved with it: Examples 1 to 5 The polymerizations were carried out with the following recipe: Component parts by weight 180 parts by weight of vinyl chloride per 100 parts by weight of monomeric deionized water 83.0 vinyl acetate 17 lauroyl peroxide 0.36 trichloroethyler 3.6 "" suspending agent 0.15 "" In a 40 liter polymerization kettle equipped with a stirrer and heating mantle water, suspending agent and catalyst were submitted, the autoclave was closed, flushed several times with nitrogen and evacuated. After turning on the stirrer was Add all of the vinyl acetate, half the amount of vinyl chloride and the regulator and heated to the desired temperature of 70, after pressure drop was at constant Pressure of 6 at; the remainder of the vinyl chloride is metered in within about 8 hours (in 9 equal parts). At 3atü was cooled, let down and the reaction vessel opened. The resulting slurry was separated from the supernatant liquid (Filtration). The beads were washed several times with water and then washed dried at 50 ° C. K value: 40 + 0.5 (regardless of the type of suspending agent) Exams the paint properties 20 g of the copolymers were each in 100 g of ethyl acetate solved. With stirring at 30.degree. C., more or less clear ones were obtained for 2 hours Solutions. A classification could be carried out turbidimetrically. The amount of gel particles in solution were counted on the edge of the glass to one cm², the number of Specks on an extended film.

Table 1 Used haze specks / cm² Suspension - one 20% in solution in the film medium ethyl acetate solution 1) 90 mol% methyl oxazoline 10 mol% propyl 7% approx. 30 35 oxazoline (K value ~ 50) 2) 80 mol% methyl Poly-oxazoline merisa- <20 mol-% propyl- 4% approx. 20 20 te from oxazo3.in (K value ~ 45) 3) 70 mol% methyl oxazoline 30 mol% propyl 3% approx. 15 oxazoline (K value 40) 4) Polyvinylpyrroli- 25% approx. 30 40 don (for comparison) 2 @% approx. @@ 40 5) methyl cellulose 11% approx. 50 45 (for comparison) 6) ethyl acetate 0% 0 - (for comparison) 0% 0 - Examples 6 and 7 Examples 6 and 7 (comparative example) differ in their formulation only from those mentioned above in that polymerization was carried out at a temperature of 60 ° C. and 0.2 and 0.4 parts of suspending agent were added to the batch; according to Example 6, clearer 20% ethyl acetate solutions, fewer specks in solution and no more in the film are obtained than according to Example 7, although only half the amount of suspending agent was used.

Table 2 Ge haze speckles / cm² Suspension weight- a 20% in Lö- in the film medium parts ethyl acetate solution 6) 80 mol% methyl oxazoline # 0.2 6% approx. 25 30 20 mol% propyl Polyoxazoline merisa- # 7) 50 mol% methyl te made of vinyl ether 50 mol% maleic # 0.4 8% approx. 30 30 acid anhydride (for comparison) The results listed in Tables 1 and 2 show that, surprisingly, according to the invention, vinyl chloride copolymers with significantly improved paint raw material properties can be obtained compared with prior art processes using conventional suspension stabilizers.

Products manufactured according to the invention result in clear, low-speck lacquer solutions, from which speckless, homogeneous films can be produced. It should also be borne in mind that according to the invention smaller amounts of suspending agent are to be used if equally good end products as according to the state of the art, will roll,

Claims (6)

Claims Process for the production of vinyl chloride copolymers with up to 50 percent by weight comonomer content by polymerization in aqueous suspension in the presence of suspension stabilizers and oil-soluble catalysts, wherein all or almost all of the comonomer and 40 to 60, preferably 45 to 55 percent by weight of the vinyl chloride to be polymerized before submits and at constant The remaining vinyl chloride is metered in continuously under pressure, which means that n n z e i c h n e t that 0.1 to 3.0 percent by weight as a suspension stabilizer, based on monomers, a copolymer of methyl -2-oxgzoline and propyl- # ²-oxazoline can be used. 2. The method according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the suspension stabilizer in amounts of 0.1 to 0.5 percent by weight, based on monomers, is used. 3. The method according to claim 1 and 2, d a d u r c h g e k e n n z e i c h n e t that the copolymer used as a suspension stabilizer from 90 to 50, preferably 80 to 70 mole percent methyl- # ²-oxazoline- and ZO to 50, preferably 20 to 30 mole percent propyl-L-oxazoline units, 4. Procedure r.a-h claim 1 to 3, d u r c h e k e n n n z e i c h n e t that the K value of the as suspension stabilizer copolymers to be used is 20 to 50, preferably 40 to 45. 5. The method according to claim 1 to 4, d a d u r c h g e k e n n z e i c h n e t, daP as comonomer vinyl acetate, preferably in amounts from 10 to 20 percent by weight, based on total monomers present, are used will. 6. Use of the polymers obtained according to claims 1 to 5 as raw materials for the production of lacquers and coating agents.