DE2213135C3 - Process for the production of vinylidene fluoride homopolymers - Google Patents

Description

"2 ⁰⁷

that solid polymer builds up on the reaction filter walls establishes how the attempts to equate to follow below and show examples. This desired polymer accumulation is usually . gis "reaction vessel contamination"

^ hnet
tY have obtained vinylidene fluoride polymers

Excellent physical and chemical properties. Due to an improved dispersion • they are especially suitable as dispersion over-resins which produce remarkable and permanent coatings of excellent smoothness and gloss on a large number of substrates. ^ nas inventive method has the advantage, A ß it economically and industrially feasible i * Ha is a water-soluble initiator used in place of a merenlöslichen organic peroxide. n ° by using larger amounts of monomers in relation to the used! one uses which latices with a higher solid content

η become "

apparent from the further following below Vergleichsver- G, unsatisfactory results are obtained with the initiator of the 34 75 396 regardless of whether the reaction or without additional hydrostatic pressure St, is he-η on the basis of the prior art could S; are oVhergesehen that the use of alkylene oxides together with the special water-based initiator of the process of the invention does not provide high yields, but also prevents contamination of the reaction vessels.

The /S-hydroxyethyl tert-butyl peroxide used as an initiator in the process according to the invention has the formula below

H-CH-CH ₂ -OO-

I.
OH

weight not. However, polymerizations without alkylene oxide show very severe reaction vessel contamination. The lower alkylene oxides used according to the invention have fewer than 8 carbon atoms in the S molecule, ζ. As ethylene oxide, Propyienoxid, isobutylene ^{ox 'd} · ^Al hvienoxid is preferred.

In general, about 0.02 to 0.5 percent by weight alkylene oxide, based on the weight of the alkylene oxide, is sufficient Monomers to avoid contamination of the reaction vessel

to prevent. This corresponds to about ¹ U ₀ O ₀ to about ³ U _{00 of} one mole of alkylenowd per mole of vinylidene fluoride. Larger amounts of alkylene oxide can be used without detriment to the system, but this is of no practical use. In general, the alkylene

oxide added to the polymerization system in dilute aqueous solution.

The fluorinated wetting agent used in the process according to the invention should be a good emulsion of the polymerization system effect, from which the polyraen

sate in the one suitable for the coating dispersion Particle size distribution are produced. Suitable

fluorinated wetting agents are described in US Pat. No. 3,193:> 39, 34 75 396 and 32 45 971. In principle, any water-soluble fluorinated or fluorinated wetting agent can be used, provided that the hydrophobic part of the molecule is at least half fluorinated and contains 5 to 15 carbon atoms and that the hydrophilic part is ionic and aqueous, e.g. As a carboxyl, phosphate AMRN ^ _ ^ SUJ fansäuregruppe e.ne or water-soluble ^{Su Fons} l ^ ^u ^ group contains. However, parfluorinated wetting agents of the general formula are more suitable

^. _χ ^ _{n hydrogen} . _{; Fluorine} . _{or C is} chloro atom, R is a perfluoroalkylene, perfluorocycloalkylene or perfluorochloroalkylene radical having about 6 to 20, preferably 8 to 15 carbon atoms and Y is one

_ionic e hydrophilic group. Examples of such wetting agents are fluorocarboxylic acids or their

Procedure v "" e "de, e" In, aHpmeinen

ernnaungbgcuiaiJtii u ^ .i. _b - _ο ~ - _o _ -

on vinylidene fluoride polymers, even after a long delay or do wuuuuw ....,.,

Response times, expect. speed is compared to polymerisation ions

The alkylene oxide not only accelerates poly-6c without slowing down in any way.

merization, but also prevents the reaction. This is in contrast to the inhibition speed,

which was observed in similar processes in which

Teaching that seems

-, - ■.

end different

srisates, with or without alkylene oxide, ._

were aliphatic on average molecular weight

Ά!

Peroxides used

Ethanol, isopropanol and isomeric butanols, low temperature and pressure conditions measured. In

λ aliphatic Cj_ ₈ ketones, such as acetone and methyl- in practice, this determination is made with a plasto-

Ethyl ketone, halogenated, e.g. B. chlorinated or bro-

mated, aliphatic hydrocarbons, such as trigenes dimensions at a temperature of

\ Chlorethylene, dichloroethylene and chloroform, or 5 265 ⁰ C, a total load of 12 500 g and one

Mixtures of analogous compounds also carried out fluorinated pressure of 17.6 kg / cm ² . The invention

ί «a can. Isopropanol is preferred. In general, polymers produced then have one

\ My is the chain transfer agent in an amount of "melt flow index" of about 5 to 61 or more.

^; β, 05 to 5 percent by weight, based on the mono-order optimally suited for coating dispersions

More, to be used io, the polymer should preferably have a melt

! The polymerization process according to the invention will have a flow index of 20-25.

; is preferred with a reaction time of 1 to The vinylidene prepared according to the invention

Are 5 hours to a temperature of 90-105 ⁰ C and fluoride polymers essentially colloidally

«In a pressure of about 141 kg / cm ² , which is distributed by additional and monodisperse. The polymer particles

The application of a hydrostatic pressure to 15 are relatively non-porous and very well suited.

is right, carried out suitable for the preparation of dispersions with a

; The amount of high solid content in a pseudo-solvent used under these conditions

\ 4eten ^ -hydroxyethyl tert-butyl peroxide is 0.2 ("latent solvent"), such as dimethylformamide and

; up to 3 percent by weight, preferably 0.5 to 2 gey-butyrolactone.

Weight percent, in particular 0.5 to 1.5 weight percentages of the polymers prepared according to the invention

percent based on monomer. The initiator is form on a large number of substrates one

; Liquid under normal conditions and as such becomes uniform, hard and well-adhering coatings of high quality

j fed into the polymerization system or as gloss, excellent thermal stability, chemical

Solution, dispersion or mixture of an organic shear resistance and good postformability, d. H.,

; Solvent. Such solvents can be ent- 25 the coatings can be bent, punched or in

; neither aliphatic or aromatic hydrocarbons can be deformed in any other way without being affected by the sub-

• be toffe, e. B. cyclohexane, heptane, naphtha, ben- strate jump off or split off.

j * ol, toluene or xylene, esters, ethers or chlorinated In addition to their particular application as

Hydrocarbons. Coating agents can be prepared according to the invention

To carry out the polymerization in aqueous 30, polymers were also made according to various types,

Medium is generally a reaction vessel e.g. B. by pressing or spraying, to different

deformed at room temperature with oxygen-free and deformable molds. For this

ionized water, the / 9-hydroxyethyl-tert-butyl- purpose, polymers are preferred those without

peroxide, the alkylene oxide, the wetting agent and significant amounts of chain transfer agent.

if necessary fed to the chain carrier. That 35 have been posed.
The reaction vessel is closed and with a

inert gas, such as nitrogen, purged. Example 1
Vinylidene fluoride fed under pressure. Preferably, the reaction vessel is initially only charged with the A 3.78 liter stainless steel autoclave for water and then rinsed. The components, which differ from one another at room temperature and have a weight of 1000, are then successively fed into the evacuated reaction vessel, divided into oxygen-free and deionized water. 10 parts by weight of a 75% solution of / J-Hy-Then the reaction mixture is sationsteraperatur within hydroxyethyl-tert-butyl peroxide in gasoline (7.5 g ini from 30 to 60 minutes on the desired polymer), 8.5 parts by weight of ammonium perfluorocaprylate heated. A pressure of 45 and 42 ml of aqueous ethylene oxide (1% solution) at least 106 kg / cm ^{2 is} maintained. While loaded. The autoclave is then closed, the contents of the reaction vessel are evacuated for the polymerization and preferably stirred with 908 parts by weight of vinylidene fluoride. loaded. After the end of the polymerization, the reaction mixture is ^{heated rapidly to 100 °} C. (in about 50 minutes), polymer being obtained from the reaction vessel in the form of a dispersion or a latex fed into the reaction vessel in the form of a 50-1000 ml of water. In order to keep the reaction vessel full to the brim, the smallest particles will have a colloid size, ie 0.05 to about (at a pressure of about 142 kg / cm ² ). According to Er-1 micron in diameter. This polymer dispersion of the polymerization conditions can then be continued by any conventional method, reaction for 2 ¹ I ₂ hours, coagulation in the process, in order to obtain the polymer as a powder 55 reaction vessel with about 1140 parts by weight additional with good flowability. Water is pumped in to the reaction pressure

Depending on whether and how much chain transmitter to hold.

After the polymerization, the autoclave is finished with the final polymerizate different sized average «: - chilled, vented and opened. The reaction vessel molecular weights. Changes in molecular weight 60 pollution is negligible. The latex will are separated and freeze-coagulated by the different flow velocities. The polymer displayed properties of the molten polymer. is separated off, washed with water and kept at 50 ° C These flow rates are called "melt-dried" in a vacuum. Yield: 825 g (over 90% Flow index «and according to the ASTM standard monomer conversion). The polymer has a • D 1238-65 T (method A) determined. The melt flow index is 65, a particle size exit velocity of molten resin distribution from 0.2 to 2.4 microns with a through hole of a nozzle of a certain length and an average particle size of 85% of the polymer of certain diameter under the prescribed 0.5 μ.

About the suitability of this polymer as a coating agent to test, a slurried pigment is dispersed in a solvent and added to this Dispersion added to the polymer. The dispersion is then milled in a ball mill for 4 hours. It contains 21 parts by weight of polymer, 9.5 parts by weight of titanium dioxide, 7.5 parts by weight of one Acrylic acid copolymer, 1.2 parts by weight of zinc dicyclohexyldithiophosphinate and 60.8 parts by weight a solvent mixture of 40 parts by weight of γ-butylrolactone and 60 parts by weight of isophorone.

The degree of dispersion, i.e. H. the purity of the particles in the pigmented coating is the ASTM test standard D 1210-64 accordingly with a Hegman grind measuring instrument definitely.

In this test, the resin and / or pigment particles in the dispersion are measured at a value d. H. Hegman-Weri, visible from over 5 (this corresponds to a thickness of 0.025 to 0.038 mm of the drawn one Films), which means a very finely ground dispersion.

The consistency of the dispersion is determined with a Zahn G 5 viscometer, according to Method given on page 184 of the Gardner Paint Testing Manual, 12th Edition, March 1962. the The viscosity of the dispersion is 6 Zahn seconds; i.e., the polymer particles are proportionate non-porous.

The dispersion is applied to an unprimed 10.1 χ 15.2 cm aluminum plate in such a way that that the dry film has a thickness of 0.025 mm. The coated plate is then 90 seconds long dried in a hot air oven at 297.8 ° C and then quenched with water. the finished coating is a smooth continuous film that appears completely homogeneous. The shine and the adhesive strength of the coating is tested.

The Gardner gloss value of the coating is determined according to the method for testing the 60 ° -2-parameter specular gloss determined according to ASTM D 1471-69. The tester is equipped with an automatic photometric cell in combination with a 60 ° gloss head. According to this method, the coating has a Gardner gloss value of 63 at 60 °.

For the bond strength test, a 6.45 cm ^{2 area of} the coated panel is scratched with marks 1.6 mm apart (usually referred to as "cross hatching" of the coating). The other uncoated side of the plate is exposed to a counter impact of 5.5 mkg in a Gardner counter-impact tester, in accordance with ASTM test standard D 2794-69. A transparent adhesive strip is pressed onto the beaten and scored coating and then quickly peeled off. Lack of adherence is indicated by the removal of coating through the strip. If no coating is removed, the adhesive strength is fully equivalent to an adhesive strength value of 10. According to this method, the coating of this example has an adhesive strength value of 10.

A pigment polymerization emulsion is used for comparison prepared as described above, in place of the polymer prepared according to the invention a commercially available polyvinylidene fluoride resin, is used. This resin has a melt flow index of 3. Although the cured coatings from this dispersion adhere as firmly as the ones from the polymer produced according to the invention, the coating has the commercially available polyvinylidene fluoride resin only a Gardner gloss value of about 51 at 60 °. In addition, this dispersion shows a Hegman grind of about 2, suggesting that this resin is made up of, on average, much larger Particles exist as the polymers produced according to the invention.

ίο B e i s ρ i el 2

According to Example 1, a further polymerization reaction is carried out using 210 ml instead of 42 ml of an aqueous Äthylenoxädlösung.

The end product has a melt flow index of 14, the product from Example 1 has a melt flow index of 12. Accordingly, the ethylene oxide does not act as a chain transfer agent in the process according to the invention.

Comparative experiment A

This experiment shows that the use of a lower alkylene oxide, ζ. Β. Ethylene oxide, necessary is to prevent the reaction vessel contamination in the process according to the invention.

Under the same conditions and with the same reaction mixture as in Example 1, but with the difference that no ethylene oxide is used, the polymerization is carried out at 100 ° C in 2 V ₂ hours. After the polymerization, the reaction vessel is considerably fouled and the latex contains many agglomerates. In addition, it is not possible to aspirate the product from the reaction vessel, as is normally done, because the transfer tube is severely clogged.

Example 3

Under the conditions and with the reaction mixture of Example 1, but with the difference that also (about 0.4 parts by weight) isopropanol are still used 0.5 ml, the reaction is carried out in about 2 _^3/4 hours. The yield is 95% polymer. The melt flow index of the end product is 27; the average particle size is the same as that of the product from example 1. A dispersion of this polymer is prepared according to example 1. It shows the same viscosity and the same Hegman grind value and the coatings made from it are just as smooth and more homogeneous and adhere completely. These coatings have a Gardner gloss value of 65 at 60 °.

Comparative experiments B to E

Further polymerizations are carried out, with / 5-hydroxyethyl-tert-butyl peroxide oxide, other water- or monomer-soluble peroxide initiators can be used. The reaction vessel is kept full to the brim by additionally pumping in water (141 to 144.5 kg / cm * reaction pressure). There will be about 514 parts by weight of monomers with 5 parts by weight of fluorinated wetting agent and 25 m a 1% aqueous ethylene oxide solution used The initiators used and the polymerization conditions are summarized in the table.

Ver initiator

equal

attempt

Initiator (weight percent)

Reaction temperature

( ⁰ C) response time

(Hours)

conversion

Soiling of the reaction vessel

B succinic peroxide 2.0

C peroxymaleic acid 3.0

D tert-butyl peroxypivalate 0.25 *)

E HjAi / sodium formaldehyde- 0.01 **) / 0.06

Sulfoxylate

90

100

90

50

4V ₂

90
0
30th
50

*) During the reaction slowly fed in as a 1.5% solution in gasoline.
**) Η, Ο, solution in 1000 cm ^{1 of} water at a rate of 1.0 ml / minute.

very large

very large

Product is a
suspension
large agglomerates

The initiators in the table above therefore give unsatisfactory results, e.g. B. severe reaction pollution, undesirable product and / or poor yields.

About the particular suitability of the vinylidene fluoride polymers prepared according to the invention for over-pulling agent dispersions to show were dispersions of the polymers from the comparative experiments B, D and E prepared as described in Example 1. The consistency and fineness of the grind Dispersions and the properties of the finished coatings are examined accordingly. Man receives the following results:

Dispersion - Coating Properties

Product Hegman- Zahn- Gardner- texture of the

of grinding viscose gloss / 60 ^o coating

equal value did
attempt (sec.)

After reaching the polymerization temperature of 90 ⁰ C in the course of the reaction time of 4V ₂ hours 7 1 of water was added to maintain the reaction pressure of 142 kg / cm ² (the reaction container is full). The end product has an average particle size of 0.5μ, yield 89.5%, and a melt flow index of 61.1.

The dispersions of this polymer prepared according to Example 1 and of the polymer from Example 4 have a tooth G 5 viscosity of 7 tooth seconds and a Hegman grind value of over 8. The finished coatings from these dispersions are smooth, homogeneous and completely adhesive. They have a Gardner gloss value of 67 to 68 at 60 °.

B e i s η i e 1 5

matt, full smaller

not continuously

discolored, uneven with small holes

Using the same approach and under the gleicnen conditions as in Example 4 but with 39.5 g instead of 51.1 g IsopVopanol be achieved 90 percent Ansbeute in a total reaction time of 4 "/ ₄ hours. The end product has the same

Dispersion properties like the product from Example 8, but a higher average molecular weight with a melt flow index of 24.2.

45 Comparative experiment F

The dispersion made with succinic acid peroxide. For comparison, a vinylidnuoride polymer

Contains polymer produced as an initiator, results in sat at a pressure lower than 106 kg / cm »produced

dull and defective coatings The dispersions, made. The procedure is as in Example 1, with the

J 'SfTSi £? f ^{e 1} ^^ Butylperoxy- so difference, since / only 454 parts by weight of monomers *

SfTSi £? f ^e

Example 4 T7 8

90 C fed in:

Deionized water ii 1

vSenflSrid \ or ν

ImmSmSuorcapryiaV I ::::; 5 ^ fl-Hvdroxväthvl-terL-hutvlivrnYiH

? 86% JAin b £ 53 * * 66 0 g

Ethylene oxide Z78 _e

IsoDronanol «1 ⁸

isopropanol 51.1 g

To prevent the progress of polymerization, 2000 ml of oxygen-free and deionized ^{water are initially put into the reactor, at SteUi VOD 100} ° ^{m1 '}

Ig ^{dcr Reik} * °° "" ^keiD

_fo

reaction mixture is th _{dcm Einspejsen} ^ _Components as heated very slowly to the polymer sation level to local

Response time 5 ^x / i hours
Jgwdn "* 78 to 81.5 kg / cm", which means that the monomer at the ^ r temperature entepn ^

^{After an hour} the pressure drops sharply. The true one of _{the last stages of action is the temp} erator de

11 12

System extremely difficult to control, and looking for the following mixture at a temperature

The reaction pressure drops to 8 kg / cm ^s . at a temperature of 70 and 75 ° C:

After cooling, the reaction vessel vinylidene fluoride 1383 e

open. The polymerization mixture is a thick, sodium perfluorooctanoate 5 0g

pasty mass that is scooped out. The 5 _{1% j} ethylene oxide solution 25 ', 0 ml

The rest is rinsed out with water. The structure of diisopropyl peroxydicarbonate .... 2.6 g
Polymer is on the walls of the reaction vessel and

clearly on the heating coil. The polymer is The Polymerisaiionsreaktion took place either under

removed by repeated rinsing with water. the intrinsic pressure of the monomer (about 43 kg / cm ² ),

The resulting reaction mixture is more of an OK or it was made by pumping in water

Suspension as a latex. Pressure of 64 and 78 kg / cm ² generated. At a

Although the overall conversion is quite good at a pressure of 43 kg / cm ² , the reaction was 4 hours

(over 50%), the polymer contains many agglomerates continued at a pressure of 64 kg / cm ²

merate and is with regard to particle size and intrinsic 90 minutes and at a pressure of 78 kg / cm ²

shafts not homogeneous. 15 2V ₂ hours. When the reaction was complete, the contained

From this experiment it is clear that the inventive reaction vessel is in each case a heterogeneous mixture according to the invention Process for the production of a vinyl phase mixture of solid polymers. To the Lidenfluorid-Polymerisaten at a reaction pressure, walls of the reaction vessel were found one which is higher than the pressure of the monomer, clear polymer structure, and all openings must be performed in order to obtain optimal yields and the 20 of the reaction vessel, with the exception of the water desired polymer. inlet port, were clogged.

These experiments show that even with di; r in the

Comparative experiments G US-PS 34 75 396 indicated temperature with diisopropyl peroxydicarbonate as initiator none;: satisfied-

It was with the initiator of US-PS 34 75 396 25 establishing results can be achieved regardless of

polymerized. Since this initiator, however, depends on whether the reaction takes place under its own pressure

Temperatures above about 75 ° C are no longer reliable with the monomer or with an additional hydro

responds or is already exhausted, the static printing was carried out.

Claims (1)

when using diisopropylperoxy- Claim: dicarbonate as initiator. This connection is like Di-tert-butyl peroxide in the monomer soluble method for Herstellun _t of vinylidene fluoride (s. US-PS 34 75 396). Homoporymerisaten by polymerization of 5 The only process for the polymerization of vinylidene fluoride in aqueous emulsion at Tempe vinylidene fluoride in the presence of water-soluble temperatures from 80 to HO ⁰ C and increased pressure and organic peroxides as initiators is that in US-PS a reaction time of 0.5 up to 6 hours described in 32 45 971. The water-soluble presence of organic peroxygen alkylene oxides used are peroxides of dibasic acids, acids, lower alkylene oxides with less than 10 succinic acid peroxide is preferred. In this 8 carbon atom and water-soluble fluorination process, a fluorinated wetting agent is also used, the hydrophobic part of which must also be at least half fluorinated in the polymerization system and an iron powder in the prescribed form as an initiator, or wetting agents of the general formula Quantities are added in order to generate vinylidene To obtain 15 fluoride polymers. Despite this opti- X (R) - Y paint systems have response times of 17 to 21 hours are necessary to achieve even low yields in which X is a hydrogen, fluorine or chlorine atom. R a perfluoroalkylene, perfluorocycloalkylene or subject of the procedure of JA-AS 70 18 870, Perfluorochloralkylenrest with 6 to 20 carbon ao reported in Dowent Japanese Patent Report 1970, atoms and Y an ionic hydrophilic group issue 26/27 from 25.8.70, is an improved method means in an amount of 0.2 to 3 weight to Polymerization of vinylidene fluoride in aqueous percent, based on monomer, characterized by a suspension, which is characterized in that a hydrostatic pressure is present as an organic person in addition to the pressure of the monomer in the oxygen catalyst β-hydroxyethyl-tert-butyl-25 reaction is. This peroxide in an amount of 0.2 to 3 weight hydrostatic pressure is sufficient to keep the reaction percentage, based on vinylidene fluoride, full to the brim when used. This process, in which and at pressures of 106 to 353 kg / cm ^2, a monomer-soluble, free radical-transferring polymer is merized, the total pressure from initiator being used, provides maximum yields of the partial pressure of the monomer component and 30 of polymer with special properties in a reaction time that is too minimal due to a hydrostatic pressure component. In addition, smaller ones are put together. Initiator concentrations used than before. The invention is based on the object Printing method even in the presence of a water-soluble 35 borrowed, free radical initiator with to apply optimal yields. It has long been known that vinylidene fluoride can be used in This object is achieved by the process of the dissolved in an aqueous medium under extremely high pressures. And in the presence of peroxy compounds as Ini- the invention is a method for liators polymerized to high molecular weight polymers 40 Production of vinylidene fluoride homopolymers. In US-PS 24 35 537 z. B. are used by polymerization of vinylidene fluoride in aqueous lowohl inorganic peroxy compounds, such as potassium emulsion at temperatures of 80 to HO ⁰ C and umpersulfat, as well as organic peroxides, such as increased pressure and a reaction time of 0.5 acetyl peroxide and dibenzoyl peroxide. The up to 6 hours in the presence of organic peroxides generally give polymeric oxygen catalysts, lower alkylene oxides of better quality, although only relatively low yields of less than 8 carbon atoms and water-soluble yields are achieved, e.g. B. 10 to 20% re-fluorinated wetting agents, the hydrophobic part of which changes, even at extremely high pressures. is at least half fluorinated and has 5 to 15 carbon Contains excellent yields of vinylidene fluoride atoms, or general wetting agents Polymers at low pressures, e.g. B. in the area 50 formula from 22 to 71 kg / cm ^{2 is} achieved with di-tert-butyl-X (R) - Y Beroxide as an initiator that is soluble in the monomer is, although reaction ^{temperatures of 120 to 130 0} C wherein X is a hydrogen, fluorine or chlorine atom, and reaction times of about 20 hours are necessary R a perfluoroalkylene, perfluorocycloalkylene or. In addition, a fluorinated wetting agent can optionally be added to the reactant perfluorochloroalkylene radical with 6 to 20 carbon atoms, whereby atoms and Y are an ionic hydrophilic group. The vinylidene fluoride polymer is extremely fine! In an amount of 0.2 to 3 percent by weight, particle size distribution and good thermal slabili- based on monomer, which is characterized by receiving tat (see US Pat. No. 31 9) 539). is that as an organic peroxygen catalyst Good yields of vinylidene fluoride polymers 60 /i-Hydroxyäthyl-tert.-butylperoxid in an amount of in the form of a powder with good flowability instead of 0.2 to 3 percent by weight, based on vinylidene, a hard brittle polymer composition obtained, fluoride, used and at pressures from 106 to when the US-PS 30 12 021 is ^{polymerized according to the 353 kg / cm 2} , the total aqueous medium being an alkylene oxide, such as ethylene oxide, pressure from the partial pressure of the monomers, together with a catalyst such as di-tert-butyl - 65 nents and from a hydrostatic Druckkompoperoxid, added. nente composed. Excellent yields with moderate response. This procedure produces excellent expressions and significantly shorter reaction times result in high quality polymer obtained,