DE1219688B - Process for the production of thermoplastic polymers - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C08g

German class: 39 c-30

Number: 1219 688

File number: U10204IV d / 39 c

Filing date: October 17, 1963

Opening day: June 23, 1966

It is known that thermoplastic polymers with recurring basic units

Cl

-H ₂ C

CH ₂ -

produce by pyrolysis of p-Xylylenderivaten in the vapor phase at temperatures of 500 to 600 ° C and subsequent cooling to temperatures below 200 ⁰ C.

The extraordinary physical properties of p-xylylene polymers have become unusual Efforts led to their ease of manufacture. Although these polymers Having excellent thermal and chemical stability, the presence of the aromatic creates Ring adjacent-— CH2 groups sites for possible atmospheric attack.

The invention relates to a process for the production of thermoplastic polymers with recurring basic units

- (- Y ₂ C

• V

CY ₂ j-

in which Y represents a halogen atom, by the pyrolysis of p-Xylylenderivaten at temperatures of 600 to 1000 ° C and immediate cooling of the diradicals formed to temperatures below 4O ⁰ C, which is characterized in that, as p-Xylylenderivate bis-sulfone of the general formula

RSO ₂ -Y ₂ C

Process for making thermoplastic
Polymers

Applicant:

Union Carbide Corporation,

New York, N.Y. (V. St. A.)

Representative:

Dr. W. Schalk, Dipl.-Ing. P. Wirth,

Dipl, -Ing. G. E. M. Dannenberg

and Dr. V. Schmied-Kowarzik, patent attorneys,

Frankfurt / M., Große Eschenheimer Str. 39

Named as inventor:
Sui-Wu Chow, Somerville, NJ;
Louis Anthony Pilato,
Bound Brook, NJ (V. St. A.)

Claimed priority:
V. St. ν. America October 22, 1962
(232253)

in the presence of a base, such as. B. sodium hydroxide or sodium methoxide, with a compound the general formula

.Y ₃ C

G ¥ äSO ₂ R

is used in which Y is a halogen atom and R is a lower hydrocarbon radical.

Fluorine atoms are preferred as halogen atoms. As low hydrocarbon residues, for. B. lower alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, η-butyl, isobutyl, tert-butyl or hexyl groups. Lower alkyl groups of up to 6 carbon atoms are used for the purpose easier removal of the by-products produced in the pyrolysis is preferred. R can continue for a lower aryl hydrocarbon group, such as a phenyl group or alkylated phenyl group, stand.

The p-xylylene-bis-sulfones can be easily prepared by using an alkyl or aryl mercaptan in which Y is a halogen atom, such as chlorine, bromine or iodine, means, converted to the corresponding dithioether compounds. Connections with the general formula I can by reacting known a, a, a ', a'-tetrasubstituted p-xylenes with a halogenating agent such as N-bromosuccinimide.

The dithioether can then by oxidation with hydrogen peroxide or peracetic acid to the corresponding Bis-sulfone are oxidized.

For the production of the starting products in the process according to the invention no protection sought.

The pyrolytic cleavage of the bis-sulfone produces a reactive diradica with the basic structure

Y ₂ C

CY ₂

in which Y has the above meaning, as well as gaseous sulfur dioxide and other gaseous forms Materials such as saturated and / or unsaturated hydrocarbons produced by coupling the im R residues formed by cleavage processes are produced.

Conveniently, the reaction by-products remain; H. Sulfur dioxide and the saturated ones and / or unsaturated hydrocarbons obtained by coupling the particular groups R im Bis-sulfone are formed at the temperatures and pressures used in their passage through the condensation zone in a gaseous state and can then enter further cold traps to be collected. "

In the inventive method, the reactive diradicals are by pyrolysis Bis-sulfons at a temperature between 600 and 1000 ° C, preferably between about 650 and 850 ° C. At these temperatures, practically quantitative yields of the reactive Diradikals received.

The pyrolysis temperature is practically independent of the working pressure. Preferably it is, but less or sub-atmospheric pressure applied. Most of the procedures are pressures between 0.0001 and 10 mm Hg is most appropriate. If necessary, however, higher pressures can also be used be applied. The course of the pyrolysis can be determined by observing the pressure changes accompanying the reaction To be tracked. When the cleavage begins, it causes the release of gaseous products a pressure increase; the pressure goes back to its original level when the response is finished.

The polymers prepared according to the invention can easily be removed from the polymerization zone by customary means which depends on the particular zone used. If a cold surface, such as. B. If a cooler is used, the polymer can be removed from the walls of the zone by mechanical stripping removed. By condensing the diradicals in a water sprayer under the surface The polymer is obtained in finely divided form from an aqueous medium; it can be filtered off and dried in the usual way before processing.

The polymers produced according to the invention, in particular the α, α, α ', α'-tetrafluoro-p-xylylene, possess excellent solvent resistance and thermal stability. These polymers are very suitable as films, fibers, surface coatings or electrical insulation, especially, where a high resistance to thermal and chemical decomposition is required.

The following examples illustrate the invention. Unless otherwise stated, all figures are percentages and parts percent by weight and parts by weight. ·

Preparation of the starting compounds

a) Preparation of a, a'-dibromo-a, a, a ', a'-tetra-

fluoro-p-xylene

α, α, α ', α'-tetrafluoro-p-xylene was according to Journ. At the. Chem. Soc, 82, p. 543 (1960), by reacting terephthaldehyde with sulfur tetrafluoride Temperatures of about 150 ° C produced.

0.15 mol of α, α, α ', α'-tetrafluoro-p-xylene was mixed with 0.33 mol of N-bromosuccinimide and 320 parts of carbon tetrachloride and the mixture was irradiated with a UV lamp, whereby it was heated to the reflux temperature of the solvent was held. The precipitated succinimide was filtered off and the filtrate was distilled, yielding 0.12 mol of the new aa - dibromo - α, α, α ', α' - tetrafluoro - ρ - xylene having the following structure

BrF ₂ C ■

• CF ₂ Br

and a bp 25 mm 102 to 107 ° C was obtained.

b) Preparation of α, α'-dithioalkoxy-
α, α, α, α'-tetrafluoro-p-xylene

To a solution of 0.11 mol of sodium in 40 ecm Methanol was added to 0.1 mol of ethyl mercaptan and then diluted with 100 ecm of dimethyl sulfoxide. After adding 0.045 mol of the a, a'-dibromo-a, a, a ', a'-tetrafluoro-p-xylene prepared in a), the The reaction mixture is heated to 50 to 60 ° C. for about 2 hours. Then the reaction mixture was in Poured water in which the immiscible new product, namely the a, a'-dithioethoxy-a, a, a ', α'-tetrafluoro-p-xylene having the following formula

H ₅ C ₂ SF ₂ C ■

CF ₂ SC ₂ H ₅

failed.

Following the same procedure - depending on the particular one used in the reaction Mercaptan ■ - the preparations summarized in Table 1 with the general formula

RSY ₂ C-

CY ₂ -SR

manufactured.

Table 1
a, a'-dithioalkoxy-a, a, a ', a'-tetrafluoro-p-xylenes

R-alkyl group Boiling point 90 to
(0.2 mm) 110 ° C. yield C ₂ H ₅ Boiling point 123 to
(0.5 to 1 mm) 140 ° C. 750/0 nC ₃ H ₇ ' Boiling point 130 to
(0.2 mm) 140 ° C. 76% nC ₄ H ₉ Melting point 152 to 160 ° C. 75% -C ₆ H ₅ 40%

c) making y

p-xylyl-a, a'-bis-sulfones

To a solution of 0.08 mol of a, a - dithioalkoxy - α, α, α ', α - tetrafluQrp-xylene in 300 ecm of a 1: 1 mixture of acetic acid and acetic anhydride, which is 0 to 5 ° G.ab.-

Was cooled, 57 ecm of 30% hydrogen peroxide were added within about 2 hours, the The mixture was allowed to gradually warm to room temperature and continuously for 24 hours touched. The reaction mixture was poured into water in which the immiscible new Product failed.

In Table 2 are the bis-sulfones with the general formula

R-SO ₂ - Y ₂ C

y ν

CY ₂ - SO ₂ - R

which are produced by the same process are described.

Table 2

Dialkyl-a, ct, a ', a'-tetrafluorop-xylyl-a, a'-bis-sulfone

R-alkyl group Melting point yield C ₂ H ₅ 158 to 164 ° C 83% n-CsHv 158 to 163 ° C 65% nC ₄ H ₉ 162 to 166 ° C 63% C ₆ H ₅ 232 to 240 ° C 59%

example
Production of poly (perfluoro-p-xylylene)

The bis-sulfones produced in c) were evaporated and the vapors thus formed were passed into a pyrolysis chamber, which consisted of a quartz tube heated by means of a high-performance furnace. The pyrolysis of the bis-sulfone under reduced pressure began at temperatures of about 400 ⁰ C. The heating under these conditions cleaves the bis-sulfone with liberation of sulfur dioxide and others, the pressure-increasing gaseous materials; after the reaction has ended, the pressure drops back to its initial value. The pyrolysate polymerized immediately after condensation to form a clear, transparent film which was deposited on the walls of the cooled container. The polymeric poly (perfluoro-p-xylylene) is a highly crystalline material with a crystalline melting point above 360 ° C. Its thermal stability is excellent. Heating the polymer to 300 ° C. in air for 100 hours did not cause any decomposition.

Table 3 shows the production of poly (perfluoropxylylenes) from the bis-sulfones produced in c), while Table 4 shows the excellent properties the poly (perfluoro-p-xylylene) are summarized.

Table 3
Production of poly- (a, a, a ', a'-tetrafluoro-p-xylylenes)

Evaporation Pyrolysis ] initially Pressure in mm Hg ■ finally R - SO ₂ - F ₂ C - \ _ / - CF ₂ - SO ₂ - R temperature
⁰ C temperature
⁰ C 0.1 while there
reaction 0.1 R = C ₂ H ₅ 250 700 0.05 0.3 0.03 200 650 0.1 0.3 0.1 R = C ₃ H ₇ 200 700 0.1 1.2 0.1 R = C ₄ H ₉ 200 700 0.05 0.8 0.05 R = C ₆ H ₅ 300 700 0.02 0.4 0.02 R = C ₆ H ₅ 240 800 0.5

Tabel

Properties of poly- (a, a, a ', a'-tetrafluoro-p-xylylene) Mechanical properties

Measured at Tensile module
kg / cm ² tensile strenght
kg / cm ² Electrical Properties Measured at Dielectric constant strain
° / o 25 ⁰ C 17 500 266 60 cP 2.6 to 2.7 2 275 ° C 1610 17.5 100 cP 2.55 to 2.65 70 300 ⁰ C 1 120 25.9 10 ⁶ cP 2.50 to 2. ( 88 25 ° C, after 100 hours at 300 ° C 15 400 245 30th 2 Dielectric dissipation factor 0.0017 0.0020 0.0037

Claims (1)

Claim: Process for the production of thermoplastic polymers with recurring basic units Y ₂ C- in which Y is a halogen atom, by pyrolysis of p-xylylene derivatives at temperatures from 600 to 1000 ⁰ C and immediate cooling of the diradicals formed to temperature doors below 40 ⁰ C, characterized in that as the p-Xylylenderivate bis-sulfone of the general formula RSO ₂ -Y ₂ C • CY ₂ - SO ₂ R used in which Y is a halogen atom and R is a lower hydrocarbon radical. Considered publications:
German publication No. 1 085 673. 609 580/415 β. 66 θ Bundesdruckerei Berlin