JPS6248724A - Production of reactive silane terminal polyperfluoroalkyleneoxide - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for making reactive silane terminated polyperfluoroalkylene oxides.

In the aviation industry, sealants, gaskets, 〇-rings,
Solid propellant binder, etc. have low temperature flexibility, high temperature stability,
Must have solvent resistance, and thermal and oxidative stability. Although recent prior art materials have been described that exhibit some of the above properties, to date no polymers have been provided that satisfy the above requirements and also have the desirable low temperature flexibility.

The present invention is extremely useful for the production of new polymers that have extremely low glass transition temperatures, are flexible at low temperatures, and have solvent resistance and good hydrolytic, thermal and oxidative stability. Certain novel reactive silane terminated poly(perfluoroalkylene oxides) are provided.

The present invention is based on the formula (where m and n represent the number of irregularly distributed perfluoroethyleneoxy and perfluoromethyleneoxy backbone repeat units, respectively, and the ratio m/n is 0.2
is characterized by reacting an allyl-terminated polyperfluoroalkylene oxide having a backbone of /1 to 5/1 with acetoxysilane, wherein m and n are as described above, and 2 is The present invention relates to a method for producing a reactive silane-terminated perfluoroalkylene oxide having a backbone of 1 or 2).

Compounds of formula (1) have a number average molecular weight IM ranging from 500 to 20.000 or higher, preferably from 800 to 15.000. has. Compounds of formula (1) can be homopolymerized or copolymerized to produce heat-stable, solvent-resistant polymers such as polyacrylates, polyesters, polysiloxanes, polyamides, and the like. The glass transition temperature (Tg) of compounds of formula (I[) is generally below -78°C, preferably below -100°C, and may be -125°C or even lower, for example -130°C. These advantageously low glass transition temperatures are also a property of polymers made from this compound, and by increasing the oxygen/fluorine content in the compound or by increasing the goodness of the poly(perfluoroalkylene oxide) segments. It can be further lowered by

Thus, the reactive silane-terminated poly(perfluoroalkylene oxide) compound of the formula ■ can be polymerized or copolymerized to form a compound of the formula %, where m and n are randomly distributed perfluoroethyleneoxy and perfluoroethyleneoxy, respectively. Indicates the number of methyleneoxy backbone repeating subunits, and the ratio m/n is 0.2
/1 to 5/1, preferably 0.5/1 to 2/1
A polymer containing repeating backbone units is formed. Typically,
The polymer has a molecular weight of at least 1100, preferably at least 5000. Often have a molecular weight of 2,000°,000 or higher.

The starting material, an allyl-terminated polyperfluoroalkylene oxide compound of the formula
20H) From the terminal precursor compound e.g. CH=CHCH
Obtained by reaction with 2Br. This method is carried out, for example, based on the method for producing allyl butyl ether by Talley et al. (J, Am, Che
m, Soc, Volume 73 NQ 7.

(Refer to page 3528, published July 6, 1951). Turley's method consists of reacting the alcohol as an alkoxide with allyl bromide, a reaction that is classic Williamson ether synthesis (X″Organ
ic Functional Group Prepar
ation″by 5andler &niaro, ^c
adeticPress, Ind,, N, Y,,
N, Y. (1968) p. 101). Methylol-terminated precursor compounds can also be prepared from ester (-COOCH3)-terminated compounds by reduction using, for example, L i A I H4.

The ester-terminated precursor is disclosed in Italian patent Iflti No. 8.
17.809, along with its manufacturing method.

Besides their use as prepolymers for the production of polymers, the reactive-terminated poly(perfluoroalkylene oxides) are used in lubricants, viscosity index additives for perhalogenated lubricants, hydraulic fluids, repellents. Also useful as water and oil repellents, surfactants, corrosion inhibitors, anti-stick or mold release agents for molds, flotation agents, and plasticizers for fluorinated plastics.

The following section further describes the invention.

Example 1 ' Allyl-terminated poly(perfluoroalkylene oxide) (Mo-2000,
m/n =0.6) 259 (22,4meq,), dimethylacetoxysilane 4.4g (18,4mea,)
, methyldiacetoxysilane 0.65y (4,0m
eQ, ) and H in CCl4 (PtCz -C21
-12) 3 drops of 3% solution were added. The sealed tube was heated at 80° C. for 65 hours. Liquid silane-terminated poly(perfluoroalkylene oxide): The product (where z = 1 and 2) is mixed with a catalytic amount of tetraisopropyl titanate and the mixture is heated at about 25°C for 6 days and then at 100°C for 1 hour. It was cured to a soft elastic rubber by exposure to atmospheric moisture for days. 82 parts of soft polysiloxane cured product, 8 parts of finely ground silica,
10 parts of finely ground iron oxide (Ee203) and 1 part of benzoyl peroxide were compounded with the aid of a small rubber mill. Curing the resulting material at 177°C for 6 hours in a press and then slow curing at 177°C for 24 hours gives a Shore A-2 hardness of 36, '+76K.
A polyether-polysiloxane rubber was obtained having a tensile strength of g/cm2, an elongation at break of 140%, a density of 1.93 SF/C,C, and a TCI of -125 to 114C.

Example 2 (Reference Example) Hydroxy-terminated polyperfluoroalkylene oxide (average molecular fi 2,000.m /n = 0.6
)60g<0.03mol), sodium 1.4
9 (0.06 mol) was added gradually. The mixture was heated to reflux temperature and 12.1 g (0.1 mol) of allylpromide
was gradually added and further heated to reflux temperature to obtain bisallyl ether 259 of formula (2).

Claims (1)

[Claims] Formula OCH_2-CF_2O(CF_2CF_2O)_m(
CF_2O)_nCF_2-CH_2OCH_2CH=
CH_2 (where m and n indicate the number of irregularly distributed perfluoroethyleneoxy and perfluoromethyleneoxy backbone repeating subunits, respectively, and the ratio m/n
is from 0.2/1 to 5/1) with acetoxysilane.
z(CH_2)_3OCH_2-CF_2O(CF_2
CF_2O)_m(CF_2O)_nCF_2-CH_
2O(CH_2)_3Si(CH_3)_z(O_2C
A method for producing a reactive silane-terminated perfluoroalkylene oxide having the formula CH_3)_3, where m and n are as described above and z is 1 or 2.