Method of purifying thermally processed tetrafluoroethylene copolymers and thermally processed tetrafluoroethylene copolymers

FIELD: polymer production.

SUBSTANCE: invention aims at purifying thermally processed tetrafluoroethylene copolymers so that the latter acquire high optical properties. Method of invention resides in that polymeric latex of thermally processed tetrafluoroethylene copolymers prepared via polymerization in dispersion or in water emulsion is converted into gel form by adding, at mechanical stirring, acid electrolyte to achieve pH of medium below 2 and, after which polymeric gel is washed with acidic aqueous solutions or neutral solutions within a pH range between 1 and 7.

EFFECT: increased purification efficiency.

18 cl, 3 tbl, 6 ex

 

The present invention relates to a method of cleaning teroperability copolymers of tetrafluoroethylene (TPV) to produce polymers having high optical properties and are suitable for applications in semiconductors, since they have very low levels of extractable cations.

In particular, the invention relates to a method for teroperability copolymers of tetrafluoroethylene (TPV), mostly free from inorganic salts by washing of the latex in the form of a gel with the final copolymer having a high degree of purity, low amount of extractable substances (as defined below) and high optical properties. In addition, using the method according to the invention, also significantly reduce the amount of residual surfactants during thermal treatment.

Thus obtained termperature powders of copolymers are used for applications that require high optical properties of the final product, as obtained low values of the indicator yellowing and high values of the degree of whiteness, and therefore there is no problem of coloring of the product. In addition, the powders of the present invention can also be used in the semiconductor industry, which require polymers having a low allocation ex is lagerweij substances.

It is known that in the method of polymerization in emulsion/water dispersion of fluorinated monomers injected surfactants, polymerization initiators, and other additives. Then the latex obtained from the polymerization method, coagulated. The coagulation method includes the following stages:

- dilution of the latex with water and the introduction of destabilizing the electrolyte with the coagulation of the latex;

mechanical stirring of the latex, causing the aggregation of colloidal particles, to obtain a granulation of particles and then flotation;

- Department of flotated powder from mother solutions;

perhaps washing powder water.

The powders obtained in accordance with the traditional way, have the disadvantage that are not suitable for applications in semiconductors, because they have a high allocation of extractables. In addition, they cannot be used for optical applications, since they have a high rate of yellowing and low brightness.

To reduce the content of extractables and obtain improved optical properties of the resulting polymer must be subjected to heat treatments at high temperatures. This has the disadvantage of resulting in partial degradation of the polymer.

So I felt the need to have available with the persons cleaning teroperability copolymers of tetrafluoroethylene (TPV), in the result, it was possible to obtain copolymers suitable for applications which require the obtained products having high optical properties, or for applications where it is required that the polymer had a low allocation of extracted substances, such as, for example, in the semiconductor industry, as indicated above.

The object of the present invention is therefore a method of cleaning teroperability copolymers of tetrafluoroethylene (TPV), which contains the following stages:

A) polymer latex teroperability copolymers of tetrafluoroethylene (TPV)obtained by polymerization in dispersion or aqueous emulsion is transferred in the form of a gel under mechanical stirring with addition of acid electrolyte having a pH≤2, preferably in the range of 0.4 to 1.6;

B) washed polymer gel acidic aqueous solutions or neutral aqueous solutions having a pH from 1 to 7.

The purification method of the present invention allows to obtain termperature copolymers TPV, after which stage of leaching) contain extractable cations, excluding N+in the amount of less than 1 ppm

The method of the present invention can be carried out batch or continuous method.

When the method of the present invention is carried out periodically, the stage And the floor of the treatment of the polymer latex in the form of a gel is preferably carried out in the vessel, equipped with reflectors and mixing devices. Mixing devices are preferably of the device with stepper blades.

Stage A) gelation contains the following stages:

perhaps the dilution water curing latex having a concentration of about 30-40 wt.%, to a concentration in the range of 5-25 wt.%;

- curing latex under mechanical stirring with a specific capacity from 1.5 to 5 kW/m3adding an acid electrolyte, preferably nitric acid, in such quantity that the water dispersion obtained pH value of≤2, preferably from 0.4 to 1.6.

Under the polymer in gel form, it is understood that the polymer particles are immersed in the liquid phase and are connected to each other transverse relationship so that they form a dense grid. Properties of the gel depend largely on the interaction between the polymer particles and the liquid phase. Indeed, the remnants of the liquid prevents the polymer grid from turning into a compact mass, and the polymer grid prevents fluid from exiting the gel. Depending on the chemical composition and other parameters of the method, such as, for example, the concentration of solids and the electrolyte, the consistency of the gel may vary from a viscous liquid to a fairly rigid solids.

When is OLIMAR receive in the form of a gel periodic way, this is followed by a stage of rinsing), which contains the following stages:

1) termination of mechanical mixing and the addition of an aqueous solution, as indicated in B); the amount of water added is usually between 100 and 200 hours of water per 100 hours of polymeric gel;

2) subsequent weak mechanical mixing of the gel is usually when the peripheral speed of the stirrer comprising between 0.1 and 0.6 m/s, with power density usually in the range of 0.2 to 2 kW/m3in the course of time, typically from 1 to 10 minutes; in these conditions, the gel is broken into small masses, but at the same time the contact between the gel and the air is minimized, obtaining flakes that keep hydraulic contact with water without stratification;

3) cessation of mixing, decanting flakes of gel and removal of distilled water.

Stage 1)-3) repeat up until the residual amount of extractable cations (excluding N+will not be below 1 ppm Stage leaching) usually repeat 3-10 times, preferably 4-8 times.

When the method of the present invention provide a continuous method, the polymer latex in the form of a gel (stage A) is preferably prepared as follows.

The polymer latex obtained by polymerization in a dispersion (emulsion)is fed countercurrent to the flow of the wash column.

The column had the t following options:

- multistage column equipped at each stage of the reflectors and one or more devices for mechanical mixing, for example conical disks, disk turbines, stepper blades, preferably disk turbines;

the ratio height/diameter of the column is more than 5, preferably between 8 and 20;

the number of stages is between 5 and 20;

- there are two zones of peace, the first stage at the top of the column and the last stage at the bottom of the column, without mixing devices for splitting the polymer gel and separate it from the water;

acid electrolyte serves throughout the column.

The formation of the polymer gel has a place in the upper part of the wash column.

Polymer latex directly served to the first stage in the upper part of the column, where flakes of polymer gel formed almost instantly. Washing flakes of gel is in the process of gravitational stratification throughout the column, then the flakes gel derived from the lower part of the wash column. Wash water enters the lower part of the column and flows from the upper part, usually the first stage of the column.

The acid electrolyte used in order to have the desired pH at the stage A), is served in the multi-stage column. The feed point of the acid electrolyte may vary throughout the alone with the in order to adjust the pH of the gel at the outlet of the column. The amount of acid electrolyte is such as to define the first stage of the column conditions pH below or equal to 2, preferably between 0.4 and 1.6, in order to promote the formation of polymer gel.

In addition, to obtain gelation at the first stage it is necessary that the peripheral speed of the stirrer was below 0.6 m/s, preferably between 0.1 and 0.5 m/s Temperature inside the wash column is typically in the range of 10°S-40°C.

Normally, in order to avoid entrainment of water flakes of polymer gel, the linear velocity rinse water in the column must be less than 1 cm/s When working in this way there is little loss of the polymer is below 0.1 wt.%.

The washing efficiency of the gel flush column of the present invention depends on the time spent flakes of gel in the column. The residence time is increased when the length of the column increases. Therefore, the greater the number of stages, the higher the leaching efficiency.

The applicant, in addition, it was found that the leaching efficiency of the gel is improved when increasing the mixing speed. Indeed, the increase of the stirring speed can reduce the size of the flakes of gel, and therefore, it contributes to the effectiveness of washing.

In the continuous method of cleaning the crust is asego of the invention the ratio between the flow rate of flush water and the flow rate of the latex (l/h) depends on the number of stages of the column and is typically in the range of 1:1-10:1, preferably of 1.5:1 to 5:1.

Among the acid electrolyte can be mentioned inorganic acid, preferably nitric acid, hydrochloric acid, and nitric acid is preferred.

Under termperature copolymers TPV refers to a polymer obtained by polymerization of TPV with one or more monomers containing at least one desaturation ethylene type.

Among the comonomers TPV, which are fluorinated, in particular, specify:

- C3-C8-perfluoroolefins, such as HEXAFLUOROPROPYLENE ((HFP) (FNV);

- hydrogenated With2-C8-ferritine, such as viniferin ((VF) (VF)), vinylidenefluoride ((VDF) (WDF)), triptorelin, hexafluoroisobutene, perftorpolietilena CH2=CH=Rfwhere Rfrepresents C1-C6-perfluoroalkyl;

- C2-C8-chlorine - and/or bromo - and/or golftrolley, such as chlorotrifluoroethylene ((CTFE) (HTFA));

- (per)peralkaline ethers ((PAVE) (PAVE)) CF2=CFORfwhere Rfrepresents C1-C6-(TRANS)floralcy, for example, CF3C2F5With3F7;

- (per)peroxyacetylnitrate esters CF2=CFOX, where X represents C1-C12-alkyl or C1-C12-oxyalkyl, or C1-C12-(TRANS)peroxyacyl having one or more ether the groups, for example PERFLUORO-2-propoxyphenyl;

- portixol, preferably peritoneoscopy;

- unpaired diene type:

CF2=CFOCF2CF2CF=CF2,

CFX1=CX2OCX3X4OCX2=CX1F,

where X1and X2the same or different from each other, represent F, Cl or H; X3and X4the same or different from each other, represent F or CF3that in the polymerization process cyclopolymerization;

- corviniana ethers ((MOVE) (SER)) of General formula CFXAI=CXAIOCF2ORAI(A-I)in which RAIis2-C6-a linear, branched or5-C6-cyclic (per)foralkyl group or2-C6-a linear, branched (per)peroxyacyl-group containing from one to three oxygen atoms; when RAIrepresents alkyl fluoride or peroxyacyl group, as described above, it can contain from 1 to 2 atoms, equal or different, selected from the following: H, Cl, Br, I; XAI=F, H; the compounds of General formula:

CFXAI=CXAIOCF2OCF2CF2YAI(A-II)in which YAI=f, OCF3; XAIas described above, are preferred; in particular, SER I, CF2=CFOCF2OCF2CF3(A-III), and

SER II CF2=CFOCF2OCF2CF2OCF3 (A-IV) are preferred.

Can also be specified hydrogenated olefins, preferably in addition to the above comonomers. Examples of hydrogenated olefins are ethylene, propylene, butene and isobutene.

Usually the number of co monomer in the copolymer is such that the copolymer is teroperability. It usually is in the range of 1-18 wt.%, preferably 2-10 wt.%, and depends on the type of co monomer.

The polymers of the invention are termperature and have a melt viscosity in the range of 103-108PA·C. Indeed, in the polymerization method for obtaining the latex is used to adjust the degree of polymerization, giving the specified viscosity. Specialist in the art knows how to work, to obtain the well-known termperature polymers of the prior art.

Polymer latex, which can be used for gels, as described above, is produced by polymerization in a dispersion (emulsion) of the TPV in the presence of comonomers, as described above. The original latex particles of polymer have dimensions of from 0.1 to 0.4 μm. The method of obtaining the latex can also be implemented in the micro-emulsion. See, for example, USP 4864006, USP 4990283 and EP 969027. In this case, the original diameter of the latex particles is in the range from 0.01 to 0.1 μm.

The way this izaberete the Oia allows you to get termperature copolymers TPV, which after separation of the polymer powder from mother solutions are essentially free of extractable cations (with the exception of H+).

Another object of the invention is termperature copolymers TPV, which contain the amount of extractable cations less than 1 ppm

Perhaps stage drying can be carried out on the powder Ternopiloblenergo of the polymer obtained in accordance with the method of the invention, in the late stages of the method. The drying temperature is usually in the range of 230-280°C.

It was found that after the stage of drying, the amount of extractable cations, excluding N+is less than 1 ppm After the above processing, the amount of surfactant is below the analytically detectable limit, practically it is essentially removed from the polymer powders.

Another object of the invention is termperature copolymers TPV, which contain the amount of extractable cations below 1 ppm, and in which essentially no residual surfactant, the amount of which is below the analytical limit (10 ppm), below about 10 ppm

Loss of the copolymer in the cleaning method carried out in accordance with the present invention are small, about 0.1 wt.%.

Powders termopane emotively polymers of the invention, as indicated, are particularly suitable for obtaining manufactured goods used in the semiconductor industry, for example, to get tanks and piping systems (pipes and fittings), because they do not emit extractables. Another use is optical applications having improved properties.

The present invention will now be better illustrated by the following variant examples which are only illustrative but not restrictive for the purpose of the scope of the invention.

Examples.

Methods of characterization.

Quantitative determination of cations (excluding N+).

Cations determined by ion chromatography at the introduction into the column mother solutions or rinse water.

The potassium cation is a cation that is present in large quantities, for this reason, only the cation is given in the tables. The method used for the determination of various cations, shown here on the example of the potassium ion, the same method is repeated for the other cations.

The potassium cation is determined on the mother solution and wash waters in balance with gel, and found the number refers to the total amount of powder.

The peak area refers to the number of K+present in the tested waters, on the calibration curve (the working conditions: chromatograph Dionex 4500i, equipped conductometric cell Precolomn and separation column CG12-CS12; luttmerdingova acid 20 Mn; eluting flow at 1 ml/min; autoregeneration CSRS; 100 µl loop).

By weight of water discharged after each washing, counting the number of K+deleted by leaching. The difference in relation to the amount of potassium salt introduced into the polymerization expect the number To+remaining in the powder.

The limit of detection of the method is 0.15 ppm

The definition of the index of yellowness and whiteness.

Definition data is performed in accordance with the methods of ASTM E313 and ASTM D1925, respectively.

Quantitative determination of surface-active substances.

The amount of surfactant both dry and wet powder determined by gas chromatography analysis of the corresponding complex methyl ester according to the following procedure:

0.5 g of the powder moistened with ethanol and adjusted to alkaline pH with a solution of NH4OH. The powder is dried in a stream of nitrogen. To the dried powder add 2 ml of acidic methanol. Etherification is carried out at 70°C for 16 h in a sealed tube. At this point, add a mixture of 0.5 ml Delifrene A113 and 4 ml of water.

The mixture is stirred and left to stand. 2 phases are separated, take 1 ál fluorinated lower phase containing surface is Resto-active ester. The solution is injected into the gas chromatograph with capillary column (capillary gas chromatography system, equipped with a system slot/ - free injection 200°; capillary column type CP-SIL SW 25 cm × 0.32 mm × 1,3 µm; helium carrier = 50 KPa; crevice a stream - 26 ml/min; compiled media: nitrogen 40 KPa; injected volume 1 µl; temperature profile: 40° × 4', 40°/' 60°, 8°/' 84°, 40°/' up to 220°×10'; FID detector set at 250°With (the ratio of air: hydrogen = 100:90 KPa); the electrometer: the interval 0, AT, 0).

The peak area was transferred to the present number of surfactants on the calibration curve.

Surface-active substance used to obtain the latex in the examples, is a salt of performanta ammonium ((PFOA) (PFOA)).

Detectable limit of the method of determination is 10 ppm

Example 1.

Periodic washing of the polymer in the form of a gel washing with aqueous solutions having a pH of 1.

16 l latex terpolymer TPV/PMVE/PPVE brand Hyflon MFA 640 at 18% wt./wt., obtained by polymerization in the presence of potassium persulfate, is introduced into a 50 l reactor. The mixture is subjected to mechanical stirring (stirrer with stepper blades, the power density of the stirring - 3 kW/m3) and injected with stirring with HNO3at 20%, however, h is usually used to bring the pH of the latex to a value of 1. The latex is stirred to obtain a gel.

After the formation of gel injected with 20 l of water with added HNO3at 20% in order to bring the pH of the aqueous phase to a value of 1. The pH value in a single leaching are shown in table 2.

The mixture of water/gel is subjected for 5 minutes stirring with a specific capacity of 0.5 kW/m3sufficient to break the gel into the flakes, but which is such that leaves them in close contact with water without separation.

When stirring is stopped and the polymer (gel), decanted, 20 l of water removed from the settled supernatant layer.

The washing procedure repeated 5 times.

The mixture is then stirred to obtain a flotation powder using a mixer with a power density of 5 kW/m3. Stirring is stopped and below the water is separated from the wet powder.

The conditions under which this occurs coagulation, are summarized in table 1.

Water analyze the above analytical methods (cations).

Data pH of the wash water and the amount of potassium cation, calculated based on the water analysis, translated into the amount that is present in the powder after each washing, shown in table 2. When the amount of potassium is below 1 ppm, as determined by the number of all other cations present. The total number present is their cations is less than 1 ppm

The powder after drying at 270°C for 6 h ekstragiruyut. Samples obtained after molding of pellets obtained by extrusion, have values of yellowness and the degree of whiteness, as shown in table 3.

Optical properties give very good the result is a low prevalence of yellowing and high degree of whiteness.

Example 2.

Periodic washing of the polymer in the form of a gel washing with aqueous solutions having a pH of 7.

16 l latex terpolymer TPV/PMVE/PPVE brand Hyflon MFA 640 at 18% wt./wt., obtained by polymerization in the presence of potassium persulfate, is introduced into a 50 l reactor. The mixture is subjected to mechanical stirring (stirrer with stepper blades, the power density of the stirring - 3 kW/m3) and injected with stirring with HNO3at 20% in order to bring the pH of the latex to a value of 1. The latex is stirred to obtain a gel.

After the formation of gel injected with 20 l of water having a pH of 7.

The mixture of water/gel is subjected for 5 minutes stirring with a specific capacity of 0.5 kW/m3sufficient to break the gel into the flakes, but which is such that leaves them in close contact with water without separation. The pH value in a single leaching are shown in table 2.

When stirring is stopped and the polymer (gel), decanted, 20 l of water to remove the C settled supernatant layer.

The washing procedure repeated 5 times.

The mixture is then stirred to obtain a flotation powder using a mixer with a power density of 5 kW/m3. Stirring is stopped and below the water is separated from the wet powder.

Table 1 summarizes the conditions under which this occurs coagulation.

Data pH of the wash water and the amount of potassium cation, calculated based on the water analysis, translated into the amount that is present in the powder after each washing, shown in table 2. When the amount of potassium is below 1 ppm, as determined by the number of all other cations present. The total number of cations present is less than 1 ppm

The powder after drying at 260°C for 6 h ekstragiruyut. Samples obtained after molding of pellets obtained by extrusion, have values of yellowness and the degree of whiteness, as shown in table 3.

In this case also get very good optical properties.

Example 3 (comparative).

Washing of the polymer after flotation (pH phase coagulation = 1) washing with aqueous solutions having a pH of 7.

16 l latex terpolymer TPV/PMVE/PPVE brand Hyflon MFA 640 at 18% wt./wt., obtained by polymerization in the presence of potassium persulfate, is introduced into a 50 l reactor. The mixture is subjected to the tavern the economic stirring (stirrer with stepper blades, the power density of the stirring - 3 kW/m3) and injected with stirring with HNO3at 20% in order to bring the pH of the latex to a value of 1.

The latex is stirred to obtain a flotation powder using a mixer with a power density of 5 kW/m3. Stirring is stopped and all the water (12 l)below the damp powder, remove.

The wet powder is subjected to washing 20 l of water (pH 7) for 5 min under stirring using a mixer with a power density of 3 kW/m3. The pH value in a single leaching are shown in table 2. The stop stirring and remove 20 l of wash water.

The washing procedure repeated 5 times.

Table 1 summarizes the conditions under which this occurs coagulation.

Data pH of the wash water and the amount of potassium cation, calculated based on the water analysis, translated into the amount that is present in the powder after each washing, shown in table 2. As you can see from the table, the amount of potassium even after 5 washes more than 1 ppm and does not undergo reduction during subsequent leaching. In this case, it is unnecessary to determine the number of all other cations present.

The powder after drying at 270°C for 5 h ekstragiruyut. Samples obtained after molding of pellets obtained by extrusion, by the method specified in the example the x characterization, have metric values yellowing and degree of whiteness, as shown in table 3. Optical properties are poor.

Example 4.

Continuous method according to the invention in the 11-stage column, the ratio of water flow rate/flow velocity latex = 2, the flow rate of the supply of latex = 16 l/h

Latex terpolymer TPV/PMVE/PPVE brand Hyflon MFA 640 served in countercurrent flow of wash column. The column is a multistage column and equipped at each stage of the reflectors and 4 blade disc turbines for mechanical mixing.

The diameter of the column is 0.11 m, height 1.5 m, the Number of stages is 11, the height of each stage of 0.11 m Conical disks having a height of 0.03 m, separates the stage from each other. Two zones of peace are located respectively at the top and bottom of the column.

Circumferential speed of the stirring is 0.4 m/s the temperature inside the wash column is 30°C.

Latex having a polymer concentration of 18 wt.%, served directly to the first stage of the column with a flow rate of 16 l/h

Wash water enters the lower part of the column and flows from the upper part of the column. The ratio between the flow rate and water flow rate of latex is 2.

A solution of HNO3when 20 wt.% served in a multistage column according to the 6th stage.

The flow rate of solution of HNO3equal 0,688 l/h, this, to determine, starting from the sixth stage of the column from the top of the column, the value of pH of 1.3. In these conditions, the latex instantly forms a gel.

Washing efficiency.

After washing, the concentration of extractable cations (with the exception of N+in the polymer gel is 0.6 mg/L.

The polymer after washing has a value of degree of whiteness 78 and value yellowing equal to 1.55.

The concentration of potassium (defined as above) in the polymer granules after granulation, flotation and drying at 270°C for 6 h 0.15 ppm, the Number of all other cations present was determined. The total number of cations present, including N+is less than 1 ppm, the Amount of surfactant granules is below the analytically detectable limits.

Example 5.

Continuous method according to the invention in the 11-stage column, the ratio of the velocity of flow/speed flow of latex or = 1.5, the flow rate of the supply of latex = 16 l/h

Latex terpolymer TPV/PMVE/PPVE brand Hyflon MFA 640 at a concentration of 18 wt.% served on the first stage of the wash column of example 4 with a flow rate of 16 l/h

The ratio between the flow rate and water flow rate of latex is 1.5.

A solution of HNO 3when 20 wt.% served in a multistage column in accordance with the 6th stage.

The flow rate of solution of HNO3equal 0,573 l/h, this, to determine, starting from the sixth stage of the column from the exit of the column, the value of pH of 1.0. In these conditions, the latex instantly forms a gel.

Washing efficiency.

After washing, the concentration of extractable cations (with the exception of N+in the polymer gel is 0.73 mg/L.

The polymer after washing has a value of degree of whiteness 76 and value yellowing, equal to 1.7.

The concentration of potassium in the polymer granules after granulation, flotation and drying at 270°C for 6 h is of 0.18 ppm, the Number of all other cations present was determined. The total number of cations present, including N+is less than 1 ppm, the Amount of surfactant granules is below the analytically detectable limits.

Example 6.

Continuous method according to the invention in the 11-stage column, the ratio of water flow rate/flow velocity latex = 5.5, the flow rate of the supply of latex = 10 l/h

Latex terpolymer TPV/PMVE/PPVE brand Hyflon MFA 640 at a concentration of 18 wt.% served on the first stage of the wash column of example 4 with a flow rate of 10 l/h

The ratio between the velocity of water flow and with what speed the flow of latex 5,5.

A solution of HNO3when 20 wt.% served in the lower part of the multi-stage column in accordance with the final stage.

The flow rate of solution of HNO3equal 1,49 l/h, such that to determine in the entire column value of pH=1.0 in. In these conditions, the latex instantly forms a gel.

Washing efficiency.

After washing, the concentration of extractable cations (with the exception of N+in the polymer gel is 0.6 mg/L.

The polymer after washing has a value of degree of whiteness 79 and value yellowing, equal to 1.5.

The concentration of potassium in the polymer granules after granulation, flotation and drying at 275°C for 4 h is 0.15 ppm, the Number of all other cations present was determined. The total number of cations present, including N+is less than 1 ppm, the Amount of surfactant granules is below the analytically detectable limits.

Table 1.

The coagulation conditions used in examples 1, 2 and 3 (comparative).
ExampleEnd-MFA I

% wt/wt
The electrolyteSpecific power

paramesh. When gelation, kW/m3
Water RA is creative Specific power

paramesh. when washing, kW/m3
TypepHL/kgMFApH
118HNO3134210,5
218HNO3134210,5
3 comparison18HNO3134213
Table 2.

Measured after each stage of leaching, the pH coming out of the water and the amount of potassium in ppm, translated in the amount of the polymer.
the pH of the wash watersThe number To+in the polymer, ppm
Example 1 - latex/gel116,1
After 1° wash18,5
After 2° wash 14,5
After 3° wash12,7
After 4° wash11,5
After 5° wash10,6
After 6° wash10,5
Example 2 - latex/gel116
After 1° wash1,358,9
After 2° wash1,74,6
After 3° wash22,5
After 4° wash2,331,5
After 5° wash2,730,7
After 6° wash3,10,4
Example 3 (compare the nutrient)
- latex/uterine solutions116
after 1° wash1,028
after 2° wash1,75
after 3° wash25
after 4° wash2,54,5
after 5° wash2,54
after 6° wash2,64

Table 3.

The values of the degree of whiteness and yellowing index defined on the samples obtained by molding pellets, extruded from the powder obtained in examples 1, 2 and 3 (comparative).
ExamplesWhitenessThe rate of yellowing
176,51,9
27,95 2,3
3 (comparative)69,714,16

1. Cleaning method teroperability copolymers of tetrafluoroethylene (TPV), on which:

A) polymer latex teroperability copolymers of tetrafluoroethylene (TPV)obtained by polymerization in dispersion or aqueous emulsion is transferred in the form of a gel under mechanical stirring while adding the acid electrolyte to a value of pH <2;

B) washed polymer gel acidic aqueous solutions or neutral solutions having a pH from 1 to 7.

2. The cleaning method according to claim 1, where a value of pH of the medium on the stage And in the range of 0.4 to 1.6.

3. The cleaning method according to claim 1, carried out a periodic or continuous manner.

4. The method according to claims 1 to 3, carried out periodic way in which stage (A) obtaining a polymer latex in the form of a gel is carried out in a vessel equipped with reflectors and a mixing device, preferably a device with stepper blades.

5. The method according to claims 1 to 3, which is periodic and in which stage (A) contains the following stages: the dilution water curing latex having a concentration of about 30-40 wt.%, to a concentration in the range of 5-25 wt.%; artificial latex with mechanical stirring with a specific power is Yu from 1.5 to 5 kW/m 3adding an acid electrolyte, preferably nitric acid, to pH<2, preferably from 0.4 to 1.6.

6. The method according to claims 1 to 5, which is periodic and in which stage of leaching) contains the following stages:

1) termination of mechanical mixing and the addition of an aqueous solution, as indicated in B); and added amount of water is between 100 and 200 hours of water per 100 hours of polymeric gel;

2) subsequent mechanical mixing of the gel when the peripheral speed of the stirrer comprising between 0.1 and 0.6 m/s, with power density usually in the range of 0.2 to 2 kW/m3during the time from 1 to 10 min;

3) cessation of mixing, decanting flakes of gel and removal of distilled water;

and stage leaching) usually repeat 3-10 times, preferably 4-8 times.

7. The method according to claims 1 to 3, carried out by a continuous method in which the polymer latex in the form of a gel (stage A) is obtained by applying a polymer latex flow in flow wash the column with the following settings: multi-stage column equipped at each stage of the reflectors and one or more devices for mechanical agitation, preferably conical disks, disk turbines, stepper blades, more preferably, disk turbines; the ratio of height/iameter columns is more than 5, preferably, between 8 and 20; the number of stages is between 5 and 20; the first stage in the upper part of the column and the last stage in the lower part of the column does not have a mixing device; acid electrolyte serves throughout the column; and a polymer latex is fed directly to the first stage of the column, wash water is supplied into the lower part of the column and flows from the upper part of the column.

8. The method according to claim 7, in which the amount of acid electrolyte determines the first stage of the column conditions pH below 2, preferably between 0.4 and 1.6.

9. The method according to claims 7 and 8, in which the circumferential speed of the stirrer is below 0.6 m/s, preferably between 0.1 and 0.5 m/s, and the inside temperature of the wash column is in the range of 10 to 40°C.

10. The method according to claims 7 to 9, in which the linear velocity rinse water in the column is less than 1 cm/S.

11. The method according to claims 7 to 10, in which the ratio between the flow rate of flush water and the flow rate of the latex is in the range of 1:1-10:1, preferably of 1.5:1 to 5:1.

12. The method according to claims 1 to 11, in which the acid electrolyte is an inorganic acid, preferably nitric acid, hydrochloric acid, more preferably nitric acid.

13. The method according to claims 1 to 12, in which termperature copolymers TPV is produced by polymerization of TPV with one or more of the suits, containing at least one unit of ethylene type, preferably fluorinated, selected from the following:

With3-C8-perfluoroolefins, preferably HEXAFLUOROPROPYLENE ((HFP)(FNV);

With2-C8-hydrogenated pterolepis selected from winifrida ((VF)(VF)), vinylidenefluoride ((VDF)(WDF)), triptorelin, hexafluoroisobutene and performancerating CH2=CH-Rfwhere Rfrepresents a C1-C6-perfluoroalkyl;

C2-C8-chlorine - and/or bromo - and/or golftrolley, preferably, chlorotrifluorethylene ((CTFE)(HTFA));

(per)peralkaline ethers ((PAVE)(PAVE) CF2=CFORfwhere Rf- is1-C6-(TRANS)foralkyl, preferably, CF3C2F5With3F7;

(per)peroxyacetylnitrate esters CF2=CFOX, where X represents C1-C12-alkyl, C1-C12-oxyalkyl,1-C12-(TRANS)peroxyacyl having one or more ether groups, preferably PERFLUORO-2-propoxyphenyl;

portixol, preferably, peritoneoscopy;

unpaired diene type:

CF2=CFOCF2CF2CF=CF2,

CFX1=CX2OCX3X4OCX2=CX1F,

where X1and X2identical or different, represent F, Cl

or N; X3and X4identical or different, represent F

or CF3that in the polymerization process cyclopolymerization;

corviniana ethers ((MOVE)(SER)) of General formula CFXAI=CXAIOCF2ORAI(A-I)in which RAIis2-C6-a linear, branched or5-C6-cyclic (per)alkyl fluoride group or2-C6-a linear, branched (per)peroxyacyl group containing from one to three oxygen atoms; when RAIrepresents alkyl fluoride or peroxyacyl group, as described above, it can contain from 1 to 2 atoms, equal or different, selected from the following: H, Cl, Br, I; XAI=F, H; the compounds of General formula:

CFXAI=CXAIOCF2OCF2CF2YAI(A-II)in which YAI=F, OCF3; XAIas described above, are preferred; in particular, SER I, CF2=CFOCF2OCF2CF3(A-III) and SER II CF2=CFOCF2OCF2CF2OCF3(A-IV) are preferred.

14. The method according to item 13, in which hydrogenated olefins used in addition to the fluorinated comonomers.

15. The method according to PP and 14, in which the number of co monomer in the copolymer is in the range of 1-18 wt.%, preferably 2-10 wt.%.

16. The method according to claims 1 to 15, in which sushi is Ternopiloblenergo polymer is carried out at a temperature of from 230 to 280° C.

17. Termperature copolymers TPV obtained by PP-15, containing the amount of extractable cations less than 1 ppm

18. Termperature copolymers TPV received under clause 16, containing the amount of extractable cations less than 1 ppm and the amount of residual surfactants less than about 10 ppm



 

Same patents:

FIELD: production of filled gel-like composition with viscoelastic properties.

SUBSTANCE: claimed composition contains (vol.pts): 0.5-2.0 mass % sodium tetraborate aqueous solution 1-2; 1.0-8.0 mass % polyvinyl alcohol aqueous solution 1-5; 1.0-8.0 mass % carboxymethyl cellulose aqueous solution 1-5 or 1.0-8.0 mass % polyacrylamide aqueous solution 1-2; and filler 1-3. Composition has dynamic viscosity of 642-2467.87 mPa.s; elasticity modulus of 61.12-81.12 N/m2, and adhesion of 53.76-86.79 N/m2. As filler sand with particle size of 0.23-0.5 mm; lavsan or propylene fiber of 70-100 mum in diameter and filament length of 3-6 cm, or Teflon granule at most 1 mm in diameter. Composition of present invention is useful in production of petroleum industry, oil line purification, as anticorrosion, biocide and wear resistant coatings.

EFFECT: new viscoelastic composition of improved quality.

FIELD: polymer materials.

SUBSTANCE: invention, in particular, relates to hydrophobically modified water-soluble polymers or complexes of the latter with surfactants and discloses a method for selectively inhibiting gelation of hydrophobically associating gel-forming liquid containing hydrophobically associating water-soluble polymers or complexes of the latter with surfactants. Advantage of invention resides in that, when thus inhibited liquid contacts with a hydrocarbon medium, inhibitory effect is preserved and gelation does not occur and, when liquid contacts with an aqueous medium, inhibitory effect is cancelled and gelation takes place. Inhibitor is selected such that it is well soluble in aqueous media but insoluble in hydrocarbon media, for example ethanol or methanol. Hydrophobically associating substance in associating gel-forming liquid is, in particular, hydrophobically modified water-soluble polymer based on polyacrylamide containing 84.4 or 88.8 mol % acrylamide units, 1.5 mol % n-dodecylacrylamide units, and 14.1 or 9.7 mol % sodium acrylate units. Surfactant used in polymer complexes is, in particular, cetylpyridinium chloride. Invention further discloses associating gel-forming liquid containing 1 to 10% by weight of hydrophobically associating substances and also composition for treating oil well, which comprises associating liquid. Disclosed is also a method for selectively blocking water entry into producing oil well from underground water-bearing formations. Invention can thus be used in oil production to control water inflows in oil-production well allowing restriction of water entry into well without unfavorably affecting oil production process.

EFFECT: facilitated gelation control in polymer-containing liquids.

4 cl, 2 dwg, 1 tbl

FIELD: chemical compositions, polymers.

SUBSTANCE: invention relates to aqueous compositions comprising particles of chemically cross-linked water-soluble or water-dispersed chemical microgel. Invention proposes an aqueous composition comprising particles of chemically cross-linked water-soluble or water-dispersed chemical microgel bound with at least one bridge water-soluble or water-dispersed polymer wherein its chemical composition differs from chemical composition of indicated particles. The amount of chemical microgel particles is from 0.05 to 40% dry mass of the composition mass, and the amount of bridge polymer provides exceeding the viscosity value of the composition by at least three times or preferably it exceeds or equal to 10-fold viscosity value of chemical microgel particles an aqueous solution, and exceeds viscosity value of the bridge polymer an aqueous solution under the same conditions. Also, invention proposes a method for preparing of the claimed an aqueous composition. Proposed composition can be used in the field for mining petroleum and gas deposits, and in manufacturing detergents and cosmetics also. Invention provides enhancing stability of the composition.

EFFECT: improved and valuable properties of composition.

25 cl, 2 tbl, 2 ex

FIELD: oil and gas production.

SUBSTANCE: method of preparing controlled-size microgels, which can be used in oil and gas wells to prevent water inflow, consists in introducing polymer and suitable crosslinking agent into porous and permeable medium. Passage and passage velocity of polymer and crosslinking agent are controlled such as to provide crosslinking of polymer to form microgel aggregates in porous and permeable medium and to control sizes of aggregates leaving this medium. Removed solution contains microgel aggregates essentially equal in size.

EFFECT: achieved effective size control microgel aggregates.

11 cl

FIELD: production of high-molecular compounds.

SUBSTANCE: the invention is pertaining to the field of production of high-molecular compounds, in particular, to polymeric composition used for production of cryogels on the basis of polyvinyl alcohol. The offered polymeric composition having the interrelated macropores of cryogel of polyvinyl alcohol contains 3-25 mass % of polyvinyl alcohol, 0.001-1 mass % of ionogenic-cationic anionic either amphoteric or nonionogenic surface active agent and water (up to 100 mass %). In the process of the cryogenic treatment of the indicated polymeric compositions produce a macroporous cryogel with the size of interrelated macropores from 2 up to 10 microns, The macroporous cryogel may be efficiently used in the capacity of a biomedical application material.

EFFECT: the invention allows to obtain a macroporous cryogel, which may be efficiently used as a biomedical application material.

9 ex, 1 tbl

The invention relates to radiation chemistry of polymers, in particular radiation-chemical method of obtaining hydrogels containing immobilized dicyclohexylamine crown ethers that can be used as sorbents, membranes, etc
The invention relates to chemical technology, particularly to a method for producing a gel or suspension of chitosan, and can be used in food, cosmetic, pharmaceutical and other industries

The invention relates to the use of specific modified starch as an agent to obtain a thermally reversible gel
The invention relates to a method for producing a hydrophilic gel - chromatographic media used in laboratory practice, medical and pharmaceutical industries for purification of biologically active substances from impurities

The invention relates to chemical-pharmaceutical, food production and for the creation of compositions (gels, pastes) medicinal preparations, food products, with specific adsorption, coating, ion exchange, neutralization, complex-forming properties on the basis of a simple ester of cellulose, namely on the basis of the sodium salt of carboxymethyl cellulose (Na-CMC)

FIELD: polymer materials.

SUBSTANCE: invention, in particular, relates to preparation of concentrated aqueous polytetrafluoroethylene dispersion comprised of following stages: (i) sedimentation of polytetrafluoroethylene particles by adding from 2 to 20% (based on the weight of polytetrafluoroethylene) of nonionic surfactant with mean molecular mass between 450 and 800 and ratio of inorganic to organic residues 1.07 to 1.50 and from 10 to 800% by weight of water to aqueous polytetrafluoroethylene emulsion containing 10 to 50% of polytetrafluoroethylene obtained by emulsion polymerization of tetrafluoroethylene in presence of anionic surfactant based on perfluorocarboxylate to form aqueous polytetrafluoroethylene dispersion with 1 to 40% by weight of polytetrafluoroethylene; (ii) concentration of aqueous polytetrafluoroethylene dispersion thus obtained to form polytetrafluoroethylene-enriched aqueous polytetrafluoroethylene dispersion wherein content of polytetrafluoroethylene varies between 30 and 70 % by weight and which contains supernatant; and (iii) separation of polytetrafluoroethylene-enriched aqueous dispersion from supernatant. Content of above-indicated perfluorocarboxylate-based anionic surfactant is below 500 ppm of the weight of polytetrafluoroethylene.

EFFECT: significantly reduced content of perfluorocarboxylate-based anionic surfactant in aqueous polytetrafluoroethylene dispersion.

4 cl, 3 tbl, 12 ex

The invention relates to a method for separation of fluorine-containing emulsifier from aqueous fluoropolymer dispersion obtained by aqueous emulsion polymerization of fluorinated monomer, and optionally the co monomer or comonomers in the presence of fluorine-containing emulsifier
The invention relates to a new process for the preparation of fluorinated acids emulsifiers of waste water for the purpose of regeneration, namely, that first from waste water of polymerization of fluorinated monomers remove interfering components selected from finely dispersed solids and transferred to the solid component, and then connect the fluorinated acid emulsifiers on anion exchange resin and elute from it these fluorinated acid emulsifiers
The invention relates to a method for continuous removal of vinyl chloride from aqueous dispersions of polyvinyl chloride, which can be used in technology of polymers of vinyl chloride

FIELD: chemistry of polymers, chemical technology.

SUBSTANCE: invention relates to a fluorinated polymer comprising polymeric fragments forming as result of polymerization of a monomeric mixture. The monomeric mixture comprises the following components: (i) from above 30 to 85 wt.-% of tetrafluoroethylene; (ii) from 5 to 30 wt.-% vinylidene fluoride; (iii) from above 14 to 50 wt.-% of at least one unsaturated monomer of ethylene type of the general formula: CF2=CFRf wherein Rf represents perfluoroalkyl group comprising from 1 to 8 carbon atoms, and (iv) from 0.1 to 15 wt.-% of perfluorinated ester of the general formula: CF2=CF-(OCF2CF(Rf)aOR'f wherein Rf is the same group as in (iii); R'f means perfluoroaliphatic group comprising from 1 to 8 carbon atoms and wherein value "a" has value from 0 to 3. Also, invention relates to a multilayer article, composition, a method for improving polymer flexibility and hardening composition. Invention provides preparing polymers possessing the excellent flexibility and good penetration indices.

EFFECT: improved and valuable properties of polymers.

19 cl, 14 tbl, 12 ex

FIELD: polymer materials.

SUBSTANCE: invention is dealing, in particular, with thermally processed tetrafluoroethylene copolymers having predominantly spherical shape for at least 95 wt % of material. Median microsphere size lies within a range of 25 μm to 2 mm and bulk density between 0.5 and 1.1 g/cm3. Invention also concerns coagulation apparatus and microsphere preparation process.

EFFECT: enabled preparation microspheres of thermally processed tetrafluoroethylene copolymer characterized by specified morphology, controlled size, and improved fluidity.

18 cl, 2 tbl, 14 ex

FIELD: organic chemistry, chemical technology, polymers.

SUBSTANCE: invention relates to a method for preparing copolymer of tetrafluoroethylene of dispersion type/type of finely divided powder comprising from 99.4 wt.-% to 99.98 wt.-% of tetrafluoroethylene links and from 0.02 wt.-% to 0.6 wt.-% of perfluorobutylethylene links. Method involves carrying out the dispersion copolymerization reaction of tetrafluoroethylene and perfluorobutylethylene. The copolymerization reaction is initiated by addition of potassium permanganate and its addition is ceased when the reaction has carried out by 80%, not above. The copolymerization reaction is carried out in the absence of enhancer of the medium ionic strength. Also, invention relates to tetrafluoroethylene copolymer. Invention provides preparing copolymer of tetrafluoroethylene and perfluorobutylethylene of dispersion type that shows small main size of particles and low standard specific mass value.

EFFECT: improved preparing method, valuable properties of copolymer.

22 cl, 6 ex

FIELD: chemistry of polymers, chemical technology.

SUBSTANCE: invention relates to a linear statistical tetrafluoroethylene terpolymer with functional perfluorinated co-monomers of the general structural formula: wherein M means hydrogen or alkaline metal ion; a = 5-19.5 mole%; b = 80-91 mole%; c = 0.5-5 mole%; . Terpolymer shoes endothermic peak in the temperature interval 70-75°C on the crystalline melting curve measured by scanning differential calorimeter. Terpolymer has mean-weighted molecular mass (2-8) x 105 Da and the ratio of mean-weighted molecular mass to average molecular mass = 1.2-1.35. Also, invention relates to a method for preparing terpolymer. Invention provides preparing terpolymer that is able after hydrolysis to form concentrated solutions (above 5 wt.-%) in available solvents and under mild conditions, and to enhance the strength and to reduce electric resistance of membranes made of the claimed terpolymer.

EFFECT: improved preparing method, valuable properties of terpolymer.

4 cl, 2 tbl, 3 dwg, 37 ex

FIELD: organic chemistry, chemical technology, polymers.

SUBSTANCE: invention relates to a method for concentrating an aqueous dispersion of copolymer tetrafluoroethylene with hexafluoropropylene. Method involves thermal settling, mixing the parent dispersion with non-ionogenic surface-active substance as a stabilizing agent, heating the mixture if necessary, its keeping without stirring and the following cooling by natural way if necessary, separation of the concentrated phase from upper layer, diluting the concentrated phase up to the content of copolymer 50-55 wt.-% if necessary. Method involves using neonol AF-9-n as a non-ionogenic surface-active substance representing a mixture of polyethylene glycol esters of monoalkylphenols of the formula: R-C6H4O-(CH2CH2O)nH wherein R means isononyl as radical -C9H19 joined to phenol at para-position with respect to hydroxyl group; n means average number of ethylene oxide moles joined to one mole of alkylphenols = 9-10. Indicated neonol is added in the amount 7-10% of water mass in the parent dispersion. Mixture is heated to temperature 55°C, not above, kept its without stirring up to complete separation of phases. Cooling is carried out up to temperature 20-40°C and separation of the concentrated phase from upper layer is carried out at indicated temperature. Invention provides reducing time required for separation of phases.

EFFECT: improved method for concentrating.

7 cl, 1 tbl, 26 ex

FIELD: polymers, in particular method for production of tetrafluoroethylene copolymers.

SUBSTANCE: tetrafluoroethylene copolymers with hexafluoropropylene and perfluoroalkylvinyl ester are obtained by copolymerization of said monomers in liquid medium in presence of radical initiator at elevated temperature and pressure. Charged monomer mixture contains (mol %): tetrafluoroethylene 18.75-54.5, hexafluoropropylene 17-66.75, and perfluoroalkylvinyl ester 7.8-28.5. Additional feeding is carried out by using monomer mixture containing (mol %): tetrafluoroethylene 76-90, hexafluoropropylene 5-12, and perfluoroalkylvinyl ester 5-12. Method of present invention makes it possible to inhibit copolymerization without losses of high efficiency and to produce copolymer with constant desired composition.

EFFECT: copolymer with increased elasticity, high resistance at elevated temperature and decreased reprocessing temperature.

3 cl, 10 ex, 2 tbl

The invention relates to a method for concentrating aqueous dispersion of a copolymer of tetrafluoroethylene with HEXAFLUOROPROPYLENE by thermal sludge, comprising mixing the original variance with nonionic surfactants selected from the class of ethoxylated alkyl phenols, heating the mixture, extract it without stirring, followed by cooling in a natural way, the separation of the concentrate from the upper layer and, if necessary, diluting it to a concentration of 50 to 55 wt.%
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