GB2031017A - Molecular distillation of siloxanes and video disc lubricants - Google Patents
Molecular distillation of siloxanes and video disc lubricants Download PDFInfo
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- GB2031017A GB2031017A GB7929378A GB7929378A GB2031017A GB 2031017 A GB2031017 A GB 2031017A GB 7929378 A GB7929378 A GB 7929378A GB 7929378 A GB7929378 A GB 7929378A GB 2031017 A GB2031017 A GB 2031017A
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- lubricant
- record
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- methyl alkyl
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- 239000000314 lubricant Substances 0.000 title claims abstract description 49
- 238000000199 molecular distillation Methods 0.000 title abstract description 11
- -1 siloxanes Chemical class 0.000 title description 2
- 125000000217 alkyl group Chemical group 0.000 claims abstract description 5
- 125000004432 carbon atom Chemical group C* 0.000 claims abstract description 5
- 239000003963 antioxidant agent Substances 0.000 claims description 18
- 239000000203 mixture Substances 0.000 claims description 17
- 230000003078 antioxidant effect Effects 0.000 claims description 14
- 238000004821 distillation Methods 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 7
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical class [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 claims description 5
- 230000000694 effects Effects 0.000 claims description 5
- 125000002704 decyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 claims description 3
- 238000000576 coating method Methods 0.000 claims description 2
- 239000004020 conductor Substances 0.000 claims description 2
- 238000011084 recovery Methods 0.000 claims 2
- 239000011248 coating agent Substances 0.000 claims 1
- 230000009429 distress Effects 0.000 description 22
- 239000000463 material Substances 0.000 description 12
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 8
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 8
- 239000010410 layer Substances 0.000 description 6
- 241001422033 Thestylus Species 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- 238000009835 boiling Methods 0.000 description 4
- 229910003460 diamond Inorganic materials 0.000 description 4
- 239000010432 diamond Substances 0.000 description 4
- 150000004678 hydrides Chemical class 0.000 description 4
- 238000005507 spraying Methods 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 230000032683 aging Effects 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 238000005194 fractionation Methods 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 239000000499 gel Substances 0.000 description 2
- 238000002329 infrared spectrum Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 229910052594 sapphire Inorganic materials 0.000 description 2
- 239000010980 sapphire Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000006873 Coates reaction Methods 0.000 description 1
- SNRUBQQJIBEYMU-UHFFFAOYSA-N Dodecane Natural products CCCCCCCCCCCC SNRUBQQJIBEYMU-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 125000005376 alkyl siloxane group Chemical group 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000013590 bulk material Substances 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 229920006026 co-polymeric resin Polymers 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 125000003438 dodecyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 125000004051 hexyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 239000002991 molded plastic Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 125000002347 octyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- WVDDGKGOMKODPV-ZQBYOMGUSA-N phenyl(114C)methanol Chemical compound O[14CH2]C1=CC=CC=C1 WVDDGKGOMKODPV-ZQBYOMGUSA-N 0.000 description 1
- 239000000088 plastic resin Substances 0.000 description 1
- 229910052990 silicon hydride Inorganic materials 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
- C07F7/02—Silicon compounds
- C07F7/08—Compounds having one or more C—Si linkages
- C07F7/20—Purification, separation
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
- G11B23/50—Reconditioning of record carriers; Cleaning of record carriers ; Carrying-off electrostatic charges
- G11B23/505—Reconditioning of record carriers; Cleaning of record carriers ; Carrying-off electrostatic charges of disk carriers
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2229/00—Organic macromolecular compounds containing atoms of elements not provided for in groups C10M2205/00, C10M2209/00, C10M2213/00, C10M2217/00, C10M2221/00 or C10M2225/00 as ingredients in lubricant compositions
- C10M2229/04—Siloxanes with specific structure
- C10M2229/041—Siloxanes with specific structure containing aliphatic substituents
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/30—Refrigerators lubricants or compressors lubricants
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/32—Wires, ropes or cables lubricants
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/34—Lubricating-sealants
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/36—Release agents or mold release agents
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/38—Conveyors or chain belts
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/40—Generators or electric motors in oil or gas winning field
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/42—Flashing oils or marking oils
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/44—Super vacuum or supercritical use
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/50—Medical uses
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2050/00—Form in which the lubricant is applied to the material being lubricated
- C10N2050/04—Aerosols
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Lubricants (AREA)
- Silicon Polymers (AREA)
Abstract
Molecular distillation of methyl alkyl siloxanes of the formula <IMAGE> wherein R1 and R2 are alkyl groups of 4-20 carbon atoms and m and p are integers to produce a distillate having a molecular weight fraction wherein the sum of m and p becomes about 4, produces an improved lubricant for a video disc. A video information record is coated with a lubricant which is a methyl alkyl siloxane of formula <IMAGE> where R1 and R2 are as above, x is 2-4, z is 0-2 and x + y = 4 or less.
Description
SPECIFICATION
Video disc lubricants
This invention relates to improved lubricants for video discs. More particularly, this invention relates to the purification and fractionation of methyl alkyl siloxane lubricants which give improved performance as video disc lubricants.
U.S. Patent 3,833,408 equivalent to U.K. Specification 1,423,912 which is herein incorporated by reference, describes the application of methyl alkyl siloxane compositions as lubricants for conductive video discs comprising a molded plastic disc having audio and video information in the form of geometric variations in a spiral groove. These discs are coated first with a conductive material which acts as a first electrode, then with a dielectric layer and a final layer of lubricant. A metal tipped stylus acts as a second electrode of a capacitor and the information signals are monitored by the stylus which notes changes in capacitance between the stylus and the disc surface as the information, in the form of depressions, passes beneath the stylus.
Further developments in this system have produced a video disc which is made of a conductive plastic material e.g., a PVC copolymer resin containing sufficient amounts of conductive carbon particles so that the disc can provide capacitance readout, while the plastic resin surrounds the carbon particles providing a dielectric surface layer on the conductive particles. This development has eliminated the need for separate coatings of metal and dielectric on the plastic disc.
The stylus, formerly made of metallized sapphire, has also been improved so that metallized diamond can be used. Diamond is a harder, longer wearing material than sapphire, and also requires good lubrication of the disc surface.
Video discs are also being developed which do not require a conductive surface or a grooved surface, the stylus being maintained in synchronization with the information pattern track by means of electrical signals rather than the groove walls.
These changes in the materials used for the video disc and stylus have somewhat changed the requirements for the lubricant and in certain respects the commercially available methyl alkyl siloxane lubricant is now unsatisfactory. One commercially available methyl alkyl siloxane composition has the formula
wherein R is a straight chain decyl group, and n is an integer. This material has a molecular weight of about 1 500 and a viscosity of about 50 centistokes and is sold by General Electric Company as SF 1 147. This composition also contains about 1.5 percent of antioxidant compounds.
When the present video discs molded from carbon-loaded PVC compositions are spray coate'd with the So~1147 lubricant and played back with a diamond stylus, the play-back performance and stability are less than desirable. Thus an attempt was made to improve the performance of this class of lubricant and the present invention resulted.
FIG. 1 is a cross-sectional view of a molecular distillation apparatus useful in preparing compositions of the invention.
FIG. 2 is a graph which shows the variation in amount of distillate versus temperature.
FIG. 3 shows the infrared spectrum of distilled and undistilled methyl alkyl siloxane compositions at 2150 cm#1.
We have found that the methyl alkyl siloxanes having the formula
wherein Ra and R2 are alkyl groups of 4 20 carbon atoms, x is an integer of 2-4 and y is an integer of 0--2 and wherein the sum of x and y is 4 or less, have improved lubricity for video disc applications and improved stability to high temperatures, high and low humidity conditions and improved resistance to ageing.
The methyl alkyl siloxane compositions of the invention have a distillation temperature of about 100~205 C at a pressure of 10-5 torr, have a molecular weight range of about 500-800 and a polydispersity, defined as the weight average molecular weight divided by the number average molecular weight, of less than about 1.07. The fractions useful herein can be obtained by molecular distillation of a mixed siloxane starting material of the formula
wherein R1 and R2 are as defined above and m and p are integers, under high vacuum low temperature conditions, to obtain a narrow molecular weight fraction.
Molecular distillation is known and is described in "Molecular Distillation of Thermally
Supersensitive Liquids", Frank et al, Analytical Chemistry, Vol. 36, No.11, October 1964. The method can be explained in detail by referring to FIG. 1 which is a schematic view of a molecular still 10. The material to be distilled is fed to feed reservoir 12 which is evacuated by diffusion pump 14 through line 16 which passes through a liquid nitrogen trap 18. The feed reservoir 12 is connected to a distillation chamber 20 containing a glass column 22 which has a spiral glass winding 24 wrapped around it and a receptacle 26 at one end to contain hot fluid.The distillation chamber 20 also contains two additional receptacles, a distilland receptacle 28 and a distillate receptacle 30. Afeed tube 32 allows material from the feed reservoir 1 2 to flow to the distillation chamber 20 through valve 34. A high vacuum is maintained in the distillation chamber 20 through line 36, which also leads to the diffusion pump 14. During operation, the system is evacuated to an initial pressure of about 10-7 torr. Boiling water is maintained in the receptacle 26 and rises through column 22 to heat the said column and the glass winding 24 to a temperature of about 1000C. The control valve 34 is opened to allow a small stream of the material to be distilled to drop onto the heated column 22 from the feed reservoir 12.The material is spread out by the wrapped coil 24 to form a smooth, thin film which is turned over periodically as it passes along the winding 24, enabling the more volatile constituents to evaporate. The material which vaporizes at 1 000C or less evaporates from the heated column 22 and is condensed on the wall of the distillation column 20, flows down the wall and is collected in distillate receptacle 30. The remaining material is collected in distilland receptacle 28. To separate out the material which boils above 1000 and below 2050C, for example, the receptacle 26 is filled with benzyl alcohol, which boils at 2050C, and the distillate from the first fractionation is fed to the feed reservoir 12 and the distillation repeated.The desired distillate collects in distillate receptacle 30 as before and the higher boiling, higher molecular weight fractions are collected in distilland receptacle 28. By using this method of fractionation, the liquid bulk material itself is not heated, but only contacts a heated column where it undergoes a collision-free evaporation at minimum temperatures with the least damage to thermally sensitive molecules.
We have found that molecular distillation of the present methyl alkyl siloxane feedstock not only fractionates the feedstock, but also purifies it, both by removing all antioxidant compounds and chromophores and silicon hydrides as well, thereby providing a much improved lubricant for the video disc. This purification result was highly unexpected and surprising and is highly desirable, since hydrides are chemically active and can produce gel formation which would lead to dropouts and increased noise on playback of the video disc.
The presence of aromatics such as metal-aromatic complex chromophores and antioxidants is also highly undesirable since such compounds are reactive to the video disc surface and contribute to a deterioration of the play-back quality with time. The antioxidants generally added to the methyl alkyl siloxane compounds are in the form of both free antioxidants and chemically bound antioxidants. The free antioxidant has the formula
and the chemically bound antioxidant has the formula
Since the concentration of unbound antioxidant varies from batch to batch, leading to nonuniformities in playback performace of the video disc, the unbound lubricant can be removed by dissolving in acetone and separating the acetone layer from the methyl alkyl siloxane.However, the presence of the chemically bound antioxidant renders the video disc unplayable, often in a matter of weeks, and thus the presence of aromatic impurities and antioxidant compounds cannot be tolerated at all in the lubricant for the present video discs.
That the present molecular distillation procedure would remove silicon hydrides, particularly to the distilland portion or high molecular weight fraction, was highly unexpected, since silicon hydrides are generally low boiling compounds. It is believed that even at comparatively low temperatures, the hydrides present are reacting with the methyl alkyl siloxane compounds, either to produce higher molecular weight fractions or to produce gelling. This also contributes to the ageing process by using up the lower molecular weight fractions and producing gels which lead to a massive dropout of information during playback of the video disc. This result was highly unexpected.
The fractionated methyl alkyl siloxanes of the invention can be dissolved in a suitable solvent, such as heptane or isopropanol or other solvent which is inert with respect to the disc surface, typically at a loading of from about 0.2 to 2.0 percent by weight of the solution of the methyl alkyl siloxane. The solution is then sprayed onto the disc surface to form a siloxane film about 200-300 angstroms thick.
The lubricant film can also be applied by evaporation.
The present lubricant fractions do not age, are stable with respect to atmospheric effects and provide high uniformity and reproducibility for the video disc. In addition, the fractions provide excellent lubricity as measured by low stylus and disc wear, and improved initial playback performance.
The invention will be further illustrated by the following Examples but the invention is not to be limited to the details described therein. In the Examples, percent is by weight unless otherwise noted.
EXAMPLE 1.
A methyl alkyl siloxane feedstock having the formula
wherein n is an integer from 1 to about 8, having a viscosity of 49.4 centistokes at 220C, a number average molecular weight of 1239 and a weight average molecular weight of 1 557, thus a polydispersity of 1.26, and a refractive index of 1.4463 was molecularly distilled at an average pressure of 10-5 torr in a distillation apparatus according to FIG. 1.
FIG. 2 shows the amount of distillate as a percent by weight of the feedstock versus temperature.
The fraction which distilled at from 1 00--2050C was collected.
The distillate had a viscosity of about 14 centistokes at 250C; a weight average molecular weight of 660, which corresponds to a composition of the general formula (1) wherein y isO, x is 3 and R, is decyl, a dispersity of 1.06 and a refra#ctiye index of 1.435.
The color of the distillate was measured by determining optical density at various wavelenghts for a 1.0 millimeter thick sample and compared to the feedstock color and the distilland color after molecular distillation. The data are summarized below in Table I.
TABLE 1.
Optical Density
Sample 500 nm 400 nm 300 nm
Feedstock 0.060 0.125 1.60
Distillate 100~205 C 0.035 0.055 1.40
Distilland 0.080 0.17 1.80
Thus the distillate contains less color-forming material than either the feedstock or the distilland at all wavelengths tested.
The hydride content of the distillate was also greatly reduced from that of the feedstock. As shown by infrared absorption, at a wavelength of 21 50 cm~ (SiH) for a 1.0 millimeter thick sample, the feedstock contained about 5-12 cm- of silicon hydride. The distillate contained less than 0.1 cm~' hydride. The infrared spectra for the feedstock is shown in Curve 1 and the distillate spectra is shown in
Curve 2 of FIG. 3.
Thus molecular distillation both fractionates and purifies the methyl alkyl siloxane feedstock.
EXAMPLE 2.
The feedstock of Example 1 was molecularly distilled into 5 fractions using appropriate heating fluids and various measurements were taken. The data are summarized in Table 11 below, wherein fraction I was collected at 400C, fraction II was collected at 1000C, fraction Ill was collected at 1 530C.
fraction IV was collected at 211 C and fraction V was collected at 239 C.
TABLE II.
Density,
gm./ml. Viscosity, - - Refractive
Fractions at 22 C. cs at 220C. Mn Mw Polydispersity Index, 220C.
Feedstock 0.868 49.4 1239 1557 1.26 1.4463
Distilland I 0.868 49.2 1216 1507 1.24 1.4452
Distilland II 0.869 53.0 1323 1654 1.25 1.4453
Distilland lil 0.869 55.9 1450 1794 1.24 1.4455
Distilland IV 0.874 63.2 1525 1872 1.23 1.4472
Distilland V 0.874 73.5 2229 2700 1.21 Distillate II 0.849 10.6 500 526 1.05 1.4353
Distillate ill 0.852 15.5 644 690 1.07 1.4363
Distillate IV 0.862 22.7 800 836 1.05 1.4385
Distillate V 0.863 27.9 1248 1304 1.04
The above table shows that methyl alkyl siloxanes can be fractionated into narrow molecular
weight fractions by the molecular distillation technique.
EXAMPLE 3.
A series of video discs were tested by applying various lubricant compositions and fractions to the disc by evaporation or spraying techniques and playing back with a titanium metallized diamond stylus.
Lubricant A was a methyl decyl siloxane of the formula
with a molecular weight range as described in Example 1, free of any antioxidant and was applied by vacuum evaporation; lubricant B was the same lubricant applied by spraying from a 1 percent solution in heptane; and lubricant C was the fraction molecularly distilled at 100--2050C, also applied by spraying as above. The lubricant layers were about 200 angstroms thick.
The quality of the video discs during playback was measured by determining the carrier distress time, which is measured by adding the amount of time, in seconds (but discounting intervals of less than 10 microseconds) during total disc playback when the R.F. output of the player arm is less than 150 millivolts peak to peak, and the time when the R.F. output gave above 8.6 megahertz or below 3.1 megahertz in frequency, indicating a defect. Such defects are noted by the viewer as dropouts. The pass criterion for a video disc is a maximum of 3 seconds in 30 minutes of playback time, and good video quality is considered to be less than 0.3 second in 30 minutes of playback.
Twelve discs having the above lubricants were tested and the percentage of discs which passed each standard was calculated. The data are summarized below in Table Ill.
TABLE Ill
Carrier Distress Time, sec./30 min.
% < % <
Lubricant 0.3 sec. 1 sec. 3 sec. 6 sec.
A 41.7 58.4 83.4 100
B 66.7 75 91.7 91.7
C 91.7 91.7 91.7 91.7
Stylus and disc surface wear tests were made on the above twelve discs by carrying out 35
playbacks on the same 20 minute band of each disc and measuring styli wear and examining the
disc surfaces before and after the test for gross, visible wear and significant surface damage visible
to the eye and/or under a microscope. The data are summarized below in Table IV.
TABLE IV.
% of discs with gross wear
Stylus wear, and significant
Lubricant ju3/hour surface damage
A 0.003 25
B 0.014 33.3
C 0.003 8.4
EXAMPLE 4.
The effect of low humidity on a lubricant fraction as in Example 1, was tested by measuring the carrier distress time of 12 video discs under ambient conditions (760F and 18 percent relative humidity, hereinafter RH). All of the discs had carrier distress times of less than 0.3 seconds in 30 minutes of playback. They were then stored at 660F and 6 percent RH for 72 hours and played again. All of the discs played well and had a carrier distress of less than 0.3 second in 30 minutes of playback.
When a feedstock lubricant was applied to video discs and tested as above, 42 percent of the discs exhibited carrier distress times of less than 0.3 second and 75 percent of the discs had carrier distress times of less than 3 seconds in 30 minutes of playback. This was unchanged after low humidity storage.
EXAMPLE 5.
The effect of low temperature on the present lubricant was tested by measuring carrier distress times of 12 video discs coated with the fractionated lubricant as in Example 1 under ambient conditions (760F, 20 percent RH). All of the discs had a carrier distress time of less than 0.3 second in 30 minutes of playback. They were then stored in a low temperature chamber at 59--626F and 25 percent RH for 72 hours and immediately played again. All of the discs exhibited good performance before and after storage and all still had a carrier distress time of less than 0.3 seconds in 30 minutes of playback.
When a feedstock lubricant control was applied and tested as above, only 33 percent of the discs had carrier distress times of less than 0.3 second and 7.5 percent of the discs had carrier distress times of less than 3 seconds in 30 minutes of playback. These results were unchanged after low temperature storage.
EXAMPLE 6.
The effect of high temperature and high humidity on the present lubricant was tested by measuring carrier distress times of 12 video discs coated with the fractionated lubricant as in Example 1 after storage in a chamber at 950F and 75 percent RH for 24 hours. Carrier distress time results are summarized below in Table V.
TABLE V
Carrier Distress Time, sec./30 min.
%r % < 9/01 9/01
Lubricant 0.3 sec. 1 sec. 3 sec. 6 sec.
A 16.7 66.7 100 100
B 16.7 50 83.3 100
C 33.3 83.3 100 100
EXAMPLE 7.
A mixed methyl alkyl siloxane of the formula
wherein m and p are integers of 2-7 was prepared and molecularly distilled to collect the fraction boiling from 100~205 C. This lubricant fraction was sprayed from a 1- percent heptane solution onto a video disc-as in Example 1#. Playback data initially and after storage at high temperature and high humidity conditions (950F and 75 percent RH) are summarized below in Table Vl.
TABLE Vl Carrier Distress Time, sec./30 min.
.
0.3 sec. 1 sec. 3 sec. 6 sec.
Initial play 87.5 100 100 100
After storage 12.5 62.5 62.5 87.5
EXAMPLE 8.
A series of me#thyl alkyl siloxanes of the formula
wherein R was hexyl, octyl and dodecyl respectively and m was an integer of 2-7 were prepared.
Each lubricant was sprayed on 8 vides discs and the carrier distress time measured. The data are summarized below in Table Vll.
TABLE VII.
Carrier Distress Time, sec./30 min.
%I %I %I 9bI
Initial Play 0.3 sec. 1 sec. 3 sec. 6 sec.
C6 Lubricant 87.5 100 100 100
C8 Lubricant 87.5 87.5 100 100
C12 Lubricant 87.5 100 100 100
The discs were then stored at 950F and 75 percent RH for 72 hours and retested. The carrier distress data obtained are summarized below in Table VI II.
TABLE VIII
Carrier Distress Time, sec./30 min.
% < % < % < % <
After Storage 0.3 sec. 1 sec. 3 sec. 6 sec.
C6 Lubricant 0 62.5 62.5 87.5
C8 Lubricant 12.5 75 100 100 C12 Lubricant 12.5 62.5 87.5 100
Stylus wear tests were also made. All of the tests showed stylus wear below 0.04 ,upper hour.
COMPARATIVE EXAMPLE
A commercially available methyl alkyl siloxane composition sold as SF~1147 was treated to remove free antioxidant as follows: a lubricant was shaken with an equal volume of acetone twice and the layers separated. The free antioxidant is dissolved in the acetone layers along with some low molecular weight silicone oils. The siloxane (ayer was collected, stripped at 800C under vacuum and evacuated at 10 millimeters of mercury at 800C to remove all free antioxidant while leaving the chemically bound antioxidant and the molecular weight distribution of the feedstock intact. This composition was then molecularly distilled as in Example 1 and the fraction distilling between 1 00-2050C was collected.
The lubricant fraction was applied by spray coating from heptane onto a video disc. The initial playback data was good; 84 percent of 12 discs had a carrier distress time of 0.3 second in 30 minutes of playback or less. The discs were then stored for 1 week under ambient conditions. Very high carrier distress times, about 100 seconds up to about 1000 seconds in 30 minutes of playback, were noted on all discs. The lubricant was found to have been removed in places, indicating ageing and lack of compatibility with the present disc system when chemically bound antioxidant is present in the lubricant.
Claims (9)
1. In a video information record, adapted for use with a playback stylus to effect recovery of signals occupying a bandwidth of at least several megahertz when relative motion at a desired rate is established between said record and said stylus, said record comprising a disc of a conductive material containing an information track constituted by a surface relief pattern in said track to accommodate recovery of signals of said bandwidth upon establishment of relative motion at said rate, said record being coated with a methyl alkyl siloxane lubricant coating, the improvement which comprises utilizing as said lubricant, a composition of the formula
wherein R, and R2 are alkyl groups of 4~20 carbon atoms, x is an integer of 2-4, y is an integer of 0--2, and wherein the sum of x plus y is 4 or less.
2. A record according to claim 1 wherein x is 2.4 and y is 0.
3. A record according to claim 1 wherein said composition has a distillation range of from about 100~205 C at 10-5 torr.
4. A record according to claim 1 wherein R, and R2 are alkyl groups of 4-12 carbon atoms.
5. A record according to claim 4 wherein R, is a decyl group and y is O.
6. A record according to claim 1 wherein said methyl alkyl siloxane composition is free of silicon hydrides.
7. A record according to claim 1 wherein said methyl alkyl siloxane composition is free of antioxidant.
8. A method of purifying and fractionating a composition of the formula wherein Rr and R2 are alkyl groups of 4-20 carbon atoms and m and p are integers which comprises molecularly distilling said composition and collecting the fraction which distills at from about 100--205"C.
9. A video information record substantially as hereinbefore described.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US93781978A | 1978-08-29 | 1978-08-29 |
Publications (2)
Publication Number | Publication Date |
---|---|
GB2031017A true GB2031017A (en) | 1980-04-16 |
GB2031017B GB2031017B (en) | 1983-05-11 |
Family
ID=25470451
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB7929378A Expired GB2031017B (en) | 1978-08-29 | 1979-08-23 | Molecular distillation of silxanes |
Country Status (6)
Country | Link |
---|---|
JP (1) | JPS5925288B2 (en) |
CA (1) | CA1128922A (en) |
DE (1) | DE2934282A1 (en) |
FR (1) | FR2435102B1 (en) |
GB (1) | GB2031017B (en) |
IT (1) | IT1123480B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002046860A2 (en) * | 2000-12-05 | 2002-06-13 | Imation Corp. | Data storage media |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0046304B1 (en) * | 1980-08-20 | 1985-04-17 | Hitachi Maxell Ltd. | Magnetic recording medium |
US4355062A (en) * | 1981-02-05 | 1982-10-19 | Rca Corporation | Bis(hydroxyalkyl)disiloxanes and lubricant compositions thereof |
JPS59171051A (en) * | 1983-03-18 | 1984-09-27 | Victor Co Of Japan Ltd | Recording medium of high density information signal |
JPS59191152A (en) * | 1983-04-14 | 1984-10-30 | Victor Co Of Japan Ltd | Recording medium for high density information signal |
JPS59195355A (en) * | 1983-04-20 | 1984-11-06 | Victor Co Of Japan Ltd | High density information signal recording medium |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE521395A (en) * | 1953-02-12 | Rhone Poulenc Sa | ||
US3833408A (en) * | 1972-04-19 | 1974-09-03 | Rca Corp | Video discs having a methyl alkyl silicone coating |
US4206256A (en) * | 1975-08-21 | 1980-06-03 | Rca Corporation | Metallized video disc having an insulating layer thereon |
JPS5240624A (en) * | 1975-09-27 | 1977-03-29 | Nagoya Kinzoku Shinpu Kk | Apparatus for transfering intermediate fiber of tandem card |
-
1979
- 1979-07-26 IT IT24707/79A patent/IT1123480B/en active
- 1979-08-16 CA CA333,886A patent/CA1128922A/en not_active Expired
- 1979-08-23 GB GB7929378A patent/GB2031017B/en not_active Expired
- 1979-08-24 DE DE19792934282 patent/DE2934282A1/en not_active Withdrawn
- 1979-08-27 FR FR7921429A patent/FR2435102B1/en not_active Expired
- 1979-08-28 JP JP54110144A patent/JPS5925288B2/en not_active Expired
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002046860A2 (en) * | 2000-12-05 | 2002-06-13 | Imation Corp. | Data storage media |
WO2002046860A3 (en) * | 2000-12-05 | 2003-08-07 | Imation Corp | Data storage media |
Also Published As
Publication number | Publication date |
---|---|
CA1128922A (en) | 1982-08-03 |
DE2934282A1 (en) | 1980-03-13 |
JPS5925288B2 (en) | 1984-06-16 |
IT7924707A0 (en) | 1979-07-26 |
FR2435102B1 (en) | 1986-11-07 |
GB2031017B (en) | 1983-05-11 |
FR2435102A1 (en) | 1980-03-28 |
IT1123480B (en) | 1986-04-30 |
JPS5538699A (en) | 1980-03-18 |
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