GB2036504A - Ultrasonic stand-off unit - Google Patents
Ultrasonic stand-off unit Download PDFInfo
- Publication number
- GB2036504A GB2036504A GB7936837A GB7936837A GB2036504A GB 2036504 A GB2036504 A GB 2036504A GB 7936837 A GB7936837 A GB 7936837A GB 7936837 A GB7936837 A GB 7936837A GB 2036504 A GB2036504 A GB 2036504A
- Authority
- GB
- United Kingdom
- Prior art keywords
- unit according
- polyether polyol
- prepolymer
- attenuation
- ultrasonic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000005855 radiation Effects 0.000 claims abstract description 24
- 229920003225 polyurethane elastomer Polymers 0.000 claims abstract description 21
- 239000000314 lubricant Substances 0.000 claims abstract description 5
- 239000012188 paraffin wax Substances 0.000 claims abstract description 4
- 229920001296 polysiloxane Polymers 0.000 claims abstract description 4
- 239000004721 Polyphenylene oxide Substances 0.000 claims description 15
- 229920000570 polyether Polymers 0.000 claims description 15
- 229920005862 polyol Polymers 0.000 claims description 15
- 150000003077 polyols Chemical class 0.000 claims description 15
- 239000003054 catalyst Substances 0.000 claims description 14
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 11
- 238000006243 chemical reaction Methods 0.000 claims description 9
- UKLDJPRMSDWDSL-UHFFFAOYSA-L [dibutyl(dodecanoyloxy)stannyl] dodecanoate Chemical compound CCCCCCCCCCCC(=O)O[Sn](CCCC)(CCCC)OC(=O)CCCCCCCCCCC UKLDJPRMSDWDSL-UHFFFAOYSA-L 0.000 claims description 7
- 239000012975 dibutyltin dilaurate Substances 0.000 claims description 7
- 125000005442 diisocyanate group Chemical group 0.000 claims description 4
- 229920001451 polypropylene glycol Polymers 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 3
- IQPQWNKOIGAROB-UHFFFAOYSA-N isocyanate group Chemical group [N-]=C=O IQPQWNKOIGAROB-UHFFFAOYSA-N 0.000 claims description 2
- 239000012948 isocyanate Substances 0.000 claims 2
- 150000002513 isocyanates Chemical class 0.000 claims 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- NIMLQBUJDJZYEJ-UHFFFAOYSA-N isophorone diisocyanate Chemical compound CC1(C)CC(N=C=O)CC(C)(CN=C=O)C1 NIMLQBUJDJZYEJ-UHFFFAOYSA-N 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 239000005058 Isophorone diisocyanate Substances 0.000 description 6
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- KSBAEPSJVUENNK-UHFFFAOYSA-L tin(ii) 2-ethylhexanoate Chemical compound [Sn+2].CCCCC(CC)C([O-])=O.CCCCC(CC)C([O-])=O KSBAEPSJVUENNK-UHFFFAOYSA-L 0.000 description 6
- DOIRQSBPFJWKBE-UHFFFAOYSA-N dibutyl phthalate Chemical compound CCCCOC(=O)C1=CC=CC=C1C(=O)OCCCC DOIRQSBPFJWKBE-UHFFFAOYSA-N 0.000 description 4
- 229920001971 elastomer Polymers 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 239000005060 rubber Substances 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 description 4
- IMNIMPAHZVJRPE-UHFFFAOYSA-N triethylenediamine Chemical compound C1CN2CCN1CC2 IMNIMPAHZVJRPE-UHFFFAOYSA-N 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- SJRJJKPEHAURKC-UHFFFAOYSA-N N-Methylmorpholine Chemical compound CN1CCOCC1 SJRJJKPEHAURKC-UHFFFAOYSA-N 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000004014 plasticizer Substances 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- YNAVUWVOSKDBBP-UHFFFAOYSA-N Morpholine Chemical compound C1COCCN1 YNAVUWVOSKDBBP-UHFFFAOYSA-N 0.000 description 2
- 150000001412 amines Chemical class 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- JQVDAXLFBXTEQA-UHFFFAOYSA-N dibutylamine Chemical compound CCCCNCCCC JQVDAXLFBXTEQA-UHFFFAOYSA-N 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000004519 grease Substances 0.000 description 2
- HJOVHMDZYOCNQW-UHFFFAOYSA-N isophorone Chemical compound CC1=CC(=O)CC(C)(C)C1 HJOVHMDZYOCNQW-UHFFFAOYSA-N 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 1
- ZJCCRDAZUWHFQH-UHFFFAOYSA-N Trimethylolpropane Chemical compound CCC(CO)(CO)CO ZJCCRDAZUWHFQH-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 238000003618 dip coating Methods 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 239000011369 resultant mixture Substances 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/28—Details, e.g. general constructional or apparatus details providing acoustic coupling, e.g. water
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/02—Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Polyurethanes Or Polyureas (AREA)
Abstract
Ultrasonic stand off unit fabricated from a polyurethane rubber and having an attenuation of ultrasonic radiation of frequency 2MHz of from 0.5 to 4.0 dB/cm and an acoustic impedance of from 1.45 to 1.6 M Rayls. The unit preferably has a hardness of from 15-50 IRHD and is substantially inert to paraffin and silicone lubricants. It may also be transparent. <IMAGE>
Description
SPECIFICATION
Ultrasonic stand-off unit
This invention relates to an ultrasonic stand-off unit. In the operation of ultrasonic diagnostic apparatus it is necessary to provide an efficient means whereby the ultrasonic radiation generated by the apparatus is transmitted to the object being examined which is normally, of course, the body of the patient. It is necessary that this means, normally referred to as a stand-off unit, should form a close contact with the body, aided if necessary by a lubricant such as paraffin or silicone grease and thus it is desirable that the means be sufficiently resilient to conform to the body contours and preferably also should be chemically resistant to the lubricant required.In addition, and most importantly, the means must be fabricated from a material which does not unduly attenuate the ultrasonic radiation, which is normally of a frequency in the region of 2MHz.
It is an object of the present invention to provide a stand-off unit which satisfies the above criteria.
Accordingly we provide an ultrasonic stand-off unit fabricated from a polyurethane rubber and having an attenuation of ultrasonic radiation of frequency 2MHz of from 0.5 to 4.0 dB/cm and an acoustic impedance of from 1.45 to 1.6 M Rayls. Preferably the unit has a hardness of from 1 5 to 50
IRHD, more preferably from 30 to 50 IRHD, and is substantially inert to paraffin and silicone lubricants. It is also desirable, for ease of operation, that the unit be opticaliy substantially transparent, although a suitable colouring may in certain instances be included.
Units having an attenuation of from 2.0 to 3.0 dB/cm can conveniently be prepared, as hereinafter described in certain of the specific examples.
We have found that a particularly suitable polyurethane rubber is that formed by the reaction of a polyether polyol having high molecular weight segments between the functional hydroxyl groups and a diisocyanate. Suitable polyether polyols which satisfy this condition include certain polyoxypropylene glycols of molecular weight between 3500 and 6000, and having a chemical structure such that the ratio of molecular weight to hydroxyl number is at least 90.
The reaction between the polyether polyols and the diisocyanate (toluene diisocyanate and isophorone diisocyante are preferred) may take the form of a 'one shot' process in which stoichimetric or near stoichimetric quantities of the reactants are used to produce the required product directly or, alternatively, the polyether polyol may first be reacted with an excess of diisocyanate to form a prepolymer which is then reacted with a further quantity of the polyether polyol sufficient to react with the remaining unreacted isocyanate groups. It has been found to be particularly convenient to prepare a prepolymer containing from 3.5% to 5.0% by weight of unreacted isoycanate groups.The exact percentage may be determined for any particular prepolymer by standard methods e.g. by reacting the prepolymer with an amine such as di-n-butylamine and back titrating the excess amine with hydrochloric acid. These reactions, particularly the reaction of the prepolymer with further polyether polyol may be catalysed; we have found that 1 ,4-diazobicyclo-(2,2,2)-octane, stannous octoate, Nmethyl morpholine and dibutyl tin dilaurate are particularly suitable catalysts. We have found that where it is preferred to keep the temperature of the material low, i.e. not above 400C, during the reaction of prepolymer and polyether polyol, dibutyl tin dilaurate in a concentration of from 1.2% to 2.1 1% by weight of total reactants is particularly useful.
The unit of our invention may be in any suitable form including a strip of slab of polyurethane rubber, which should of course be substantially uniform in texture and include no voids since these lead to a marked increase in attenuation. A plasticiser may be incorporated such as n-butyl phthalate. The amount of plasticiser used may vary over a wide range from 0.5% to 60% of the total weight of the plasticised product. Conveniently the unit includes a portion which is shaped by suitable casting or molding to fit closely over the head of the apparatus which is the source of the ultrasonic radiation. In certain designs where the array of elements from which the ultrasonic radiation is produced is recessed into the head it is convenient to fill this recess with material according to the present invention to present a surface which is flush with the rest of the head.In such a case it is particularly preferred to mould the material into the recess by forming it, in situ, using a low temperature (400 C) polymerisation process from the prepolymer and polyether polyol. To give added protection from mechanical damage and possible moisture absorption a PVDF film of thickness from 10-3 to 2.1 0-3 inches may be applied over this insert.
In one form, as illustrated in the accompanying drawing wherein Figure 1 is a perspective view of a stand-off unit the unit comprises an integral one-piece moulding of polyurethane rubber in which a
lower diverging portion, 1 is surmounted by a portion of rectangular section which defines a rectangular opening 3 into which fits the working head of an ultrasonic generator, which head conveniently contains an array of transducers. The precise geometrical shape of the stand-off unit may be modified for example as described and claimed in our copending application no. 48918/77 wherein the input face, 3, and the output face 4 are inclined to one another at an angle such that reflected waves components from different parts of the output face interfere destructively and/or as in our co-pending application no.
53110/77 wherein the output face, 4, is corrugated.
Optionally, to afford mechanical protection to the boot and in particular to the rectangular opening 3 which may be subjected to significant wear when the head of the ultrasonic generator is inserted or removed therefrom, at least the side walls of this opening may be coated e.g. by dip coating with a thin layer (about 10-3 inches) of a mechanically stronger polymeric material e.g. a more cross-linked polyurethane.
The preparation of a number of polyurethane rubber compositions suitable for production of the stand-off units of the invention will now be illustrated by the following Examples. It will be understood that the invention is in no way limited to particular embodiments described therein.
EXAMPLE 1
A polyoxypropylene glycol of molecular weight 5300 and hydroxyl number 32
(molecular weight
= 166)
hydroxyl number was used as the starting material in the following reactions. For convenience this starting material will be referred to as T32/75, this being the code number under which it is commercially available (from l.C.I. Limited). T32/75 (50g.), toluene diisocyanate (2.79) and, as catalyst, N-methyl morpholine (0.15g) were mixed, degassed and placed in an oven at 1000C for 1 6 hours. The resultant-polyurethane rubber had an impedance of 1.48 M Rayl, an attenuation of 2MHz radiation of 3.5 dB/cm and a hardness of 32
IRHD.
EXAMPLE 2
The procedure of Example 1 was repeated using as catalyst 1 ,4-diazobicyclo-(2,2,2)-octane (0.025g) to yield a polyurethane rubber of impedance 1.48 M Rayl, an attenuation of 2 MHz radiation of 2.6 dB/cm and a hardness of 33 IRHD.
EXAMPLE 3
(a) T32/75 (1 1.5g), isophorone diisocyanate (0.8g),n-butyl phthalate (12.3g) and, as catalyst stannous octoate (0;01g) were mixed, degassed and placed in an oven at 1000C for 1.5 hours. The resultant 50% plasticised polyurethane rubber which was very soft and floppy had an impedance of 1.50 M Rayl and an attenuation of 2MHz radiation of 0.6 dB/cm.
(b) The procedure of Example 3(a) was repeated using the different amounts of n-butyl phthalate plasticiser as set out in the following table to give materials which had the values of impedance and attenuation as also set out in the table.
Amount of | n-butyl phthalate % by weight of final Impedance Attenuation of 2MHz Weight (g) product M. Rayl Radiation (dB/dm) 8.2 40 1.58 1.1 1.4 10 1.61 1.8 3.1 20 1.55 1.8 5.3 30 1.58 1.3 18.5 60 1.50 0.8 EXAMPLE 4
To toluene diisocyanate (82g) under nitrogen and stirred at 800C was added over one hour
T32/75 (500g) and then the mixture heated whilst continuing to stir to 1 200C for 15 minutes. The resultant prepolymer was used in the following procedures (a) and (b).
(a) Prepolymer (1 00g), T32/75 (200g) and, as catalyst, 1 ,4-diazobicyclo-(2,2,2)-octane (0.1 g) were heated for 1 6 hours at 1000C to yield a polyurethane rubber having an impedance of 1.50 M Rayl and an attenuation of 2MHz radiation of 2.5 dB/cm.
(b) Prepolymer (100g), T32/75 (200g) and, as catalyst, dibutyl tin dilaurate (0.29) was heated for 1 hour at 1000C and 16 hours at 400C to yield a polyurethane rubber having an impedance of about 1.50 M Rayl, an attenuation of 2 MHz radiation of 3.2 dB/cm and a hardness of 28 íRHD. Repetition of this experiment using a curing cycle of 1 6 hours at 400C (i.e. omitting the 1 hour at 1000C) yielded a rubber of slightly less attenuation of 3.1 dB/cm.
EXAMPLE 5
To isophorone diisocyanate (1059) under nitrogen and stirred at 80 C was added over one hour
T32/75 (5009) and then the mixture heated whilst continuing to stir to 1200C for 1 5 minutes. This product contained 4.1% free NCO content. The resultant prepolymer was used in the following procedures (a), (b) and (c).
(a) Prepolymer (100g), T32/75 (200g) and, as catalyst, 1 ,4-diazobicyclo-(2,2,2)-octane (0.1g) were heated for 1 6 hours at 1000C to yield a polyurethane rubber having an impedance of about 1.50
M Rayl, an attenuation of 2MHz radiation of 2.3 dB/cm and a hardness of 1 6 IRHD.
(b) Prepolymer (1 00g), T32/75 (200g) and, as catalyst, dibutyl tin dilaurate (0.29) were heated for 1 hour at 1000C and 16 hours at 400C to yield a polyurethane rubber having an impedance of about 1.50 M Rayl, an attenuation of 2MHz radiation of 2.8 dB/cm and a hardness of 31 IRHD. Repitition of this experiment using a curing cycie of 1 6 hours at 400C (i.e. omitting the 1 hour at 1000C) yielded a rubber of similar attenuation (3.0 dB/cm), but the material was rather soft.
(c) Prepolymer (1 00g), T32/75 (200g) and, as catalyst stannous octoate (0.1 g) were heated for 1.5 hours at 1000C to yield a polyurethane rubber having an impedance 1.46 M Rayl, an attenuation of 2MHz radiation of 2.4 dB/cm and a hardness of 33 IRHD.
EXAMPLE 6
(a) To isophorone diisocyanate (3,39Kg) under nitrogen and stirred at 90 to 1000C was added over a period of 2 to 3 hours T32/75 (1 6.0Kg) preheated to 100 to 11000. The temperature of the reaction mixture was maintained between 110 and 1200C during the addition and then allowed to rise slightly to 120 to 1300C for a further 6 hours. The prepolymer product had a free NCO content of 4.5%.
(b) A sample of the prepolymer so prepared (65.49), T32/75 (1209) and, as catalyst dibutyltindilaurate (2.89, 1.59/0 by weight) were heated for 24 hours at 400C to yield a polyurethane rubber having an impedance of 1.50 M Rayl, an attenuation of 2 MHz radiation of 2.6 dB/cm and a hardness of 32 IRHD.
(c) The procedure of Example 6(b) was repeated with the exception of the addition of 0.06% by weight of nubian black B.T. and the resultant black polyurethane rubber had an impedance of 1.50 M
Rayl, an attenuation of 2 MHz radiation of 2.4 dB/cm and a hardness of 32 IRHD.
EXAMPLE 7
A polyoxypropylene glycol of molecular weight 3700 and hydroxyl number 30
(molecular weight = 123) hydroxyl number commercially available from ICI Limited, under the code number F 3001, (50g) toluene diisocyanate (2.6g) and, as catalyst, stannous octoate (0.05g) were mixed, degassed and heated to 1000C for 40 hours. The resultant polurethane rubber which was very soft and tacky had an impedence of 1.57 M
Rayl had an attenuation of 2MHz radiation of 2.5 dB/cm.
EXAMPLE 8
A polyether polyol (50g) having a molecular weight of 6000 and a hydroxyl number 28
(molecular weight
=214)
hydroxyl number commercially available from ICI Limited under the code name R102 was reacted with isophorone diisocyanate (3.19) at 1000C for 16 hours using as catalyst dibutyltindilaurate (0.8g) to yield a polyurethane rubber having an impedance of 1.48 M Rayl, an attenuation of 2 MHz radiation of 2.S dB/cm, and a hardness of 32 IRHD.
EXAMPLE 9
A polyoxyproplene glycol of molecular weight 4000 and hydroxyl number 41.7
(molecular weight =96) hydroxyl number commercially available from Dow Chemicals Limited under the code number CP4000 (5009) was added over one hour to isophorone diisocyanate (11 5g) with stirring under nitrogen and the resultant mixture heated to 1 2O0C for 1 5 minutes whilst continuing to stir. A portion (1009) of the prepolymer produced by this procedure was heated to 1000C with CP4000 (1 60g) and, as catalyst, stannous octoate (O.lg) for 16 hours to yield a polyurethane rubber impedance 1.57 M Rayl and attenuation of 2MHz radiation of 3.9 dB/cm.
The rubbers produced by the procedures of Examples 1, 2, 4b, 5b, 5e and 6 are particularly suitable for casting into a stand-off unit of the form illustrated in Figure 1. The walls of the rectangular opening, 3, may be strengthened for example by the following procedure. A unit as illustrated in Figure 1 was inverted and portion 2 dipped in toluene to remove any traces of grease. It was then dipped in a solution prepared as described below and slowly removed therefrom at a rate of 5 inches per minute.
This deposited a coating on the portion 2 which was first air dried for 30 minutes and then further dried in an oven at 1000C for an hour. The resulting coating, of approximately 10-3 inches thickness was found to add significantly to the mechanical strength of portion 2 without making any reduction in the properties of transmission of ultrasonic radiation. The coating solution was prepared as follows:
A polyester of molecular weight 1200 and hydroxyl number 90 was reacted with an excess of isophorone diisocyanate to give a prepolymer. A mixture of this prepolymer (500g) with trimethylol propane (27g) at 800C was dissolved in methylethyl ketone (1500ml) and toluene (50ml), stannous octoate catalyst (59) stirred in and the resultant solution allowed to cool to room temperature.
Claims (15)
1.45 to 1.6 M Rayles.
2. A unit according to Claim 1 having a hardness of from 15 to 50 IRHD.
3. A unit according to Claim 1 or Claim 2 which is substantially inert to silicone and paraffin
lubricant.
4. A unit according to any one of Claims 1 to 3 which is optically substantially transparent.
5. A unit according to any one of Claim 1 to 4 having an attenuation of ultrasonic radiation of frequency 2 MHz of from 2.0 to 3.0 dB/cm.
6. A unit according to Claim 1 wherein said polyurethane rubber is formed by the reaction of a polyether polyol and a diisocyanate said polyether polyol having a chemical structure such that the
ratio of molecular weight to hydroxyl number is at least 90.
7. A unit according to Claim 6 wherein said polyether polyol is a polyoxypropylene glycol of molecular weight between 3500 and 6000.
8. A unit according to Claim 6 or Claim 7 wherein substantially stoichmetric amounts of said polyether polyol and said isocyanate are used.
9. A unit according to Claim 8 wherein an initial reaction of said polyether polyol with excess of
said isocyanate to form a prepolymer is followed by reaction of said prepolymer with a further quantity
of said polyether polyol.
10. A unit according to Claim 9 wherein said prepolymer contains from 3.5% to 5.0% by weight of
unreacted isocyanate groups.
11. A unit according to any one of Claims 6 to 1 0 wherein a catalyst such as 1 P-diazobicyclo (2,2,2) octane is used.
1 2. A unit according to Claim 9 or Claim 10 wherein dibutyltindilaurate is used as catalyst in an
amount of from 1.2% to 2.1 % by weight.
13. A unit according to Claim 6 wherein said polyurethane rubber is formed by a method
substantially as hereinbefore described in any one of Examples 1 to 9.
14. A unit according to any one of the preceding Claims as hereinbefore described with reference
to and as illustrated in the accompanying drawing.
15. An ultrasonic diagnostic apparatus comprising a source of ultrasonic radiation and a stand-off
unit according to any one of the preceding Claims.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7936837A GB2036504B (en) | 1978-11-23 | 1979-10-24 | Ultrasonic standoff unit |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7845859 | 1978-11-23 | ||
| GB7936837A GB2036504B (en) | 1978-11-23 | 1979-10-24 | Ultrasonic standoff unit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2036504A true GB2036504A (en) | 1980-06-25 |
| GB2036504B GB2036504B (en) | 1982-12-01 |
Family
ID=26269712
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7936837A Expired GB2036504B (en) | 1978-11-23 | 1979-10-24 | Ultrasonic standoff unit |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2036504B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2552611A1 (en) * | 1983-09-28 | 1985-03-29 | Minnesota Mining & Mfg | Device suitable for the transmission and reception of waves in echography and method using this device |
| DE3733439A1 (en) * | 1986-10-03 | 1988-04-14 | Toshiba Kawasaki Kk | HEADER FOR DIAGNOSTIC ULTRASONIC PROBE |
| WO1990001902A1 (en) * | 1988-08-30 | 1990-03-08 | Fujitsu Limited | Acoustic coupler |
| EP0344773A3 (en) * | 1988-06-02 | 1990-07-25 | Takiron Co., Ltd. | Liquid segment polyurethane gel and couplers for ultrasonic diagnostic probe comprising the same |
| JPH02504356A (en) * | 1988-08-30 | 1990-12-13 | 富士通株式会社 | ultrasonic coupler |
| EP1195167A3 (en) * | 2000-10-09 | 2003-09-10 | Richard Wolf GmbH | Use of a gel |
| EP1587413A4 (en) * | 2003-01-15 | 2006-04-26 | Salutron Inc | Ultrasonic monitor for measuring heart and pulse rates |
-
1979
- 1979-10-24 GB GB7936837A patent/GB2036504B/en not_active Expired
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2552611A1 (en) * | 1983-09-28 | 1985-03-29 | Minnesota Mining & Mfg | Device suitable for the transmission and reception of waves in echography and method using this device |
| DE3733439A1 (en) * | 1986-10-03 | 1988-04-14 | Toshiba Kawasaki Kk | HEADER FOR DIAGNOSTIC ULTRASONIC PROBE |
| EP0344773A3 (en) * | 1988-06-02 | 1990-07-25 | Takiron Co., Ltd. | Liquid segment polyurethane gel and couplers for ultrasonic diagnostic probe comprising the same |
| US5039774A (en) * | 1988-06-02 | 1991-08-13 | Takiron Co., Ltd. | Liquid segment polyurethane gel and couplers for ultrasonic diagnostic probe comprising the same |
| WO1990001902A1 (en) * | 1988-08-30 | 1990-03-08 | Fujitsu Limited | Acoustic coupler |
| JPH02504356A (en) * | 1988-08-30 | 1990-12-13 | 富士通株式会社 | ultrasonic coupler |
| US5265614A (en) * | 1988-08-30 | 1993-11-30 | Fujitsu Limited | Acoustic coupler |
| EP1195167A3 (en) * | 2000-10-09 | 2003-09-10 | Richard Wolf GmbH | Use of a gel |
| EP1587413A4 (en) * | 2003-01-15 | 2006-04-26 | Salutron Inc | Ultrasonic monitor for measuring heart and pulse rates |
| US7547282B2 (en) | 2003-01-15 | 2009-06-16 | Salutron, Inc. | Ultrasonic monitor for measuring heart and pulse rates |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2036504B (en) | 1982-12-01 |
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