EP0059603A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for controlling the density of dispensed adhesive foam
Assignee: Nordson Corp
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Filing: 1982-02-24
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Granted: —
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Expires: 2002-02-24
Abstract
Abstract A method and apparatus for controlling the density of dispensed hot melt thermoplastic adhesive foam in order to assure uniform foam characteristics. In order to create the hot melt adhesive foam, air or any relatively inert gas is mixed with the thermoplastic adhesive while the adhesive is in the molten state, and the mixture is then pressurised so as to force the gas into solution with the molten adhesive. As the molten adhesive/gas solution is dispensed at atmospheric pressure, the gas is released from solution and becomes entrapped in the adhesive so as to form a homogenous closed cellular adhesive foam. According to the invention, the supply of gas is periodically discontinued so as to prevent an excess volume of gas from being admixed with the molten adhesive whenever foamed adhesive is not being dispensed, thereby stabilising the density of the adhesive foam.
Inventors
- 👤 Jan J. Wydro
- 👤 Charles H. Scholl
- 👤 William R. Coker
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 12:59
CPC Classifications
B; B29; B29B; B29B7/00; B29B7/30; B29B7/58; B29B7/72; B29B7/726
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
118 words
Apparatus for controlling the uniformity of dispensed foamed adhesive comprising means for supplying gas; means for agitating and pressurising the adhesive in the presence of the gas so as to force the gas into solution with the adhesive; means for dispensing the adhesive and gas solution at a pressure below the solution maintenance pressure of the solution whereby the gas is released from solution and forms an adhesive foam, characterised in that means are provided for selectively controlling the gas supply so that the gas is supplied in response to dispensing of the adhesive and gas solution and/or so that only sufficient gas is supplied to maintain the density of the adhesive foam at a substantially constant value.
Claim 2
Dependent Claim
118 words
Apparatus for controlling the uniformity of dispensed foamed adhesive comprising means for supplying gas; means for agitating and pressurising the adhesive in the presence of the gas so as to force the gas into solution with the adhesive; means for dispensing the adhesive and gas solution at a pressure below the solution maintenance pressure of the solution whereby the gas is released from solution and forms an adhesive foam, characterised in that means are provided for selectively controlling the gas supply so that the gas is supplied in response to dispensing of the adhesive and gas solution and/or so that only sufficient gas is supplied to maintain the density of the adhesive foam at a substantially constant value.
Claim 3
Dependent Claim
29 words
Apparatus as claimed in Claim 1 for hot melt thermoplastic adhesive including means for heating solid thermoplastic adhesive material to convert the solid adhesive material to a molten state.
Claim 4
Dependent Claim
94 words
Apparatus as claimed in Claim 1 or 2 wherein the dispensing means comprises a dispensing gun having a selectively actuable trigger mechanism for controlling flow from the gun wherein said control means includes a solenoid-operated valve for selectively feeding gas from the gas supplying means to the agitating and pressurising means, sensing means activated in response to actuation of the dispensing gun, and a control circuit responsive to activation of the sensing means for energising the solenoid-operated valve so that the gas flows from the gas supplying means to the agitating and pressurising means.
Claim 5
Dependent Claim
100 words
Apparatus as claimed in Claim 1 or wherein the dispensing means comprises an automatic dispensing device having a selectively openable valve for controlling flow from the device and means for automatically actuating the device and wherein the controlling means includes a solenoid-operated valve for selectively feeding gas from the gas supplying means to the agitating and pressurising means, sensing means activated in response to actuation of the device, and a control circuit responsive to activation of the sensing means for energising the solenoid-operated valve so that the gas flows from the gas supplying means to the agitating and pressurising means.
Claim 6
Dependent Claim
52 words
Apparatus as claimed in Claim 3 or 4 wherein the control circuit includes timer circuitry for periodically energising the solenoid-operated valve so that pulses of the gas flow from the gas supplying means to the agitating and pressurising means whereby the density of the adhesive and gas solution is more closely stabilised.
Claim 7
Dependent Claim
9 words
Apparatus as claimed in any of Claims 3 to
Claim 8
Dependent Claim
42 words
5 wherein the control circuit includes timer circuitry responsive to start up of the apparatus for energising the solenoid-operated valve so that the gas flows from the gas supplying means to the agitating and pressurising means for a predetermined period of time.
Claim 9
Dependent Claim
42 words
5 wherein the control circuit includes timer circuitry responsive to start up of the apparatus for energising the solenoid-operated valve so that the gas flows from the gas supplying means to the agitating and pressurising means for a predetermined period of time.
Claim 10
Independent Claim
131 words
A method for controlling the uniformity of dispensed hot melt thermoplastic foamed adhesive including the steps of heating solid thermoplastic adhesive material for converting the solid adhesive material to a molten state; providing a supply. of gas; agitating the -molten adhesive in the presence of the gas so as to obtain a mixture of the gas with the molten adhesive; pressurising the mixture of molten adhesive and gas for forcing the gas into solution with the molten adhesive; dispensing the molten adhesive and gas solution at a pressure below the solution maintenance pressure of the solution whereby the gas is released from solution and forms an adhesive foam; and selectively controlling the supply of gas so that the gas is supplied in response to dispensing the molten adhesive and gas solution.
Claim 11
Independent Claim
131 words
A method for controlling the uniformity of dispensed hot melt thermoplastic foamed adhesive including the steps of heating solid thermoplastic adhesive material for converting the solid adhesive material to a molten state; providing a supply. of gas; agitating the -molten adhesive in the presence of the gas so as to obtain a mixture of the gas with the molten adhesive; pressurising the mixture of molten adhesive and gas for forcing the gas into solution with the molten adhesive; dispensing the molten adhesive and gas solution at a pressure below the solution maintenance pressure of the solution whereby the gas is released from solution and forms an adhesive foam; and selectively controlling the supply of gas so that the gas is supplied in response to dispensing the molten adhesive and gas solution.
Claim 12
Dependent Claim
33 words
A method as claimed in Claim 7 further including the step of periodically supplying pulses of the gas in order to more closely stabilise the density of the molten adhesive and gas solution.
Claim 13
Dependent Claim
34 words
A method as claimed in Claim 7 or 8 further including the step of initially supplying the gas for a predetermined period of time in order to produce the molten adhesive and gas solution.
Claim 14
Dependent Claim
132 words
Apparatus for controlling the uniformity of dispensed hot melt thermoplastic foamed adhesive comprising means for heating solid thermoplastic adhesive material for converting the solid adhesive material to a molten state; a source of gas; means for agitating and pressurising the molten adhesive in the presence of said gas so as to force the gas into solution with the molten adhesive; means for dispensing the molten adhesive and gas solution at a a pressure below the solution maintenance pressure of said solution whereby the gas is released from solution and forms an adhesive foam; and means for selectively supplying the gas to the agitating and pressurising means during interrupted operation of the dispensing means so that the density of the adhesive foam created by said apparatus is maintained at a substantially constant value.
Claim 15
Dependent Claim
132 words
Apparatus for controlling the uniformity of dispensed hot melt thermoplastic foamed adhesive comprising means for heating solid thermoplastic adhesive material for converting the solid adhesive material to a molten state; a source of gas; means for agitating and pressurising the molten adhesive in the presence of said gas so as to force the gas into solution with the molten adhesive; means for dispensing the molten adhesive and gas solution at a a pressure below the solution maintenance pressure of said solution whereby the gas is released from solution and forms an adhesive foam; and means for selectively supplying the gas to the agitating and pressurising means during interrupted operation of the dispensing means so that the density of the adhesive foam created by said apparatus is maintained at a substantially constant value.
Claim 16
Independent Claim
116 words
A method for controlling the uniformity of dispensed hot melt thermoplastic foamed adhesive including the steps of heating solid thermoplastic adhesive material for converting the solid adhesive -material to a molten state; providing a "source of gas; agitating and pressurising the molten adhesive in the presence of the gas so as to force the gas into solution with the molten adhesive; dispensing the molten adhesive and gas solution at a pressure below the solution maintenance pressure of the solution whereby the gas is released from solution and forms an adhesive foam; and selectively supplying the gas during interruptions in dispensing so that the density of the adhesive foam created is maintained at a substantially constant value.
Claim 17
Independent Claim
116 words
A method for controlling the uniformity of dispensed hot melt thermoplastic foamed adhesive including the steps of heating solid thermoplastic adhesive material for converting the solid adhesive -material to a molten state; providing a "source of gas; agitating and pressurising the molten adhesive in the presence of the gas so as to force the gas into solution with the molten adhesive; dispensing the molten adhesive and gas solution at a pressure below the solution maintenance pressure of the solution whereby the gas is released from solution and forms an adhesive foam; and selectively supplying the gas during interruptions in dispensing so that the density of the adhesive foam created is maintained at a substantially constant value.
Claim 18
Independent Claim
94 words
A method for controlling the uniformity of dispensed foamed adhesive including the steps of providing a supply of gas; agitating and pressurising adhesive in the presence of the gas so as to force the gas into solution with the adhesive; dispensing the adhesive and gas solution at a pressure below the solution maintenance pressure of the solution whereby the gas is released from solution and forms an adhesive foam; and selectively supplying the gas so that only sufficient gas is supplied to maintain the density of the adhesive foam at a substantially constant value.
Claim 19
Independent Claim
94 words
A method for controlling the uniformity of dispensed foamed adhesive including the steps of providing a supply of gas; agitating and pressurising adhesive in the presence of the gas so as to force the gas into solution with the adhesive; dispensing the adhesive and gas solution at a pressure below the solution maintenance pressure of the solution whereby the gas is released from solution and forms an adhesive foam; and selectively supplying the gas so that only sufficient gas is supplied to maintain the density of the adhesive foam at a substantially constant value.
References Cited (Backward Citations)
No citation records indexed.
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