US4156754A
Expired / Lapsed
US
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Method of making foamed thermoplastic adhesive materials and adhesive process therefor
Assignee: Nordson Corp
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Filing: 1977-04-27
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Granted: 1979-05-29
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Expires: 1997-04-27
Abstract
Abstract Foamed thermoplastic materials such as coatings, adhesives and structural bodies are made by a method which offers significant advantages and economies. The method involves the steps of stabilizing a dispersion of gas in a molten thermoplastic material by adding a surfactant to the molten material in a sufficient stabilizing amount and subsequently pressurizing the stabilized dispersion to form a hot solution. Thereafter, the hot solution is dispensed under lower pressure whereby the gas is released from solution to form a foamed material. The method is especially advantageous in making hot melt thermoplastic adhesives which are very useful in bonding substrates with efficiency and superior bond strengths. Continuous and reliable foaming operations are achieved with a uniform quality and output of foamed materials. Thermoplastic materials are also capable of being foamed with relatively simple mechanical apparatus and under conditions which provide considerable savings of energy. The number of thermoplastic materials which can be foamed employing the present technique in a controlled manner is unlimited. The method of stabilization is conducted at low or ambient pressures and resulting stabilized hot thermoplastic-gas dispersions may then be pumped with pressurization and dispensed with immediate foaming.
Inventors
- 👤 Walter H. Cobbs, Jr.
- 👤 Robert G. Shong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:29
CPC Classifications
C; C09; C09J; C09J5/00; C09J5/08; C08; C08J; C08J9/00; C08J9/04; C08J9/12; Y; Y10; Y10S; Y10S261/00; Y10S261/26; Y10S521/00; Y10S521/908; Y10S521/911; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249955; Y10T428/249981; Y10T428/249982; Y10T428/249984
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
103 words
The method of bonding with a foamed thermoplastic adhesive material which comprises first stabilizing a dispersion of gas bubbles in a molten thermoplastic material at about atmospheric pressure by incorporating a surfactant in the molten material in a sufficient stabilizing amount, subsequently pressurizing said stabilized dispersion to form a hot solution of the gas in the molten thermoplastic material, dispensing said hot solution under lower pressure whereby said gas is released from said solution to form a hot foamed material, and compressing the hot foam between two substrates to force the gas from the foam and to form a bond between the substrates.
Claim 2
Independent Claim
103 words
The method of bonding with a foamed thermoplastic adhesive material which comprises first stabilizing a dispersion of gas bubbles in a molten thermoplastic material at about atmospheric pressure by incorporating a surfactant in the molten material in a sufficient stabilizing amount, subsequently pressurizing said stabilized dispersion to form a hot solution of the gas in the molten thermoplastic material, dispensing said hot solution under lower pressure whereby said gas is released from said solution to form a hot foamed material, and compressing the hot foam between two substrates to force the gas from the foam and to form a bond between the substrates.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein said pressurization is subsequently conducted at a pressure on the order of about 300 to about 1800 psig.
Claim 4
Dependent Claim
19 words
The method of claim 2 wherein said pressurization is conducted by means of a fluid pressure energy translating device.
Claim 5
Dependent Claim
11 words
The method of claim 3 wherein said device is a pump.
Claim 6
Dependent Claim
24 words
The method according to claim 1 comprising the further step of cooling the compressed adhesive to form upon solidification a bond between said substrates.
Claim 7
Dependent Claim
26 words
The method according to claim 5 wherein at least one said substrate is porous and said foam upon compression penetrates said substrate to form said bond.
Claim 8
Dependent Claim
29 words
The method according to claim 1 wherein said thermoplastic adhesive material contains a polymer selected from the group consisting of polyethylene, polypropylene, polyester, polyesteramide, polyurethane, polyamide and polyethylene vinylacetate.
Claim 9
Dependent Claim
27 words
The method of claim 1 wherein said dispersion comprises air dispersed in said thermoplastic adhesive and the step of pressurization is conducted by means of a pump.
Claim 10
Dependent Claim
59 words
The method of claim 1 wherein said stabilization is conducted by controlling the surface tension of said molten material within the range of about 10-40 dynes/cm., the viscosity being controlled within the range of about 500-1,000,000 cps and wherein the gas solubility at said dispensing pressure is within the range of about 1/2-20 cm 3 gas/gm of thermoplastic material.
Claim 11
Dependent Claim
43 words
The method of claim 1 wherein said surfactant is a mixture of a soluble surfactant contained in an amount of about 0.1 to about 5% by weight and a solid surfactant contained in an amount of about 0.01 to about 1% by weight.
Claim 12
Dependent Claim
9 words
The product produced by the method of claim 1.
Claim 13
Dependent Claim
9 words
The product produced by the method of claim 5.
Claim 14
Dependent Claim
9 words
The product produced by the method of claim 6.
Claim 15
Dependent Claim
9 words
The product produced by the method of claim 7.
Claim 16
Independent Claim
77 words
A method of making foamed thermoplastic material which comprises first stabilizing a dispersion of gas bubbles in a molten thermoplastic material at substantially atmospheric pressure by incorporating a surfactant in the molten material in a sufficient stabilizing amount, subsequently pressurizing said stabilized dispersion to form a hot solution of the gas in the molten thermoplastic material, and dispensing said hot solution under lower pressure whereby said gas is released from said solution to form a foamed material.
Claim 17
Independent Claim
77 words
A method of making foamed thermoplastic material which comprises first stabilizing a dispersion of gas bubbles in a molten thermoplastic material at substantially atmospheric pressure by incorporating a surfactant in the molten material in a sufficient stabilizing amount, subsequently pressurizing said stabilized dispersion to form a hot solution of the gas in the molten thermoplastic material, and dispensing said hot solution under lower pressure whereby said gas is released from said solution to form a foamed material.
Claim 18
Dependent Claim
10 words
The method of claim 1 wherein said gas is air.
Claim 19
Dependent Claim
23 words
The method of claim 1 wherein said pressurizing step is conducted at pressures on an order of about 100 to about 2,000 psig.
Claim 20
Dependent Claim
16 words
The method of claim 1 wherein said pressurizing step is conducted by means of a pump.
Claim 21
Dependent Claim
32 words
The method of claim 1 wherein air is dispersed in the molten thermoplastic material and stabilized under substantially atmospheric pressure followed by said pressurization by means of a fluid pressure translating device.
Claim 22
Dependent Claim
11 words
The method of claim 19 wherein said device is a pump.
Claim 23
Dependent Claim
21 words
The method of claim 1 wherein said surfactant is contained in an amount of about 0.1% to about 5% by weight.
Claim 24
Dependent Claim
13 words
The method of claim 1 wherein said surfactant is a solid phase surfactant.
Claim 25
Dependent Claim
16 words
The method of claim 22 wherein said solid phase surfactant is a finely divided inert material.
Claim 26
Independent Claim
89 words
A method of making foamed thermoplastic material which comprises first stabilizing a dispersion of gas bubbles in a molten thermoplastic material by incorporating a surfactant in the molten material in a sufficient stabilizing amount, wherein said surfactant is a mixture of a soluble surfactant and a finely divided solid surfactant, subsequently pressurizing said stabilized dispersion to form a hot solution of the gas in the molten thermoplastic material, and dispensing said hot solution under lower pressure whereby said gas is released from said solution to form a foamed material.
Claim 27
Independent Claim
89 words
A method of making foamed thermoplastic material which comprises first stabilizing a dispersion of gas bubbles in a molten thermoplastic material by incorporating a surfactant in the molten material in a sufficient stabilizing amount, wherein said surfactant is a mixture of a soluble surfactant and a finely divided solid surfactant, subsequently pressurizing said stabilized dispersion to form a hot solution of the gas in the molten thermoplastic material, and dispensing said hot solution under lower pressure whereby said gas is released from said solution to form a foamed material.
Claim 28
Dependent Claim
25 words
The method of claim 11 wherein said soluble and solid surfactants are present in a ratio to provide a synergistic stabilizing effectiveness to said dispersion.
Claim 29
Dependent Claim
39 words
The method of claim 24 wherein said soluble surfactant is contained in an amount of about 0.1 to about 5% by weight and said solid surfactant is contained in an amount of about 0.01 to about 1% by weight.
Claim 30
Dependent Claim
23 words
The method of claim 1 wherein said surfactant is selected from the group consisting of anionic, cationic and non-ionic surfactants, and mixtures thereof.
Claim 31
Dependent Claim
38 words
The method of claim 1 wherein said thermoplastic material comprises a polymer selected from the group consisting of polymers of ethylenically unsaturated monomers, polymers of conjugated diene monomers, polyesters, polyamides, polyesteramides and polyurethanes, and copolymers of said monomers.
Claim 32
Dependent Claim
59 words
The method of claim 1 wherein said stabilization is conducted by controlling the surface tension of said molten material within the range of about 10-40 dynes/cm., the viscosity being controlled within the range of about 500-1,000,000 cps and wherein the gas solubility at said dispensing pressure is within the range of about 1/2-20 cm 3 gas/gm of thermoplastic material.
Claim 33
Dependent Claim
33 words
The method of claim 1 which comprises the additional step of compressing the foamed material between two substrates to force the gas from the foam and to form a bond between the substrates.
Claim 34
Dependent Claim
23 words
The method of claim 30 comprising the further step of cooling the compressed material to form upon solidification a bond between the substrates.
Claim 35
Dependent Claim
9 words
The product produced by the method of claim 1.
Claim 36
Dependent Claim
9 words
The product produced by the method of claim 24.
Claim 37
Dependent Claim
9 words
The product produced by the method of claim 25.
Claim 38
Dependent Claim
9 words
The product produced by the method of claim 27.
Claim 39
Dependent Claim
9 words
The product produced by the method of claim 28.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-05-28 | 1982-11-27 | 1983-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-28 | 1986-11-27 | 1987-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-28 | 1990-11-27 | 1991-05-29 | $7700.00 | Window Closed / Lapsed |