US20100003497A1 - Process and plant for continuous manufacture of latex foam articles - Google Patents
Process and plant for continuous manufacture of latex foam articles Download PDFInfo
- Publication number
- US20100003497A1 US20100003497A1 US12/555,761 US55576109A US2010003497A1 US 20100003497 A1 US20100003497 A1 US 20100003497A1 US 55576109 A US55576109 A US 55576109A US 2010003497 A1 US2010003497 A1 US 2010003497A1
- Authority
- US
- United States
- Prior art keywords
- latex foam
- band
- foam
- block
- plant
- 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.)
- Abandoned
Links
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- 238000000034 method Methods 0.000 title abstract description 27
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 210000003850 cellular structure Anatomy 0.000 description 4
- 230000006835 compression Effects 0.000 description 4
- 238000007906 compression Methods 0.000 description 4
- 238000010924 continuous production Methods 0.000 description 4
- 238000000151 deposition Methods 0.000 description 4
- 229920001971 elastomer Polymers 0.000 description 4
- 230000004888 barrier function Effects 0.000 description 3
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- 230000015271 coagulation Effects 0.000 description 3
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- 239000012071 phase Substances 0.000 description 3
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- 239000005060 rubber Substances 0.000 description 3
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- 239000004952 Polyamide Substances 0.000 description 2
- 229920005830 Polyurethane Foam Polymers 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- 239000003963 antioxidant agent Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
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- 238000006243 chemical reaction Methods 0.000 description 2
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- 238000009472 formulation Methods 0.000 description 2
- 229920002521 macromolecule Polymers 0.000 description 2
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- 239000011496 polyurethane foam Substances 0.000 description 2
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 2
- 210000002966 serum Anatomy 0.000 description 2
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- PCTMTFRHKVHKIS-BMFZQQSSSA-N (1s,3r,4e,6e,8e,10e,12e,14e,16e,18s,19r,20r,21s,25r,27r,30r,31r,33s,35r,37s,38r)-3-[(2r,3s,4s,5s,6r)-4-amino-3,5-dihydroxy-6-methyloxan-2-yl]oxy-19,25,27,30,31,33,35,37-octahydroxy-18,20,21-trimethyl-23-oxo-22,39-dioxabicyclo[33.3.1]nonatriaconta-4,6,8,10 Chemical compound C1C=C2C[C@@H](OS(O)(=O)=O)CC[C@]2(C)[C@@H]2[C@@H]1[C@@H]1CC[C@H]([C@H](C)CCCC(C)C)[C@@]1(C)CC2.O[C@H]1[C@@H](N)[C@H](O)[C@@H](C)O[C@H]1O[C@H]1/C=C/C=C/C=C/C=C/C=C/C=C/C=C/[C@H](C)[C@@H](O)[C@@H](C)[C@H](C)OC(=O)C[C@H](O)C[C@H](O)CC[C@@H](O)[C@H](O)C[C@H](O)C[C@](O)(C[C@H](O)[C@H]2C(O)=O)O[C@H]2C1 PCTMTFRHKVHKIS-BMFZQQSSSA-N 0.000 description 1
- 241000531908 Aramides Species 0.000 description 1
- 244000043261 Hevea brasiliensis Species 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 229920003235 aromatic polyamide Polymers 0.000 description 1
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- 210000002421 cell wall Anatomy 0.000 description 1
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- 239000000806 elastomer Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000006261 foam material Substances 0.000 description 1
- 229920001903 high density polyethylene Polymers 0.000 description 1
- 239000004700 high-density polyethylene Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000012948 isocyanate Substances 0.000 description 1
- 150000002513 isocyanates Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229920003052 natural elastomer Polymers 0.000 description 1
- 229920001194 natural rubber Polymers 0.000 description 1
- 229920006173 natural rubber latex Polymers 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- -1 polypropylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 229920006174 synthetic rubber latex Polymers 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
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- 239000002562 thickening agent Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
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- 238000011282 treatment Methods 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
- B29C44/08—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles using several expanding or moulding steps
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/34—Auxiliary operations
- B29C44/58—Moulds
- B29C44/583—Moulds for making articles with cavities
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/0033—Moulds or cores; Details thereof or accessories therefor constructed for making articles provided with holes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/34—Moulds or cores; Details thereof or accessories therefor movable, e.g. to or from the moulding station
- B29C33/36—Moulds or cores; Details thereof or accessories therefor movable, e.g. to or from the moulding station continuously movable in one direction, e.g. in a closed circuit
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/42—Moulds or cores; Details thereof or accessories therefor characterised by the shape of the moulding surface, e.g. ribs or grooves
- B29C33/424—Moulding surfaces provided with means for marking or patterning
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C39/00—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor
- B29C39/14—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor for making articles of indefinite length
- B29C39/148—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor for making articles of indefinite length characterised by the shape of the surface
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/22—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of indefinite length
- B29C43/222—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of indefinite length characterised by the shape of the surface
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
- B29C44/12—Incorporating or moulding on preformed parts, e.g. inserts or reinforcements
- B29C44/1209—Incorporating or moulding on preformed parts, e.g. inserts or reinforcements by impregnating a preformed part, e.g. a porous lining
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C39/00—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor
- B29C39/14—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor for making articles of indefinite length
- B29C39/18—Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor for making articles of indefinite length incorporating preformed parts or layers, e.g. casting around inserts or for coating articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/22—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of indefinite length
- B29C43/28—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of indefinite length incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2021/00—Use of unspecified rubbers as moulding material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/737—Articles provided with holes, e.g. grids, sieves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/751—Mattresses, cushions
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
- Y10T442/10—Scrim [e.g., open net or mesh, gauze, loose or open weave or knit, etc.]
- Y10T442/102—Woven scrim
- Y10T442/15—Including a foam layer
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
- Y10T442/30—Woven fabric [i.e., woven strand or strip material]
- Y10T442/3325—Including a foamed layer or component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
- Y10T442/40—Knit fabric [i.e., knit strand or strip material]
- Y10T442/469—Including a foamed layer or component
Definitions
- the present invention refers to a process and plant for the continuous manufacture of latex foam rest articles such as mattresses cushions and the like, and more in particular the invention refers to a process and plant comprising a part useful both for said article manufacture steps control and to improve the features in the article wherein it remains embedded.
- Latex foam articles are known manufactured using a single mould within which a latex foam mixture is subjected to various process steps.
- a single mould generally comprises a hollow lower part and an upper part forming the cover, one or the other or even both provided with recesses formation protuberances.
- Latex is an elastomer polymer dispersion in an aqueous serum.
- components means all those substances, materials, ingredients and/or fillers whose presence is thought being useful to carry out optimally latex foam article manufacture steps with determined and desired characteristics.
- components include surfactants, thickening agents, gelation agents, stabilizers, process accelerators, vulcanisation agents, fillers, and antioxidants.
- the process employs a tank within which various components are added to a synthetic or natural rubber mixture.
- the raw components prior to their addition to latex are transformed into an aqueous dispersion by grinders as to reduce particles sizes.
- surfactants determine the presence around each single latex particle of a protective barrier opposing their approach; such barrier being formed by electric charges all of the same sign for all latex particles such that they repel each other avoiding a premature and undesired particle coagulation.
- Gelation agents have the task of breaking the abovementioned barrier such that various latex particles, non longer subjected to repulsion forces may come near or away from one another being subjected to vibrations.
- a determined solution of a gelation agent destined to carry out the gelating step is added to the latex foam.
- latex foam rest articles comprise characteristics and process steps different from other foam articles, for instance polyurethane foam.
- latex article foaming is achieved inputting an external agent such as pressurized air in the mixture
- polyurethane mixture foaming is achieved by direct contact among polyoil and isocyanate, that is the same base materials making a polyurethane.
- polyurethane foam articles have a structure mainly provided with tiny open and uniformly distributed cells for all material thickness
- polyurethane foam articles have mainly closed cells except specific polyurethanes wherein cells are blown up after specific treatments.
- a latex foam article manufacture envisages filling up the mould with mixture comprising latex and components already subjected to foaming.
- the latex mixture is dimensionally unstable such that a risk exists of a cell walls collapse.
- Gelating may be defined as a homogeneous coagulation wherein part of the foam aqueous serum remains embedded in the rubber polymer. Chemically gelating is the transition from the “sol” phase to the “gel” phase. Gelating step avoids latex foam collapse after the laying.
- the following vulcanisation step is carried out through a vulcanisation agent to determine the final article desired elasticity degree that is the elastic deformation, density and uniformity article characteristics that will assure comfort conditions for the user in a rest state.
- the mould is heated preferably with steam.
- the mould upper part is rotated or it is lifted with respect to the hollow lower part to allow for article extraction.
- latex foam mixture is an aqueous dispersion wherein a considerable amount of water embeds latex particles. For instance if the total amount of the latex foam mixture is 100 part in weight, the dry amount is 60 parts in weight and the water amount is 40 parts in weight.
- the water amount is diminishing due to phenomena relative to heat absorption by the latex foam.
- the vulcanisation agent under the temperature influence creates bridges between various latex macro-molecules forming said particles.
- the amount of water is removed by evaporation providing heat to the latex foam by hot air circulation.
- a latex foam article manufacture is very complex because firstly it comprises a stable dispersion formation of rubber particles in an aqueous medium obtained controlling the chemical-physical properties of the interface between the aqueous phase and the latex particles, then the foam formation obtained supplying the gas necessary to realize the new dispersed phase and the surface energy necessary to form a gas-liquid interface, then the foamed latex gelation achieved destabilizing the rubber particles-water interface, with eventual bonding of latex particles and formation of a reticular structure that stiffens the latex foam.
- a process for continuous manufacture of an unlimited length latex foam block to be divided in a plurality of articles by cuts transversely to said unlimited length comprising the steps of advancing along a predetermined longitudinal direction a laying surface provided with protuberances between a first and a second station, of laying in said first station a latex foam mixture on said deposit surface in continuous advancement, of gelating, of vulcanising, of drying characterized by the steps of:
- said band is from polymeric material.
- substantially flat and flexible band provided with a plurality of through openings is meant to indicate both a structure formed from a net comprising a plurality of longitudinal members cross oriented to each other to form meshes whose area corresponds to said openings either a flexible laminar structure provided with regular or irregular shape holes corresponding to said openings or anyway a flexible structure tape shaped or the like with openings through which a latex foam passes.
- polymeric material is meant to indicate a material generally adapted to said band construction, of natural or synthetic type, comprising longitudinal members, such as mono-filaments or braids or fibres for instance of aramide or in general plastic fibres distributed in an orderly way or in a loose way without preferential orientation for forming nevertheless among them said openings, and/or plates, and/or flexible straps in plastic material having openings distributed in orderly or even unorderly fashion.
- substantially flat is meant to indicate a band that might acquire a configuration little different from the flat one for instance slightly undulated.
- said band consists of a propylene or polythene or polypropylene or polyamide plastic polymer.
- the band is a net or a plate, in single shape or in overlaid layers.
- the process is characterized by laying over said band a latex foam of density comprised between 40 to 270 grams/litre when such laying surface rate is comprised between 0.3 to 1.5 meters/minute.
- the process is characterized by laying over said protuberances a band resistant to compression forces acting following at least a first and a second direction perpendicular to each other in a same plane and following a third direction perpendicular to said plane, said at least first and second direction corresponding to the longitudinal and the cross direction of said latex foam block in continuous advancement.
- the process is characterized by depositing a band wherein the reaction to said forces exerted on a foam block matches the dimensional reductions along said first and second direction up to 5% compression value.
- a foam block sample provided with said band with width comprised between 180 cm to 220 cm, length comprised between 60 cm to 220 cm, thickness comprised between 10 cm to 240 cm, has a lift value comprised between 3% to 15% more as compared a same sample without band.
- an unlimited length latex foam block continuous manufacture plant to be subdivided in a plurality of articles by cuts transversely to said unlimited length, said plant being formed by a structural part comprising a laying surface in continuous advancement along a predetermined direction between a first latex foam laying station and a second said block extraction station, a plurality of protuberances cantilevering from that laying surface to a plane parallel to said laying surface plane, a latex foam gelation device, a vulcanisation device before said second extraction station, a drying device, that plant being characterized by comprising an auxiliary part in continuous advancement able to take part to the operation step and to remain embedded in said article by a determined length after said block cutting, said auxiliary part comprising an unlimited length flat band and provided with a plurality of through openings, said band being placed continuously on said protuberances and associated to said protuberances by the latex foam passing through said openings.
- the invention is relative to a latex foam block comprising a plurality of lower recesses extending up to a predetermined height “s 1 ”, characterized by chemically incorporating along the plane boarding the recesses ends a polymeric material flexible band provided with through openings.
- said band in a plastic material net provided with a plurality of meshes forming said openings.
- the foam block comprises a plurality of openings ordered according two directions perpendicular to each other in a same plane, said openings having in a direction a pitch comprised between 1 cm to 4 cm, and in the other direction a pitch equal to that of the first direction or even different.
- FIG. 1 is a longitudinal partial schematic view of the plant according to the invention.
- FIG. 2 is a longitudinal partial schematic view of the final part of FIG. 1 plant
- FIG. 3 is a longitudinal partial schematic view of the plant of FIG. 1 during a foam block production
- FIG. 4 is a plan view of an auxiliary part of FIG. 1 plant
- FIG. 5 is a schematic plan view of some forces acting on the auxiliary part of the plant shown in FIG. 4 ;
- FIG. 6 is a plan view of a second embodiment of FIG. 1 plant auxiliary part
- FIG. 7 is a perspective partial view of the latex foam block shown by FIG. 1 plant 1 ;
- FIG. 8 is a plan view of a third embodiment of FIG. 1 plant auxiliary part
- FIG. 9 is a longitudinal view of a further embodiment of the latex foam continuous block manufacture plant.
- FIG. 10 shows a detail of FIG. 9 plant
- FIG. 11 shows a further detail of FIG. 9 plant
- FIG. 12 is a longitudinal section of a mattress manufactured by FIG. 9 plant.
- FIGS. 1-3 1 is a plant for the continuous manufacture of an unlimited length latex foam 2 to be subdivided in a plurality of rest articles such as for instance mattresses.
- Plant 1 comprises structural parts and auxiliary parts.
- plant structural parts means, as already known in traditional techniques, means, accessories and devices necessary for block manufacture and the expression “plant auxiliary parts” indicates, according to the present invention, means capable to influence advantageously both the block manufacture steps and the final articles performances.
- Such plant 1 structural parts comprise a latex foam laying surface 3 in continuous advancement along a predetermined longitudinal direction “F” between first foam laying station 4 and an extraction station 5 .
- a counter-rotating rollers pair 6 in extraction station 5 carries block 2 towards drying device and further possible plant devices and finally to a cutting station for the formation of an plurality of articles.
- Laying surface 3 comprises a plurality of protuberances 7 cantilevering from the base to form, as it is known, a plurality of lower recesses in the foam block.
- the protuberances ends lie along an imaginary plane at a determined height “s 1 ” with respect to laying surface 3 .
- Plant 1 structural parts comprise gelation means 8 followed by vulcanisation means 9 .
- Both such means 8 , 9 are placed between first and second station 4 , 5 .
- Gelation means in their most general embodiment must be able to stabilize the latex foam and to this purpose they use heat sources able to provide temperatures from 18° to 55° degrees centigrade, and more preferably from 27° to 49° C., in the environment crossed by the latex foam block.
- Near first station 4 is placed a laying device 10 of a latex foam base mixture destined to form a block 2 base layer and at a short distance from first station is placed a foam levelling doctor blade 11 .
- Said laying device 10 is moved in a cross direction to surface 3 advancement direction and coming near or away from such surface 3 in arrows “f” direction by adequate slide guide and drive means not illustrated because of any known type.
- Further laying device 10 is connected to a latex mixer.
- Said mixer comprises multiple tanks and various equipment, among which the control, supply, send and connection ones.
- gelation means 8 and vulcanisation means 9 comprise a single tunnel type device partitioned in a first and a second chamber 15 , 16 .
- the tunnel is heated with 100° C. steam.
- the plant final part comprises a drying device 14 and a cutting station 17 wherein a blade or similar means separate the continuously moved block portion from the block portion destined to form the single mattress ( FIG. 2 ).
- Said auxiliary parts consist in a flexible plastic band flat shaped provided with a plurality of through openings.
- Said band is an active part in the manufacture process in conjunction with laying surface 3 protuberances 7 .
- said band is formed from a plastic net 18 comprising ( FIG. 4 ) a plurality of longitudinal members 19 cross oriented one to another to form a plurality of meshes bounding through openings 20 .
- plastic material net 18 such as high density polyethylene or propylene or polyamide or other equivalent materials, is obtained for example in some instances by extrusion and in others by heat-seal.
- Said various longitudinal members 19 may be thermoplastic mono-filaments, placed according rows preferably but not necessarily perpendicular to each other in the same plane.
- Such longitudinal members have a diameter comprised from 1 to 7 mm and are restrained solidly between themselves in their reciprocal meeting points wherein they form nodes 21 .
- Net 18 presents meshes preferably square shaped, nevertheless according to what will be explained later such meshes might take up a different geometrical configuration.
- Net 18 comprises said plurality of square shaped meshes whose area is identified from one side by dimensions comprised from 10 to 40 mm.
- Plant 1 operation for an unlimited length foam block 2 manufacture initially comprises the step of sending net 18 towards laying surface 3 already in continuous advancement in F direction towards extraction station 5 .
- net 18 has been preset on already known appropriate accumulation and feeding means, for instance of the type comprising a plurality of return pulleys set in such a way as to guide the net according to an undulated path formed by multiple loops with a fly-wheel function.
- accumulation and feeding means are schematised with single collection coil 22 on which cylindrical surface is wound a plurality of net concentric loops.
- the various loops are unwound and guided, manually or through motorization, towards plant 1 .
- net 1 has bending characteristics to wind itself up according concentric loops on the cylindrical surfaces of one or more coils with diameters comprised from 5 cm to 100 cm.
- Net 18 head is connected to some laying surface 3 protuberances 7 top.
- Net 18 dragging by laying surface 3 advancement brings the net in first station 4 zone wherein laying device 10 is activated.
- first station 4 laying head 13 moved in a direction and in the oppose one across to the laying surface 3 advancement direction sends latex foam downward forcing it to pass through net openings 20 .
- net 18 is now already stably anchored to latex foam.
- Foam block 2 proceeds its path in longitudinal direction “F” and in passing under doctor blade 11 is leveled acquiring on the outside a substantially flat shape.
- the foam blocks manufactured with the process being described have a thickness s 1 in lower portion 23 comprised from 9 cm to 15 cm, and a thickness s 2 in upper portion 24 comprised between 9 to 15 cm.
- block 2 always associated to laying surface 3 reaches and passes through gelation 8 and vulcanisation 9 device receiving the heat necessary with respect to its dimensional stabilization and its chemical reticulation.
- Foam block 2 along the whole path from laying station 4 to vulcanisation device and thereafter to drying device 14 is subjected to contraction forces and thereafter to the weight force exerted by upper portion 24 towards lower portion 23 .
- Advantageously net 18 forms that plant 1 auxiliary part able to limit if not to completely cancel the cited forces effect.
- Net 18 is pressed towards the plurality of protuberances 7 .
- upper portion 24 weight unload itself on the various sections of longitudinal member lying on the ends of a protuberances pair 7 proximate to each other; each said portion behaves like a civil construction beam which uniformly loaded for all its length, unload the weight loaded on it to the extreme abutments realized with high mechanical strength.
- upper portion weight 24 unloads itself on the wide surface distribution of resisting members in the net reducing in this manner the compression effect on lower portion 23 , therefore stabilizing said lower portion density as desired.
- foam block 2 incorporating net 18 advances in predetermined longitudinal direction “F” remaining associated to laying surface 3 until when in the passage through 6 rollers pair is detached from said laying surface and pushed continuously towards drying device 14 and then towards cutting station 17 .
- foam block 2 advances underneath an appropriate cutting blade 26 for a section corresponding to a desired width dimension of a single mattress.
- blade 26 is lowered until it separates the single mattress for cross cutting ( FIG. 7 ) from foam block 2 always in continuous advancement.
- net 18 from the vulcaniser exit to cutting station 17 goes on carrying out its plant auxiliary part function and after cutting, net portion 18 incorporated in single mattress body contributes with its characteristics to improving the elastic strength of the foam whole cellular structure wherein it is embedded.
- Such laying surface 3 might take up various embodiments and among these is mentioned that described in patent EP 0,358,914 herein incorporated in case a detailed explanation of its operation might be necessary.
- laying surface 3 belongs to a motion transmission made up by a plurality of lower plates side by side to each other and cross-anchored to two chains (not shown) arranged in an annular configuration around two pulleys, one of which a drive one.
- Such plates preferably in aluminium, comprise protuberances 7 , preferably hollow, useful both for lower recesses moulding 7 ′ ( FIG. 7 ) in the base layer and to gelate and vulcanise in a diffused manner the latex foam mass.
- plant 1 description has been made referring to a flexible plastic band with a net shape, nevertheless said band might take up different configurations.
- FIG. 8 it has been indicated with the same reference numerals of previous figures a further perforated band, made up from plastic material and with a configuration corresponding to a flexible laminar structure 18 provided with through holes 20 .
- Said through holes might be of circular shape, non necessarily of equal diameter, or of square or rectangular shape, or realized according to other geometrical shapes such as for instance hexagonal, octagonal or egg-shaped as both with an equal geometry with each other and with a different geometry in one and the same laminar structure.
- the laminar shape of flexible band 18 allows to distribute over a wide continuous surface the weight force exerted from upper portion 24 towards lower portion 23 , accordingly the pressures exerted on said lower portion are reduced leaving substantially unvaried the density with respect to the programmed one at the start.
- the materials forming the flexible band must be such as to keep substantially unaltered their mechanical strength physical characteristics throughout all foam block 2 manufacture steps.
- the band must be able to withstand, without loosing its starting characteristics, at high temperatures both in the vulcanisation step carried out in the presence of 100° C. steam and in the dying step carried out with hot air temperature higher than 100° C.
- openings 20 size is selected at a start such as to allow a latex foam easy passage thorough band 18 .
- flexible bands 18 may have openings 20 distributed unevenly or even according to orderly rows.
- openings 20 distributed evenly in the following are defined some geometrical characteristics of said openings 20 that allow to obtain an even latex foam distribution when arranged in combination both with protuberances 7 , and with the foam density and the surface 3 advancement rate having previously cited values.
- said band openings 20 have a minimum dimension, in any direction, at least greater than 8 mm and extend themselves in a first longitudinal dimension with a pitch from 1 cm to 4 cm and in a second direction perpendicular to the first one with equal pitch values.
- Laying 3 surface protuberances 7 have a circular base with a diameter from 2 to 24 mm and a cross dimension of the upper end from 1 to 18 mm.
- Further laying 3 surface comprises a number of protuberances 7 from 6 to 84 protuberances/square decimetre.
- FIG. 9 a preferred embodiment of a plant 27 for a latex foam block 2 continuous manufacture comprising both upper recesses and lower recesses.
- Plant 27 similar to that described for plant 1 of FIG. 1 is made up by structural parts and by auxiliary parts.
- Said structural parts comprise a laying surface made up by a plurality of trucks 28 with protuberances 29 ( FIG. 10 ) moved along an annular circuit comprising two teethed pulleys one of which a drive one 30 , the other a tail one.
- the trucks are provided at the lower surface ends with pairs of rollers geared with the two pulleys grip means and are pushed by drive wheel 30 in contact to each other along the active upper branch wherein they receive the latex foam through deposition head 13 .
- the trucks displacement is guided in the upper branch through the sliding of wheels 31 along appropriate guides 32 of a fixed structure.
- Lower branch trucks may be in number lower as compared to the upper branch ones and in this solution they are moved through displacement means, such as conveyors 33 and the like, in an way independent from the drive pulley drives, at a rate higher than the upper branch one.
- Plant 27 upper part comprises a plurality of plates 35 ( FIGS. 9 , 11 ) each of which is provided with a plurality of protuberances 36 adapted to form upper recesses on the foam block.
- Said auxiliary parts the same as described in FIG. 1 comprise plastic net 18 with holes 20 illustrated in FIG. 2 .
- Net 18 is wound around a collection coil 37 to later pass around coil 22 and there from towards the trucks protuberances.
- Plant 27 lower part operation is substantially analogous to that of FIG. 1 , therefore in the following is omitted, for the sake of simplicity, the description relative to plastic net 18 deposition and embeddement in the foam as well as the function realized by the net as an auxiliary part of plant 27 .
- a latex foam body 38 ( FIG. 12 ) wherein a plastic net 18 is embedded in contact with the upper ends of protuberances 29 advances solidly with trucks 28 towards the gelation and vulcanisation device.
- the body 38 whole thickness may be from 10 to 30 cm.
- Plates 35 are moved along the annular circuit indicated with ABCD.
- Plant 27 comprises plates 35 lifting and lowering means, realized by pneumatic drives 39 of vertical and horizontal displacement, the latter displacement being realized through a member 40 adapted to grip in an opening 41 of each plate 35 ( FIG. 11 ).
- Said displacement means act in sections AB, CD.
- Plates 35 displacement in upper branch DA is realized through conveyors 42 .
- foam block 38 advances continuously associated to the trucks until the extraction station where it passes through rollers 6 detaching itself from the trucks.
- the successive steps comprise the block pushing towards the drying and cutting device such as explained referring to FIGS. 1-3 .
- Foam block 38 after the cut ( FIG. 12 ) comprises upper recesses 43 and lower recesses 44 .
- Recesses 44 upper ends are bounded by net 18 .
- Plants comprising previously described structural parts and auxiliary parts allow to reach the predefined aims as highlighted from the following test.
- a first and a second latex foam mixtures have been prepared, both of the same composition and preparation.
- the material quantity employed has been determined with the aim to continuously manufacture two foam blocks each of 100 metres length, 200 cm width, total thickness “S” of 18 cm.
- the first mixture has been used to continuously manufacture a first block without a flexible perforated band, the other to manufacture a second block incorporating a flexible perforated band with the characteristics described in relation to FIG. 4 example.
- the latex foam formulation was as follows:
- test results have highlighted the dimensional values shown in the following table relative to without band block 1 and with the band block 2 :
- the table results show a significant block 2 material shrinkage reduction with respect to block 1 referring to the length and width desired values.
- FIG. 12 Now the advantages derived from the article illustrated in FIG. 12 are highlighted be it a mattress or a pillow or a part thereof.
- the main characteristic of such latex foam is in the combination of a plurality of determined height recesses and of a perforated net placed on the plane where the recesses upper ends are.
- the recesses presence in the article then guarantees both an improved air passage in combination with the channels created by the latex foam cellular structure itself and a uniform elastic deformability with consequent advantage for the user rest.
- the perforated net presence then entails a uniform increased lift of the article at equal foam density.
- the net blocked during the manufacture process, whatever it may be, over the protuberances due to an upper latex foam portion weight effect, determines the formation of a plurality of latex foam annular configurations concentrically interlinked with innumerable hole pairs of the net.
- the article carrying capacity is equal in all such various sections differently from what might happen if the net were placed not aligned relative to the recesses ends, for instance at first aligned and then with a loop that brings the net to a different height relative to the recesses upper ends.
Abstract
Process for continuous manufacture of latex foam rest articles (2, 38) such as mattresses, cushions and the like comprising a part (18) able to participate to the manufacture steps and to remain embedded in the article with consequent improvements of final performances.
A flexible perforated band, preferably a flat polymeric material net (18) with longitudinal and cross reinforcement members (19), is placed over a foam laying surface (3) provided with protuberances (7) and in continuous advancement between a foam laying station (4) and an unlimited length article extraction station (5).
The latex foam passes through net holes (20) forming an upper portion (24) and a lower portion (23) relative to said net. The net continuously opposes contraction forces and weight force exerted from upper portion on lower portion.
The unlimited length article is subjected to successive cross cuts originating rest articles wherein a foam embedded net is arranged on ends of recesses originated by the protuberances.
Description
- The present invention refers to a process and plant for the continuous manufacture of latex foam rest articles such as mattresses cushions and the like, and more in particular the invention refers to a process and plant comprising a part useful both for said article manufacture steps control and to improve the features in the article wherein it remains embedded.
- Latex foam articles are known manufactured using a single mould within which a latex foam mixture is subjected to various process steps.
- A single mould generally comprises a hollow lower part and an upper part forming the cover, one or the other or even both provided with recesses formation protuberances.
- As it is known, initially a latex and its components containing mixture are prepared.
- Latex is an elastomer polymer dispersion in an aqueous serum.
- Herein following the term “components” means all those substances, materials, ingredients and/or fillers whose presence is thought being useful to carry out optimally latex foam article manufacture steps with determined and desired characteristics.
- Generally said “components” include surfactants, thickening agents, gelation agents, stabilizers, process accelerators, vulcanisation agents, fillers, and antioxidants.
- The process employs a tank within which various components are added to a synthetic or natural rubber mixture.
- The raw components prior to their addition to latex are transformed into an aqueous dispersion by grinders as to reduce particles sizes.
- Herein following among most significant components surface active and gelation agents are recalled.
- As it is known surfactants determine the presence around each single latex particle of a protective barrier opposing their approach; such barrier being formed by electric charges all of the same sign for all latex particles such that they repel each other avoiding a premature and undesired particle coagulation.
- Gelation agents have the task of breaking the abovementioned barrier such that various latex particles, non longer subjected to repulsion forces may come near or away from one another being subjected to vibrations.
- During such alternative motion latex particles touch and bond each other carrying out latex coagulation step.
- Referring back to the mould manufacture process, to the latex and its components mixture in the container a pressurized gas is added and the mixture is agitated at high speed until its foaming is obtained.
- A determined solution of a gelation agent destined to carry out the gelating step is added to the latex foam.
- At this time, for a greater clarification in the present invention field of application we recall briefly herein that latex foam rest articles comprise characteristics and process steps different from other foam articles, for instance polyurethane foam.
- As far as the process steps one should remember that latex article foaming is achieved inputting an external agent such as pressurized air in the mixture, while polyurethane mixture foaming is achieved by direct contact among polyoil and isocyanate, that is the same base materials making a polyurethane.
- Further latex foam articles have a structure mainly provided with tiny open and uniformly distributed cells for all material thickness, polyurethane foam articles have mainly closed cells except specific polyurethanes wherein cells are blown up after specific treatments.
- A latex foam article manufacture envisages filling up the mould with mixture comprising latex and components already subjected to foaming.
- It is to be noted that after foaming the latex mixture is dimensionally unstable such that a risk exists of a cell walls collapse.
- With the aim of facing such risk the gelating step is carried out.
- Gelating may be defined as a homogeneous coagulation wherein part of the foam aqueous serum remains embedded in the rubber polymer. Chemically gelating is the transition from the “sol” phase to the “gel” phase. Gelating step avoids latex foam collapse after the laying.
- The following vulcanisation step is carried out through a vulcanisation agent to determine the final article desired elasticity degree that is the elastic deformation, density and uniformity article characteristics that will assure comfort conditions for the user in a rest state.
- During the vulcanisation step the mould is heated preferably with steam.
- At the end of the vulcanisation step the mould upper part is rotated or it is lifted with respect to the hollow lower part to allow for article extraction.
- As already mentioned latex foam mixture is an aqueous dispersion wherein a considerable amount of water embeds latex particles. For instance if the total amount of the latex foam mixture is 100 part in weight, the dry amount is 60 parts in weight and the water amount is 40 parts in weight.
- In the various manufacture steps the water amount is diminishing due to phenomena relative to heat absorption by the latex foam.
- In the gelation step, necessary to the latex foam dimensional stabilization, there occur reactions thereto takes part a temperature sensitive gelation agent in the sense that gelation time decreases with temperature increase.
- Following gelation latex particles coagulate and free water.
- In the vulcanisation step the vulcanisation agent under the temperature influence creates bridges between various latex macro-molecules forming said particles.
- In practice there are formed chemical bonds destined to restrain macro-molecules unrestrained among themselves and consequently the volume reduces itself.
- After in the drying step the amount of water is removed by evaporation providing heat to the latex foam by hot air circulation.
- The various cited process steps determine material shrinkage phenomena with consequent reduction of final desired sizes.
- Continuous latex foam rest articles manufacture processes are also known.
- Such continuous processes are used and described in the assignee patents EP-B-0,380,963, U.S. Pat. No. 5,229,138, U.S. Pat. No. 6,086,802, EP-A-1,361,033.
- Understandably continuous processes permit to achieve high productivity levels as compared to single mould processes.
- Nevertheless continuous processes as single mould ones bring about the cited material shrinkage phenomena relative to the starting programmed amount.
- Such material shrinkage is a few percent but brings about anyway a final product dimensional reduction as compared to the programmed.
- In particular the material shrinkage is more evident in continuous processes where a latex foam block at the end of a daily manufacture cycle takes usually unlimited defined length values.
- To clarify which is the material shrinkage phenomenon one thinks that a 4% shrinkage relative to a latex foam block of 1,000 meters would imply a shrinkage in the block length direction of 40 meters with consequent less production of 40 mattresses if each of them were assigned a 1 meter width.
- Unfortunately a latex foam article manufacture is very complex because firstly it comprises a stable dispersion formation of rubber particles in an aqueous medium obtained controlling the chemical-physical properties of the interface between the aqueous phase and the latex particles, then the foam formation obtained supplying the gas necessary to realize the new dispersed phase and the surface energy necessary to form a gas-liquid interface, then the foamed latex gelation achieved destabilizing the rubber particles-water interface, with eventual bonding of latex particles and formation of a reticular structure that stiffens the latex foam.
- The conditions in which such steps occur are obtained by specific process parameters such as time and temperature and appropriate component dosage, according to rules dictated more by experience than by a perfect knowledge of the phenomena involved.
- Therefore trying to leave the normal and tested operational conditions to obviate to the prior cited material shrinkage phenomena may bring about a variation even negative of the final article performances.
- It has then been thought that it was possible to find a solution to the cited problem using a process element able to act on the latex foam block on continuous manufacture without altering the operational parameters nor the foam composition and the steps sequence.
- Nevertheless even this potential solution did not appear a workable one because the shrinkage phenomena occurred within the latex foam and the process element might not be extracted from the foam block without impairing the cellular structure.
- It was then felt that a possible solution might be found using at least an element able to be active both in the process steps to control and anyway to counteract the article shrinkage phenomenon and in the final article to provide it with possibly improved performances.
- It forms therefore a first aspect of the invention a process for continuous manufacture of an unlimited length latex foam block to be divided in a plurality of articles by cuts transversely to said unlimited length, comprising the steps of advancing along a predetermined longitudinal direction a laying surface provided with protuberances between a first and a second station, of laying in said first station a latex foam mixture on said deposit surface in continuous advancement, of gelating, of vulcanising, of drying characterized by the steps of:
- a) providing, proximate to said first station, a substantially flat flexible band of unlimited length and provided with a plurality of through openings;
- b) placing said flexible band on said laying surface protuberances;
- c) advancing continuously said flexible band with said laying surface;
- d) introducing said mixture in said band openings;
- e) forming a latex foam layer comprising a lower portion and an upper portion respectively below and above said band;
- f) pressing with said upper portion weight said band against said laying surface protuberances;
- h) gelating, vulcanising, drying said foam block incorporating said band;
- i) cutting said foam continuous block incorporating said band with consecutive cross cuts displaced one from the other a predetermined distance.
- Preferably said band is from polymeric material.
- In the following with the expression “substantially flat and flexible band provided with a plurality of through openings”, is meant to indicate both a structure formed from a net comprising a plurality of longitudinal members cross oriented to each other to form meshes whose area corresponds to said openings either a flexible laminar structure provided with regular or irregular shape holes corresponding to said openings or anyway a flexible structure tape shaped or the like with openings through which a latex foam passes.
- In the following with the expression “polymeric material” is meant to indicate a material generally adapted to said band construction, of natural or synthetic type, comprising longitudinal members, such as mono-filaments or braids or fibres for instance of aramide or in general plastic fibres distributed in an orderly way or in a loose way without preferential orientation for forming nevertheless among them said openings, and/or plates, and/or flexible straps in plastic material having openings distributed in orderly or even unorderly fashion.
- By the term substantially flat is meant to indicate a band that might acquire a configuration little different from the flat one for instance slightly undulated.
- Preferably said band consists of a propylene or polythene or polypropylene or polyamide plastic polymer.
- Typically the band is a net or a plate, in single shape or in overlaid layers.
- Conveniently the process is characterized by laying over said band a latex foam of density comprised between 40 to 270 grams/litre when such laying surface rate is comprised between 0.3 to 1.5 meters/minute.
- Advantageously the process is characterized by laying over said protuberances a band resistant to compression forces acting following at least a first and a second direction perpendicular to each other in a same plane and following a third direction perpendicular to said plane, said at least first and second direction corresponding to the longitudinal and the cross direction of said latex foam block in continuous advancement.
- Preferably the process is characterized by depositing a band wherein the reaction to said forces exerted on a foam block matches the dimensional reductions along said first and second direction up to 5% compression value. Conveniently a foam block sample provided with said band with width comprised between 180 cm to 220 cm, length comprised between 60 cm to 220 cm, thickness comprised between 10 cm to 240 cm, has a lift value comprised between 3% to 15% more as compared a same sample without band.
- It constitutes a second aspect of the invention an unlimited length latex foam block continuous manufacture plant to be subdivided in a plurality of articles by cuts transversely to said unlimited length, said plant being formed by a structural part comprising a laying surface in continuous advancement along a predetermined direction between a first latex foam laying station and a second said block extraction station, a plurality of protuberances cantilevering from that laying surface to a plane parallel to said laying surface plane, a latex foam gelation device, a vulcanisation device before said second extraction station, a drying device, that plant being characterized by comprising an auxiliary part in continuous advancement able to take part to the operation step and to remain embedded in said article by a determined length after said block cutting, said auxiliary part comprising an unlimited length flat band and provided with a plurality of through openings, said band being placed continuously on said protuberances and associated to said protuberances by the latex foam passing through said openings.
- In a third aspect the invention is relative to a latex foam block comprising a plurality of lower recesses extending up to a predetermined height “s1”, characterized by chemically incorporating along the plane boarding the recesses ends a polymeric material flexible band provided with through openings.
- Conveniently said band in a plastic material net provided with a plurality of meshes forming said openings.
- Preferably the foam block comprises a plurality of openings ordered according two directions perpendicular to each other in a same plane, said openings having in a direction a pitch comprised between 1 cm to 4 cm, and in the other direction a pitch equal to that of the first direction or even different.
- The present invention will be now further described with the aid of the accompanying figures, provided in a non-limiting illustrative way, wherein:
-
FIG. 1 is a longitudinal partial schematic view of the plant according to the invention; -
FIG. 2 is a longitudinal partial schematic view of the final part ofFIG. 1 plant; -
FIG. 3 is a longitudinal partial schematic view of the plant ofFIG. 1 during a foam block production; -
FIG. 4 is a plan view of an auxiliary part ofFIG. 1 plant; -
FIG. 5 is a schematic plan view of some forces acting on the auxiliary part of the plant shown inFIG. 4 ; -
FIG. 6 is a plan view of a second embodiment ofFIG. 1 plant auxiliary part; -
FIG. 7 is a perspective partial view of the latex foam block shown byFIG. 1 plant 1; -
FIG. 8 is a plan view of a third embodiment ofFIG. 1 plant auxiliary part; -
FIG. 9 is a longitudinal view of a further embodiment of the latex foam continuous block manufacture plant; -
FIG. 10 shows a detail ofFIG. 9 plant; -
FIG. 11 shows a further detail ofFIG. 9 plant; -
FIG. 12 is a longitudinal section of a mattress manufactured byFIG. 9 plant. - In
FIGS. 1-3 , 1 is a plant for the continuous manufacture of an unlimitedlength latex foam 2 to be subdivided in a plurality of rest articles such as for instance mattresses. -
Plant 1 comprises structural parts and auxiliary parts. - In the following the expression “plant structural parts” means, as already known in traditional techniques, means, accessories and devices necessary for block manufacture and the expression “plant auxiliary parts” indicates, according to the present invention, means capable to influence advantageously both the block manufacture steps and the final articles performances.
- Therefore said plant structural parts are absent in the final article while said plant auxiliary parts to achieve the invention aims are present both during the plant operation and in the final article.
- Now the
plant 1 structural parts are described. -
Such plant 1 structural parts comprise a latexfoam laying surface 3 in continuous advancement along a predetermined longitudinal direction “F” between first foam laying station 4 and anextraction station 5. A counter-rotating rollers pair 6 inextraction station 5 carriesblock 2 towards drying device and further possible plant devices and finally to a cutting station for the formation of an plurality of articles. - Laying
surface 3 comprises a plurality ofprotuberances 7 cantilevering from the base to form, as it is known, a plurality of lower recesses in the foam block. - The protuberances ends lie along an imaginary plane at a determined height “s1” with respect to laying
surface 3. -
Plant 1 structural parts comprise gelation means 8 followed by vulcanisation means 9. - Both
such means 8, 9 are placed between first andsecond station 4, 5. Gelation means in their most general embodiment must be able to stabilize the latex foam and to this purpose they use heat sources able to provide temperatures from 18° to 55° degrees centigrade, and more preferably from 27° to 49° C., in the environment crossed by the latex foam block. - Near first station 4 is placed a laying
device 10 of a latex foam base mixture destined to form ablock 2 base layer and at a short distance from first station is placed a foamlevelling doctor blade 11. - Said laying
device 10 is moved in a cross direction to surface 3 advancement direction and coming near or away fromsuch surface 3 in arrows “f” direction by adequate slide guide and drive means not illustrated because of any known type. - Further laying
device 10 is connected to a latex mixer. - Said mixer comprises multiple tanks and various equipment, among which the control, supply, send and connection ones.
- For description shortage said mixer has been exemplified with a
single tank 12 provided with appropriate connection piping to amixture laying head 13. - Preferably gelation means 8 and vulcanisation means 9 comprise a single tunnel type device partitioned in a first and a
second chamber 15, 16. - The tunnel is heated with 100° C. steam.
- The plant final part comprises a drying
device 14 and a cuttingstation 17 wherein a blade or similar means separate the continuously moved block portion from the block portion destined to form the single mattress (FIG. 2 ). - At the end of the plant structural part description now the
plant 1 auxiliary parts are described that form the inventive solution of the present invention. - Said auxiliary parts consist in a flexible plastic band flat shaped provided with a plurality of through openings.
- Said band, as explained later, is an active part in the manufacture process in conjunction with laying
surface 3protuberances 7. - In a description example said band is formed from a plastic net 18 comprising (
FIG. 4 ) a plurality oflongitudinal members 19 cross oriented one to another to form a plurality of meshes bounding throughopenings 20. - In the description example
plastic material net 18, such as high density polyethylene or propylene or polyamide or other equivalent materials, is obtained for example in some instances by extrusion and in others by heat-seal. - Said various
longitudinal members 19 may be thermoplastic mono-filaments, placed according rows preferably but not necessarily perpendicular to each other in the same plane. - Such longitudinal members have a diameter comprised from 1 to 7 mm and are restrained solidly between themselves in their reciprocal meeting points wherein they form
nodes 21. -
Net 18 presents meshes preferably square shaped, nevertheless according to what will be explained later such meshes might take up a different geometrical configuration. -
Net 18 comprises said plurality of square shaped meshes whose area is identified from one side by dimensions comprised from 10 to 40 mm. - Now
plant 1 operation is described. -
Plant 1 operation for an unlimitedlength foam block 2 manufacture initially comprises the step of sending net 18 towards layingsurface 3 already in continuous advancement in F direction towardsextraction station 5. - Before this
step net 18 has been preset on already known appropriate accumulation and feeding means, for instance of the type comprising a plurality of return pulleys set in such a way as to guide the net according to an undulated path formed by multiple loops with a fly-wheel function. - In a particular embodiment visible in
FIG. 1 said accumulation and feeding means are schematised withsingle collection coil 22 on which cylindrical surface is wound a plurality of net concentric loops. - The various loops are unwound and guided, manually or through motorization, towards
plant 1. - Conveniently net 1 has bending characteristics to wind itself up according concentric loops on the cylindrical surfaces of one or more coils with diameters comprised from 5 cm to 100 cm.
-
Net 18 head is connected to some layingsurface 3protuberances 7 top. -
Net 18 dragging by layingsurface 3 advancement brings the net in first station 4 zone wherein layingdevice 10 is activated. - In first station 4 laying
head 13 moved in a direction and in the oppose one across to the layingsurface 3 advancement direction sends latex foam downward forcing it to pass throughnet openings 20. - Now latex foam propagates between laying
surface 3protuberances 7 and overnet 18. - It is highlighted that net 18 is now already stably anchored to latex foam.
- The net bounds two foam portions in the following called
lower portion 23 with a thickness s1 andupper portion 24 with a thickness s2 (FIG. 3 ).Foam block 2 proceeds its path in longitudinal direction “F” and in passing underdoctor blade 11 is leveled acquiring on the outside a substantially flat shape. - The foam blocks manufactured with the process being described have a thickness s1 in
lower portion 23 comprised from 9 cm to 15 cm, and a thickness s2 inupper portion 24 comprised between 9 to 15 cm. - Then block 2 always associated to laying
surface 3 reaches and passes throughgelation 8 and vulcanisation 9 device receiving the heat necessary with respect to its dimensional stabilization and its chemical reticulation. -
Foam block 2 along the whole path from laying station 4 to vulcanisation device and thereafter to dryingdevice 14 is subjected to contraction forces and thereafter to the weight force exerted byupper portion 24 towardslower portion 23. - In the state of the art relative to traditional plants, said forces effect is not counteracted, therefore the foamed material reduces itself with respect to the desired dimensions.
- Advantageously net 18 forms that plant 1 auxiliary part able to limit if not to completely cancel the cited forces effect.
-
Net 18 is pressed towards the plurality ofprotuberances 7. - Due to the effect of
upper foam weight 24 all crossing nodes of net 18longitudinal members 19 are blocked, therefore any relative motion among various nodes is prevented. - Referring now to net 18 schematically represented in
FIG. 5 plain view it is highlighted that latex foam possible contractions indicated with opposite arrows in a determined direction and with t letter unload themselves uponlongitudinal members 19, but due to thefact nodes 21 remain in an unchanged position, contraction forces effect “t” might not be able to do nothing but bendlongitudinal member 19. - Nevertheless the conveniently adapted mechanical characteristics for the net are such as to substantially limit the deformation values, counteracting in such manner the effects otherwise following the contractions presence.
- The previous consideration has been made relative to the horizontal contraction forces present in one
block 2 plane but because variousupper portion 24 planes are bound to one another by the same cellular structure, one has the effect that all planes contractions transfer itself to the plane provided with more resistance and that is the nearest to net 18. - Further the previous considerations referred to horizontal contractions may be referred in the same manner to
upper portion 24 weight effects with respect tolower portion 23. - In particular as may be noted in
FIG. 3 ,upper portion 24 weight unload itself on the various sections of longitudinal member lying on the ends of aprotuberances pair 7 proximate to each other; each said portion behaves like a civil construction beam which uniformly loaded for all its length, unload the weight loaded on it to the extreme abutments realized with high mechanical strength. - The previous description was made relative to a net wherein various
longitudinal members 19 are cross-oriented to each other and restrained tonodes 21, nevertheless are within the scope of the invention plastic nets whose various longitudinal members are not rigidly restrained to each other in the cross points such as illustrated by way of example inFIG. 6 or also for instance when the net takes up a configuration similar to a non woven fabric and anyway be provided with openings able to be crossed by a latex foam. Referring toFIG. 6 net it is to be observed thatlongitudinal members 19 meet in the plurality ofpoints 21 subjected to compression forces due to foamupper portion 24 weight. - Thus
such points 21 stay in an unvaried position to each other allowing net 18 to abide to its plant auxiliary part previously explained function. - Further a major part of
upper portion weight 24 unloads itself on the wide surface distribution of resisting members in the net reducing in this manner the compression effect onlower portion 23, therefore stabilizing said lower portion density as desired. - Taking back up the plant operation it is to be noted that
foam block 2 incorporating net 18 advances in predetermined longitudinal direction “F” remaining associated to layingsurface 3 until when in the passage through 6 rollers pair is detached from said laying surface and pushed continuously towards dryingdevice 14 and then towards cuttingstation 17. - In cutting station 17 (
FIG. 2 )foam block 2 advances underneath anappropriate cutting blade 26 for a section corresponding to a desired width dimension of a single mattress. - After such section measurement, carried out by various optical and/or mechanical devices known by themselves,
blade 26 is lowered until it separates the single mattress for cross cutting (FIG. 7 ) fromfoam block 2 always in continuous advancement. - It is to be noted that net 18 from the vulcaniser exit to cutting
station 17 goes on carrying out its plant auxiliary part function and after cutting,net portion 18 incorporated in single mattress body contributes with its characteristics to improving the elastic strength of the foam whole cellular structure wherein it is embedded. - Up to this point the description has been made relative to a
plant 1 comprising a layingsurface 3 schematically indicated with a straight line. - Such laying
surface 3 might take up various embodiments and among these is mentioned that described in patent EP 0,358,914 herein incorporated in case a detailed explanation of its operation might be necessary. - In the following it is briefly indicated that laying
surface 3 belongs to a motion transmission made up by a plurality of lower plates side by side to each other and cross-anchored to two chains (not shown) arranged in an annular configuration around two pulleys, one of which a drive one. - Such plates, preferably in aluminium, comprise
protuberances 7, preferably hollow, useful both for lower recesses moulding 7′ (FIG. 7 ) in the base layer and to gelate and vulcanise in a diffused manner the latex foam mass. - To understand even better the core of the invention is underlined that
plant 1 description has been made referring to a flexible plastic band with a net shape, nevertheless said band might take up different configurations. - To that end in
FIG. 8 it has been indicated with the same reference numerals of previous figures a further perforated band, made up from plastic material and with a configuration corresponding to a flexiblelaminar structure 18 provided with throughholes 20. - Said through holes might be of circular shape, non necessarily of equal diameter, or of square or rectangular shape, or realized according to other geometrical shapes such as for instance hexagonal, octagonal or egg-shaped as both with an equal geometry with each other and with a different geometry in one and the same laminar structure.
- Advantageously the laminar shape of
flexible band 18 allows to distribute over a wide continuous surface the weight force exerted fromupper portion 24 towardslower portion 23, accordingly the pressures exerted on said lower portion are reduced leaving substantially unvaried the density with respect to the programmed one at the start. - In all the chosen solutions of the present invention the materials forming the flexible band must be such as to keep substantially unaltered their mechanical strength physical characteristics throughout all
foam block 2 manufacture steps. - In particular the band must be able to withstand, without loosing its starting characteristics, at high temperatures both in the vulcanisation step carried out in the presence of 100° C. steam and in the dying step carried out with hot air temperature higher than 100° C.
- It is to be underlined at this point as a further characteristic of the invention the function that might be carried out by
openings 20 of perforatedflexible band 18 to control foam density and viscosity. - Relative to the advancement rate of laying
surface 3,openings 20 size is selected at a start such as to allow a latex foam easy passagethorough band 18. - If after in the manufacture process there might be noticed foam stagnations and/or poor foam filling between
protuberances 7, it will be possible to check if the mistake is to be charged to a variation of foam density or viscosity and correct its value, for instance adjusting again changing during the foaming step the pressurized air to the latex amount ratio. - It was found convenient to adopt a density of the foam inputted by
deposition head 13 comprised from 10 to 270 grams/litre when the laying 3 surface rate is comprised from 0.3 to 1.5 meters/minute. - In particular it has been found convenient to adopt a perforated band (
FIG. 8 ) with a laminar shape wherein the total voids area is considerably greater then full area and preferably a band with a voids to full ratio from 5 to 2 in combination with foam density and advancement values just cited. - It is to be underlined that
flexible bands 18 may haveopenings 20 distributed unevenly or even according to orderly rows. - Referring to
flexible bands 18 withopenings 20 distributed evenly in the following are defined some geometrical characteristics of saidopenings 20 that allow to obtain an even latex foam distribution when arranged in combination both withprotuberances 7, and with the foam density and thesurface 3 advancement rate having previously cited values. - It has been found convenient to adopt flexible
bands comprising openings 20 oriented according orderly rows in two major directions perpendicular to each other such as represented inFIGS. 4-6 . - Preferably said
band openings 20 have a minimum dimension, in any direction, at least greater than 8 mm and extend themselves in a first longitudinal dimension with a pitch from 1 cm to 4 cm and in a second direction perpendicular to the first one with equal pitch values. - Laying 3
surface protuberances 7 have a circular base with a diameter from 2 to 24 mm and a cross dimension of the upper end from 1 to 18 mm. - Further laying 3 surface comprises a number of
protuberances 7 from 6 to 84 protuberances/square decimetre. - Now in
FIG. 9 is described a preferred embodiment of aplant 27 for alatex foam block 2 continuous manufacture comprising both upper recesses and lower recesses. -
Plant 27 similar to that described forplant 1 ofFIG. 1 , is made up by structural parts and by auxiliary parts. - The plant structural parts correspond substantially to what already described in patent EP-A-1,361,033 herein incorporated for any further possible clarification.
- In the following are briefly cited the structural parts necessary to the understanding of their operation.
- Said structural parts comprise a laying surface made up by a plurality of
trucks 28 with protuberances 29 (FIG. 10 ) moved along an annular circuit comprising two teethed pulleys one of which a drive one 30, the other a tail one. - The trucks are provided at the lower surface ends with pairs of rollers geared with the two pulleys grip means and are pushed by
drive wheel 30 in contact to each other along the active upper branch wherein they receive the latex foam throughdeposition head 13. - The trucks displacement is guided in the upper branch through the sliding of
wheels 31 alongappropriate guides 32 of a fixed structure. - Lower branch trucks may be in number lower as compared to the upper branch ones and in this solution they are moved through displacement means, such as
conveyors 33 and the like, in an way independent from the drive pulley drives, at a rate higher than the upper branch one. - In the tail branch the trucks rest with
side flanges 34 onconveyors 33. -
Plant 27 upper part comprises a plurality of plates 35 (FIGS. 9 , 11) each of which is provided with a plurality ofprotuberances 36 adapted to form upper recesses on the foam block. - Now the auxiliary parts of
plant 27 are described. - Said auxiliary parts the same as described in
FIG. 1 comprise plastic net 18 withholes 20 illustrated inFIG. 2 . -
Net 18 is wound around acollection coil 37 to later pass aroundcoil 22 and there from towards the trucks protuberances. -
Plant 27 lower part operation is substantially analogous to that ofFIG. 1 , therefore in the following is omitted, for the sake of simplicity, the description relative to plastic net 18 deposition and embeddement in the foam as well as the function realized by the net as an auxiliary part ofplant 27. - It will be simply said that a latex foam body 38 (
FIG. 12 ) wherein a plastic net 18 is embedded in contact with the upper ends ofprotuberances 29 advances solidly withtrucks 28 towards the gelation and vulcanisation device. - The
body 38 whole thickness may be from 10 to 30 cm. -
Plates 35 are moved along the annular circuit indicated with ABCD. - In the
AB portion plates 35 are lowered on the foam body, in the BC portion the plates rest at their ends to the side walls (not illustrated) of the trucks andprotuberances 36 are embedded in the foam body. - In the
CD portion plates 35 are extracted and lifted one at the time relative to the foam body and in portion DA the plates go through the return branch. -
Plant 27 comprisesplates 35 lifting and lowering means, realized bypneumatic drives 39 of vertical and horizontal displacement, the latter displacement being realized through amember 40 adapted to grip in anopening 41 of each plate 35 (FIG. 11 ). - Said displacement means act in sections AB, CD.
-
Plates 35 displacement in upper branch DA is realized throughconveyors 42. - Advantageously
upper plates 35 andrelative protuberances 36, preferably in aluminium, come to the tunnel entry already pre-heated by the previous passage thorough active section BC. - In
plant 27 following sections foam block 38 advances continuously associated to the trucks until the extraction station where it passes through rollers 6 detaching itself from the trucks. - The successive steps comprise the block pushing towards the drying and cutting device such as explained referring to
FIGS. 1-3 . -
Foam block 38 after the cut (FIG. 12 ) comprises upper recesses 43 and lower recesses 44. Recesses 44 upper ends are bounded bynet 18. - Plants comprising previously described structural parts and auxiliary parts allow to reach the predefined aims as highlighted from the following test.
- A first and a second latex foam mixtures have been prepared, both of the same composition and preparation.
- The material quantity employed has been determined with the aim to continuously manufacture two foam blocks each of 100 metres length, 200 cm width, total thickness “S” of 18 cm.
- The first mixture has been used to continuously manufacture a first block without a flexible perforated band, the other to manufacture a second block incorporating a flexible perforated band with the characteristics described in relation to
FIG. 4 example. - The latex foam formulation was as follows:
-
% parts in weight for 100 Materials parts of dry polymer Natural rubber latex — Synthetic rubber latex 100 Potassium resinate 1 Antioxidants 0.8 Zinc oxide 2 Sulphur 2.5 Accelerators 2 Byphenil- gualidyne 1 Gelation agent: SSF 3 - Both mixtures have been used with
FIG. 9 plant 27, nevertheless the first mixture has been used withplant 27 comprising only the structural parts and the second mixture withplant 27 comprising also the auxiliary parts. - The test results have highlighted the dimensional values shown in the following table relative to without
band block 1 and with the band block 2: -
Dimensions Programmed Block 1Block 2Length (mt) 100 97 99 Width (cm) 200 198 199 Thickness (cm) 18.5 18.4 18.4 % length shrinkage 0 3 1 % width shrinkage 0 1 0.5 % thickness shrinkage 0 0.5 0.5 - Advantageously the table results show a
significant block 2 material shrinkage reduction with respect to block 1 referring to the length and width desired values. - As far as the thickness values are concerned one may have
block 2 thickness reductions moderately greater to block 1 thickness reduction, nevertheless it is possible to compensate easily this thickness reduction adding a small quantity of latex foam material to the starting formulation. - But what has to be highlighted is that thanks to the net presence in
block 2 it is possible to significantly reduceblock 2 density with respect to block 1 keeping the same the two blocks carrying capacity. - If it is now considered an algebraic sum whose factors are the cited modest latex foam addition for the possible moderate reduction of the thickness of the
block 2 with respect to block 1, one can readily see that the algebraic sum economic value is considerably advantageous forblock 2 as compared toblock 1. - In fact, as is obviously understandable, to the cited
block 2 density reduction at equal carrying capacity withblock 1 would correspond a high material reduction that may be estimated equal to 10% in percent value maintaining a carrying capacity value in both blocks substantially equal such as for instance 170 Newtons. - Now the advantages derived from the article illustrated in
FIG. 12 are highlighted be it a mattress or a pillow or a part thereof. - The main characteristic of such latex foam is in the combination of a plurality of determined height recesses and of a perforated net placed on the plane where the recesses upper ends are.
- The formation of a plurality of recesses obtained, whatever the article manufacture process might have been, has guaranteed in the vulcanisation step through a corresponding protuberances presence an uniform heat transmission through said protuberances with consequent capillary and uniform crosslinking.
- The recesses presence in the article then guarantees both an improved air passage in combination with the channels created by the latex foam cellular structure itself and a uniform elastic deformability with consequent advantage for the user rest.
- The perforated net presence then entails a uniform increased lift of the article at equal foam density.
- In fact in this article it is noted that the net, blocked during the manufacture process, whatever it may be, over the protuberances due to an upper latex foam portion weight effect, determines the formation of a plurality of latex foam annular configurations concentrically interlinked with innumerable hole pairs of the net.
- As may be understood such linkage forces the net to lye over the recesses upper ends plane.
- Thus if various consecutive cross sections upon the article are considered the article carrying capacity is equal in all such various sections differently from what might happen if the net were placed not aligned relative to the recesses ends, for instance at first aligned and then with a loop that brings the net to a different height relative to the recesses upper ends.
Claims (14)
1-8. (canceled)
9. A plant for the continuous manufacture of an unlimited length latex foam block to be subdivided in a plurality of articles by cuts transversely to said unlimited length, said plant comprising:
a structural part comprising a laying surface for continuously advancing along a predetermined direction between a first latex foam laying station and a second block extraction station,
a plurality of protuberances cantilevering from said laying surface to a plane parallel to said laying surface, a latex foam gelation device,
a vulcanisation device before said second extraction station,
a drying device,
an auxiliary part in continuous advancement capable of participating to the operation steps and remaining embedded in said article for a predetermined length after said block cutting, said auxiliary part comprising a flexible band substantially flat of unlimited length and provided with a plurality of through openings, said band being arranged continuously over said protuberances and associated to said protuberances by the latex foam passing through said openings.
10. Plant according to claim 9 , wherein said band is in polymeric material.
11. Plant according to claim 9 , wherein said band embedded in said continuously advancing foam forms means contrasting the contraction forces present on said block.
12. Plant according to claim 9 , wherein said band has a laminar structure provided with holes.
13. Plant according to claim 9 , wherein said band is made up from a plastic net comprising a plurality of longitudinal members directed transversely to each other to form a plurality of meshes.
14. Plant according to claim 9 , comprising a coil with a collection seat of said band loops having a cylindrical surface with diameter from 5 to 100 cm.
15. Latex foam block comprising a plurality of lower recesses extending up to a predetermined height “s1”, incorporating along the plane delimiting the recesses upper ends a polymeric material flexible band provided with through openings.
16. Latex foam block according to claim 15 , wherein the latex foam density is from 40 to 270 grams/litre.
17. Latex foam block according to claim 15 , wherein said band is in plastic material.
18. Latex foam block according to claim 15 , wherein said band comprises a plurality of through openings arranged according to two directions perpendicular to each other in a same plane, said openings having a pitch from 1 to 4 cm.
19. The plant according to claim 9 , wherein said block is continuous and the latex foam of the latex foam block mainly comprising open cells.
20. Latex foam block according to claim 15 , wherein said block is continuous and the latex foam of the latex foam block mainly comprising open cells.
21. A plant for the continuous manufacture of an unlimited length latex foam block to be subdivided in a plurality of mattresses by cuts transversely to said unlimited length, comprising:
means for advancing along a predetermined longitudinal direction a laying surface provided with protuberances, having tapered ends to form recesses in said mattresses, said laying surface advancing between a first and a second station,
means for laying in said first station a latex foam mixture on said laying surface in continuous advancement, and
further comprising:
a) means for providing proximate to said first station a substantially flat flexible band of unlimited length and provided with a plurality of through openings;
b) means for laying said flexible band on said laying surface protuberances;
c) means for advancing continuously said flexible band with that laying surface;
d) means for introducing said mixture in said band openings, downwardly passing a portion of the mixture through the openings;
e) means for forming from the mixture a continuous latex foam layer comprising a lower portion and an upper portion respectively below and above said band, the latex foam mainly comprising open cells;
f) means for pressing with said upper portion weight said band against said laying surface protuberances;
g) means for gelating, vulcanising, drying said foam layer incorporating said band to form said foam block of continuous latex foam incorporating said band;
h) means for cutting said foam block of continuous latex foam incorporating said band with consecutive cross cuts at a predetermined distance from each other.
Priority Applications (1)
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US12/555,761 US20100003497A1 (en) | 2006-05-11 | 2009-09-08 | Process and plant for continuous manufacture of latex foam articles |
Applications Claiming Priority (4)
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ITMI2006A000936 | 2006-05-11 | ||
IT000936A ITMI20060936A1 (en) | 2006-05-11 | 2006-05-11 | PROCEDURE AND PLANT FOR THE CONTINUOUS MANUFACTURE OF ARTICLES IN LATEX FOAM |
US11/469,770 US7604761B2 (en) | 2006-05-11 | 2006-09-01 | Process and plant for continuous manufacture of latex foam articles |
US12/555,761 US20100003497A1 (en) | 2006-05-11 | 2009-09-08 | Process and plant for continuous manufacture of latex foam articles |
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US12/555,761 Abandoned US20100003497A1 (en) | 2006-05-11 | 2009-09-08 | Process and plant for continuous manufacture of latex foam articles |
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EP (1) | EP1854610B1 (en) |
KR (1) | KR20070109773A (en) |
AT (1) | ATE536976T1 (en) |
IT (1) | ITMI20060936A1 (en) |
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Cited By (1)
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CN105996576A (en) * | 2016-07-15 | 2016-10-12 | 开平市荣发机械有限公司 | Wet type latex mattress production line |
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US7469437B2 (en) | 2005-06-24 | 2008-12-30 | Tempur-Pedic Management, Inc. | Reticulated material body support and method |
JP5132168B2 (en) * | 2007-03-08 | 2013-01-30 | 株式会社リコー | Manufacturing method and manufacturing apparatus for structure for image display element, and manufacturing method and manufacturing apparatus for electrophoretic display element |
ITMI20072356A1 (en) * | 2007-12-18 | 2009-06-19 | Sapsa Bedding S R L Assago Mi | PLANT FOR THE CONTINUOUS MANUFACTURE OF A FOAM LAYER FOR FORMING ARTICLES FOR REVERSE |
IT1394090B1 (en) * | 2009-04-09 | 2012-05-25 | Gommec S R L | METHOD OF MANUFACTURE OF A MICROPOROSA SHEET AND SHEET OBTAINED SO |
IT1397879B1 (en) * | 2009-10-29 | 2013-02-04 | Sapsa Bedding Srl | PROCEDURE AND PLANT FOR THE CONTINUOUS MANUFACTURE OF AT LEAST ONE LATEX FOAM LAYER WITH ALVEOLI. |
CN104015291B (en) * | 2014-06-09 | 2016-06-22 | 江苏金世缘乳胶制品股份有限公司 | A kind of latex pillow production line |
IL269149B1 (en) * | 2017-03-15 | 2023-12-01 | Aspect Biosystems Ltd | Systems and methods for printing a fiber structure |
EP3626422A1 (en) * | 2018-09-24 | 2020-03-25 | LTA S.r.l. | Method for making a material in sheets or rolls for manufacturing medical devices and respective material |
CN111660474A (en) * | 2020-07-17 | 2020-09-15 | 江苏金世缘乳胶制品股份有限公司 | Processing technology of high-quality clean latex pillow |
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US20070228594A1 (en) * | 2006-04-04 | 2007-10-04 | Sapsa Bedding Srl | Process and plant for continuous manufacture of resting articles of latex foam |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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CN105996576A (en) * | 2016-07-15 | 2016-10-12 | 开平市荣发机械有限公司 | Wet type latex mattress production line |
Also Published As
Publication number | Publication date |
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EP1854610B1 (en) | 2011-12-14 |
EP1854610A3 (en) | 2009-05-27 |
KR20070109773A (en) | 2007-11-15 |
ITMI20060936A1 (en) | 2007-11-12 |
PL1854610T3 (en) | 2012-07-31 |
US7604761B2 (en) | 2009-10-20 |
EP1854610A2 (en) | 2007-11-14 |
US20070264484A1 (en) | 2007-11-15 |
ATE536976T1 (en) | 2011-12-15 |
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