Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
  • B65D65/38—Packaging materials of special type or form
  • B65D65/40—Applications of laminates for particular packaging purposes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/0427—Coating with only one layer of a composition containing a polymer binder
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/043—Improving the adhesiveness of the coatings per se, e.g. forming primers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/052—Forming heat-sealable coatings
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
  • C09J7/21—Paper; Textile fabrics
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/35—Heat-activated
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/47—Condensation polymers of aldehydes or ketones
  • D21H17/49—Condensation polymers of aldehydes or ketones with compounds containing hydrogen bound to nitrogen
  • D21H17/50—Acyclic compounds
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/10—Coatings without pigments
  • D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
  • D21H19/20—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H19/22—Polyalkenes, e.g. polystyrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2465/00—Characterised by the use of macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain; Derivatives of such polymers
  • C08J2465/02—Polyphenylenes
• • 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
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S138/00—Pipes and tubular conduits
  • Y10S138/07—Resins
• • 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
  • Y10T428/28—Web or sheet containing structurally defined element or component and having an adhesive outermost layer
  • Y10T428/2813—Heat or solvent activated or sealable
  • Y10T428/2817—Heat sealable
  • Y10T428/2826—Synthetic resin or polymer

Definitions

• This invention relates to a heat-scalable wrapping material comprising a hydrophilic base or support and a polyethylene which is firmly anchored to the support by a thermosetting resin in the thermoset condition.
• polyethylene such as its resistance to chemicals and solvents, resistance to the permeation of fluids and ases, and its heatsealing properties are desirable in a packaging material.
• unsupported films or sheets of polyethylene have not proved to be entirely satisfactory for wrappin purposes, especially where a strong heat-sealed bond is required and it is desired to perform the heat-sealing operation on conventional wrapping machinery.
• Unsupported polyethylene films lack stiffness and are diflicult to handle on the automatic wrapping machine in general use. When it is attempted to heat-seal the unsupported film to itself on the wrapping machine, unless the condi tions are carefully controlled the polythene melts, creating a messy condition and resulting ina weak heat-sealed bond or no heat-sealed bond at all. It is, therefore, desirable to associate the polythene film with a reinforcin base or support which permits of obtaining a strong heatsealed bond when the composite sheet is used as a wrapping material and heat-sealed on a basedetermines the strength of the heat-sealed bond, the better the adhesion, the stronger the bond.
• cellophane and paper are widely used as Wrapping materials, they are not suitable as such for use as a reinforcing support for a polythene film or coating.
• Cellophane and paper are both hydrophilic and the polythenes, which are of hydrophobic character,
• the adhesion between the cellophane and polythene is so poorthat the cellophane carrying a the polythene can be used in transfer coating, the polythene being placed in contact with another base to which it is to be transferred by heat, and the cellophane being easily stripped off, leaving the polythene in contact with the other base.
• An object of this invention is to provide a superior, heat-sealab1e wrapping material comprising a hydrophilic base havin a polythene coating or film tenaciously associated with it, the base and polythene film or coating being inseparable under the conditions to which wrappin materials are normally subjected in manufacture or use. Another object is to provide such aheat-sea1able Wrapping material which is easily handled and heat-sealed on conventional wrappin machines to obtain an extremely strong heat-sealed bond.
• a further object is to provide a wrapping material comprising the hydrophilic base and substantially permanently adhered polythene film or coating which can be made without fundamental change in the methods and apparatus conventionally used in the manufacture of nonfibrous pellicles, or in conventional paper-making methods or equipment.
• the objects of the invention are accomplished by providing a wrapping material comprising a hydrophilic base containin a substantially uniformly distributed thermosetting resin in the thermoset state which conditions the base to receive and bond with polythene, and a film or coating of a polythene which is firmly anchored to the base by the thermoset resin
• the hydrophilic base is conditioned to receive the polythene by pre-treatment with the thermosetting resin which is brought to the thermoset condition in or on the base, the polythene is deposited on the prepared base either in the molten state or in the form of a hot, preformed film, and the base carrying the polythene is pressed and cooled.
• the improvement in the adhesion of the polythene to the base is particularly advantageous in the case of cellophane and paper, both of which are made available for use as commercially acceptable supports for the polythenes by the present invention.
• thermosetting resin incorporated with or applied to the hydrophilic base may be varied somewhat, but preferably the resin is present in an amount of about 0.5% to 2% by weight.
• the hydrophilic base may be a non-fibrous pellicle produced from any suitable water-insoluble hydrophilic film-forming material, such as regenerated cellulose, Whether formed from viscose solutions, cuprammonium cellulose solutions or solutions of cellulose in inorganic or organic solvents, gelatin, casein, deacetylatecl chitin, Water-insoluble polyvinyl alcohol, cellulose ethers which are insoluble in but swollen by water, and water-insoluble alginate salts.
• the pellicles may be in the form of films, sheets, tubing, bands or shaped hollow bodies.
• the hydrophilic base may be paper of any type, including heavy duty kraft paper, formed from or comprising cellulose fibers.
• the hydrophilic base is prepared and conditioned to receive the polythene by pi e-treating it with an aqueous solution or dispersion of the unpolymerized or partially polymerized thermosetting resin.
• an aqueous solution or dispersion of the unpolymerized or partially polymerized thermosetting resin there may be used for this particular purpose the water-soluble precondensates of melamine formaldehyde, urea formaldehyde, ketone-formaldehyde and phenol-formaldehyde resins, and mixtures of the several resin types.
• the water-soluble precondensates of those thermosetting resins which have been recommended for use with paper to improve its wet strength are satisfactory.
• the .hydrophilic base is a non-fibrous pellicle such as is obtained by extruding a filmforming material into an appropriate bath, it is preferably pre-treated with the thermosetting resin as a step in the manufacture of the pellicle by treating the latter, in the wet gel state, with the aqueous solution or dispersion of the unpolymerized or partially polymerized resin.
• the Wet regenerated cellulose gel obtained by extruding viscose into a coagulatin and regenerating bath through a suitable film-forming device and subjecting it to the usual after-treating liquids may be treated with the aged aqueous acid colloidal solution of the melamine-formaldehyde precondensate suitably diluted, prior to passing it through the usual aqueous bath containing a softening agent or plasticizer. Since regenerated cellulose normally carries a negative electrical charge, the positively charged resin particles in the aged dispersion or colloidal solution are preferentially absorbed by the cellulose.
• the pellicle After heating and washing the pellicle, it is treated with the aqueous medium containing the softening or plasticizing agent (which may be glycerol, ethylene glycol, sorbitol, ethanolamine lactate, ammonium sulfamate or another hydroscopic substance), washed, and dried.
• the softening or plasticizing agent which may be glycerol, ethylene glycol, sorbitol, ethanolamine lactate, ammonium sulfamate or another hydroscopic substance
• the softening or plasticizing bath may also contain the partially condensed melamine-formaldehyde resin, or the resin may be applied after the softening bath.
• the final, dried pellicle containing the thermoset melamine-formaldehyde resin is dyed uniformly throughout by a stain which is selectively absorbed by the resin but which does not affect the regenerated cellulose, indicating that the resin either unites chemically with the regenerated cellulose or is dispersed throughout the film in such small particles and so uniformly that variation in the stain is not detectable by ordinary instruments.
• the aqueous acid colloidal solution of the melamine-formaldehyde precondensate described above may be added to the paper-making stock in the beater and slieeted onto the paper-making wire or other forming means, the product'or article so obtainedbeing dried to obtain a sheet or other shaped article comprising paper-making fibers having associated therewith the melamine-formaldehyde resin in fully condensed, insoluble condition.
• the polythener may be associated with the base by forming a layer of polythene ona metal surface, pressing the baseagainst the layer while the polythene is molten, cooling the polythene layer until its surface incontact with the metal is solid, and removing the base to which the polytheneis firmly bonded from the metalisurface.
• ahot filmiof the polythene is applied directly touthebase.
• the cellophane comprising the thermoset.
• thermoset resin melamine-formaldehyde resin, or the paper comprising the thermoset resin
• the hot polythene film falls downwardly onto the base which thenpasses into the nip between the rolls.
• the polythene lays; evenly on the surface of the base and is pressed onto the base between the chilled rolls so that the sheet leaving the nip of the rolls is.
• a composite sheet comprising a polythene film or coating which is tenaciously anchored to the base by the thermoset resin.
• lIhe hot polythene film maybe stretched between the extruding device and the nip of the rolls to vary the thicknesslof the polythene film or coating bonded to. the base.
• the sheet is cooled as rapidly as possible while under the pressure of the rolls. This cooling or chilling sets the melamine formaldehyderesin-impregnated hydrophilic base and the polythene inthe bonded relation, and increases the toughness, transparency,
• a sheet of washed regenerated cellulose in the wet gel state was passed through a solution obtained by diluting the melamine-formaldehyde resin solution prepared as above to a resin content of 3%. In the contact time of 201 seconds, sufficient resin solution penetrated the film to give a concentration in the film of. about 1% by weight of resin.
• the composite sheet was out into strips one inch in width and the force in grams required to pull the polythene film from the paper base was determined on the 1P4 Scott tester and compared to the force required to separate the sheet components of a product obtained by depositing molten polythene on a sheet of Kraft paper obtained from a kraft pulp containing 1% alum but which did not contain a thermosetting resin, with the results shown in Table II.
• A represents the composite sheet the paper component of which was pre-treated with the melamine-formaldehyde resin and B represents the sheet the paper component of which was not pretreated with a thermosetting resin.
• a hot film of a polythene as characterized herein was applied to a surface of the paper under pressure, and with cooling.
• the composite sheets thus produced were cut into strips 1" wide and the force in grams required to pull the polythene film from the paper base was measured on the 1P4 Scott tester. The results are shown in the following table, which also gives the results of the same test applied to a paper made from a pulp of the same type but without the use of any thermosetting resin.
• the paper pulp to which the acidic colloidal solution of the melamine-formaldehyde resin is added may contain the usual paper-making sizing materials and fillers, such as rosin size, wax size, alum, starch, glue and clay.
• the molten polythene may be blended with parafiin wax for special purposes, before it is deposited on the paper base, the invention has the advantage that, because of the presence of the melamine-formaldehyde resin in the paper base, the parafiin wax is not required to insure penetration of the molten polythene into the paper or to facilitate adhesion of the polythene to the paper base, and may be omitted.
• the hot polythene film may be applied to one or both sides of the cellophane, paper, or other support containing the thermoset resin.
• the invention provides pellicles of regenerated cellulose having bonded thereto a thin film or sheet of polythene which are strong, tough, exhibit low permeability and resistance to creasing, and from which the cellulose base does not tend to separate.
• These sheets are useful for many purposes, for example, as liners for bottle tops, as backing for pressure-sensitive tapes, and as superior wrapping and packing materials for a wide variety of products including foodstuffs, tobacco, pharmaceuticals and other substances susceptible to deterioration by oxygen, both as the wrapping which contacts such products directly and as the exterior wrapping for the cartons or other containers in which the wrapped products are packaged for shipping.
• the composite sheets may also be used as linings for multi-wall bags for fertilizers and chemicals, as well as for dried mill: and other powdered foodstuifs.
• the composite sheets comprising a paper base having a polythene film anchored to it by the thermoset resin, particularly the melamine-formaldehyde resin specifically exemplified herein, are characterized by high wet strength as well as excellent dry strength and fold endurance. They may be used as camouflage strips and netting, in the manufacture of paper bags which must substi tute for burlap in times of emergency, and as shipping containers which do not fall apart in the presence of water. In all of these applications, the overlapping edges of the wrapping or bag may be tightly sealed by heat and moderate pressure. The strength of the heat-seal thus obtained is such that is not destroyed by a force less than the force required to destroy or partially destroy one or both components of the composite sheet.
• a composite heat-scalable wrapping material which comprises a base comprising a normally hydrophilic sheet selected from the group consisting of regenerated cellulose pellicles and paper carrying a substantially uniformly distributed thermoset melamineiormaldehyde resin characterized in that in a state of partial polymerization less than that characterizing a gel it forms acidic, aqueous solutions of from 0.5% to 20% by weight concentration which are water-dilutable, colloidal in nature, and have positively charged, hydrophilic particles of less than'about 1 micron in diameter, and a film of a polythene having a molecular weight between 10,000 and 38,000 and a softening point between 100 C.
• the polythene film being firmly anchored to the thermoset melamine-formaldehyde resin and, through said resin, to the normally hydrophilic sheet whereby the wrapping material is adapted to be heatsealed on conventional wrapping machines without separation of the polythene film from the base.
• a composite heat-scalable wrapping material which comprises a regenerated cellulose sheet carrying a substantially uniformly distributed thermoset melamine-formaldehyde resin characterized in that in a state of partial polymerization less than that characterizing a gel it forms acidic aqueous solutions of from 0.5% to 20% by weight concentration which are water-dilutable, colloidal in nature, and have positively charged, hydrophilic particles of less than about 1 micron in diameter, and a film of polythene having a molecular weight between 10,000 and 38,000 and a softening point between C.
• the polythene film being firmly anchored to the thermoset melamine-formaldehyde resin and through said resin to the regenerated cellulose sheet whereby the wrapping material is adapted to be heat-sealed on conventional wrapping machines without separation of the polythene film from the regenerated cellulose sheet.
• a composite heat-scalable wrapping material comprising a regenerated cellulose pellicle as a base sheet, said pellicle carrying on at least one surface thereof a substantially uniformly distributed thermoset resinous reaction product of formaldehyde with a substance selected from the group consisting of melamine, urea, ketone, phenol and mixtures thereof, and a film of a polythene having a molecular weight between 10,000 and 38,000 and a softening point between 100 C.
• the polythene resin being firmly anchored to the thermoset resinous product and through said resinous product to the normally hydrophilic sheet whereby the wrapping material is adapted to be heat-sealed on conventional wrapping machines without separation of the polythene film from the base.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Laminated Bodies (AREA)

Priority Applications (3)

Applications Claiming Priority (1)

Publications (1)

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ID=22949884

Family Applications (1)

Country Status (3)

Cited By (21)

Citations (6)

• 1951
  • 1951-10-11 US US250960A patent/US2686744A/en not_active Expired - Lifetime
• 1952
  • 1952-08-11 BE BE513446A patent/BE513446A/fr unknown
  • 1952-09-11 NL NL172422A patent/NL104620C/nl active

Patent Citations (6)

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