Classifications

• • 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
  • C09J123/00—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers
  • C09J123/02—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers not modified by chemical after-treatment
  • C09J123/04—Homopolymers or copolymers of ethene
  • C09J123/08—Copolymers of ethene
  • C09J123/0807—Copolymers of ethene with unsaturated hydrocarbons only containing more than three carbon atoms
  • C09J123/0815—Copolymers of ethene with aliphatic 1-olefins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
  • C08L51/06—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
• • 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
  • C09J7/10—Adhesives in the form of films or foils without carriers
• • 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
• • 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
  • C09J2301/00—Additional features of adhesives in the form of films or foils
  • C09J2301/10—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet
  • C09J2301/12—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers
  • C09J2301/124—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers the adhesive layer being present on both sides of the carrier, e.g. double-sided adhesive tape
• • 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
  • C09J2423/00—Presence of polyolefin
• • 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
  • C09J2451/00—Presence of graft polymer

Definitions

• the invention relates to an adhesive product defined in the preamble of claim 1.
• the in ⁇ vention relates to a method defined in the preamble of claim 12 for making an adhesive product.
• the invention relates to use of an adhesive product de ⁇ fined in the preamble of claim 18.
• the inven ⁇ tion relates to a layered product defined in the pre ⁇ amble of claim 20.
• the objective of the invention is to disclose a new adhesive product and method for making an adhe ⁇ sive product. Further, another objective of the inven ⁇ tion is to produce a new type of a layered product with good quality.
• the adhesive product according to the present invention is characterized by what is presented in claim 1.
• the method for making adhesive product ac ⁇ cording to the present invention is characterized by what is presented in claim 12.
• the use of the adhesive product according to the present invention is characterized by what is pre ⁇ sented in claim 18.
• the layered product according to the present invention is characterized by what is presented in claim 20.
• Fig. 1 is a flow chart illustration of a method according to one embodiment of the present in ⁇ vention
• Fig 2 is a flow chart illustration of a blow film process
• Fig 3 is a structural picture of the film.
• the adhe ⁇ sive product is in the form of a film (8) which con ⁇ tains at least one adhesive layer (20) including ther ⁇ moplastic polymer and thermoplastic polymer with anhy- dride moieties and at least one inert surface layer (22) containing thermoplastic polymer, and the inert surface layer is formed on at least one surface of the adhesive layer by reconstructing the surface of the adhesive layer, preferably toward lower surface free energy, so that the thin inert surface layer consist ⁇ ing of mainly pure non-polar thermoplastic polymer is formed on the surface of the adhesive layer, and a thickness of the thin inert surface layer is below 100 nm on the surface of the adhesive layer.
• thermoplastic polymer (2) and thermoplastic polymer with anhydride moieties (3) are mixed (1), e.g. in an extruder or other device, to form an adhesive composition (4) , the film (8) which contains at least one adhesive layer including the adhesive composition (4) is formed (7) by means of heat and with pressure or without pressure, and the film (8) is cooled (9) to provide sufficient time for a surface reconstruc ⁇ tion in order to form at least one inert surface layer containing thermoplastic polymer on at least one sur ⁇ face of the adhesive layer by reconstructing the surface of the adhesive layer, preferably toward lower surface free, energy so that the thin inert surface layer consisting of mainly pure non-polar thermo- plastic polymer is formed on the surface of the adhe ⁇ sive layer, and a thickness of the thin inert surface layer is below 100 nm on the surface of the adhesive layer.
• the film (8) is cooled (9) slowly to provide sufficient time for a surface reconstruction.
• the anhydrides of the adhesive composi ⁇ tion (4) hydrolyzed to acids are activated (5) back to anhydrides during the forming of the adhesive composi ⁇ tion .
• FIG. 1 An embodiment of the method of the present invention is shown in figure 1.
• the invention is specifically based on a re ⁇ construction of the film surface so that long non- modified thermoplastic polymer is arranged on the sur ⁇ face.
• polar anhydride moie- ties e.g. anhydride groups
• non-polar and pure thermoplastic polymer segments point out.
• Pure non-polar thermoplastic polymer mole ⁇ cules forms protective layer on the surface.
• free energy is achieved.
• the re ⁇ construction rate can be raised by increasing temperature or reducing molecular weight and crystallinity of film components.
• the reconstruction is energy and en- tropy driven phenomena and hence spontaneous.
• Reactive anhydride moieties groups may be protected with thin surface layer of thermoplastic polymer molecules.
• the thin inert surface layer contains mainly only thermo ⁇ plastic polymer substantially without the anhydride moieties, preferably without free anhydride and corre ⁇ sponding acid and their residue.
• thermoplastic polymer molecules preferably without thermoplastic polymer substantially without the anhydride moieties, preferably without free anhydride and corre ⁇ sponding acid and their residue.
• thermo- plastic polymer should be understood as any thermo ⁇ plastic polymer suitable to be used in the present in ⁇ vention including also its derivatives and modifica ⁇ tions.
• Different thermoplastic polymers may have dif ⁇ ferent properties, e.g. molecular composition, molecu- lar weight and molar mass.
• thermo ⁇ plastic polymer can include at least one polymer com ⁇ ponent or combination of different polymer components.
• the thermoplastic polymer is grafted.
• thermoplastic polymer is polyolefin.
• polyolefin is selected from a group consisting of polyethylene, polypropylene, other polyolefin and their co-polymers and combinations.
• polyolefin should be understood as any polyolefin suitable to be used in the present invention including also its derivatives and modifica ⁇ tions. Different polyolefin may have different proper ⁇ ties, e.g. molecular weight and molar mass.
• polyolefin can include at least one polyole- fin component or combination of different polyolefin components .
• thermoplastic polymer can be other suitable thermoplastic polymer, e.g. EVA (eth ⁇ ylene vinyl acetate copolymer) or PUR (polyurethane) or the like, or their combination or mixture.
• EVA eth ⁇ ylene vinyl acetate copolymer
• PUR polyurethane
• thermoplastic polymer and thermoplastic polymer with anhydride moieties can com ⁇ prise same polymer, e.g. polyolefin, or polymer composition, e.g. polyolefin composition.
• thermoplastic polymer and thermoplastic polymer with anhydride moieties contain different polymer, e.g. polyolefin, or comprise different polymer composi ⁇ tions .
• inert surface should be understood as any inert or stable surface of the film.
• the adhesive layer contains less than 1.1 % anhydride moieties, free anhydride and corresponding acid and their residue in relation to quantity of thermoplastic polymer in the adhesive lay ⁇ er.
• the film contains less than 1.07 mol-%, preferably less than 0.6 mol-% and more prefer ⁇ ably less than 0.3 mol-%, free anhydride moieties, such as unbounded anhydride and corresponding acid, in relation to total amount of anhydride moieties, such as anhydride and corresponding acid.
• anhydride moieties act as adhesion promoters.
• anhydride moieties point out. Then the anhydride moieties set on the surface of the film (8) in order to make the film reactive .
• a migration of the anhydride moieties into the inside of the film happens during the reconstruction of the film. In the migration the anhydride moieties go inside in the film.
• a re-migration of the anhydride moieties onto the surface of the film hap- pens during the re-reconstruction of the film.
• the anhydride moieties go from the inside the film toward onto the surface of the film.
• the surface free energy of the material can be determined by means of contact angle measurements .
• the inert surface layer has contact angle with distilled water which contact angle is substantially same than the contact angle of said pure non-polar thermoplastic polymer in the surface layer.
• the contact angle is measured to ensure the forming of the inert surface layer.
• the contact angle of the inert surface is 0.9 - 1.1 times the contact angle of the pure same thermoplastic polymer, in one embodiment 0.95 - 1.05 times the contact angle of the pure same thermoplastic polymer. Then gloss of the surface is preferably similar. In contrast to similar film mate ⁇ rial without moieties the contact angle of the film is between 90 - 110 %, when measured with distilled wa ⁇ ter .
• wettability of the modified ther ⁇ moplastic polymer film is directly related to the chemical composition of its surface.
• the wettability is measured by contact angle.
• the contact angle of the film must be substantially in the level of pure thermoplastic polymer when the film is in the stable form.
• the contact angle of the film must be low at melted state against polar other material, e.g. wood based veneer.
• the film is re ⁇ activated by means of re-reconstruction of the surface before the use of the film. Then the inert surface changes from inert to reactive, preferably to adhe ⁇ sive.
• the film can be made chemically reactive by re- reconstructing the surface layer so that anhydride moieties are pointing toward surface to be adhered by exposing it to polar matter.
• the film is stable before the re-activation of the film.
• the film is re-activated by heat and polar substrate .
• a technical effect of the invention is that a stable adhesive film is achieved but film can be easi- ly re-activated by re-heating.
• An additional technical effect is forming adhesive product which is moisture resistant and heat resistant under normal surrounding conditions.
• One additional technical effect is that long term stability against moist air is achieved.
• the thickness of the inert surface layer is arranged below 70 nm, preferably 50 nm and more preferably below 30 nm. In one embodiment of the present invention the thickness of the inert surface layer is arranged between 0.1 - 100 nm, in one embodiment between 5 - 100 nm. In one embodi ⁇ ment the thickness of the inert surface layer is between 5 - 70 nm, in one embodiment between 5 - 50 nm, in one embodiment between 5 - 30 nm and in one embodiment be ⁇ tween 10 - 50 nm.
• the inert surface protects the film and its reactive anhydride moieties groups, and wa ⁇ ter is not absorbed on the surface of the film.
• the inert surface protects the film and its reactive anhydride moieties groups, and wa ⁇ ter is not absorbed on the surface of the film.
• free surface energy is determined as a function of temperature.
• the inert surface is hydrophobic.
• the film (8) is formed (7) by means of an extrusion process. In one embodiment the film (8) is formed (7) by means of a blown film process. In one embodiment the film is formed by a blown film ex ⁇ trusion and especially by a blown film co-extrusion. In one embodiment the film is formed by means of a cast film extrusion or similar film making extrusion process. The film can be formed any suitable film making process but always the cooling (9) is carried out slowly, for example against non-polar substrate such as air, to en ⁇ sure inert outer layers on the surface of the film (8) . In one embodiment the blown film production is carried out after an extruder.
• Blown film extrusion can be used to make thermoplastic films, tubes or bags.
• the cross-section of the film can be uniform or multilayered .
• the film extrusion can be carried out by blowing the film upward, downward or horizontal depending on the machine construction used.
• the thermoplastic polymer material starts in a pellet form, which are successively com ⁇ pacted and melted in extruder and molten thermoplastic material is then forced, or extruded, through an annu- lar die.
• the extruder temperature is typically around 190 - 200°C and temperature can be different in dif ⁇ ferent zones of the extruder heating unit.
• thermo-plastic material there can be one or more extruders forcing one or more thermo- plastic materials in the die unit and the orifices in the die are arranged such that the different material layers merge together before cooling.
• This method is called blown film co-extrusion producing multilayered films.
• the thermoplastic used to make the film can be homogeneous or mixture of different thermoplastic pol ⁇ ymers with or without additives. Measured at the annu ⁇ lar die opening, the temperature of blown film can be as less as about 125 - 135°C or higher. Additionally, higher die temperatures or heated extrusion die lips can be used if needed. Typically production rates are usually in the level of 100 m/min, but can be up to 300 m/min with special machines.
• Air or other gaseous substance is blown through a hole in the center of the die.
• the pressure inside the film bubble causes the extruded melt to stretch and expand into a bubble.
• the gas entering the bubble replaces gas leaving it, so that even and constant pressure is maintained to en ⁇ sure uniform thickness of the film.
• the bubble is pulled continually forwards from the die and a cooling ring blows air or other gaseous substance onto the film.
• the film can also be cooled from the inside using internal bubble cooling. This reduces the temperature inside the bubble, while main ⁇ taining the blown film diameter at the same time.
• the film moves into a set of nip rollers which collapse the bubble and flatten it into two flat film layers.
• Blown film has a less effective cooling process than flat film keeping the film surface at melted state for longer time.
• Flat film cooling is done by means of chill rolls or water, which have significantly higher spe- cific heat capacities than the air or other gaseous substance used in the blown film cooling process.
• the film is then pulled by puller rolls onto windup roll ⁇ ers. Typically the film passes through idler rolls during this process to ensure that there is uniform tension in the film.
• the film may pass through a treatment zone also. During this zone or stage, the film may be slit to form one or two films, or surface treated with flame, corona or plasma for example.
• the adhesive product is a blown-formed product which has been arranged in the form of the film.
• the film (8) is cooled (9) by air.
• a technical effect is that then sufficient slow time for a surface reconstruction is achieved.
• An addi ⁇ tional technical effect is that the surface stays warm sufficient long time against non-polar substrate. Then a sufficient surface reconstruction is achieved on the surface before the thermoplastic surface reaches glass transition temperature.
• air is cold or warm.
• air is dried.
• air is typical room air.
• air dur ⁇ ing the film making (7) to ensure the coming of the pure thermoplastic polymer onto the surface of the film (8) and the going of the anhydride moieties into the inside of the film (8) .
• the air used can be dry air or moisture content in the air can be even 80 %.
• the re-migration of the anhydride moieties towards the surface can happen when the air is completely removed and the film is pressed against a solid surface, pref ⁇ erably polar surface.
• the adhesive product is in the form of a film (8) which contains two adhesive layers including thermoplastic polymer (2) and thermoplastic polymer with anhydride moieties (3) and at least one intermediary thermo ⁇ plastic polymer layer, e.g. polyolefin layer, and the intermediary thermoplastic polymer layer is arranged between two adhesive layers and the inert surface lay ⁇ er is arranged on the outer surface of the film (8) .
• the thickness of the inter ⁇ mediary thermoplastic polymer layer is between 100 - 300 ym. In one embodiment the thickness of the adhe ⁇ sive layer is between 30 - 100 ym.
• the thinner adhesive layer can be achieved more effective process in the film manufacturing and in the final product manufacturing. Then the manufac ⁇ turing can be performed at lower temperatures and/or at higher running speed.
• the inert surface layers containing thermoplastic pol ⁇ ymer, e.g. polyolefin, are formed on the both surfaces of the film (8) .
• the inert surface layer is formed only on one surface of the film.
• the adhesive product has been activated (5) before the form ⁇ ing of the inert surface.
• any free anhydride moieties or pre-compound of the anhydride moieties, e.g. carboxylic acid of the same, is removed or decreased.
• the ac ⁇ tivation (5) is carried out at temperatures over about 150 °C.
• the activation process (5) is started at temperature over 150 °C.
• the activation pro ⁇ cess (5) can be accelerated by increasing temperature and/or by catalyst. In a preferred embodiment all water generated during the activation (5) must be evaporated out .
• thermoplastic polymer (2) and thermoplastic polymer with anhydride moieties (3) are mixed (1) and heated to temperature over 180 °C during the activation (5) .
• the thickness of the anhydride moieties con ⁇ taining layer in the film (8) must be small enough to make stable end products. Thin film (8) releases inter ⁇ nal moisture produced in the activation (5) more easily. The internal moisture ruins the stability. Moisture, as well as hazardous impurities, needs to be removed before and/or during the film manufacturing (7) .
• the anhydride moieties containing layer includes less than 500 ppm, preferably less than 200 ppm and more preferably 150 ppm, free anhydride and corresponding ac ⁇ id.
• the film includes less than 70 %, preferably less than 50 % and more preferably less than 30 %, water in relation to total amount of the anhydride moieties .
• maleic anhydride is used as the anhydride moieties.
• the anhy ⁇ dride moieties are activated (5) so that free and/or grafted maleic acid in the adhesive composition is con ⁇ verted to reactive maleic anhydride during less than 2 minutes, preferably during about 1 minute, at tempera ⁇ ture over 180 °C.
• the anhydride moie ⁇ ties are activated (5) so that free and/or grafted male ⁇ ic acid in the adhesive composition is converted to re ⁇ active maleic anhydride during 2 - 4 minutes at tempera ⁇ ture over 180 °C.
• free and/or grafted maleic acid is converted at temperature 180 - 190 ° C.
• the adhesive composition includes maleic anhydride and maleic acid before the converting maleic acid to maleic anhydride.
• the anhydride moi ⁇ eties are activated so that free maleic acid is removed. Free and residual maleic acid and free anhydrides can be removed or decreased during this process and/or after an extrusion, e.g. in a cooling stage. Further, moisture and contaminants can be removed. In one embodiment con ⁇ version with over about 80 % anhydride and below about 20 % acid is provided by the activation.
• the inert surface layer is formed so that there is no free maleic anhydride on the surface of the film.
• the free maleic anhydride or corresponding carboxylic acid can be any monomer, oligomer or polymer containing these moieties and able to evaporate or surface segregate below the melting point of the base thermoplastic polymer of the adhesive layer.
• any suitable agent, com ⁇ pound or composition containing anhydride or derivate of anhydride can be used as anhydride moieties.
• the anhydride moieties can include one or more than one anhydride moieties component.
• the anhydride moieties contain functional groups which may be activated into reactive form and which are capable of forming bonding with the other material.
• thermoplastic polymer with anhydride moieties is anhydride grafted thermo ⁇ plastic polymer or anhydride grafted thermoplastic polyolefin .
• thermoplastic polymer has similar or lower molecular weight than molecular weight of the thermoplastic polymer with anhydride moieties .
• the adhesive layer contains less than 10 % by weight, preferably 1 - 4 %, in one embodiment 2 - 7 %, maleic anhydride grafted thermoplastic polymer.
• the adhesive product in ⁇ cludes suitable additives which can be selected from the group: reinforcement fiber, filler, stabilizer agent, fire retardant agent, coloring agent and other suitable additive and their combinations.
• the intermediary layer includes at least one said additive.
• the adhesive product is capable of forming covalent bonding with the other material, e.g. wood, metal, pa ⁇ per, plastic or other suitable material.
• the invention relates to use of the present adhesive product (8) as glue so that the adhe ⁇ sive product (8) is heated (10) at least over the melting point of the thermoplastic polymer in the in ⁇ ert surface for activating the adhesive product and the adhesive product (8) is used in the gluing.
• the adhesive product is heated over the melt ⁇ ing point of the thermoplastic polymer in the inert sur- face.
• the adhesive product is heated over the melting points of the thermoplastic polymers in the inert surface and in the adhesive layer.
• the adhesive product (8) is used in the manufacturing (12) of a layered product (11) in which layers of the layered product are glued together by means of the adhesive product ( 8 ) .
• the adhesive product (8) is used directly as the glue.
• the glue includes the adhesive product of the present invention which can be treated in a desired way.
• the protective inert surface layer disappears while polar anhydride moieties groups turn pointing toward interface.
• Temporarily anhydride moieties free zone under interface anhydride moieties will be fulfilled with bulk anhydride moieties by mo ⁇ lecular diffusion. Diffusion/migration is energy and entropy driven and hence spontaneous. After this reac- tive anhydride moieties are able to make covalent bonds with the other material. Re-reconstruction and diffusion rate are higher at elevated temperatures.
• the invention relates to a layered product (11) formed of two or more layers, such as ve- neers, being arranged the one above the other and com ⁇ bined by means of gluing with glue including said ad ⁇ hesive product (8) of the present invention.
• a layered product (11) can be selected from a group consisting of a veneer product, wood board, panel product, plywood, fiber board, film product, composite board, block board, strand board, moulding product or their combinations.
• a layered product (11) is formed of two or more veneers being arranged the one above the other and combined by means of glue.
• a layer of the layered product can be formed any suitable material.
• the layer of the layered product is formed wood, metal, paper, glass, plastic, other suitable material or their com- binations.
• a layered product (11) is formed of two or more wood based veneers being ar ⁇ ranged the one above the other and combined by means of glue of the present invention.
• the method of the present invention offers a possibility to prepare stable adhesive products which are moisture and temperature resistant and are capable of forming covalent bonding with the other material, e.g. with wood, metal, paper, plastic or other suita- ble material.
• the adhesive product is easy to process, and it gives good protection to the final product. Further, the layered product with good dimension sta ⁇ bility can be achieved.
• the layered product is post- and re-formable after re-heating, and it has good im ⁇ pact strength, moisture resistance and fatigue re- sistance.
• the adhesive product and final product e.g. the layered product, can be formed cost-effectively.
• 3-layer film 8 is formed.
• the film comprises two adhesive layers 20 and one polyole- fin layer 21 between the adhesive layers.
• the adhesive layers of the film 8 are formed from the adhesive composition 4 containing maleic anhydride grafted polyethylene 3 in polyethylene 2. Pure polyethylene 2 is mixed 1 with maleic anhydride graft ⁇ ed polyethylene 3 at temperature over 180 °C. The re ⁇ sidual and hydrolysed maleic acid in the adhesive com ⁇ position 4 is converted to reactive maleic anhydride during 2 - 4 minutes at temperature 180 - 190 ° C in the activation step 5. Then maleic acid content de ⁇ creases significantly and reactive maleic anhydride content increases.
• the adhesive composition 4 contain ⁇ ing 2 to 10 % by weight maleic anhydride grafted poly ⁇ ethylene 3 in polyethylene 2.
• Maleic anhydride grafted polyethylene 3 includes 0.2 to 5 mol-% maleic anhy ⁇ dride. Then total molecular anhydride concentration is 0.004 to 0.25 mol-%.
• the film 8 is formed 7 by a blow film co- extrusion which is shown in figure 2.
• production rate is about 6 m/min and temperature of the extruder is between 180 - 200 °C in the blown film co-extrusion.
• the extrusion step 7 in which the anhydride moieties are activated takes about 1 minute.
• the length of the film bubble is about 17 m, and the temper ⁇ ature of the film is about 40 °C before nip rollers.
• the activation step 5 is a part of the ex ⁇ trusion step 7.
• the thickness of the polyolefin layer is about 200 - 300 ym, and the thickness of the adhesive layer is about 50 ym.
• the film 8 is cooled 9 slowly to provide sufficient time for re-crystallization of the polyethylene and surface re ⁇ construction and/or to provide sufficient time for so ⁇ lidification of the polyethylene and surface recon ⁇ struction.
• the cooling is made at a rate of about 1 degree per second. In one embodi ⁇ ment, the cooling happens so that the film cools about 50 degrees per meter from about 200 °C to 100 °C dur ⁇ ing the first two meters, i.e. about 5 degrees per se ⁇ cond.
• Thin inert surface layers 22 are formed on the both outer surfaces of the film 8, on the surfaces of the adhesive layers.
• the inert surface layer is formed by means of reconstruction of the surface. In the re ⁇ construction the polar anhydride groups turn inside the film and non-polar polyethylene segments points out, toward the surface of the film.
• the inert surface layer contains polyethylene but not reactive maleic anhydride grafted polyethylene. During forming inert surface layers residual moisture can be removed.
• the thickness of the inert surface layer is arranged be- tween 5 - 50 nm.
• the reactive maleic anhydride is pro ⁇ tected with the inert surface layers.
• the formed polyethylene film 8 does not ex ⁇ hibit any moisture adsorption.
• the stable structure in humid air is achieved.
• the formed adhesive film 8 is used as glue in plywood application 12 to glue veneers together.
• the adhesive film 8 is heated 20 - 50 ° C over the melting temperature of polyethylene in the heating step 10. Then the re-reconstruction of the surface happens and the active maleic anhydride groups go from inside of the film toward onto the contacting surface of the film. The veneers and the adhesive film are brought into contact in the heating step 10.
• the adhesive film of the present invention acts very good in the gluing ap- plication.
• the 3-layer film is formed in accordance with example 1.
• the adhesive product according to the present invention is suitable in different embodiments to be used for gluing.
• the method according to the present invention is suitable in different embodiments to be used for making the most different kinds of adhesive products.
• the adhesive product according to the pre- sent invention is suitable in different embodiments to be used in different final products, e.g. adhesive compositions and layered products.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Laminated Bodies (AREA)
• Adhesive Tapes (AREA)

Priority Applications (4)

Applications Claiming Priority (1)

Publications (1)

Family

ID=45922704

Family Applications (1)

Country Status (4)

Citations (3)

• 2012
  • 2012-03-13 EP EP12711425.4A patent/EP2825607A1/de not_active Withdrawn
  • 2012-03-13 WO PCT/FI2012/050238 patent/WO2013135942A1/en active Application Filing
  • 2012-03-13 CN CN201290001222.XU patent/CN204848730U/zh not_active Expired - Lifetime
  • 2012-03-13 DE DE212012000255.3U patent/DE212012000255U1/de not_active Expired - Lifetime

Patent Citations (3)

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