MXPA97001942A - Polyamide adhesives that have improved characteristics of binding - Google Patents

Abstract

A binding method comprising the steps of a) applying a film comprising at least one polyamide that melts with heat at an application temperature of between about 175øC and about 190øC on the spine of a book block, the film has a strength at a tensile greater than about 28.12 kg / cmýy a Young's modulus of less than about 843.68 kg / cmý and b) covering the block of the book having the polyamide film with a book cover having a portion thereof in substantial relation parallel to the movie

Description

IAMIDA PO ADHESIVES THAT HAVE IMPROVED BINDING CHARACTERISTICS DESCRIPTION OF THE INVENTION This application is a Continuation in Part of copending Application Serial No. 08/616853, filed March 15, 1996, incorporated herein by reference. The present invention relates to a method for using a heat-melted polyamide blend for binding applications, such as one-cycle and two-cycle binding. The present invention also relates to polyamide blends particularly suitable for binding which have lower application temperatures and good properties. Binding in a cycle, which is also known in commerce as a perfect union, is the most common method by which books are joined. Using this method, the sheets or sheets which form a book are interspersed or stacked and then held in a gag to form a book block. The adhesive is then applied to the spine of the book block using, for example, a container of two or three glue wheels. The cover is then applied to the skeleton of the book block before the adhesive hardens. The spine of the book block may be wrinkled or trimmed before the application of the adhesive, but this is not a uniform practice. The binding of two cycles is also commonly used to join books. Using this method, the book block is initially joined using a primer. The primer is typically a water based system, but it can also be a hot melt adhesive. Due to the low drying times of water-based systems, the spine of the book can be passed over burners or heaters to decrease the drying time. A second adhesive known as a cover or second cycle adhesive, which is usually a hot-melt adhesive, is then applied using a two- or three-wheel glue applicator on the spine of the book. The binding process is then completed using the application of protective paper, gauze or coarse canvas and kraft paper before the application of the cover. The bindings of a cycle and two cycles are used to join a variety of items including, but not limited to, paperbacks and paperbacks, magazines, catalogs, telephone directories or other types of directories, manuals such as computer manuals and textbooks. Heat-melting adhesives are widely used for the binding of a cycle and for two cycles, due to the rapid rate of hardening that can be achieved, thus increasing the number of books that can be joined in a set amount of time. The most frequently used types of hot-melt adhesive are based on ethylene copolymers and block copolymers. However, with the increasingly increasing use of recycled paper and highly coated glossy substrates, such as for high fashion magazines, increased bonding efficiency is often required and such hot melts sometimes lack the capacity to join these substrates. The heat resistance of these hot melts often does not exceed 65 ° C. Heat resistance refers to the temperature at which the adhesive will soften and fall off, leaving the cover separation of the spine of the book, or separation of the sheets or sheets from each other. The resistance to heat is very important in the transport of books in the summer months, when temperatures in a transport vehicle can be in an excess of 70 ° C. Another disadvantage of the use of heat melts based on ethylene copolymers or block copolymers is that the solvent resistance of the ink is low. The ink solvents will migrate through the pages to the spine of the book where the cover of the book prevents further migration. The concentration of the solvent at this point leads to the delamination of the cover of the book on the back of the book. This has led to the use of polyurethanes that melt with heat or PUR that melt with heat. These adhesives are also known in the industry as moisture cures of the melt. PUR are high performance adhesives with excellent adhesion for difficult substrates, such as recycled paper and bright, highly coated substrates. PURs have excellent solvent resistance to the ink and excellent resistance to heat, which often exceeds 100 ° C. There are disadvantages to using PUR, however, such as very slow cure rates and cost. Due to the speed of slow healing, books can be sent before healing. No mechanical test can be performed in the book before healing. Quality control is therefore not carried out and there is no guarantee that the books will meet the specification. The binders in which the melts are currently being used can not change rapidly for the use of the PUR, because different application equipment is required. This in turn leads to high conversion costs and equipment must be purchased. PURs also have high manufacturing and raw material costs resulting in increased cost to consumers. For the binding of two cycles, the polyurethane dispersions, which are water-based systems, can be used as the primer. Polyamides are commercially available from many sources, including Henkel Kommandiigesellschaft auf Aktien located in Dusseldorf, Germany; Union Camp located in Jacksonville, FL and H.B. Fuller Co. a company located in St. Paul, Minnesota. U.S. Patent No. 4,419,494 of Puletti et al., Issued December 6, 1983, teaches the use of polyamides based on dimeric fatty acid in combination with block copolymers A-B-A. The tensile strength of these products are substantially lower than those of the present invention which are less than about 7.03 kg / cm2 (100 psi) at 100% elongation at 21 ° C. This patent does not disclose the use of polyamides for binding applications. European Patent No. 633,919 to Heucher et al., Issued October 14, 1993, describes polyamide based on dimeric fatty acid used in combination with ethylene-vinyl acetate or ethylene-methacrylate copolymers and styrene-block copolymers. styrene-butene and hydroabietyl alcohol or polybutene. This is distinguishable from the present invention, in that it requires the use of a copolymer of polypropylene and block copolymer and a plasticizer all in combination with the polyamide. The resulting properties of these adhesives are not the same as those required for binding applications. This patent describes how to use these adhesives for joining polyethylene, PVC and metal, but does not teach how to use them for binding applications. These products are therefore useful for the limited purpose of joining these difficult materials. U.S. Patent No. 4,791,164 to ichelhaus et al., Issued December 13, 1988, discloses a compatible mixture of an ethylene-based terpolymer and a polyamide. However, this patent, like European Patent No. 633,919, teaches the use of these products for the limited purpose of joining metals and polar and apolar plastics, such as polypropylene or polyethylene. It does not teach how to use polyamide blends for use in binding applications. U.S. Patent No. 4,018,733 of López et al., Issued April 19, 1977, describes mixing polyamides with ethylene acid polymers and tackifiers. It again teaches how to use these mixtures for the limited purpose of joining plastics such as polyethylene and metals such as lead. It does not describe how to use these mixtures for binding applications. U.S. Patent No. 5,026,756 issued June 25, 1991 and U.S. Patent No. 5,091,454 issued February 25, 1992 to Arendt teach the use of 1,4-cyclohexane dimethanol, dibenzoate in combination with polyamides but does not teach how to use this combination for binding applications. U.S. Patent No. 4,409,373 to Iemers et al., Issued October 11, 1983 and U.S. Patent No. 4,777,238 issued October 11, 1988 and U.S. Patent No. 4,914,162 issued on April 3, 1990 to Leoni et al., describes how to prepare polyamides but does not describe the use for binding. U.S. Patent No. 4,728,688 to Tizzard et al., Issued March 1, 1988, teaches the use of a water-based primer for the first adhesive and the segmented EVA copolymer or a monoalkene-acetate copolymer. segmented vinyl and a tackifying resin as the second adhesive, for the binding of two cycles, but does not teach the use of polyamide blends for the binding of two cycles. Polyamide adhesives that melt with heat have not been used as binding adhesives due to the low heat stability. Typically, polyamides that melt with heat have to be applied above 200 ° C due to their high melting points and high viscosities. These very high application temperatures can cause the polyamide to degrade and prevent its use in binding applications. The degradation of polyamides results in carbonization. The carbonization causes uneven application of the polyamide that melts the book with heat, which results in poor adhesion at certain points. Also, polyamide adhesives that melt with heat typically have low elongation values, which prevents good flat lay characteristics for books. Flat placement refers to the ability of books to remain open when no pressure is applied such as from a hand. Surprisingly, the present inventors have found that by mixing heat-melting polyamides or mixing other polymers, tackifiers or plasticizers without heat-melting polyamides, the properties required for binding applications can be achieved. These blends lead to better specific adhesion, which is required for UV coated paper, glossy coated paper or recycled paper. By mixing the polyamides with other materials, lower viscosities can be obtained which require lower application temperature which improves the stability in the container. The problem with the degradation of the polyamides, therefore, is eliminated. Higher values of elongations are obtained which are required for good flat placement. Polyamide blends that melt with heat have a fast hardening time, which allows the quality control test before shipment, ensuring that the books are meeting the required specifications. The heat resistance of polyamide blends that melt with heat can exceed 95 ° C, which is much higher than that of melts based on polyethylene copolymers or block copolymer based melts. The standard melt application equipment can be used to apply polyamide blends that melt with heat in such a way that the conversion costs realized with the use of the PUR is not a factor. A method of binding comprises the steps of: I. Applying a film comprising at least one polyamide that melts with heat at an application temperature of between about 175 ° C and about 190 ° C on the back of a book block, the film has a tensile strength greater than approximately 28.12 kg / cm2 (400 psi) and a Young's Modulus of less than approximately 843.68 kg / cm2 (12,000 psi); and II. Cover the skeleton of the block of the book that has the polyamide film that melts with heat with a cover of the book that has a portion of it in a substantially parallel relationship for the film. The polyamide blend that melts with heat is between the book block and the book cover and adheres substantially to the pages of the book which forms sheets, the book block and the book cover each other. The present invention further discloses an adhesive melting with heat of polyamide blend, suitable for binding, comprising: I. An adhesive that melts with heat for use in binding, comprising from about 50% to about 70% by weight of a polyamide-based fatty acid dimer; from about 10% to about 30% by weight of a tackifying resin of the rosin group and rosin derivatives; and modified terpenes and terpenes; and aliphatic and cycloaliphatic and aromatic hydrocarbons and hydrogenated derivatives; and its mixtures; from about 10% to about 30% by weight of an ethylene-vinyl acetate copolymer containing from about 25% to about 40% by weight of vinyl acetate and having a melt index greater than about 40 g / 10 minutes .

II. A hot melt adhesive for use in binding, comprising from about 70% to about 95% by weight of a polyamide based on fatty acid dimer; and from about 5% to about 30% by weight of 1,4-cyclohexane-dimethanol dibenzoate, wherein the heat-melting adhesive can be used at an application temperature of from about 175 ° C to about 190 ° C with degradation minimal Heat-melting polyamide blends are further characterized by elongation values of more than about 350% and preferably greater than about 500% and tensile strengths of more than about 28.12 kg / cm2 (400 psi) and preferably greater than about 56.24 kg / cm2 (400 psi) and Young Modules of less than about 843.68 kg / cm2 (12,000 psi) and preferably less than about 703.07 kg / cm2 (10,000 psi). The books thus formed by the method of binding a cycle or by a binding method of two cycles have good characteristics of flat placement. Surprisingly, polyamide heat-melting blends can be applied at temperatures from about 175 ° C to about 190 ° C with reduced degradation.

The heat-melting polyamide blend comprises at least one polyamide. This polyamide is present in amounts of from about 20 to about 100 percent by weight, preferably from about 40 to about 100 percent by weight, more preferably from about 60 to about 100 by weight and more preferably from about 80 to about 100 percent by weight. These polyamides can be based on a fatty acid dimer, or other fatty acids. Such polyamides are available from Henkel Ko mandiigesellschaft auf Aktien located in Dusseldorf, Germany; of Union Camp located in Jacksonville, Florida and of H.B. Fuller Co. located in St. Paul, Minnesota. Preferred polyamides are HM-1580, HM-1525, HM-0652 and HL-6527-X available from H.B. Fuller Co. Someone with skill in the art will recognize that there are many different grades of polyamides available and will select those with the desired physical properties. The tackifying resins useful herein are selected from the group consisting of rosins and rosin derivatives; and modified terpenes and terpenes; and aliphatic and cycloaliphatic and aromatic hydrocarbon resins and hydrogenated derivatives; and its mixtures. Such tackifying resins typically have a Ring and Ball softening point of between about 70 ° C and about 150 ° C, however, some are available in lower softening point versions and still in liquid form. Useful resins include Nirez ™ V-2040, a phenolic modified terpene available from Arizona Chemical Co. located in Panama City, FL; Sylvatac ™ 1103 available from Arizona Chemical Co. , Unitac ™ R-100 Light available from Union Camp Corp. located in Jacksonville, Fl, Permalyn ™ 305 available from Hercules in Wilmington, Delaware which are all esters of pentaerythritol rosin; Eastotac ™ H-100 and H-130 available from Eastman Chemical Co. in Kingsport, TN which is a partially hydrogenated cycloaliphatic petroleum hydrocarbon resin; Wingtack ^ R Extra available from Goodyear Chemical Co. in Akron, OH which is a partially hydrogenated cycloaliphatic petroleum hydrocarbon resin; Hercolite ™ 2100 available from Hercules which is a partially hydrogenated cycloaliphatic petroleum hydrocarbon resin; Zonatac ™ 105 Lite available from Arizona Chemical Co. which is a hydrocarbon resin with terpene and styrene made from d-limonene; Escorez ™ 5300 available from Exxon Chemical Co. located in Houston, TX which is a partially hydrogenated cycloaliphatic hydrocarbon resin. The tackifying resin is present up to about 40 percent, preferably from about 10 to about 40 percent, more preferably from about 10 to about 30 percent and more preferably from about 15 to about 30 percent. The copolymers useful herein are copolymers of ethylene. The ethylene-vinyl acetate copolymers useful herein are those containing from about 10 to about 50 weight percent vinyl acetate monomer and preferably from about 25 to about 40 weight percent acetate monomer. vinyl; and having a melt index greater than about 5 g / 10 minutes and preferably a melt index greater than about 40 g / 10 minutes. Preferred copolymers are Elvax ™ 40 and Elvax ™ 150 available from DuPont Chemical Co., in Wilmington, DE. A variety of other grades of ethylene-vinyl acetate copolymers are available from DuPont, from Quantum Chemical Corp. in Rolling Meadows, IL and from AT Polymers and Film, Inc. in Charlotte, NC. The copolymers are present up to about 60% by weight, preferably from about 10 to about 40% by weight, more preferably from about 10 to about 30% by weight and more preferably from about 15 to about 30% by weight. The plasticizers useful herein are selected from the group consisting of benzoate plasticizers and are available from Van Waters and Rogers in Twinsburg, OH and Velsicol Chemical Co. in Rose ont, IL. Someone skilled in the art would recognize that there are many different grades of benzoate plasticizers available for use. Some examples include 1,4-cyclohexanedimethanol dibenzoate available under the tradename Benzoflex ™ 352; Benzoflex ™ S-404 which is a glyceryl tribenzoate; Benzoflex ™ S-552 which is a pentaerythritol tetrabenzoate all available from Velsicol Chemical Co. Morflex ™ 150, which is a plasticizer of dicyclohexyl fatalate available from Morflex Inc. located in Greensboro, NC may also be used. A stabilizer or antioxidant can also be used in polyamide blends that melt with heat. These compounds are added to protect the adhesive from degradation caused by the reaction with oxygen induced by things such as heat, light or residual catalyst from the raw materials, such as the tackifying resin. Such antioxidants are commercially available from Ciba-Geigy, Ha thorne, NY and include Irganox ™ 1010 and Irganox ™ 1076 which are hindered phenols. These are primary antioxidants which act as radical scavengers and can be used alone or in combination with other antioxidants such as phosphite antioxidants such as Irgafox ™ 168 available from Ciba-Geigy. Phosphite antioxidants are considered secondary antioxidants and are generally not used alone. These are mainly used as agents that break down peroxide. Other available catalysts are CyanoxMR LTDP available from American Cyanamide, Stamford, CT and EthanoxMR 1330 available from Albemarle, Baton Rouge, LA. Many such antioxidants are available either to be used alone or in combination with another such antioxidant. These compounds are added to the melts with heat in small amounts and have no effect on the other physical properties. Other compounds that can be added so little affect the physical properties are pigments, which add color or fluorescent agents to mention just one pair. Additives similar to these are known to those skilled in the art. Additional additives that are useful for the present invention in amounts of less than about 10% are fatty amide waxes such as Kenamide ™ W-40 or oxidized Fischer-Tropsch fences such as Paraflint ™ A-3 or Paraflint ™ A-28. This increases the speed of hardening of the polyamide mixture and allows it to be used with binders at a higher speed without significant reduction adhesion. Ethylenebis-aids are available from Witco located in Memphis, Tennessee under the trade name of Kenamide ™. Several degrees are available. This invention contemplates the use of other functionalized waxes, including, but not limited to, oxidized polyethylenes. The adhesives are prepared by mixing the components in the melt at temperatures between about 170 ° C and 200 ° C until a homogeneous mixture is obtained. The various methods of mixing are used in the industry of adhesives and any method that works is satisfactory. The resulting adhesives are characterized by tensile strengths of more than about 28.12 kg / cm2 (400 psi) and preferably greater than about 56.24 kg / cm2 (800 psi); elongation values greater than about 350% and preferably greater than about 500%; Young modules of less than about 843.68 kg / cm2 (12,000 psi) and preferably less than about 703.07 kg / cm2 (10,000 psi) and more preferably less than about 421.84 kg / cm2 (6,000 psi); the programmed release values greater than approximately 65 ° C; the programmed shear values greater than approximately 85 ° C; cold fracture values of less than about 2 ° C and preferably less than about -4 ° C; and viscosities of less than about 22,000 cPs to about 175 ° C and preferably less than about 10,000 cPs to about 175 ° C. These adhesives are ideal for use in one-cycle and two-cycle binding applications. The resulting books show excellent flat placement characteristics. Surprisingly, polyamide heat-melting blends can be applied at temperatures from about 175 ° C to about 190 ° C with reduced degradation. High application temperatures of about 200 ° C typically associated with heat melting polyamides can prevent their use in standard melt application equipment. The degradation of the heat-melting polyamide occurs at elevated temperatures that result in carbonization. The carbonization will result in uneven coverage of the melt with heat on the book, which in turn results in the lack of adhesion at the binding points. Lowering application temperatures can reduce these problems. The commonly used heat melt application equipment is a two or three wheel glue container. The adhesives are applied to the books using binders manufactured by Mueller Martini, Harris or Kolbus. Someone skilled in the art might recognize that there are other manufacturers of binders for books, but Mueller Martini is the most commonly used equipment. Some of the model numbers that can be used are Pony 3020, Normbinder SC, Normbinder SFC all manufactured by Mueller Martini located in Sofingen, Switzerland; the Systembinder KM 490 and Systembinder KM 495 manufactured by Kolbus located in Mahwah, NJ; and the UB-2, UB-3 and UB-5 binders available from Harrie now owned by AM Graphies located in Cincinnati, Ohio. The most commonly used heat-melt adhesive application equipment is manufactured by Comstock-Wescott located in Cambridge, MA and is a two or three wheel glue container. These hot melt adhesives can be used for the binding of a cycle and two cycles, glue with cement, airtight backing, top coating, formation of upper band and binding of the book. In the union of the book of a cycle, or Union Perfect, the adhesive is applied to the spine of the book block and the cover is applied before the adhesive hardens. In a binding of a cycle for soft cover books, which is also known in the industry as Otabind or representative cover, the cover is attached to the book in much the same way as a book with a traditional hard cover. The sheets or sheets are interspersed or stacked and then held in a jaw to form the block of the book. The adhesives are applied to the spine and the flap edges of the book block. A reinforcement liner is rolled over the spine and the cover is pressed into place and fixed by glue on one side. The reinforcement lining can be crepe paper, gauze or paper. This results in the cover of the book that is unbound to the spine on the contrary to a binding of a cycle for hard cover books. In the binding of two cycles, the book block is initially bonded using a primer. A second adhesive known as a cover adhesive or a second cycle is then applied to the spine of the book. The polyamide adhesive of the present invention can be used for both of these operations. In hard cover books the binding process can be terminated by using protective paper, gauze or coarse canvas applications and then kraft paper before the application of the cover to increase the strength. The main bands can also be applied to the spine before the application of the cover. These are additional stages which include cement bonding, upper lining, watertight backing, upper band formation and is described in the following. These applications may require lower viscosity adhesives which can be obtained by the use of lower viscosity polyamides or by the addition of other modifiers such as waxes, solid plasticizers and tackifiers. These adhesives may require viscosity of less than 5000 cPs at 175 ° C, especially where application extrusion methods are used, such as for hermetic backing and superior web formation. The lower viscosity adhesives often have lower tensile and elongation properties than those required for one- or two-cycle binding applications. The object of applying the glue is to cause the glue to penetrate inside the spine to a limited degree between the sheet sections, thereby reinforcing the effect of the seam. Sometimes in the binding process, the upper bands are applied to the spine. These are narrow bands of cloth which can be glued with cement to the top and back of the spine of the book, or sometimes only to the top. This is usually done for decorative purposes. The lining is the process of gluing with cement protection paper, gauze or coarse canvas to the spine of a book after bonding with adhesive or stitching to improve the strength or firmness of the book. Kraft paper can also be applied. The airtight backing is the process of attaching the book block and / or the liner compound to the cover by means of extrusion or roller coating of the adhesive, which results in a spine firmly attached to the cover. This can be on the contrary to the loose back cover attached, which can better facilitate flat placement at the expense of rigidity and total strength. The binding of the book is another method by which adhesives can be used. In this method, the book block of a hard cover book is attached to the cover by applying hot melt strips, which adheres to the book block to the cover. This method is similar to the side with glue in soft cover books. This is an extrusion method that also requires lower viscosity adhesives having viscosities less than about 5000 cPs at about 175 ° C. This invention is further illustrated by the following non-limiting examples. Comparative examples A and B are conventional heat-melt adhesives based on ethylene-vinyl acetate copolymers. EXAMPLES Test Methods 1. Traction and Elongation, Yong Module The traction and elongation, Deformation Point and the Yong Module were determined using ASTM D-638. The matrix used is a matrix of type 4 ASTM D-638. A 2.54-centimeter gauge with a video extensometer is used to monitor the elongation. The deformation speed used is 25.4 centimeters / minute. The Yong Module is a method of classifying the relative flexibility of adhesive films. The thickness of the film used is 20-25 thousandths of an inch. The resistance to tensile deformation is measured at small stresses. 2. Release and shear stress The values of shear and shear were determined by placing samples in a programmed oven with a weight of 100 g used for the mode of shedding and weight of 500 g used by the shear stress mode and increasing the temperature of approximately 25 ° C to 175 ° C at 25 ° C / hour. The oven automatically records the temperature at which the samples fail. Each sample was coated on kraft paper by hand using glass bars or wedges. The resulting coating is a band 2.54 centimeters wide that is about 8-10 mils or about 0.02 inches to about 0.03 inches thick. 4 to 5 joints were made for the shedding mode and 4 to 5 joints were prepared for the shear stress mode and the results were averaged. 3. Cold Fracture Films with a 20-30 mil thickness were prepared by hand using a glass rod or wedge. Several samples that are 2.54 centimeters (1 inch) x 7.62 centimeters (3 inches) are cut from the film. The samples are placed in a base in a freezer at 10 ° C for 1 hour. The base is made of a rigid plastic and has a through hole that is cut into the base at an angle of 90 ° C. After 1 hour, a pressure bar that is cut to exactly fit the base is forced into the samples. The cold fracture is the temperature at which the sample of 2.54 centimeters fails (1 inch) x 7.62 centimeters (3 inches). The temperature is decreased by approximately 2.8 ° C every hour until the adhesive fails. 4 • Viscosities of the Melt Mass The viscosities of the melt of the hot melt adhesives were determined on a Brookfield Thermosel Viscometer using a number 27 spindle. 5. Bonding Tests Joints were prepared by extruding an adhesive bead onto the substrates using an applicator on the top of the table, held by hand Slaurtterback Moni-Squirt. The application temperature was from about 160 ° C to about 200 ° C. The second substrate is immediately coupled to the first and a weight of 1000 grams is then rotated over the length of the bond line. The adhesive count is maintained at approximately 20.32 centimeters (8 inches) with a weight of 1 gram. The joints are allowed to age at ambient conditions for 24 hours and then rotated manually to determine if there was fiber tear or delamination. 6. Mettler R & B Softening Point Mettler R & B softening points are determined using the ASTM D-3461 test method. 7. Ink Solvent Test The Kraft to Kraft joints were prepared using the same method that was used to prepare the shear and shear samples in # 2 in the test methods section. The wedge size used is 20 thousandths of an inch. The samples are cut into strips of 2.54 centimeters (1 inch). The samples are placed in a hood where 50 microliters of the printing ink are supplied in the center of each joint using an Eppendor micropipette. The ink is allowed to soak in the bond line for 60 minutes. The detachment samples are then placed in a programmable oven as in # 2 above with a weight of 50 g. The oven is increased to 25 ° C per hour until all the samples have failed. Control samples, without ink, are used. 8. Heat Stability Tests A sample of 200 g of each of the adhesives is placed in a forced air oven at 175 ° C and allowed to settle in the oven for 96 hours. A small portion of the adhesive, from about 10 g to about 20 g, was removed from the container at 24, 48, 72 and 96 hours. The viscosity was measured for these time intervals and the sample was observed for changes in physical appearance. The change in the viscosity of reagent as a change in percentage of the initial viscosity was calculated by subtracting the viscosity taken in each time interval from the initial viscosity and dividing by the initial viscosity. Less change in viscosity and better physical appearance better heat stability. Physical appearance refers to carbonization, skin formation, film and gel.

Examples 1 to 7 and Comparative Examples A and B TABLE 1 ADHESIVE COMPONENTS Example 1 1 1 i 5 6 HM-1580 100 60 95 60 25 HM-1525 60 HM-0652 75 Silvatac 1103 20 20 20 EVA (40-55) 20 20 EVA (33-44) 20 Benzoflex 352 5 HI-3296X 100 TABLE 2 TEST DATA Example 6 Viscosity @ 176 7 ° C 0,500 11,500 15,425 5,285 16,250 14,475 5 Mettler softening point (* F) 294 284 335 285 Detachment at 100g (* F) 227 163 188 187 171 228 192 Shear force at 500g (° F :) > 227711 224 214 261 231 301 260 Cold fracture (ßF) 15 15 15 0 20 25 15 Final drive (psi) 700 533 760 550 704 1,389 600 Elongation (%) 770 m 630 600 69 $ 456 500 Deformation point (psi) 651 3Í3 660 530 425 1,811 .. Youpg module (psi) 4,835 1,364 6,260 2,290 2,236 11,217 4500 J traction 100% Elongation (psi) 64 310 490 350 410 lF190 Heat stability tests were performed for Example 7. No film or gel formation was observed after 96 hours. Some carbonization and discoloration was observed. An approximate increase in viscosity of approximately 30% was observed after 96 hours. This is a substantial improvement over commercial heat melting polyamides, standards.

COMPARATIVE TABLE 3 NS 34-1116 / A HBF / B Viscosity @ 176.7 ° C 9,000 9,125 Mettteerr softening point ( { °° FF)) 207 222 Detachment at 100g (° F) | 139 148 Shear force at 5Q0g (* F)) 164 176 Cold fracture 45 40 Traction (psi) 1,890 2,050 Elongation. { %) 560 530 Deformation point (psi) 1 960 1,010 The heat-melting polyamide blends of the present invention have higher heat resistance than the comparative ethylene-vinyl acetate based formulations, as evidenced by higher shear and shear values. In addition, the blends of the present invention exhibit excellent tensile properties allowing them to be used for binding applications where flat placement is needed. The low elongation values typically achieved with polyamides have so far avoided their use in binding applications. The lower viscosities also allow these mixtures to be applied at temperatures of less than about 205 ° C, which is advantageous because typical polyamides must be applied at temperatures of about 205 ° C where their stability in the container is not good.

TABLE 4 TEST OF INK SOLVENT NS HBF HBF = # S HBF E HBF «# 3 34-1116 5362-80-1 5466-6-2 5466-18-1 5466-22-4 Control - 50g / inch2 PAFT 1 1 158 > 200 > 200 200 Inking - 50g / inch2 115 134 190 195 198 These heat melt masses conventions, 34-1116 and 5362-80-1, represent the products developed to be solvent resistant and achieve superior results for those obtained with heat melts for standard binding.

The adhesives of the present invention exhibit improved solvent resistance to ink, over conventionally used heat-melt based ethylene-vinyl acetate.

Claims (11)

1. CLAIMS 1. A method for binding, characterized in that it comprises the steps of: a) applying a film comprising at least one polyamide that melts with heat at an application temperature of about 175 ° C and about 190 ° C on the back of a block of book, the film has a tensile strength greater than about 28.12 kg / cm2 and preferably greater than about 56.24 kg / cm2 and a Young's modulus of less than about 843.68 kg / cm2 and preferably less than about 703.07 kg / cm2; and b) covering the block of the book having the hot melt polyamide film with a cover of the book having a portion thereof in substantially parallel relationship with the film. The method according to claim 1, characterized in that the heat-melting polyamide film is interposed between the block of the book and the cover of the book and substantially adheres the sheets of the book which form sheets, the block of the book and the cover of the book with each other. 3. The method according to claim 1, characterized in that the reinforcement lining is wound on the spine of the book block before covering the block of the book with the cover of the book. 4. The method according to claim 1, characterized in that the additional stage selected from the group consisting of upper lining, the hermetic backing and the formation of the upper band is interposed before covering the back of the block of the book with the cover of the book. 5. The method according to claim 1, 2, 3, or 4, characterized in that the polyamide film that melts with heat is a one-cycle or two-cycle adhesive. 6. An adhesive that melts with heat for use in binding, characterized in that it comprises from about 50% to about 70% by weight in the adhesive of a polyamide based on a fatty acid dimer; from about 10% to about 30% by weight in the adhesive of a tackifying resin selected from the group consisting of rosins and rosin derivatives; terpenes and modified terpenes; and aliphatic and cycloaliphatic and aromatic hydrocarbons; hydrogenated derivatives and their mixtures; from about 10% to about 30% by weight of an ethylene-vinyl acetate copolymer comprising from about 25% to about 40% by weight of vinyl acetate and having a melt index greater than about 40g / l0 min, wherein the hot melt adhesive can be used at an application temperature of about 175 ° C to about 190 ° C with minimal degradation. 7. The hot melt adhesive according to claim 6, characterized in that the adhesive is a film. The adhesive according to claim 1 or 7, characterized in that the polyamide film that melts with heat has an elongation greater than 350% and preferably greater than 500%. The adhesive according to claim 1 or 7, characterized in that at least one polyamide which melts with heat is based on a dimer fatty acid. 10. The method of compliance with the claim 1, characterized in that the heat-melting polyamide further comprises up to 80% by weight in the adhesive of additives selected from the group consisting of thermoplastic polymers, tackifying resins, solid plasticizers and waxes. The method according to claim 1, 6, 9, 10 or 11, characterized in that the polyamide further comprises from about 5% to about 30% by weight in the adhesive of a solid plasticizer dibenzoate 1,4-cyclohexane dimethanol .