MXPA01010667A - Pressure sensitive cohesive - Google Patents

Abstract

A pressure sensitive adhesive/cohesive exhibits excellent cohesive body properties, and other desirable features, even when exposed to heat and polysiloxane based lubricants, such as in a laser printer. The formulation comprises 100 parts by weight natural rubber (e.g. electrosterically stabilized natural rubber graft and block terpolymer), and expressed as percentages by weight of the rubber the following components:about 5-35%(e.g. about 28%) acrylate monomer or monomers (such as methyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, and/or isobornyl methacrylate);about .5-8%acrylic acid and /or about 1-10%4-acetoxystyrene;about 0-20%ethyl hexyl acrylate;about 1-50%(e.g. about 10-30%) finely divided hard particulate material (such as silica gel);0-50%(preferably about 10-30%) starch;and 0-40%(preferably at least about 5%) carboxylated styrene-butadiene latex, or carboxylated polychloroprene latex, or a styrene-acrylate-acrylonitrile latex, or vinyl-pyridine styrene-butadiene latex, or pre-crosslinked natural rubber latex, or a tackifier, or combinations thereof. The cohesive is coated onto paper and seals to like cohesive upon the application of a force of at least 100 lbs per lineal inch.

Description

COHESIVE SUBSTANCE SENSITIVE TO PRESSURE BACKGROUND AND COMPOSITION OF THE INVENTION The present application is a partial continuation of the application Serial No. 09 / 507,932, filed on February 22, 2000, now pending. U.S. Patent Nos. 4,918,128 and 5,190,818 provide pressure sensitive adhesives / cohesives, which are revolutionary in their utility, when used in postal documents or similar documents or business forms. These patented adhesives have enabled the practical embodiment in the mail and postal items industry, which can be produced quickly and effectively and sealed without the drawbacks associated with conventional adhesives, activated by heat or moisture. While the adhesives, in the above-identified patents, are extremely effective, the ability to produce an adhesive having even better properties is desirable. While the adhesives, in the patents identified above, are not tacky, after application to the paper, and do not adhere / seal unless a high level of pressure is applied (which prevents the adhesive from clogging during printing, which would slow the process, due to paper jams or the like), sometimes the adhesive action can be hindered by the contamination of the printing surface and the adhesive with the silicone lubricants used in conventional printers (particularly laser printers) . The adhesive, in accordance with the present invention, when coated on paper or similar substrates used in postal type business forms, or the like, have the same advantageous properties as the adhesives of the patents identified above and also the increased functionality when they are contaminated with silicone lubricants. As in the preferred embodiments in the patents identified above, the cohesive, according to the present invention, contains a natural rubber graft, one or more suitable acrylate monomers, such as methyl methacrylate or cyclohexyl methacrylate or methacrylate of benzyl or isobornyl methacrylate or trimethyl-cyclohexyl methacrylate or isobornyl acrylate, and finely divided hard particles, such as silica. When the cyclohexyl methacrylate is employed, it is typically present in an amount of about 0.5 to 1.5% by weight, more usually about 1% by weight, based on the weight of the modified latex. Methyl methacrylate and polymethyl methacrylate, when used, are typically present in an amount of about 10 to 18% by weight, more usually about 15% by weight. The cohesive, according to the present invention can also include starch, acrylic acid and / or 4-acetoxystyrene and, optionally, ethylhexyl acrylate. According to the present invention, a pressure sensitive adhesive / cohesive is provided, comprising the following components: 100 parts by weight of natural rubber; about 5 to 35% by weight of rubber, acrylate monomer; about 0.5 to 8% by weight of rubber, acrylic acid and / or about 0 to 10%, typically 1 to 10% by weight of rubber, 4-acetoxystyrene, and 1 to 50% by weight of the rubber, hard particulate material, finely divided, which does not have substantially thermoplasticity. The composition may also advantageously comprise about 0 to 10% by weight, for example 1 to 10 & in rubber weight, 4-acetoxystyrene. The composition may further comprise from about 0 to 20% by weight of the rubber, ethylhexyl acrylate, from 0 to 50% by weight of the rubber, starch; and from 0 to 40% by weight of the rubber, carboxylated styrene-butadiene latex, or carboxylated polychloroprene latex, or vinyl-pyridine-styrene-butadiene latex or latex from the previously entangled natural rubber, or a tackifier , or their combinations. In the case of 4-acetoxystyrene, as a comonomer in the graft / rubber block, the grafted rubber has an antioxidant incorporated, as a result of the hydrolysis of the acetoxy group, which provides the cohesive antioxidant property that helps in its shelf life, as a coated cohesive, acting as a free radical scavenger. The pressure sensitive adhesive / cohesive, according to the present invention, is typically coated on a piece of paper. More typically, since the material, according to the invention, is better as a cohesive, it is coated on two portions of a piece of paper, the cohesive portions being in contact with each other, as a result of folding the paper (as in the formation of a postal item), or carrying a similar sheet in contact with them, and sealing them together by pressure (such as by operation through conventional pressure sealant equipment, such as the "Speedisealer®" equipment, available from Moore USA, of Lake Forest, Illinois), in order to cause the paper fibers to tear, if their separation is attempted by pulling them.

In the following discussion, the percentages are by weight, unless stated otherwise. Preferably, the adhesive / cohesive comprises at least 1% ethylhexyl acrylate, and at least 1% starch, for example about 10-30% starch (such as about 20% starch), which has an average particle size of around 5 to 25 microns. The hard particulate material preferably comprises silica gel, for example about 10 to 30% (such as 20%), the silica gel has an average particle size of about 0.2 to 20 microns (e.g., about 0.3 at 4 microns) or a smoked silica (for example from 0.1 to 0.3 microns). There may also be at least 5% carboxylated styrene-butadiene latex, or a carboxylated polychloroprene latex, or a vinyl-pyridine-styrene-butadiene latex, or a previously interlaced natural rubber latex,. or a styrene-acrylate-acrylonitrile latex or a tackifier, or combinations thereof. The acrylic monomer preferably comprises methyl methacrylate, for example about 5 to 30% or 0.5 to 8% of 4-acetoxystyrene, cyclohexyl methacrylate, benzyl methacrylate, trimethyl-cyclohexyl methacrylate or isobornyl methacrylate. Acrylic acid is typically present between about 0.5 to 4% and 4-acetoxystyrene between about 1 to 3%. The modified natural rubber latex is preferably an electrosterically stabilized natural rubber graft and block terpolymer. Generally, the acrylate monomer is selected from cyclohexylmethyl methacrylate, methyl methacrylate and mixtures of the two. The methacrylate of trimethyl-cyclohexyl-methyl, methyl methacrylate and their mixtures can also be used. In both cases, the natural rubber may be an electrostatically stabilized latex of the natural rubber graft / block terpolymer. In the present case, the term "electroesthetically" is used when there are ionizable / hydrolysable groups grafted onto the natural rubber, for example acrylic acid or 4-acetoxystyrene. These ionizable groups impart a negative charge to the latex particles, which stabilize the emulsion. The term "electrostatically" is used when the non-ionizable / hydrolysable groups are grafted onto the natural rubber and thus, the only charge on the latex particles arises from the electric double layer. According to another embodiment, the cohesive can be manufactured by synthesizing a modified natural rubber latex through the reaction of 1, -cis-polyisoprene (natural rubber) with two or more acrylate monomers, followed by reactions and subsequent processes. Typically, the modification is carried out using cyclohexyl methacrylate (CHMA) (approximately 1 to 5% by weight) and / or methyl methacrylate (MMA) (approximately 10 to 18% by weight). For discussion purposes, the synthesis of the natural rubber latex graft / block terpolymer modified with the CHMA / MMA will be described below. However, it will be understood that the invention is not limited to the modified natural rubber latexes, which use these two acrylate monomers. Examples of other acrylates that can be used are benzyl methacrylate and / or isobornyl methacrylate and / or trimethylcyclohexyl methacrylate and / or isobornyl acrylate. A graft / block terpolymer of the natural rubber latex with the CHMA / MMA can be synthesized by conducting a seeded emulsion polymerization of the natural rubber latex (e.g., about 100 parts by weight) with the CHMA (e.g. 5 parts by weight), initiating a graft polymerization by the redox pair under a nitrogen atmosphere, in a reaction vessel at 35 ° C. After the CHMA begins to polymerize and begins to be consumed, the MMA (about 11 parts by weight) is added to the reaction mixture, initiating a reaction with a redox initiator initiating system. MMA polymerizes together with polymer CHMA chains that grow, creating partial blocks of poly CHMA and poly MMA grafted into 1,4-cis-polyisoprene. This results in a molecular architecture of modified natural rubber latex, which is a graft / block terpolymer latex. Some polymethyl methacrylate (PMMA) is also formed during the synthesis of modified natural rubber latex, because the concentration of the surfactant is well above the CMC (critical concentration of micelles), which promotes the formation of some polymerized MMA in emulsion in the micelles. This is about 0.2 to 0.5% by weight of the polymerized PMMA in emulsion in the modified natural rubber colloid. The reaction of the MMA and / or CHMA is believed to be accompanied by some chemical entanglement to form the graft / block terpolymer of 1,4-cis-polyisoprene (natural rubber) with the CHMA and the PMMA. The modified natural rubber latex is then mixed with a styrene-butyl acrylate latex, typically Acrygen 41135 latex, which has a narrow particle size distribution (average particle size of 400 ranks), a surface tension of 49 dynes / cm, and a Brookfield viscosity (# 2 @ 6 rpm) of 1500 cps. Acrygen 41135 latex has an excellent mechanical stability, tensile strength of 35.7 kg / cm2 and an elongation of 700%, and is compatible with modified natural rubber latex, works as a binder, has a mechanical stability and acts as an intensifier of colloidal stability. The chemical entanglement between the Acrygen 41135 latex and the modified natural rubber latex is not believed to occur. A sulfated fatty acid, typically Modical S, is then added to the formulation as an intensified mechanical and chemical stability. This is followed by stirring the mixture to form a cohesive, colloidally stable formulation. The styrene present in the cohesive is Acrygen 41135 latex, which is an alternative copolymer latex of styrene and butyl acrylate, with a narrow particle size distribution. Styrene is not a part of the latex of the modified natural rubber, used as the starting material. In yet another embodiment, the cohesive of the invention can be synthesized as follows. The modified latex (a 1, 4-cis-poisoprene graft / block terpolymer (natural rubber - synthesized as described above) is mixed with the Acrygen 41135 latex (Omnova Solutions) in a blender The Modical S (Henkel Corporation) is a sulfated fatty acid, and is added to the formulation as an enhancer of mechanical and chemical stability, followed by mixing all the components to form a colloidally stable mixture.An aqueous silica hydrogel paste, typically the Syloid W-300 ( Grace-Davison Corporation), is added to the colloidal mixture and agitated.The Syloid W-300 has an average particle size of 5 μm and a pore volume of 1.2 cc / g.The silica hydrogel also modifies the modulus of the Cohesive compound and helps absorb silicone lubricant A non-ionic surfactant agent of acetylene diol, with mean hydrophilic-lipophilic balance (HLB) of +13, typically Surfynol GA (Air Products and Chemical), was added to the colloidal mixture and this mixture was stirred. The Surfynol GA works as a pigment dispersant and helps the colloidal stability of the formulation. A defoaming agent based on silicone, for example SN-381 (San Nopco) was added to the mixture and this mixture was stirred. This is followed by the addition of a sodium polyacrylate thickener, with a very high pseudoplastic index, typically the Algocgum 296W (Aleo Chemical), and the mixture is stirred until the thickener is dispersed. A yellow dye ammoniacal solution, typically FDC No. 5 (BF Goodrich - 4,5-dihydro-5-oxo-l- (4-sulfophenyl) -4- [4-sulfophenylazole] -lH-pyrazole trisodium salt -3-carboxylic acid) was added and the mixture was stirred. An antimicrobial agent, typically Do 75, active ingredient, 1- (3-chloroalyl) -3,5-7-triazaadamantane chloride (Dow Chemical), was then added to the formulation and the mixture was stirred, followed by addition of an antioxidant, typically the Tinos # 22MB-2, 2'-methylenebis (4-methyl-6-tert-butylphenol (Technical Solutions Inc.) in aqueous dispersion, to the colloidal mixture and this mixture was stirred. controls the high-cut mechanical degradation of latex polymer chains from modified natural rubber (graft terpolymer / 1,4-cis-polyisoprene block (natural rubber) with CHMA and PMMA), which occurs when the formulation is applies, with high cut, in a coating press The antioxidant also helps to prevent entanglement of the modified natural rubber latex According to another aspect of the present invention, a method of obtaining postal-type business forms is provided. This method includes: (a) applying the cohesive as cooperating patterns to the sheet of paper, so that when the sheet is bent, or brought into contact with a similar sheet, the patterns move in mutual contact. The cohesive comprises a pressure sensitive cohesive, which includes: 100 parts by weight of natural rubber; about 5 to 35% by weight of the rubber acrylate monomer; about 0 to 8% (preferably about 5 to 8%) by weight of the acrylic acid of rubber and / or about 0 to 10% (preferably about 1 to 10%) by weight of 4-acetoxystyrene; about 0 to 20% by weight of the ethylhexyl acrylate of the rubber; from 1 to 50% by weight of the rubber, a finely divided hard particle material, which has substantially no thermoplasticity; from 0 to 50% by weight of the rubber starch; and from 0 to 40% by weight of carboxylated rubber styrene-butadiene latex, styrene-acrylate-acrylonitrile latex, or carboxylated polychloroprene latex, or vinyl-pyridine-styrene-butadiene latex, or natural rubber latex previously interlaced, or an agent that forms stickiness, or combinations thereof. When the film is formed on the surface paper, there is a compatibilizing effect between the Acrygen 41135, a styrene-acrylate latex, which helps to change the surface characteristics of the film. Acrygen 41135 latex has a glass transition temperature (Tg) of 15 ° C. The method may comprise the subsequent steps of: (b) folding the paper to move the cohesive patterns in mutual contact and (c) applying a sealing pressure of at least 17,858 kilograms / linear centimeter (eg 35,716 kg / cm) to the patterns to seal together the cohesive substances and cause the fibers to tear, if their separation is attempted by pulling. The present invention provides a pressure sensitive adhesive / cohesive, which exhibits an adhesive bond, a cohesive bond, heat resistance, blocking resistance, abrasion resistance, excellent, does not form tack and has good drag properties and substantially no there is loss of adhesion / cohesion when exposed to heat and polysiloxane-based lubricants. Further aspects of the invention will become clear from an inspection of the detailed description of the invention and the appended claims.

DETAILED DESCRIPTION OF THE INVENTION The general invention, as described above, will now be set forth with respect to some specific examples.

Example 1: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 1.5% by weight of acrylic acid and about 28.5% by weight of methyl methacrylate and 0% by weight of ethylhexyl acrylate, mixed with silicon dioxide (silica gel) smoked / precipitated, with an average particle size of aggregates of about 0.2 to 0.6 μm, in an amount of about 20% by weight and a starch, with a specified range of an average particle diameter of about 10 μm, in an amount of about 14.5% by weight per 100 parts by weight of the modified, electroesthetically stabilized natural rubber, to prepare a pressure sensitive adhesive / cohesive. The latex of the terpolymer in this example is referred to as the latex 1 and the preparation of the formulation in this example will be referred to as the cohesive 1.

Example 2: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with 3% by weight of acrylic acid and about 28% by weight of methyl methacrylate and 0% by weight of ethylhexyl acrylate, was mixed with dioxide silicon (silica gel) smoked / precipitated, with an average particle diameter of about 0.4 μm, in an amount of about 20% by weight and a starch, with a specified range of an average particle diameter around of 10 μm, in an amount of about 14.5% by weight per 100 parts by weight of the natural, electroesthetically stabilized, modified rubber, to prepare a pressure sensitive adhesive / cohesive. The latex of the terpolymer in this Example 2 is referred to as the latex 2 and the preparation of the formulation in this example will be referred to as the cohesive 2.

EXAMPLE 3 The cohesives of Examples 1 and 2, i.e. cohesive I and II, were coated on 20 pound (9,072 kg) paper, using a Meyer No. 4 rod.

Example 4: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 1.5% by weight of acrylic acid and about 23% by weight of methyl methacrylate and 0% by weight of ethylhexyl acrylate, was mixed with silicon dioxide (silica gel) smoked / precipitated, with an average particle diameter of about 0.3 ~ 0.4 μm, in an amount of about 20% by weight per 100 parts by weight of natural rubber, stabilized electroestéricamente, modified, to prepare a adhesive / cohesive sensitive to the pressure. The latex of the terpolymer in this Example is referred to as the latex 4 and the preparation of the formulation in this example will be referred to as the cohesive 4.

Example 5: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 1.5% by weight of acrylic acid and about 20% by weight of methyl methacrylate and 0% by weight of ethylhexyl acrylate, was mixed with silicon dioxide (silica gel) smoked / precipitated, with an average particle diameter of about 0.3 ~ 0.4 μm, in an amount of about 20% by weight per 100 parts by weight of natural rubber, stabilized electroestéricamente, modified, to prepare a adhesive / cohesive sensitive to the pressure. The latex of the terpolymer in this Example is referred to as the latex 5 and the preparation of the formulation in this example will be referred to as the cohesive 5.

Example 6: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 1.5% by weight of acrylic acid and about 16% by weight of methyl methacrylate and 0% by weight of ethylhexyl acrylate, was mixed with silicon dioxide (silica gel) smoked / precipitated, with an average particle diameter of about 0.3 ~ 0.4 μm, in an amount of about 20% by weight per 100 parts by weight of natural rubber, stabilized electroestéricamente, modified, to prepare a adhesive / cohesive sensitive to the pressure. The latex of the terpolymer in this Example is referred to as the latex 6 and the preparation of the formulation in this example will be referred to as the cohesive 6.

Example 7: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 2.5% by weight of acrylic acid and about 15% by weight of methyl methacrylate and 0% by weight of ethylhexyl acrylate, was mixed with silicon dioxide (silica gel) smoked / ipitated, with an average particle diameter of about 0.3 ~ 0.4 μm, in an amount of about 20% by weight per 100 parts by weight of natural rubber, stabilized Electroestéricamente, modified, to are an adhesive / sure sensitive cohesive. The latex of the terpolymer in this Example is referred to as the latex 7 and the aration of the formulation in this example will be referred to as the cohesive 7.

Example 8: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 3% by weight of 4-acetoxystyrene and about 15% by weight of methyl methacrylate and 0% by weight of acrylic acid, was mixed with silicon dioxide (silica gel) smoked / ipitated, with an average particle diameter of about 0.3 ~ 0.4 μm, in an amount of about 20% by weight per 100 parts by weight of the natural rubber, electroesthetically stabilized, modified, to are an adhesive / cohesive sensitive to sure. The rubber of 4-acetoxystyrene has an antioxidant incorporated in the polymer chain, which helps the polymer against oxidation. The latex of the terpolymer in this Example is referred to as the latex 8 and the aration of the formulation in this example will be referred to as the cohesive 8.

Example 9: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 1.5% by weight of 4-acetoxystyrene and about 15% by weight of methyl methacrylate and 0% by weight of acrylic acid, was mixed with silicon dioxide (silica gel) smoked / ipitated, with an average particle diameter of about 0.3 ~ 0.4 μm, in an amount of about 20% by weight per 100 parts by weight of the natural rubber, electroesthetically stabilized, modified, to are an adhesive / cohesive sensitive to sure. The rubber of 4-acetoxystyrene has an antioxidant incorporated in the polymer chain, which helps the polymer against oxidation. The latex of the terpolymer in this Example is referred to as the latex 9 and the aration of the formulation in this example will be referred to as the cohesive 9.

Example 10 Cohesive, commercially available (TN-124) is referred to as cohesive 10.

Example 11 Cohesive, commercially available (TN-124F) is referred to as cohesive 11.

Example 12: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 4% by weight of the cyclohexyl methacrylate and about 12% by weight of methyl methacrylate and 0% by weight of acrylic acid, was mixed with silicon dioxide (silica gel) smoked / ipitated, with an average particle diameter of about 0.3 ~ 0.4 μm, in an amount of about 20% by weight per 100 parts by weight of the natural rubber, electroesthetically stabilized, modified, to are an adhesive / cohesive sensitive to sure. The latex of the terpolymer in this Example is referred to as the latex 12 and the aration of the formulation in this example will be referred to as the cohesive 12.

Example 13: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 5% by weight of the cyclohexyl methacrylate and about 11% by weight of methyl methacrylate and 0% by weight of acrylic acid, was mixed silica hydrogel, with an average particle size of about 4 ~ 5 μm, in an amount of about 42% by weight per 100 parts by weight of the natural, electroesthetically stabilized, modified rubber, to are an adhesive / cohesive sensitive to the sure. The latex of the terpolymer in this Example is referred to as the latex 13 and the aration of the formulation in this example will be referred to as the cohesive 13.

Example 14: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 5% by weight of the cyclohexyl methacrylate and about 11% by weight of methyl methacrylate and 0% by weight of acrylic acid, was mixed with silica gel, with an average average particle size of about 4 ~ 5 μm and a pore volume of 1.2 cc / g, in an amount of about 20% by weight per 100 parts by weight of natural rubber, stabilized electroestéricamente, modified, to prepare a adhesive / cohesive sensitive to the pressure. The latex of the terpolymer in this Example is referred to as the latex 14 and the preparation of the formulation in this example will be referred to as the cohesive 14.

Example 15: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 5% by weight of the tri-methyl-cyclohexyl methacrylate and about 11% by weight of methyl methacrylate and 0% by weight of acid acrylic, silica hydrogel was mixed with an average particle size of about 4 ~ 5 μm, in an amount of about 42% by weight per 100 parts by weight of the natural rubber, electroesthetically stabilized, modified, to prepare an adhesive / cohesive sensitive to pressure. The latex of the terpolymer in this Example is referred to as the latex 15 and the preparation of the formulation in this example will be referred to as the cohesive 15.

Example 16: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 2% by weight of the cyclohexyl methacrylate and about 12% by weight of methyl methacrylate and 0% by weight of acrylic acid, was mixed with silica hydrogel with a particle size of about 4 ~ 5 μm. in an amount of about 42% by weight per 100 parts by weight of the natural rubber, electroesthetically stabilized, modified, to prepare a pressure sensitive adhesive / cohesive. The latex of the terpolymer in this Example is referred to as the latex 16 and the preparation of the formulation in this example will be referred to as the 16 cohesive.

Example 17: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 5% by weight of the tri-methyl-cyclohexyl methacrylate and about 11% by weight of methyl methacrylate and 0% by weight of acid Acrylic, was mixed with silica gel with a particle size of about 4 ~ 5 μm. and a pore volume of 1.2 cc / g, in an amount of about 20% by weight per 100 parts by weight of the natural, electroesthetically stabilized, modified rubber, to prepare a pressure sensitive adhesive / cohesive. The latex of the terpolymer in this Example is referred to as the latex 17 and the preparation of the formulation in this example will be referred to as the cohesive 17.

Example 18: Latex, electroesthetically stabilized, of the graft terpolymer and natural rubber block, with about 2% by weight of the cyclohexyl methacrylate and about 12% by weight of methyl methacrylate and 0% by weight of acrylic acid, was mixed with silica gel with a particle size of about 4 ~ 5 μm and a pore volume of 1.2 cc / g, in an amount of about 20% by weight per 100 parts by weight of the natural rubber, electroesthetically stabilized, modified , to prepare a pressure sensitive adhesive / cohesive. The latex of the terpolymer in this Example is referred to as the latex 18 and the preparation of the formulation in this example will be referred to as the cohesive 18.

Example 19 FORMULATION OF COHESIVES I, II, III, IV, V, VI, VII, VIII, IX, XII-XVIII Application and Test The resulting formulations, Cohesives I, II, IV, V, VI, VII, VIII, IX and XII-XVIII were applied to a paper of 24 pounds (10,886 kg) to form a film, by a rod repeller No. 4 Meyer, and dried in an oven to form a thin film of approximately 7 ~ 9 μm, for this paper of 24 pounds (12 samples each). Two of the samples were sealed with the PS-4 Speedisealer® equipment, available from Moore North America, Inc., Lake Forest, Illinois, at a pressure of 35,716 kg / linear cm, without exposure to the image-forming medium. Two minutes later, the samples were sealed, and then detached. All samples sealed properly and showed a fiber tear and it was also observed that the dry samples were not sticky. Of the 10 remaining samples, 5 samples were used in a Xerox 4050 Laser printer, and 5 samples were used in a Xerox 4635 printer , in order to expose the cohesive film to heat and silicone lubricants.

After waiting for 2 minutes, all samples were sealed with a PS-4 Speedisealer® device, with a pressure of 35,716 kg / linear cm. Two minutes later the samples were sealed, then peeled off to examine the quality of the seal and it was also observed that the dried samples were not sticky in any way. Likewise, after being used in Xerox 5040 and Xerox 4635 printers, the samples showed no signs of blockage or clogging in these Xerox printers. Together with the aforementioned samples, for comparison, 12 samples each were prepared with TN-124 and TN-124F (commercially available) by coating with Meyer's No. 4 application rod, and dried in an oven to form a thin film about 7 ~ 9 μm thick, for a 24-pound paper. Two minutes later, the samples were sealed, peeled off to examine the quality of the seal and it was also observed that the dried samples were not sticky in any way. All test data are given in Table I.

TABLE Formulation of Cohesives 13, 15 and 16 Formulation of Cohesives 14, 17 and 18 If used, the carboxylated styrene-butadiene latex may be of Ameripol-Synpol, and / or the carboxylated polychloroprene latex of Butachior XL 415 of Enichem Elastomers America, and / or the vinyl-pyridine-styrene-butadiene latex of Pliocord Vp-5622 from Goodyear and / or the styrene-acrylate-acrylate latex from OMNOVA Inc. The details of acrylic acid, ethylhexyl acrylate, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, 4-acetoxystyrene, the range of the percentage of the various components and the average particle diameter for the starch and the finely divided hard particulate material, which has substantially no thermal plasticity (preferably silica gel), are as described above in the Background and Compendium of the Invention . Other modifications are also possible, which include coatings on other types of paper, in addition to paper of 20, 24 pounds and 28 pounds (0.072, 10,886 and 12,701 kilograms) and postal items of all kinds can be obtained, which include the fold in V, fold in Z and fold in C, as they are conventional, or the sheets of paper that correspond surface with surface. Other types of sealing equipment, like conventional bending equipment, can be used in the practice of the method of the invention, and in the production of the business forms according to the invention. Likewise, other types of products can be produced in addition to postal-type business forms. The documents / sheets of paper can be pre-printed, before being fed to a laser printer or the like, this laser printer prints on the same variable and / or non-variable indications, by the application of the toner. The invention also specifically includes all narrower ranges within a wide range. For example, 1 to 10% means 2.9%, 1.9 to 3%, 6 to 9.5% and all other narrower intervals within the broad range. Therefore, it will thus be seen that, in accordance with the present invention, a highly advantageous pressure-sensitive adhesive / cohesive, postal-type business forms and / or paper parts coated thereon are provided, as well as a method to obtain postal type business forms. While the invention has been shown and described herein in what is presently conceived as its most practical and preferred embodiment, many modifications can be made within the scope of the invention, this scope will be in accordance with the broadest interpretation of the invention. appended claims, to cover all products, formulations and equivalent methods.

Claims (35)

1. CLAIMS 1. An adhesive / cohesive, pressure sensitive, which comprises: 100 parts by weight of natural rubber; about 5 to 35% by weight of the rubber is at least one acrylate monomer; and about 1 to 50% by weight of the rubber is a hard, finely divided particulate material that does not substantially have a thermoplasticity.
2. 2. A pressure sensitive adhesive / cohesive, as defined in claim 1, further comprising about 0 to 8% by weight of the rubber, of acrylic acid.
3. 3. A pressure sensitive adhesive / cohesive, as defined in claim 1, further comprising from 0 to 10% by weight of the rubber, of 4-acetoxystyrene.
4. 4. A pressure sensitive adhesive / cohesive, as defined in claim 1, further comprising from 1 to 10% by weight of the rubber, of 4-acetoxystyrene.
5. 5. A pressure sensitive adhesive / cohesive, as defined in claim 1, further comprising from about 0 to 20% by weight of the rubber, of ethylhexyl acrylate.
6. 6. A pressure sensitive adhesive / cohesive, as defined in claim 1, further comprising about 0 to 50% by weight of the rubber, of starch.
7. 7. A pressure sensitive adhesive / cohesive, as defined in claim 1, further comprising about 0 to 40% by weight of the rubber, of the carboxylated styrene-butadiene latex, or the carboxylated polychloroprene latex, or the latex of vinyl-pyridine-styrene-butadiene, or the styrene-acrylate-acrylonitrile latex, or the previously crosslinked natural rubber latex, or a tackifying agent, or combinations thereof.
8. 8. A pressure sensitive adhesive / cohesive, as defined in claim 1, wherein the natural rubber is an electrosterically stabilized latex of the graft terpolymer and natural rubber block.
9. 9. A pressure sensitive adhesive / cohesive, as defined in claim 1, wherein the acrylate monomer is selected from the group consisting of methyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, trimethyl-cyclohexyl methacrylate, isobornyl acrylate and isobornyl methacrylate.
10. 10. A pressure sensitive adhesive / cohesive, as defined in claim 1, wherein the monomer is cyclohexyl methacrylate and is present in an amount of about 1% by weight, based on the weight of the natural rubber .
11. 11. A pressure sensitive adhesive / cohesive, as defined in claim 1, wherein the monomer is methyl methacrylate and is present in an amount of about 12% by weight.
12. 12. A pressure sensitive adhesive / cohesive, as defined in claim 1, wherein the adhesive / cohesive is coated on a piece of paper.
13. 13. A pressure sensitive adhesive / cohesive, as defined in claim 12, coated on two portions of a piece of paper, said cohesive portions being in contact with each other, as a result of folding the paper, and sealing together under pressure , in order to cause the fibers of the paper to tear if you try to separate the portions by pulling them.
14. 14. A pressure sensitive adhesive / cohesive, as defined in claim 3, having an antioxidant incorporated in the electroesthetically stabilized latex of the graft terpolymer and natural rubber block, when 4-acetoxystyrene is used as a monomer in the graft, which provides oxidative stability to the pressure sensitive adhesive / cohesive.
15. 15. A pressure sensitive adhesive / cohesive, as defined in claim 1, comprising at least 1% of the ethylhexyl acrylate.
16. 16. A pressure sensitive adhesive / cohesive, as defined in claim 1, comprising at least 1% starch, and wherein the natural rubber comprises a graft terpolymer and natural block, electroesthetically stabilized.
17. 17. A pressure sensitive adhesive / cohesive, as defined in claim 1, which comprises about 10 to 30% starch, which has an average particle size of about 5 to 25 microns.
18. 18. A pressure sensitive adhesive / cohesive, as defined in claim 17, wherein the hard particulate material comprises about 10 to 30% silica gel, having an average particle size of about 1 to 20 microns .
19. 19. A pressure sensitive adhesive / cohesive, as defined in claim 1, comprising at least 5% carboxylated styrene-butadiene latex, or a carboxylated polychloroprene latex, or a vinyl-pyridine-styrene latex. -butadiene, or a previously interlinked natural rubber latex, or a styrene-acrylate-acrylonitrile latex, or a tackifying agent, or combinations thereof.
20. 20. A pressure sensitive adhesive / cohesive, as defined in claim 1, comprising about 1.5 to 4% acrylic acid, and wherein the acrylic monomer comprises about 15 to 35% methyl methacrylate.
21. 21. A pressure sensitive adhesive / cohesive, as defined in claim 20, wherein the acrylic monomer comprises methyl methacrylate.
22. 22. A pressure sensitive adhesive / cohesive, as defined in claim 13, comprising at least 1% starch, and wherein the natural rubber comprises a graft terpolymer and natural block, electroesthetically stabilized.
23. 23. A pressure sensitive adhesive / cohesive, as defined in claim 13, comprising about 10 to 30% starch, having an average particle size of about 5 to 25 microns.
24. 24. A pressure sensitive adhesive / cohesive, as defined in claim 13, wherein the hard particulate material comprises about 10 to 30% silica gel, which has an average particle size of about 0.3 to 0.4. mieras
25. 25. A pressure sensitive adhesive / cohesive, as defined in claim 13, comprising at least 5% carboxylated styrene-butadiene latex, or a carboxylated polychloroprene latex, or a vinyl-pyridine-styrene latex. -butadiene, or a previously interlinked natural rubber latex, or a styrene-acrylate-acrylonitrile latex, or a tackifying agent, or combinations thereof.
26. 26. A pressure sensitive adhesive / cohesive, as defined in claim 13, comprising about 1.5 to 4% acrylic acid, and wherein the acrylic monomer comprises about 5 to 30% methyl methacrylate.
27. 27. A pressure sensitive adhesive / cohesive, as defined in claim 8, comprising at least 1% starch.
28. 28. A pressure sensitive adhesive / cohesive, as defined in claim 27, comprising at least 1% ethylhexyl acrylate, and wherein the natural rubber comprises a grafted terpolymer and natural block, stabilized electroestéricamente.
29. 29. A pressure sensitive adhesive / cohesive, as defined in claim 26, comprising at least 5% carboxylated styrene-butadiene latex, or carboxylated polychloroprene latex, or vinyl-pyridine-styrene latex. -butadiene, or a previously interlinked natural rubber latex, or a styrene-acrylate-acrylonitrile latex, or a tackifying agent, or combinations thereof.
30. 30. A pressure sensitive adhesive / cohesive, as defined in claim 1, wherein the acrylate monomer is selected from the group consisting of cyclohexyl methacrylate and methyl methacrylate.
31. 31. A pressure sensitive adhesive / cohesive, as defined in claim 1, wherein the acrylate monomer is selected from the group consisting of trimethyl-cyclohexylmethyl methacrylate and methyl methacrylate,
32. 32. A sensitive adhesive / cohesive to the pressure, as defined in claim 30, wherein the natural rubber is an electrostatically stabilized latex of the graft terpolymer / natural rubber block.
33. 33. A pressure sensitive adhesive / cohesive, as defined in claim 31, wherein the natural rubber is an electrostatically stabilized latex of the natural rubber graft / block terpolymer.
34. 34. A method to obtain a form of business of type of printed material that is distributed by mail, this method comprises: (a) applying cohesive as cooperating patterns to a sheet of paper, so that when the sheet is folded or moved in contact with a similar coated sheet, the patterns move in mutual contact, the cohesive comprising a pressure-sensitive cohesive, which includes: 100 parts by weight of natural rubber; about 5 to 35% by weight of the rubber of at least one acrylate monomer; about 5 to 8% by weight of the acrylic acid rubber and / or about 1 to 10% of the 4-acetoxystyrene rubber; about 0 to 20% by weight of the ethylhexyl acrylate rubber; from 1 to 50% by weight of the rubber of a hard, finely divided particulate material, which has substantially no thermoplasticity; from 0 to 50% by weight of the starch rubber; and from 0 to 40% by weight of the carboxylated styrene-butadiene latex rubber, or the carboxylated polychloroprene latex, or the vinyl-pyridine-styrene-butadiene latex, or the styrene-acrylate-acrylonitrile latex, or a latex of previously interwoven natural rubber, or a tackifying agent, or combinations thereof.
35. 35. A method, as defined in claim 34, further comprising b) folding the paper to move the cohesive patterns into mutual contact and (c) applying a sealant pressure of at least 17,858 kilograms per linear centimeter to the patterns, to seal these cohesive patterns together to cause the fibers to tear if you try to separate them by pulling them.