MXPA00009365A - Soap gel based glue stick - Google Patents

Abstract

Disclosed is a dimensionally stable rub-off glue stick consisting of an aqueous synthetic polymer preparation with adhesive characteristics and a soap gel acting as a form-giving builder, in addition to other possible auxiliary agents. The aqueous, synthetic polymer preparation contains a mixture of polyurethane and polyvinyl pyrrolidon. Said polymer combination results in better tack and quicker setting with increased resistance to traction and heat when compared to individual polymers. These properties enable the inventive glue stick to be used as an all-purpose glue in addition to being used as a paper glue.

Description

ADHESIVE PENCIL BASED ON SOAP GEL This invention relates to an adhesive pencil produced from a water-based preparation of a synthetic polymer of adhesive nature and a soap gel as the generating component of the gel and giving conformation and, optionally, other auxiliaries. The invention also relates to a process for the production of these pencils and their use. Adhesive pencils (= pencil adhesives with dimensional stability that leave behind a sticky film when rubbed on a receiving surface) are now part of daily life. These contain synthetic water-soluble or water-dispersible polymers of an adhesive nature dissolved in an aqueous, organic liquid phase together with a gel-producing component that gives it the form. The gel-forming component is selected in particular from alkali metal or ammonium salts of aliphatic carboxylic acids, more specifically containing from about 12 to 22 carbon atoms. If the water-based, highly sticky preparations of the synthetic polymers of adhesive nature are heated together with small amounts of the gel-forming component based on fatty acid soaps, at relatively high temperatures, more particularly, above 50 ° C, and if this solution is subsequently allowed to stand until cooled, the mixture solidifies in a more or less rigid soap gel in which the conformation and structure of the comparatively rigid micelles of the soap gel is the main evidence at the beginning. This allows the known production and handling of the pencil-shaped adhesives in tubes that can be closed. When the pencil is rubbed on a receiving surface, the micellar structure is destroyed so that the rigid mixture becomes a paste-like state in which its adhesive character is predominant. Originally, the polyvinyl pyrrolidone (PVP) mentioned in DE 18 11 466 was the most important adhesive polymer. Although the adhesive pencils made with polyvinyl pyrrolidone offered sufficient strength to gum paper, it would be beneficial to obtain pencils that can be used in a more universal way and with which unions with greater strength can be produced. In particular, there was a need to again avoid separation of the paper / paper bonds established with the pencils under unfavorable climatic conditions. The use of polyurethane as the polymer of adhesive nature contributed to solve this problem. EP 405 329 discloses firm, soft rubbing sticks based on soap gel as the forming component of the gel that forms it and an aqueous polyurethane dispersion as the adhesive component. The polyurethane is a reaction product of a polyol or a mixture of polyol, a difunctional or polyfunctional isocyanate component, a component capable of forming salt in aqueous alkaline solution and / or a hydrophilic, nonionic modifying agent and, optionally, an agent chain extender. Although in fact improvements were obtained in this way, the values of firmness and thermal resistance were not yet very good for special cases. Accordingly, the problem undertaken by the present invention was to provide a composition with dimensional stability, of soft rub which does not have any of these disadvantages and which are distinguished not only by its easy handling but also by its favorable operating properties. In particular, the easy application would be combined with the initial reposicionability of the adhesive and the high tack would be combined with the high final strength and also with high thermal resistance. The solution provided by the invention is defined in the clauses and consists mainly of the use of a mixture of polyurethane and polyvinyl pyrrolidone as the synthetic polymer of adhesive nature. The adhesive pencil has "dimensional stability" because its constituent composition is able to form stable geometric figures at room temperature (20 ° C). More specifically, the adhesive pencil with a diameter of 16 mm must have a deformation load of 25 to 50 N measured by the compression resistance method described below, at a temperature of 20 ° C. The constituent paste of the adhesive pencil is preferably that of "soft rubbing" because a uniform film without unevenness is obtained on the copying paper (Sonnecken 5015 Speziell Copier) under low pressure (see the "rub" test). An "aqueous-based preparation" in the context of the invention means an aqueous mixture of the polymers regardless of the degree of dispersion (actual solution, colloidal solution or dispersion). Adhesive pencils according to the invention contain polyurethane (PU) as the adhesive polymer component. The polyurethane is a reaction product of at least one polyol, at least one polyfunctional isocyanate, at least one component capable of forming salt in aqueous alkaline solution and / or a hydrophilic, nonionic modifying agent and, optionally, at least one extender. chain. According to the invention, polyurethane dispersions are the preferred starting materials for adhesive pencils that are opaque, translucent or transparent in appearance, and in which the polymer will be present at least partially in solution. The specialized knowledge of the polyurethane experts, who can influence the degree of distribution through the percentage content of the ionic and / or non-ionic constituents, is important in this regard. Accordingly, the water-based preparation preferably contains the polyurethane in the form of a dispersion. The polyurethane dispersions which are used as the synthetic polymer in adhesive pencils are prepared from a polyol or a mixture of polyols as an essential starting product. In a broad sense, these polyols must contain at least two reactive hydrogen atoms and must be substantially linear, although they can also be branched. Its molecular weight is in the range from 300 to 40,000 and, preferably, in the range from 500 to 20,000. Suitable polyols are polyester polyols, polyacetal polyols, polyether polyols, polythioether polyols, polyamide polyols or polyester amide polyols containing from 2 to 4 hydroxyl groups and which can also be partially substituted by alkyl groups. Polyurethanes of polyether polyols and / or polyester polyols are preferred. Suitable polyether polyols are, for example, the polymerization products of ethylene oxide, propylene oxide, butylene oxide and their products of copolymerization or graft polymerization and polyethers obtained by condensation of polyhydric alcohols or mixtures thereof. and those obtained by alkoxylation of polyhydric alcohols, amines, polyamines and amino alcohols. It is also possible to use isotactic polypropylene glycol. The preferred polyether polyol is polytetra idrofuran. Polytetrahydrofuran in the context of the present invention is the collective name of polyethers which can be prepared theoretically or actually by ring opening polymerization of tetrahydrofuran and which contain a hydroxyl group at either end of the chain. Convenient products have a degree of oligomerization of about 1.5 to 150, and preferably in the range of 5 to 100. Another class of preferred polyols are polycarbonate polyols. Preferred polycarbonate polyols are the aliphatic types, ie esters of carbonic acid with C-C dihydric alcohols. The polycarbonate polyols based on carbonic acid and bisphenol A are less convenient. Suitable polyacetal polyols are, for example, the compounds obtained from glycols, such as diethylene glycol, triethylene glycol, 4,4'-dioxethoxydiphenyl dimethylmethane, hexanediol and formaldehyde.

Suitable polyacetals can also be produced by polymerization of cyclic acetals. Among the polythioether polyols, the products of the thiodiglycol condensation itself and / or with other glycols, dicarboxylic acids, formaldehydes, amino carboxylic acids or amino alcohols are particularly suitable. Depending on the co-components, the products are polythioethers, polythio ether ethers, polythioethers esters, polythioethers ester amides. Polyhydroxyl compounds like these can also be used in alkylated form or in admixture with alkylating agents. Polyester, polyester amide and polyamide polyols include mainly linear condensates obtained from polybasic, saturated and unsaturated carboxylic acids or anhydrides thereof and saturated and unsaturated polyhydric alcohols, amino alcohols, diamines, polyamines and mixtures thereof, and, for example, polyterephthalates or polycarbonates. Lactone polyesters, for example, caprolactones or hydroxycarboxylic acids can also be used. The polyesters may contain terminal hydroxyl or carboxyl groups. Polymers or condensates of relatively high molecular weight such as, for example, polyethers, polyacetals or polyoxymethylenes can also be used as the alcohol component for their synthesis. The aqueous polyurethane dispersion preferably contains a reaction product of a polyether and / or polyester polyol as the polyol component. Polyhydroxyl compounds that already contain urethane or urea groups and optionally modified natural polyols, such as castor oil, can also be used. Basically, pohydroxyl compounds containing basic nitrogen atoms, for example, polyalkoxylated primary amines or polyester or polythioethers containing co-condensed alkyldiethanolamine, are also convenient. The polyols which are obtained by ring-opening, in whole or in part, of the epoxidized triglycerides with primary or secondary hydroxyl compounds, for example, the reaction product of soybean oil epoxidized with methanol, can also be used. The polyols may also contain amino alcohols or diamines. Suitable polyisocyanates for the production of the polyurethanes useful in accordance with the invention are any of the aromatic and aliphatic diisocyanates, such as, for example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4-diisocyanate. '-difenyldimethylmethane, di- and tetraalkyldiphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, the isomers of toluene diisocyanate, optionally in mixture, 1-methyl -2,4-cyclohexane diisocyanate, 1/6-diisocyanate-2,2,4-trimethylhexane, 1,6-diisocyanato-2,4,4-trimethylhexane, l-isocyanatomethyl-3-isocyanate-1, 5, 5 trimethylcyclohexane, chlorinated and brominated diisocyanates, diisocyanates containing phosphorus, 4,4'-diisocyanatophenylperfluoroethane, tetramethoxybutan-1,4-diisocyanate, butan-1,4-diisocyanate, hexan-1,6-diisocyanate, dicyclohexylmethane diisocyanate, cyclohexan-1 , 4-diisocyanate, ethylene diisocyanate, phthalic acid -bis-isocyanatoethyl ester, also polyisocyanates containing reactive halogen atoms, such as l-chloromethylphenyl-2,4-diisocyanate, l-bromomethylphenyl-2,6-diisocyanate, 3, 3-bis-chloromethyl ether-4, 4 ' -difenildiisocianato. Sulfur-containing polyisocyanates are obtained, for example, by the reaction of 2 moles of hexamethylene diisocyanate with 1 mole of thiodiglycol or dihydroxydihexyl sulphide. Other important diisocyanates are trimethylhexamethylene diisocyanate, 1,4-diisocyanatobutane, 1/2-diisocyanate dodecane and diisocyanate of the fatty acid dimer. The aforementioned isocyanates can be used individually or in the form of mixtures. Preferred isocyanates are branched or cyclic aliphatic diisocyanates, such as isophorone diisocyanate, but also hexamethylene diisocyanate. Particularly preferred is tetramethylxylene diisocyanate (TMXDI). Trifunctional isocyanates can also be used in small amounts. The aqueous polyurethane dispersion is preferably a reaction product of at least one difunctional or trifunctional aliphatic isocyanate. Chain extenders containing reactive hydrogen can also be used in the production of the polyurethane dispersions used according to the invention. Suitable chain extenders containing reactive hydrogen atoms include: - normal saturated and unsaturated glycols, such as ethylene glycol or condensates of ethylene glycol, butan-1,3-diol, butan-1,4-diol, butanediol, propan-1,2-diol, propan-1,3-diol, neopentyl glycol, hexanediol, bis-hydroxymethylcyclohexane, dioxyethoxyhydroquinone, terephthalic acid-bis-glycol ester, succinic acid di-2-hydroxyethylamide, di-N-methyl succinic acid - (2-hydroxyethyl) -amide, 1,4-di- (2-hydroxy-methylmercapto) -2,3,5,6-tetrachlorobenzene, 2-methylpropan-1, 3-diol, 2-methylpropan-1, 3 -diol; - aliphatic, cycloaliphatic and aromatic diamines, such as ethylenediamine, hexamethylenediamine, 1/4-cyclohexylenediamine / benzidine / diaminodiphenylmethane, dichlorodiaminodiphenylmethaneO / phenyldiamine / hydrazine isomers, ammonia, carbohydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, piperazine, N- methylpropylenediamine, diaminodiphenylsulfone, diaminodiphenyl ether, diaminodiphenyldimethylmethane, 2,4-diamino-6-phenyltriazine; - amino alcohols such as ethanolamine, propanolamine, butanolamine, N-methyl-ethanolamine, N-methyl-isopropanolamine; - aliphatic, cycloaliphatic, aromatic and heterocyclic mono- and diaminocarboxylic acids such as glycine, 1- and 2-alanine, 6-aminocaproic acid, 4-aminobutyric acid, isomeric mono- and diaminobenzoic acids, isomeric mono- and diaminonaphthoic acids; - Water. The polyols which are used as chain extender agents preferably have a molecular weight of less than 300. It should be noted that it is not possible in the context of the present invention to strictly differentiate between polyols having a molecular weight of 300 to 20,000 and the called "chain extenders" because the transitions between the two classes of compounds are fluid. Compounds that are not composed of several monomer units, but have a molecular weight of 300, such as 3,3'-dibromo-4,4'-diaminodiphenylmethane, for example, are classified as chain extenders, as in reality is pentaethylene glycol although, by virtue of its composition, pentaethylene glycol is actually a polyether diol. Special chain extenders containing at least one basic nitrogen atom are, for example, primary aliphatic, cycloaliphatic, aromatic or mono-, bis- or polyalkylated heterocyclic amines, such as N-methyldiethanolamine, N-ethyldiethanolamine, N- propyldiethanolamine, N-isopropyldiethanolamine, N-butyldiethanolamine, N-isobutyldiethanolamine, N-oleldiethanolamine, N-stearyldiethanolamine, ethoxylated coconut fat amine, N-allyldiethanolamine, N-methyldisopropanolamine, N-ethyldiisopropanolamine, N-propyldiisopropanolamine, N-butyldiisopropanolamine, C -cyclohexyldiisopropanolamine, N, N-diethoxylaniline, N, N-diethoxyltoluidine, N, N-diethoxyl-1-aminopyridine, N, N'-diethoxypiperazine, dimethyl-bis-ethoxylhydrazine, N, N'-bis- (2-hydroxyethyl) -N, N'-diethylhexahydro-p-phenylenediamine, N-12-hydroxyethylpiperazine, polyalkoxylated amines such as propoxylated ethyldiethanolamine, also compounds such as N-methyl-N, N-bis-3-aminopropylamine, N- (3-aminopropyl) - N, N '-dimethylethylenediamine, N- (3-aminopropyl) -N-methylethanolamine, N, N'-bis- (3-aminopropyl) -N, N' -dimethylethylenediamine, N, N'-bis- (3-aminopropyl) - piperazine, N- (2-aminoethyl) -piperazine, N, N'-bis-hydroxyethylpropylenediamine, 2,6-diaminopyridine, diethanolaminoacetamide, diethanolamidopropionamide, N, N'-bis-hydroxyethylphenylthiosemicarbazide, N, N-bis-hydroxyethylmethylsemicarbazide, p, p'-bis-aminomethyldibenzylmethylamine, 2,6-diaminopyridine, 2-dimethylaminomethyl-2-methylpropan-l, 3-diol. In addition, the polyurethanes in which the polyurethane dispersions according to the invention are used contain a functional component which is solubilized in water as an important component. This component can be selected from dihydroxy or a diamino compounds containing a carboxylic acid, ionizable sulfonic acid, amino group or ammonium. These compounds can be used as such or can be prepared in situ. To introduce the compounds carrying ionizable carboxylic acid groups in the polyurethane, the person skilled in the art can add a dihydrocarboxylic acid capable of salt formation to the polyols. A preferred dihydroxycarboxylic acid is, for example, dimethylolpropionic acid. To introduce sulfonic acid groups capable of forming salt, it is possible to add a diamino sulfonic acid to the polyols. Examples are 2,4-diaminobenzenesulfonic acid and also N- (? -aminoalcan) -α-acid -aminoalkanosulfonic acid described in DE 20 35 732. If these are anionically modified, the polymers are present in the polyurethane dispersions used according to the present invention in salt form. In the case of the preferred polymers modified with carboxylic acids or sulfonic acids, the salts of alkali metals, ammonia or amines, ie primary, secondary, or tertiary amines, are present as counterions. According to the invention, the neutralizing agents are preferably used in stoichiometric or excess ratio based on the acid groups. Accordingly, groups capable of forming salts can be partially or completely neutralized by the counterions. An excess of the neutralizing agent is also possible. In addition to, or in lieu of the preferred modification with the components capable of salt formation, the non-ionic modification can also induce water solubility. The monoalcohols obtained by reaction of primary alcohols with ethylene oxide are mainly suitable for the non-ionic modification. The necessary amounts of the nonionic modifying agents are determined for the hydrophilicity of the system as a whole, that is, it is lower where the polyols based on polyethylene glycol have already been used as polyols in the polymer synthesis. Of course, the amount is also smaller when the ionic groups are incorporated additionally. The upper limit is determined by the water resistance of the adhesive film. For example, up to 85% by weight of the polyurethane, based on the solid, can originate from ethylene oxide. In the absence of ionic modification, the common values are 5 to 50% by weight. However, where ionic modifying agents are used, lower values may also be set. In addition, the monohydric alcohols, more particularly the ether alcohols, can additionally be added as hydrophilic, non-ionic modifiers. The reaction products of Ci-Cio alcohols with ethylene oxide in the molecular weight range of up to 20,000 and, preferably, from 200 to 6,000 are preferred. In order to produce the polyurethanes particularly suitable for the purposes according to the invention, the polyols and an excess of diisocyanate are reacted to form a polymer terminated by isocyanate groups, the reaction conditions and convenient reaction times and also the temperatures being variable. according to the particular isocyanate. The experts know that the reactivity of the constituents to be reacted requires a corresponding balance between the reaction rate and the unwanted side reactions which can cause discoloration and a reduction in molecular weight. Typically, the reaction is carried out with stirring for a period of about 1 to 10 hours at a temperature of about 50 to about 120 ° C. Other particulars of the production of suitable polyurethanes can be found in EP 405 329, to which reference is expressly made. However, the polyurethane dispersions used in the adhesive pencils according to the invention can also be produced without using acetone as a solvent. In this case, the starting materials may be the preferred polyols for the purposes of the invention based on polytetrahydrofuran or their copolymers with ethylene oxide or propylene oxide, low molecular weight polyols, for example, those with a molecular weight up to 2000 or up to 1000, preferably being used. The polyols are then reacted in the presence of a polyol carrying acidic groups, ie, for example, dimethylol propionic acid, in an OH: NCO ratio greater than 1: 1.2 to form resins which can be stirred and which can then be directly dispersed in water. The clear or opaque polyurethane dispersions are preferably used for the purposes of the invention.

To obtain polyurethane dispersions practically transparent, ie transparent, opaque or clear as water, it is important to maintain a certain proportion between the component capable of forming the salt and the other components involved in the synthesis of the polyurethane. Thus, the component capable of forming salt, expressed as dimethylol propionic acid, is used in amounts of 1 to 30% by weight, preferably 2 to 20% by weight and, more preferably, 10 to 18% by weight, based on the polyol. Based on the solids of the polyurethane and expressed as dimethylol propionic acid, this corresponds to 5 to 35% by weight, preferably 5 to 20% by weight and, more preferably, 5 to 15% by weight. In addition, transparency depends on the degree of neutralization. The skilled person will be able to perform some preliminary tests to determine the amount of the modifying agent capable of forming ions or the amount of neutralizing agent beyond which an adequate degree of transparency is obtained. In general, as little of these substances as possible will be used because excessive use can affect the water resistance of the adhesive film. An important factor in the production of the polyurethane dispersions on which the adhesive pencils according to the invention are based is the ratio of the hydroxyl groups to the isocyanate groups which may be between 1.0: 0.8 and 1.0: 4.0. The 1.0: 1.1 to 1.0: 2.0 ratios are preferred, with proportions of 1.0: 1.1 to 1.0: 1.8 being particularly preferred. Aqueous polyurethane dispersions with these proportions are particularly suitable when these are a reaction product of a mixture of polyols, a component capable of forming salt in alkaline solution and a polyisocyanate. Suitable polyurethane dispersions can be prepared over a wide range of concentrations. Preparations with a solids content of 20 to 80% by weight are preferred, those with a solids content of 30 to 60% by weight are particularly preferred. The polyurethane should constitute from 10 to 60% by weight and, more specifically, from 15 to 35% by weight of the adhesive pencil as a whole, based on the total weight of the polymers, soap and other auxiliaries and water. According to the invention, polyvinylpyrrolidone (PVP) is used as a second adhesive polymer. It must have a molecular weight of at least about 10,000, more specifically from about 50,000 to 3,000,000 and, above all, from about 400,000 to 1.5 million. The PVP must be added in an amount of 0.5 to 30% by weight, and preferably in an amount of 1 to 15% by weight, based on the adhesive as a whole. The content in percent of both adhesive polymers should be between 15 and 65% by weight and, preferably between 18 and 35% by weight. Adhesive pencils according to the invention contain alkali metal salts, more specifically, sodium salts, of C 2 -C 22 fatty acids of natural or synthetic origin such as soaps to form the gel structure. Mixtures of C14-C18 fatty acids are preferred. The sodium salts of the fatty acids, ie the soaps, are present in amounts of 2 to 20% by weight and, preferably, 3 to 12% by weight, based on the adhesive pencil. The auxiliaries commonly used in adhesive pencils can also be used in the adhesive pencils according to the invention, in amounts of 0 to 25% by weight, based on the adhesive pencil. The auxiliaries in question are, in particular, water-soluble plasticizers, dyes, perfumes, resins, preservatives and / or moisture regulators. However, plasticizers and / or moisture regulators, i.e. water-soluble organic solvents commonly used in adhesive pencils, are preferably not used for the purposes of the present invention. However, these compounds may optionally be present in small amounts. The compounds in question are polyglycol ethers, more specifically polyethylene glycol and polypropylene glycol, the preferred polyethers having an average molecular weight in the range from 200 to 4,000, and preferably in the range from 500 to 2000. In addition, the polyhydric alcohols Glycerol, trimethylolpropane, propylene glycol, sorbitol, sugar, polyglycerol, low molecular weight starch hydrolysates and / or polyether glycols can also be used. For example, it is possible to optionally use a mixture of glycerol and polyethylene glycol. The mentioned non-volatile organic solvents should be used in amounts of not more than 50% by weight, based on the water content of the pencils. In addition, it is also possible to use other auxiliaries, for example, substances that favor easy and gentle rubbing. Substances such as these are, for example, amino carboxylic acids and / or their lactams. Suitable aminocarboxylic acids or lactams should contain up to 12 carbon atoms and, more specifically, from 4 to 8 carbon atoms. Preferred representatives in terms of practical application are? -caprolactam or the 7-aminocaproic acid derivative thereof. The amount in which the respective lactams or aminocarboxylic acids are normally used is not more than 15% by weight and, for example, between 1% by weight and 10% by weight, based on the pencil as a whole. Adhesive pencils according to the invention may contain pigments, dyes, antioxidants, embrittling substances, fillers, fragrances, preservatives, resins, water soluble plasticizers and / or moisture regulators as other auxiliaries. These auxiliaries are present in the normal small amounts of 0 to about 20%, based on the adhesive pencil as a whole. Examples of special dyes are pH and heat-dependent dyes, optical brighteners, dyes designed to change color with the application, particularly in the functional range. The colorant can be evenly distributed in the adhesive. However, structured coloration is also possible, for example, a core / shell structure. Examples of pigments or fillers are graphite, talc, Ti02, highly dispersed silica (Aerosil), bentonite, wollastonite, clay, magnesium oxide and glass fibers. Other possible additives are, for example, dextrins, cellulose derivatives and unstructured starch derivatives [sic]. Other additives that may be present in the adhesive pencils according to the invention are mornings, more specifically, galactomannans. The fruit galactomananas of the carob tree and guar flour are particularly convenient. Deconstructed ethers [sic] can also be replaced to a small degree by unstructured mornings. The individual components are preferably present in the adhesive pencil in the following amounts: from 3 to 10% by weight of soaps, from 15 to 65% by weight of PU or PVP polymers and from 0 to 25% by weight of auxiliaries. The difference for 100% is water. The water of preference is present in an amount of 35 to 65% by weight and, more preferably, of 40 to 55% by weight, based on the adhesive pencil as a whole. To produce the adhesive pencils according to the invention, the soap gel forming constituents, the polyurethane dispersion, the PVP and the auxiliaries are mixed together, heated at temperatures of at least 50 ° C and preferably up to 100 ° C. C (or the boiling point) until a uniform mixture is formed, the resulting mixture is emptied into molds and then allowed to cool in the absence of canine agitation to form a gel. These mixtures, which are easily poured into the aforementioned temperature range, are preferably poured directly into molds, more specifically, into pencil tubes or similar containers and allowed to solidify in the absence of mechanical action to form the required gels. The adhesive pencil is stored in a tube that can be closed, more particularly polyolefin.

Although the tack is very high, the stick moves in the tube. Accordingly, the adhesive position according to the invention easily becomes a pencil in the tubes in which it will subsequently be handled. This method of forming is so simple that, after the adhesive pencil has been used, anyone can make a pencil easy to use in the previous tube by simply heating another adhesive composition according to the invention and emptying it into the pencil tubes. In other words, the tube is reusable. Since the adhesive pencil according to the invention is solid and smoothly rotating, its use in geometrical form, more specifically cylindrical, is preferred. The cylinder may have a circular, oval or polygonal cross section. Its dimensions will be determined by the application, for example, by the required width of the surface to be covered. Square blocks are also possible. The most suitable form is determined by the application of the adhesive composition to the substrate. The adhesive sticks according to the invention have the advantage of relatively high adhesive strength and, consequently, can be used not only for gumming paper, but also and in particular cardboard, wall hangings, leather, wood, wood materials, plastics, glass, metals, ceramics, plaster, materials of the same class or different, more specifically, for absorbent woods or other substrates, such as cardboard, even in combination with PVC, PMMA, PBS, aluminum. By virtue of its high adhesive strength on very different substrates, the adhesive pencil can be used as an "adhesive" for multiple purposes, especially since its application of the tube is simple and uniform, specific examples include manual work where the resistances of conventional adhesive pencils are not satisfactory, such as the bonding of foam rubber to cardboard or wood, because of its high thermal resistance, the adhesive pencil according to the invention is suitable, for example, for gluing posters of window exposed directly to light, although PU and PVP are soluble or dispersible in water, the water resistance of the joint is considerable. Thus, 20% of the original adhesive strength is present, for example, in a humid climate of 30 ° C / 80% relative humidity. Errors and residues of the adhesive can be easily removed with alkaline water covering the affected areas with a damp cloth for 10 minutes to soften the adhesive and then clean the debris. The adhesive composition according to the invention hardens relatively quickly compared to multi-purpose adhesives, normal, for example, on wood / PVC. However, there is enough time for correction, the open time is between 10 and 120 seconds, and preferably between 20 and 60 seconds. The pencil shape is particularly convenient where the composition of the solid, soft rub adhesive according to the invention is to be applied by hand. Other applications may serve better with other forms, for example, a square shape, where relatively large areas will be machine covered.

E ploses I. Initial materials 1: Preparation of polyurethane solutions or dispersions Polyurethane adhesive raw materials are produced by the acetone process, although other methods are possible, for example, dispersion of the extruded pre-polymer melt (process of melt extrusion). Polyisocyanates and diol compounds (polyether diol and dimethylolpropionic acid) are first introduced and stirred at reflux at about 65 to 100 ° C to the constant NCO value. Upon completion of the reaction, the indicated amount of water, which contains the calculated amounts of alkali and any chain extender, is added with vigorous stirring. It is very important the intense shearing for the quality and especially for the homogeneity of the dispersion. After stirring for several hours, the solvent is distilled until the concentration of acetone is well below 0.1 and the viscosities and solids contents are reached as shown in Table 1. 2. A PVP with a K value of 90 was used (manufacturer: ISP9 3. ? -caprolactam. 4. Sodium palmitate (Henkel KGaA) Table I Polyurethane No. I Parts by weight of water 1363 Parts by weight of TMXDI 242 Parts by weight of polypropylene glycol (MW 400) 40 Parts by weight of polypropylene glycol (MW 1000) 300 Parts by weight of polytetrahydrofuran (MW 850) 65 Parties in weight of dimethylolpropionic acid 67 Parts by weight of NaOH (100%) 20 Solids content (%) 35 Viscosity at 20 ° C (mPas) 35000 II: Production of pencil compositions. The pencil compositions are obtained by mixing the individual components of Table II at 65-100 ° C and then emptying them into pencil tubes to cool, the pH of the composition is optionally adjusted to a value of 8 to 11 by adding little Sodium hydroxide diluted.

Table II III. Tests 1) Resistance to compression Compression resistance is understood as the maximum load measured parallel to the longitudinal axis to collapse the pencil under pressure. The compressive strength is measured with a Erichsen Model 464L compressive strength tester, measuring force 709 (manufacturer: Erichsen, Simonshofchen, Wuppertal). The cut of the adhesive with a minimum length of 30 mm immediately on the piston is placed between two hooks in the form of thin disks of approximately 10 mm of rigid PVC that are formed with a circular depression of 3 mm adapted to the particular diameters of the pencil . The pencil provided with the hooks is placed in the center of the table of the compression resistance tester. The height of the instrument that measures the force on the table adapts to the height of the pencil to be tested. The measuring head is then advanced against the pencil that is to be tested at a speed of approximately 70 mm per minute. Upon reaching the maximum compression force, the value is read from a digital screen. Adhesive pencils according to the invention have a compressive strength of about 25 to 50 N / diameter of 16 mm. 2) Drying time. To determine whether the adhesive properties of the pencils are sufficient for the proposed application, hand binding tests are performed under certain processing conditions and evaluated. The following procedure is adopted: A supply of white chrome paper (weight per unit area of approximately 100 g / m2) coated on one side and adhesive pencils to be tested are conditioned for at least 24 hours at 20 ° C / 65 ° C humidity relative air. The test paper is cut into strips 5 cm wide and approximately 30 cm long. An adhesive pencil is rubbed twice in the longitudinal direction under uniform pressure on the uncoated side of a paper strip and should produce a uniform film. Immediately thereafter, a second strip of paper that has not been coated with the adhesive is placed on the coated strip with its face on the uncoated side inward and rubbed by hand. Then an attempt is made to separate the paper strips slowly one from the other. The time in which the separation in the area of adhesion is only possible with tearing of paper across the width characterizes the drying time. 3) Open time The open time is the time after the application of the adhesive inside which the materials to be joined have to be adjusted to each other so that, after hardening, obtain a complete tear of the paper in the separation test. The method is the same as that used to determine the drying time except that the paper strips are only adapted to each other after defined times after the application of the adhesive. Starting with 15 seconds, the open time can be graduated, for example, in 15 second intervals. With slow-drying adhesives, which have long open times, longer intervals will be selected accordingly. 4) Rub The rub is evaluated subjectively by at least two examiners. The operating properties are characterized and classified as follows: soft, foldable, flat, lumpy, greasy, hard, soft and sticky.

) Tensile shear strength of wood / wood joints Seed samples of beech wood and PVC test specimens are rubbed with adhesive at their ends and adjusted to each other in such a way that the two ends covered with adhesive overlap with 2 cm (joint area 2 cm x 2.5 cm). The test specimens are fixed with two clamps and measured after 24 hours. The result is expressed in N / mm2. 6) Thermal resistance For the preparation of the joints, see the tensile shear test. The applied pressure is 1.0 N / mm2. When the final force has developed after approximately 3 to 5 days at room temperature, the test samples are hung in a heating cabinet. Then a load of 1 kg is applied to the joint. The heating cabinet increases the temperature in stages from 30 ° C to 120 ° C for a period of 30 hours. Normal program: 30 ° C to 120 ° C in 30 h, 10 ° C of temperature increases every 3 h. If the joint supports the weight throughout the program, the load is first increased to 2 kg and then to 5 kg. Each measurement is made in at least 3 joints per adhesive. The thermal resistance of the adhesive is determined by comparing the time measured with the Table: 7) Pegajosida The test is performed in a normal climate of 23 ° C / 50% relative humidity of the air using test samples of beechwood veneer stored in the chamber for at least three days. Two wooden test samples measuring 80 mm x 25 mm x 4 mm are coated with the particular adhesive with a 20 mm long overlap corresponding to an overlap area of 500 mm2, compressed together for 5 seconds under a pressure of 0.2 N / mm2 and are subjected to a cutting force of 200 g immediately and after 2, 4, 6 and 8 minutes. The test measures the relative slip of one piece with another after one hour. Depending on the time required, the stickiness is evaluated in the following scale: Very good immediately (0 minutes) Good between 0 and 2 minutes Average between 2 and 4 minutes Poor between 4 and 6 minutes Very poor over 6 minutes The results of the test (see Table II) show that the adhesive composition according to the invention based on the combination of both polymers gives rise to better tack and higher thermal resistance compared to the individual polymers by themselves.

Claims (11)

1. An adhesive pencil produced from a water-based preparation of a synthetic polymer of adhesive nature and a gel of soap as the forming substance of the gel and that gives it shape and, optionally, other auxiliaries, characterized in that the preparation with base Aqueous of a synthetic polymer contains a mixture of polyurethane and polyvinylpyrrolidone.

2. The adhesive pencil as claimed in claim 1, characterized in that the aqueous-based preparation contains the polyurethane in the form of a dispersion, the polyurethane being a product of the reaction of at least one polyol, at least one polyfunctional isocyanate, at least one component capable of salt formation in aqueous alkaline solution and / or a hydrophilic, nonionic modifying agent and optionally at least one chain extender agent.

3. The adhesive pencil as claimed in claim 1 or 2, characterized in that the aqueous polyurethane dispersion contains a reaction product of a mixture of polyols, a component capable of forming salt in alkaline solution and a polyisocyanate in an OH ratio: NCO from 1.0: 0.8 to 1.0: 4.0, preferably 1.0: 1.1 to 1.0: 2.0 and, most preferably 1.0: 1.1 to 1.0: 1.8.

4. The adhesive pencil as claimed in claim 1, 2 or 3, characterized in that the aqueous polyurethane dispersion contains a reaction product of a polyether and / or polyester polyol as the polyol.

5. The adhesive pencil as claimed in any of claims 1 to 4, characterized in that the aqueous polyurethane dispersion contains a reaction product of a dihydroxycarboxylic acid capable of salt formation.

6. The adhesive pencil as claimed in any of claims 1 to 5, characterized in that the aqueous polyurethane dispersion is a reaction product of at least one difunctional or trifunctional aliphatic isocyanate.

7. The adhesive pencil as claimed in at least one of the preceding claims, is characterized by the molecular weight of polyvinyl pyrrolidone of at least 10,000.

8. The adhesive pencil as claimed in any of claims 1 to 7, characterized in that the sodium salts of the C 2 -C 22 fatty acids of natural or synthetic origin are present as the soap forming the structure of the gel.

9. The adhesive pencil as claimed in any of claims 1 to 11, characterized in that the water-soluble plasticizers, colorants, perfumes, resins, preservatives and / or moisture regulators are present as other auxiliaries.

10. A process for the production of the adhesive pencil claimed in claims 1 to 9, characterized in that the constituents forming the soap gel and the polyurethane dispersion, the PVP and the auxiliaries are mixed together, heated to temperatures of at least 50 ° C until a uniform mixture is formed, the mixture thus formed is poured into molds and left therein to cool without mechanical agitation until a gel is formed.

11. The use of the claimed adhesives in at least one of the preceding claims for bonding paper, cardboard, leather, plastics, ceramic metals, glass to materials of the same or different kind.