WO1999028404A1 - Friction-activated adhesive substances which are solid at room temperature and which have a base of partially crystalline graft-copolymer compounds - Google Patents

Abstract

The invention relates to graft copolymer compounds which are solid at room temperature but which soften when rubbed on a solid substrate so as to adhere to the surface on which they are being rubbed, and which can preferably be thinly spread. The graft polymers chemically bond the sub-areas in their molecular structure which are crystalline at room temperature to those which are amorphous at room temperature and are produced by reacting a) preformed polymer chains which have an average molecular weight of 1,000 to 35,000 and an at least partially crystalline structure at room temperature and b) monomers which form the amorphous sub-areas in the molecular structure of the graft copolymer, the reaction being radically initiated. The graft copolymer compounds are intended for use as structure-forming adhesive solid constituents in friction-activated adhesive substances. The invention also relates to solid friction-activated adhesive substances which are shaped and therefore configured especially for applying by hand and which are free or practically free of water and/or diluting agents which are volatile at room temperature. These substances are characterised in that they contain graft copolymer compound-based friction-activated adhesive substances.

Description

 Friction activatable adhesive masses based on partially crystalline graft copolymer compounds

The subject of the technical teaching described below is a further development from the field of adhesive masses which are solid at room temperature and which can be activated by friction without the use of liquid auxiliaries. This term of the friction activability encompasses in particular the suitability of the respective adhesive, by rubbing during application on at least one of the substrates to be bonded to one another - in particular by rubbing by hand - to form a pressure-sensitive adhesive film which reappears after the substrates to be bonded to one another have been joined converts the solid state and thus ensures the permanent bond. The teaching according to the invention thus particularly affects the field of adhesive sticks, but also adhesive compositions designed in other spatial forms, which can be applied in particular to the elements to be bonded to one another by hand application.

The teaching according to the invention is in particular a further development of friction-activatable adhesive compositions, as is the subject of the disclosure of the publication according to PCT-WO 96/37566 by the applicant. The statements in this publication - to the extent detailed below - also apply to the teaching and understanding of the current development. Accordingly, for the purpose of the disclosure of the invention, the teaching of this document is hereby expressly made the subject of the present disclosure of the invention. EP 405 329 describes the use of adhesive compositions which are solid at room temperature and which are suitable for gluing without melting and are designed, for example, in the form of glue sticks. However, the adhesive composition here is an aqueous preparation of a polymeric adhesive, for example a polyurethane as a binder and a soap gel as a shaping framework, if desired together with auxiliaries. By simply spreading the glue stick over the substrate to be glued, the pressure-sensitive layer is formed, from which, after the parts to be glued together, the solvent or water evaporates or diffuses into the substrate.

Such glue sticks have the disadvantage of requiring tight packaging. Otherwise there is a risk of dehydration and thus a deterioration in the property profile. In addition, paper, for example, can curl due to the high water content.

Disadvantages of this type are avoided with an adhesive stick which consists of a solid adhesive component and microencapsulated solvent, as described, for example, in GB 995 524. The disadvantage here, however, is that after use, a skin is formed on the surface of the pen, which must be removed before re-use.

Based on these difficulties and limitations, the teaching of the aforementioned publication on PCT WO 96/37566 proposes to design an adhesive which is solid at room temperature in such a way that the adhesive force is activated by internal and / or external friction. This adhesive activation by external friction is preferably such that the adhesive mass is rubbed onto the substrate surface to be equipped. The static friction enables the application of pressure-sensitive adhesive films with a film thickness of 2 to 200 μm, in particular from 10 to 100 μm, when the adhesive is coated once at a speed of 1 to 500 cm / sec, preferably 2 to 100 cm / sec a pressure of 1 kPa to 10 mPa, preferably 5 kPa to 5 mPa (normal conditions 20 ° C. and 50% relative atmospheric humidity on a paper of the following quality: 5015 special copy paper from Soennecken). The adhesive suitable for this is characterized in the publication mentioned as follows: It is solid and partially crystalline at room temperature (20 ° C) and is characterized by

a) a degree of crystallization, determined by DSC in the range from -40 ° C to + 120X, which corresponds to a melting enthalpy of 10 to 150 mJ / mg, preferably 15 to 80 mJ / mg and particularly preferably 20 to 70 mJ / mg

b) by at least one crystallization temperature at 20 to 110 ° C, in particular at 30 to 80 ° C and

c) by a crystallization rate of a few seconds to several days, in particular from 30 sec to 30 min. The enthalpy of fusion and the crystallization temperature are determined by DSC in a manner known per se. The rate of crystallization is determined by observing a sticky layer in the polarizing microscope.

The following working hypothesis is formulated for the functionality of these semi-crystalline adhesive masses: The crystalline areas are converted into an amorphous form by the mechanical action of the friction. This amorphous shape creates the stickiness. As long as the adhesive does not recrystallize, it remains tacky. In this phase, the parts to be glued together must be joined. The subsequent recrystallization then gives the adhesive its final strength.

The decisive component of the adhesive compositions from the applicant's publication cited here are polymeric binders, consisting of homogeneous mixtures of A) at least one partially crystalline polymer component and B) at least one amorphous and / or liquid polymer component. Polyester components in particular are named as polymer types. Both binder components A) and B) are not soluble in water. Their average molecular weight MG _W is 1,000 to 25,000, in particular 2,000 to 15,000. With suitable crystallinity, the A component can make up 100%. The decisive factor is the quantitative ratio of the crystalline: amorphous fraction. In general, should the partially crystalline polyester preferably makes up a proportion of 5 to 95% by weight, in particular 15 to 60% by weight and preferably 20 to 40% by weight.

It is also crucial that components A) and B) may only be compatible with one another to a limited extent, so that a mixture of crystalline and amorphous areas can be recognized morphologically (recognizable by observation with a polarizing microscope, DSC and X-ray examination).

However, the following is still crucial: macroscopically there is an apparently homogeneous distribution that must not change over time. Separation phenomena must not occur, especially at elevated storage temperatures. To ensure these conditions are met, the applicant's publication cited here suggests achieving compatibility and stabilization by using so-called compatibility agents, e.g. special polyester plasticizers or special block polymers. According to the information in this document, however, the compatibility - and thus the homogenization - is preferably stabilized by chemically combining components A) and B), e.g. through subsequent chemical linking of active groups with polyisocyanates.

The further development of solvent-free, friction-activatable adhesive compositions based on partially crystalline polymer compounds, which is described below, is based on the difficulties indicated here of reliable homogenization of the crystalline and the amorphous partial areas. The concept on which the further development is based lies in the teaching to design the polymer molecular structure from the outset in such a way that partially crystalline and partially amorphous regions are present in the same polymer molecule, and the type and amount can be varied freely in the production of the polymer molecule, so that ultimately an optimized one Control of the diverse requirements for the adhesive mass is accessible.

Subject of the invention

The subject matter of the invention is accordingly in a first embodiment

Solid at room temperature, but by rubbing on a solid substrate Graft copolymer compounds that soften the pressure-sensitive adhesive and preferably spread over a thin surface, which in their molecular structure at room temperature combine crystalline parts in chemical bonding with parts that are amorphous at room temperature, produced from the radical-initiated reaction of (a) pre-formed polymer chains with an average molecular weight of 1,000 to 35,000 and at Room temperature at least partially crystalline structure with (b) monomers which form amorphous subregions in the molecular structure of the graft copolymer. According to the invention, these graft copolymers are to be used as structure-forming solid adhesive components in friction-activatable adhesive compositions.

In a further embodiment, the invention relates to a shaped, friction-activatable adhesive composition, which is especially designed for use by hand and is free or practically free of water and / or diluents which are volatile at room temperature and is characterized by a content of friction-activatable adhesives based on the previously defined graft copolymer compounds. Finally, the subject of the invention is the use of these adhesive compositions for bonding flat substrates, in particular paper, cardboard and / or wooden surfaces, preferably by spreading the adhesive composition onto at least one of the surface areas to be bonded to form a pressure-sensitive adhesive film of the adhesive composition and then joining the surfaces to be combined.

Further details on the teaching according to the invention

The core of the teaching according to the invention for obtaining optimized friction-activatable adhesive compositions based on polymers is the use of the principle known per se for the production of so-called graft copolymers, which are also referred to as graft copolymers. This type of polymer compounds, which is well known in polymer chemistry, is known for the fact that a generally chain-shaped polymeric base molecule is first produced in a first stage, which is then in a subsequent reaction stage with suitable, in particular radical initiation with further and usually structurally modified monomer compounds is implemented. There is extensive freedom in the choice of reactants for the two stages of polymer formation. dung. It immediately makes sense that the intended optimization of the molecular components forming the graft copolymer molecule as a whole is accessible and technically feasible for the intended use of the copolymer compounds. In the following, reference is made to the relevant specialist literature on the practical implementation of the graft copolymerization. First, however, essential further basic parameters for the teaching according to the invention are listed.

Preferred graft copolymer compounds in the sense of the teaching according to the invention have as the previously defined component (a) solid and at least partially crystalline polymers and / or copolymers with chain structure from the range of polyesters, polyethers, polyurethanes, polyamides and / or their copolymers at room temperature on. Basic chemical knowledge from the polymer classes concerned here enables optimization of the intended use in a variety of ways: the desired crystallinity according to the type and amount of this polymer basic chain can be controlled in a manner known per se by selecting the monomeric reactants used here. For example, particularly good crystalline polyesters (PES) can be produced from aliphatic components such as adipic acid, hexanediol and the like which are built up as regularly as possible and are preferred. The crystallinity of a chain-shaped polymeric polyether molecule can be controlled in a manner known per se via the basic structure of the polydiols used - in particular diols or diol-forming cyclic components. The corresponding basic chemical knowledge applies to the production and regulation of polymer properties in the field of polyurethanes and polyamides. Finally, the same laws apply to copolymers of the substance classes mentioned here, such as polyester urethanes, polyester amides, polyether urethanes and the like. Regarding the relevant technical knowledge, reference can be made, for example, to the very detailed and concrete disclosure of the classes of polymer and copolymer compounds mentioned here in PCT WO 96/37566 mentioned at the beginning. This information - there in particular for the at least partially crystalline polymer components for A - in the sense of the modification now available according to to understand the teaching according to the invention as a disclosure of the constitution and nature of the preformed polymer chains (a) which are at least partially crystalline at room temperature and which, in the sense of the lying invention in the subsequent stage of the graft or graft copolymerization with the resulting from (b) amorphous molecular components. For the rest, reference can be made to the specific literature of the polymer classes for (a) the basic literature accessible to experts. "ENCYCLOPEDIA OF POLYMER SCIENCE AND TECHNOLOGY", John Wiley & Sons, Inc., 1969, and "Ullmann's encyclopedia of industrial chemistry", VCH Verlagsgesellschaft mbH, Weinheim 1992 (5th edition) may be mentioned here merely by way of example. Detailed factual information is summarized under the keyword of the respective polymer or copolymer class concerned.

This basic component (a), which is preferably chain-shaped and produced in a first reaction stage, is then subjected to graft copolymerization in at least one subsequent reaction stage using the monomer components to (b). In its preferred embodiment, the invention is based here on forming and maintaining the grafted-on residues of these components to (b) as amorphous subregions of the macromeric polymer molecule. The reaction between the preformed chain polymer to (a) and the monomers now to be grafted on to (b) takes place in a manner known per se by free radical initiation using customary reactive systems, in particular catalysts which form free radicals. Here, too, reference can be made to the general specialist knowledge, which will be mentioned below.

Particularly suitable monomer components for (b) are representatives of the following classes: vinyl esters of monocarboxylic acids with 1 to 6 C atoms, vinyl acetate being of particular importance here, acrylates and / or methacrylates of monofunctional alcohols with up to 6 C atoms, acrylonitrile or Methacrylonitrile, acrylamide and / or methacrylamide, N-vinyl-pyrrolidone, N-vinyl-carbazole. However, pure hydrocarbon-based monomer compounds of the type of styrene, of α-methylstyrene and / or 1,3-dienes are also suitable.

The comparatively large breadth mentioned here in the special embodiment of the binder component according to the invention based on the graft copolymers makes it understandable that diverse possibilities exist by means of the polymer molecule basic structure influencing the pressure-sensitive tackiness or adhesive strength of the ultimately trained adhesive layer to take. Both the structure of the polymeric basic chain for (a) and the selection or structure of the components forming the amorphous partial areas for (b) can be used to control these parameters which are essential in practical use. For example, it is possible to use functional groups in (a) and / or (b) which act as an adhesion promoter which ultimately strengthens the adhesive bond. Almost any fine control can be taken in the direction of the intended use of the adhesive composition, both in terms of the type and the amount of such elements in the polymer molecule that promote the pressure-sensitive properties. The general specialist knowledge of the specialist concerned in this context also applies here in principle.

Another important possibility of modification and thus control of the ultimately required adhesive properties in total is as follows: The graft copolymers can be based on a selected basic component to (a). However, it is also possible to use mixtures of 2 or more different components to (a) for the reaction with the components to (b). In addition to this possibility of variation or instead of such a variation, it is of course also possible to subsequently mix graft copolymer compounds prepared separately from one another within the scope of the ultimately desired adhesive compositions which are solid at room temperature and in particular can be applied by hand.

Preferred graft copolymers in the sense of the teaching according to the invention are distinguished by the following parameters, which can be of decisive importance for practical use, for example as a glue stick:

The graft copolymers which are solid at room temperature, ie in the range from 15 to 20 ° C., have a melting enthalpy, which can be determined by DSC, in the range from 10 to 150 mJ / mg, in particular in the range from 15 to 80 mJ / mg. Further limitations of this parameter on the melting enthalpy, which influences the ability to activate friction, are the number ranges from 20 to 55 mJ / mg and in particular values in the range from 25 to 35 mJ / mg. The melt peak temperatures, which can also be determined by DSC, are characteristic values for the definition of the temperature range of the pressure-sensitive softening of the graft copolymers used according to the invention. Preferred melting peak temperatures here are in the range from 30 to 90 ° C., preferably in the range from 40 to 70 ° C. and in particular in the range from 45 to 55 ° C.

Another important parameter for influencing and controlling the properties of the graft copolymer compounds is the selection of the proportions of component (s) to (a) to the monomers to be grafted on according to. (b). The corresponding quantitative ratios are expediently in the range from 90 to 20% by weight (a) to 10 to 80% by weight (b). Preferred quantitative ranges here are 80 to 30% by weight (a) to 20 to 70% by weight (b), graft copolymers in particular being preferred, the quantitative ratio of (a) to (b) in the range from 70 to 45% by weight (a) to 30 to 55% by weight (b).

By suitable variation of these multifarious parameters of the graft copolymers shown so far, it is in principle possible to produce a graft copolymer composition which is suitable for practical use and which, as such, represents the ultimately shaped adhesive material which is to be applied in particular by hand application. In general, however, it will be expedient to incorporate additional modifications into the adhesive composition ultimately intended for practical use by using additional mixture components - also referred to below as additives.

In this connection, the following general information applies first of all: the graft copolymer compounds of the type described according to the invention contain at least about 35 to 40% by weight, but preferably at least about 50 to 60% by weight, in particular of the shaped adhesive. Suitable additives are - as a rule homogeneously mixed in - mixing components, the composition of which is especially adapted to the technical application of the adhesive mixture and / or to its visual appearance. Suitable mixing components can in particular be partially crystalline polymer compounds in the sense of the teaching of the document mentioned at the outset for PCT-WO 96/37566 or the corresponding PCT / EP 96/02194. The polymer compounds referred to there as binders, in particular from the class of the at least partially crystalline and / or the amorphous polyesters, polyester amides or polyester urethanes with molecular weights (MW of 1,000 to 20,000, can be useful mixing components for blending with the graft copolymers of the type described above provided according to the invention The physical parameters of preferred mixed components of this type described above can be found in the above-mentioned publication In particular, corresponding components with enthalpies of melting - determined by DSC - in the range from 10 to 150 mJ / mg and preferably from 15 to 80 mJ / mg are suitable, the crystallization temperatures - comparable to the previously defined melting peak temperatures - also determined by DSC in the range from 20 to 110 ° C and preferably at 30 to 80 ° C.

Also suitable as additives are, in particular, components such as are described in the applicant's previously published published property right and are listed again here to complete the disclosure of the invention:

a) Crystallinity-modifying additives, preferably in amounts of max. 50% by weight.

b) Fine-particle water-insoluble pigments or fillers, in particular from the group: alkali stearates, graphite, talc, titanium dioxide, bentonite, wollastonite, chalk and pyrogenic silica, magnesium oxide and optionally fibrous materials, expediently in amounts up to max. about 20% by weight.

c) Non-volatile plasticizers in amounts of up to about 20% by weight, preferably up to about 10% by weight.

d) Minor amounts, for example up to 5% by weight of other additives such as antioxidants, preservatives, dyes and odorants. e) auxiliaries improving the adhesive effect, so-called tackifiers, expediently, in amounts of up to about 30% by weight.

Examples of the crystallinity-modifying additives acc. a) are: salts of aromatic and aliphatic carboxylic acids (eg Ca stearate), wax, polyacrylate, polyethylene, polyvinyl acetate, polyamide, polyurethane and polyvinyl chloride as well as polyester or polyurethane, especially if the basic structure of the binder forms a chain-like component (a ) is a polyurethane or a polyester.

Specific examples of the additional component acc. b) have already been mentioned. Non-volatile plasticizers in the sense of the aforementioned additional components to c) are, for example, phthalates, sebacates, phosphates such as diphenyl, benzyl butyl phthalate, trioctyl phosphate and n-ethyl-o-p-toluenesulfonamide. Typical examples of the class of tackifiers are terpene-phenol resins, rosin-glycerol esters, polycyclopentadiene resin, hydrocarbon resins and methylstyrene / styrene copolymers.

The additives vary in type and amount depending on the chemical nature of the binder. For example, PEG, PPG, PTHF and / or polyester can be used for polyurethane-based binders and here in particular corresponding polyether urethane-based binders as crystallinity-modifying additives. The function of non-volatile plasticizers can also be carried out here by water-miscible hydrophilic components of the type glycerol, ethylene glycol and / or diglyme. If liquid plasticizers are used, they should have boiling points above 150 ° C. under normal pressure in the preferred embodiment, so that the adhesive mixtures are practically free of volatile components.

The graft copolymers used as structuring solid binders according to the invention and the additives which may be used are expediently mixed in the melt. This mixing process is preferably continued until there are no differences in homogeneity can be determined with the eye. The adhesive compositions obtained in this way can be brought into any desired shape, for example in block or stick form. .

The adhesive compositions according to the invention are activated by internal and / or external friction. In its simplest form, this is done by spreading the solid adhesive mass on at least one of the adhesive substrates. In this way, thin, pressure-sensitive layers are formed in the manner shown, the open time of which can be regulated by the particular configuration of the graft copolymer and / or its mixtures with the additives. Depending on the intended use, the time period for recrystallization of the pressure-sensitive adhesive layer and thus for its hardening can range from a few seconds to days.

The practical implementation of the graft or graft copolymerization by radical-initiated reaction of the preformed polymer components to (a) with the components to be grafted on to (b) is carried out in a manner known to the person skilled in the art. For the relevant literature, reference is made, for example, to the publication "Comprehensive Polymer Science", volume 3, "Chain Polymerization" (1989), Pergamon Press, London, p. there in particular chapter 3 "Block and Graft Copolymers" - here in particular subchapter 3.3 "GRAFT COPOLYMER SYNTHESIS". Detailed factual information on the principle of block or graft copolymerization can also be found in the relevant patent literature. GB-PS 922 457, WO 95/23527, DE 4403866, DE 3915070, EP 0219048, US 5049302, US 4999869 and WO 95/22593 are mentioned here merely by way of example.

The following examples describe a number of specific embodiments of the teaching according to the invention, the substance mixtures used in each case being produced in the form of an adhesive stick as follows:

The mixtures of substances used - usually approx. 10 g per stick - are weighed into an aluminum bowl. The mass is melted on a heating plate with a spatula while stirring and mixed thoroughly until it is visually homogeneous. The melt formed is then filled into sleeves which have been prepared as follows: The sleeves - cut open and fixed again with pressure-sensitive adhesive tape - are silicone hoses with a diameter of 10 mm, which are placed on plastic ground glass stoppers 12/21. After cooling overnight, the pin is removed from the sleeve. For each example, 2 pens approx. 5 cm long are produced. The tests described in the following examples are then carried out with these pins.

B e i s p i e l e

In Examples 1 to 8 below, two different graft copolymer types - Type I and Type II - are used in different blends with other additional components. The following applies in particular:

Examples 1, 3, 5 and 7 use the Type I graft copolymer.

Examples 2, 4, 6 and 8 are based on the type II graft copolymer.

These two basic components in the sense of the teaching according to the invention are defined as follows:

Type I graft copolymer

Graft copolymer based on polyethylene glycol with an average molecular weight of 6,000 (PEG 6,000): grafted vinyl acetate (VAc) in a weight ratio of PEG 6,000: VAc of 40:60.

The copolymer showed a melting enthalpy of 35.0 mJ / mg determined by DSC and a melting peak temperature of 51 ° C. triggering the pressure-sensitive softening.

Type II graft copolymer

This is a graft copolymer based on a partially crystalline polyester (Dynacoll 7360) with vinyl acetate in the Dynacoll 7360: VAc ratio of 50:50. Dynacoll 7360 is a polyester made of adipic acid and hexanediol with an average molecular weight of 3,500.

The graft copolymer shows a melting enthalpy determined by DSC of 33.3 mJ / mg at a melting peak temperature of 54 ° C. which triggers the pressure-sensitive adhesive. Examples 1 to 8 below describe the respective composition of the multicomponent mixture worked up to the glue stick in the example concerned.

example 1

Type I graft copolymer in an amount of 90% by weight, in admixture with 10

% By weight of an amorphous polyester with an average molecular weight of

2,000, made from the following polyester-forming components: 38 mole% o-phthalic acid, 10 mole% adipic acid, 33 mole% neopentyl glycol and 19 mole%

Glycol.

Example 2

Graft copolymer type II in an amount of 80% by weight, mixed with 20% by weight of the amorphous polyester used as a mixing component in Example 1, based on phthalic acid / adipic acid-neopentylglycol / glycol.

Example 3

Graft copolymer type I in an amount of 90% by weight, mixed with 10% by weight of the commercial product "Bevilite 62-107 from Bergvick (Arizona, USA). Bevilite 62-107 is a rosin ester based on highly stabilized Resin acids.

Example 4

Type II graft copolymer in an amount of 90% by weight, in admixture with 10

% By weight of the commercial product "Bevilite 62-107" acc. the details of the example

Third

Example 5

Graft copolymer type I in an amount of 90% by weight, in admixture with 10% by weight of sucrose benzoate - commercial product from Velsicol Chemical Corporation.

Example 6 Graft copolymer type II in an amount of 90 wt .-%, in admixture with 10 wt .-% of the sucrose benzoate product acc. Example 5.

Example 7

Type I graft copolymer in an amount of 95% by weight, in admixture with 5% by weight of a high molecular weight polyester based on diethylene glycol (46 parts by weight), ethylene glycol (12.1 parts by weight), isophthalic acid (63.6 parts by weight) and Adipic acid (28.8 parts by weight) with an OH number of 9 and an acid number of 6.

Example 8

Type II graft copolymer in an amount of 90% by weight, in admixture with 10

% By weight of the high molecular weight copolyester acc. Example 7 based on diethylene glycol / ethylene glycol isophthalic acid / adipic acid.

Testing the glue sticks acc. Examples 1 to 8 and the determination of the respective characteristic adhesive parameters is carried out in accordance with. the following investigations:

1

Apply adhesive for subsequent gluing

The adhesive is applied using a pressure of approx. 500 kPa, at a spreading speed of approx. 100 cm / sec and at room temperature. The

Film thickness is approx. 50 μm each.

Second

The following tests are carried out: a) Determination of the adhesive strength after 10 sec - hereinafter also referred to as the "initial stack": gluing a cardboard strip as a ring with subsequent evaluation of the adhesive duration (indication of the time): a cardboard strip with the size 29 is used, 1 cm x 5 cm and a thickness of 250 g / m ² . Measured from the edge, a 2 cm wide area is coated on one side by the adhesive on one narrow side of the strip. Then the strip is put into a ring and the glue is pressed together for 10 seconds. The time is measured until the ring opens again. b) Abrasion: rub on the copying paper from Soennecken 5015 special paper; The assessment of the bond is done in school grades.

c) tensile shear value, determined on the one hand on the rubbed-on adhesive, additionally determined on the melted adhesive.

The tensile shear strength of wood / wood bonds is determined: 2 beechwood test specimens are provided with the adhesive at their end and folded together so that the two ends provided with adhesive overlap by 2 cm (adhesive surface 2 cm x 2.5 cm). The test specimens are fixed with 2 clamps and measured after 24 hours. The measured values determined in each case are given in N / mm ² .

d) Determination of the setting speed: The adhesive is applied in a width of 2 cm to a sheet of the previously mentioned copy paper, then covered with a second sheet of the copy paper and coated twice by hand. The period until the first tear when separating the leaves is subsequently determined. Tests are carried out at intervals of 0.5 minutes up to a period of 4 minutes, then the adhesive behavior is determined at 5 minutes, 7 minutes, 10 minutes and 15 minutes.

e) Determination of the adhesive strength after one day: gluing of copy paper from the Soennecken company (5015 special copy), test for paper tear after one day (indication of the percentage of paper tear).

The determined in these tests on the glue sticks for Examples 1 to 8. Values are summarized in the table below:

Claims

Expectations 1. Graft copolymer compounds which are solid at room temperature, but rubbing on a solid substrate by pressure rubbing on the friction surface and preferably spreadable on a thin surface, which, in their molecular structure, combine partial crystalline areas at room temperature in chemical bonding with partial areas amorphous at room temperature, produced from the radically initiated implementation of (a) preformed polymer chains with an average molecular weight of 1,000 to 35,000 and at least partially crystalline structure at room temperature (b) Monomers which form amorphous subregions in the molecular structure of the graft copolymer for use as structure-forming solid adhesive components in adhesive compositions that can be activated by friction. 2. Graft copolymer compounds according to claim 1, characterized in that they have - by DSC determinable - enthalpies of melting in the range from 10 to 150 mJ / mg, in particular in the range from 15 to 80 mJ / mg, and a - triggering the pressure-sensitive softening - melting peak -Temperature in the range of 30 to 90 ° C, preferably from 40 to 70 ° C. 3. Graft copolymer compounds according to claims 1 and 2, characterized in that the melting enthalpies determinable by DSC in the range from 20 to 55 mJ / mg and preferably in the range from 25 to 35 mJ / mg and the melting peak temperatures in the range from 45 to 55 ° C. 4. graft copolymer compounds according to claims 1 to 3, characterized in that they contain the components to (a) and (b) in proportions of 90 to 20 wt .-% (a) to 10 to 80 wt .-% (b) and preferably contain 80 to 30% by weight (a) to 20 to 70% by weight (b), it being possible for graft copolymers to be preferred whose quantitative ratio of (a) to (b) is in the range from 70 to 45% by weight .-% (a) to 30 to 55 wt .-% (b). 5. graft copolymer compounds according to claims 1 to 4, characterized in that they are as component (a) solid and at least partially crystalline polymers and / or copolymers with chain structure from the range of polyesters, polyethers, polyurethanes, polyamides and / at room temperature or contain their copolymers. 6. graft copolymer compounds according to claims 1 to 5, characterized in that they contain at least partially copolymerized as component (s) (b) monomers from the following classes: vinyl esters of monocarboxylic acids having 1 to 6 carbon atoms, acrylates and / or methacrylates of monofunctional alcohols with up to 6 carbon atoms, (meth) acrylonitrile, (meth) acrylamide, N-vinyl-pyrrolidone, N-vinyl-carbazole, styrene, α-methylstyrene and / or 1, 3-dienes. 7. graft copolymer compounds according to claims 1 to 6, characterized in that they have in the molecular structure pressure-sensitive adhesive or adhesive strength-forming functional groups, which at least partly in the amorphous, formed by component (s) (b), but partly if desired also in the molecular areas crystalline at room temperature acc. (a) are present. 8. graft copolymer compounds according to claims 1 to 7, characterized in that they are based on a selected basic component to (a), if desired, but also by reacting a mixture of two or more different components to (a) with the components to (b) have been produced. 9. Shaped, and in particular for a hand-formed solid friction-activatable adhesive composition which is free or practically free of water and / or diluents volatile at room temperature, characterized by a content of friction-activatable adhesives based on graft copolymer compounds in accordance with. Claims 1 to 8. 10. Shaped adhesive composition according to claim 9, that its content of graft copolymer compounds is at least 35 to 40 wt .-%, but preferably at least 50 to 60 wt .-%, with the rest - preferably homogeneously mixed - mixing components based on other friction activators - Barely and preferably partially partially crystalline polymer compounds and / or conventional additives for modifying the adhesive compositions may be present. 11. Shaped adhesive composition according to claims 9 and 10, characterized in that it contains in a preferably homogeneous blend with the graft copolymers polyesters, polyethers, polyurethanes, polyamides and / or their copolymers, which can also have at least partially semi-crystalline structure, preferred average molecular weights have in the range from 1,000 to 20,000, but are not graft copolymer compounds in the sense of the teaching of claims 1 to 8. 12. Shaped adhesive compositions according to claims 9 to 11, characterized in that they, together with the graft copolymer compounds, are customary additives from the field of adhesives which can be activated by friction, such as crystallinity-modifying additives, finely divided pigments and / or fillers, plasticizers and / or tackifiers, antioxidants , Preservatives, dyes and / or odors. 13. Shaped adhesive compositions according to claims 9 to 12, characterized in that they have a block or pin shape. 14. Use of the adhesive compositions according to claims 9 to 13 for bonding paper, cardboard and / or wooden surfaces, preferably by spreading the adhesive composition onto at least one of the surface areas to be bonded to form a pressure-sensitive adhesive film of the adhesive composition and then joining the surfaces to be combined.