DE3330119A1 - PEN OR CHALK AND METHOD FOR THE PRODUCTION THEREOF - Google Patents

Description

The invention relates to pens or chalks which consist of a shaft and a lead permanently connected to this and where the fixed connection between mine and shaft and possibly also the shaft parts with one another - provided the shaft composed of half-shells or several individual parts is effected by gluing. The invention also relates to Process for the manufacture of such pens. As such pens or chalks are in particular writing, painting, cosmetic erasers and similar pens and / or chalks with fixed shafts or grips.

Writing or painting, ifte and processes produced by means of gluing 19 53 985 are known, for example, from DE-AS 19 53 985 for their production. Here, a polyvinyl acetate is used to glue the lead (PVAc) dispersion adhesive and a hot melt adhesive used to glue the shaft halves or boards in order to allow for heating to be able to dispense with the hardening of the gluing of the shaft.

From GB-PS 956 119 pens and methods are known, according to which the glueing of the lead and the shaft parts with vinyl resin adhesives - For example with polyvinyl acetate and under the action of heat - should be done.

According to DE-PS 28 45 078 a gluing of pins with leads is proposed in such a way that the adhesive connection between the two Lead and shaft made from an emulsifier contained in the lead and from a copolymer of methyl vinyl ether and maleic anhydride is formed.

The shaft parts themselves are also made up of a polyvinyl acetate dispersion glued together. In addition, the overall bonding takes place under the action of heat - preferably using high frequency or microwave heating systems.

The disadvantages of the known pins and methods are in particular that it is necessary to use the Keep grooves for the mines dimensionally within tight tolerance limits as well as clean and with even and relative

run smooth surface because of the adhesives used otherwise not applied in sufficient quantity or, on the other hand, in a layer that is too thick and therefore not sufficient result in a firm connection between the lead and the shaft or form a relatively hard layer of adhesive as a crust around the lead. Both of these can affect the sharpening of the pencils in particular and lead to frequent lead breakage during use to lead.

It is also necessary to use either heating systems to harden the glue or two different adhesives, to achieve the solidification of the adhesive layers in an economically justifiable time.

When gluing water-soluble leads - for example for watercolor pencils - the Mine as a protective measure or the use of special adhesive systems and corresponding heating systems are required so that the mine is not already affected by the usually highly aqueous PVAc dispersion adhesive or partially dissolved or attacked by the plasticizers they may contain during the bonding phase as a result of which it may no longer be possible to achieve a firm bond or which creates a relatively hard adhesive layer.

It is therefore the object of the present invention, pencils and chalks of the type mentioned, or a gluing for this, as well as suitable processes to create, whereby the disadvantages mentioned do not occur or only to a very limited extent. In particular, through the invention creates inexpensive and high quality pens or chalks, the leads of which without protective insulation are securely anchored in the shaft, their mine grooves in relatively large tolerance ranges and possibly with a rough surface can be manufactured - without affecting the durability of the glue or the quality of the pens the sharpening and the gluing-related breaking strength - with which optionally only the leads, only the Shaft parts or the leads and the shaft parts can be firmly connected with one and the same adhesive and in which a Modifiable within wide limits, but essentially

similar or uniform adhesive can be used, which can result in a relatively soft adhesive layer and yet still adheres very well to the lead and to the shaft material.

This object is achieved in that as Adhesive exclusively or additionally the product of a polyreaction of an isocyanate with a compound that is reactive Contains hydrogen is used. This product will continue to be referred to as a reactive adhesive.

Advantageous refinements and developments of the invention are included in the further claims.

It is known that polyurethane (PU), a polyaddition formed from isocyanate and functional hydroxyl groups Plastic, among other things, has been used for a long time for the production of adhesives (see also Kunststoff-Handbuch, Vol. VII, "Polyurethane", Carl Hanser Verlag, Munich 1966, p. 24 and 719-735). Such PU adhesives are already widely used in the Furniture industry for gluing wood or for joining wood and plastic or ceramic parts.

Although therefore according to the invention in part not an absolutely new adhesive is proposed, it was not obvious that they contain products from polyreactions of isocyanate and reactive hydrogen Connections are extremely suitable for gluing pens or chalks together. One of the main arguments against is the fact that the resulting adhesive layer in certain There are limits in the foam structure and consequently has apparently not been viewed as sufficiently stable up to now. Because it is precisely because of the sharp point of the pencils that considerable demands are placed on the strength of the adhesive connections, both between the lead and the shaft, as well as mutually with the shaft parts.

Overall, the prevailing opinion so far was that such a bond is a relatively hard or firm layer must form and that an elastic or even porous adhesive film is not suitable for this. - 9 -

Surprisingly, it was found that, despite these concerns and the known problems, isocyanate and reactive Hydrogen-containing compounds formed reaction products as adhesives (reaction adhesives) for pens result in a very good and widely variable gluing.

Reaction products that arise from moisture-reactive isocyanate have proven to be particularly suitable: as well as those that are formed from isocyanate and compounds containing functional hydrolxyl groups and those that which consists of a blocked I so cyanate compound and a plastic dispersion, e.g. an aqueous polyvinyl acetate dispersion and preferably a prepolymer, z. B. with a diphenylmethane diisocyanate to form the adhesive or result in the corresponding adhesive components.

If moisture-reactive isocyanate is used, the The amount of water required for polymerisation is contained in the lead, in the shaft material or in an impregnating agent be. If the shaft is made of wood, the boards can have increased residual moisture if necessary. Likewise, if necessary, the mines - e.g. colored mines - can be green, i. H. not or not completely pre-dried or water- or contain emulsion-containing impregnation agent. If a polyurethane is formed as a polyreaction product from functional hydroxyl groups and the corresponding isocyanate, so can the hydroxyl groups either also as components of the lead, the impregnation agent or the shaft material exist or be separated by means of a second component. As such component, polyether polyols or polyester polyols can preferably come into consideration, these being Component should have a hydroxyl number between 20 and 400.

- 10 -

'/ admitted

Instead, however, advantageous polyreaction products made from isocyanate and containing reactive hydrogen can also be used Polyaminotriazole, polyethylene amine, polycarboxylic acid, polyester amide and / or polyether amine can be formed as an adhesive for the pens.

The preferred embodiment of the invention for the isocyanate components are an isocyanate 8-55 wt -.% Have. A particularly suitable component of this type is, for example, 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, naphthylene-1-5 diisocyanate or 4,4 ', 4 "- triphenylmethane triisocyanate.

Depending on the type of isocyanate and the given processing conditions can the reaction mixture an organometallic compound, a metal salt and / or an amine or a compound with acidic hydrogen or another catalyst or accelerator can be added to the temporal To keep the course of the polymerization within the desired framework.

Likewise with the blocked isocyanate compounds that may be used, · the the access to water to the isocyanate preventing or retarding substance, z. B. a slowly evaporating Solvent to adjust to the existing working conditions or to be selected accordingly.

In principle, the known methods and devices can be used to produce pencils or chalks according to the invention Find application.

Instead of the usual adhesive, isocyanate or isocyanate + reaction component or Isocyanate + plastic dispersion, separately or mixed, applied .

If only the leads with the reactive adhesive according to the invention are to be glued in, the isocyanate is added in doses

- 11 -

Amount, for example, in the grooves of the shaft material, e.g. B. the boards made of wood, introduced, then put in the leads, put two small boards together and press them together until the adhesive layer is firm is.

In this case, the ridges of the boards themselves would be with a different adhesive (e.g. with PVAc glue) before being pressed together to be coated separately.

Preferably, however, the lead and board gluing can be done uniformly with reactive adhesive. The choice of the most suitable procedure in each case depends mainly on the requirements of the manufacturing process or the existing systems. Any additional heating used during the curing process can influence this phase of production in terms of time. d. H. usually shorten. In principle, however, heating to solidify the bond is not necessary because the particular reactivity of isocyanates with reactive hydrogen or with functional hydroxyl groups or with water par excellence, a complete and relatively fast polymerization and thus curing causes. For example, polyurethane is formed from polyfunctional reactants by the following reaction:

HO-R-OH + OCN - R ¹ - NCO

R - 0 - CO - NH - R ¹ - NH - CO - 0

Here means:

R = a residue of the hydroxyl-containing component R ¹ = a residue of the isocyanate

HO or OH = hydroxyl group

- NCO or OCN - = isocyanate group

- 0 - CO -NH- = urethane group

N = nitrogen; C = carbon; 0 = oxygen;

If a moisture-reactive isocyanate and water are used, the bonding or the polymerization takes place and Curing of the adhesive layer after the isocyanate is applied has been caused by the moisture in the mine or in the wood.

In order to adjust the reaction time so that the leads can be inserted, the moisture content of the individual Adjust parts accordingly.

In addition, a retarder or an accelerator can be added to the isocyanate to achieve the most suitable reaction time to obtain. The moisture in the reaction or the reactive hydrogen groups that may be required for the reaction for other isocyanates or the functional hydroxyl groups, can in the mine or in the shaft material or in a suitable impregnating agent for the mine or for the shaft or in an additional component to be applied or to be admixed with the isocyanate immediately before application be included.

The reactive adhesive is made from isocyanate and from a further Component formed, a homogeneous mixture can first be produced from this, which is then suitably Way is applied.

However, it is also possible to apply both components separately from one another.

The response times must always be adapted to the circumstances or requirements. This can be done by selecting and / or Modification of the isocyanate or the working conditions or can be achieved by appropriate additives.

In the same way as the one described in more detail below Manufacture of pens or chalks according to the invention as pens or crayons, cosmetic pens, Eraser or other correction pens, scribing pens, etc., pens or chalks with a glued handle or the like Manufacture shaft or shaft part. - 13 -

The invention is explained in more detail below using a few exemplary embodiments in conjunction with a graphic representation.
The figures show:

Fig. 1: a first board 1 with grooves 3 and intervening Web 5, with adhesive 7 introduced into the grooves 3 via the nozzles 13 and further adhesive 8 was applied to the webs 5 via rollers 14. In some grooves 3 there are also already mines 11;

Fig. 2: a second board 2, which is referred to as the cover board can be and without leads (11), but with adhesive 7 and incorporated into the grooves 4 the webs 6 applied adhesive 8 is provided and

Fig. 3: a glue formed from the boards 1 and 2 12, which is pressed together by pressing parts 15 and which in the grooves 3 and 4, the mines 11, surrounded by an adhesive layer 9, while between the webs 5 and 6 contains another Adhesive layer 10 causes the connection of the shaft parts to one another.

The following exemplary embodiments are each used for clarification necessary scope with reference to the positions in the figures. The individual adhesives 7, 8 may also be used here View adhesive components.

example 1

In the prefabricated grooves 3 of a wooden board 1 as shaft material 4,4'-diphenylmethane diisocyanate is introduced as adhesive components 7 by means of nozzles 13.

The webs 5 between the grooves or the contacting shaft surfaces are made with aqueous PVAc dispersion glue as an adhesive coated by means of a roller 14.

Then the leads 11 are inserted into the grooves 3 of the board 1 and covered with a second board 2, in whose grooves 4 isocyanate (7) was also applied.

While the boards 1, 2 as so-called glue pieces 12 are now pressed against one another by pressing parts 15 _? the formation of the reactive adhesive (9) or the polymerization and hardening of the isocyanate takes place through the moisture contained in the wood and additionally in the PVAc glue (8). The leads 11 are thereby firmly glued in, while the shaft halves are connected by a conventional PVAc adhesive layer. The glue pieces 12 are then sawn in a known manner and the shafts of the pins are shaped and, if necessary, painted and sharpened.

Example 2

In the prefabricated grooves 3, 4 corresponding wooden boards 1, and on their webs 5, 6 between the grooves 3, 4 is 4,4'-diphenylmethane diisocyanate applied as an adhesive component 7, 8. After inserting the leads 11 in the first board 1 and the Placing the equally coated second board 2 on the glue 12 is pressed.

The hardening or the formation of the adhesive layers 9, 10 takes place here by the reaction of the isocyanate with the moisture contained in the wood and / or in the mines 11. The further processing takes place as in example 1.

Example 3

The production and treatment of the glue pieces 12 takes place according to Example 2. The leads 11 are, however, before being inserted with a Impregnated polyether polyol, which has a viscosity of 800- lOOOmPa.s. and has an OH number of 160.

The hardening of the adhesive layer formed from reactive adhesive 9 between the mine dog and the wood takes place here through the reaction of the isocyanate with the hydroxyl groups of the polyether polyol, while the gluing of the shaft halves - the wooden parts to one another - by the reaction of the wood contained moisture with the isocyanate formed adhesive layer 10 takes place. The particular advantage of this type of bonding is, among other things, that the hardness of the bond by the selection of the appropriate impregnation agent within wide limits is variable. _ 15 _

In this way, if necessary, one can always be adapted to the type or hardness of the lead or matched to the shaft material Hardness of the reaction adhesive or the adhesive layers and 10 can be selected.

Example 4

Toluylene diisocyanate is made from two different containers A and B (A) and polyester polyol (B) with a viscosity of 700 to 900 m Pa.s and an OH number of 90 Pumped through separate lines into a two-component low-pressure mixing head and mixed there intimately. the Mixture AB contained therefrom is introduced as an adhesive (7,8) into the grooves 3.4 of the boards 1.2 and onto the webs 5.6 applied.

The gluing takes place during the pressing together of the Glues 12 through the crosslinking reaction of the isocyanate with the polyester or the functional hydroxyl groups of the polyester.

Example 5

90 parts by weight of a 50 % aqueous polyvinyl acetate dispersion with a viscosity of 6000 m Pa.s are stirred with 10 parts by weight of a blocked diphenylmethane diisocyanate prepolymer. This mixture is applied or further processed as in Examples 2 or 3. The bonding takes place here through the reaction of the prepolymer and through the curing of the polyvinyl acetate.

Example 6

80 parts by weight of a 20 # aqueous polyacrylic acid solution are with 20 parts by weight of an inhibited 4.4.4 "-triphenylmethane triisocyanate prepolymer stirred.

The further processing takes place as in Example 2, with the curing of the reactive adhesive or the adhesive layers 9, 10 takes place through the reaction of the prepolymer with the acrylate and the water of the polyacrylic acid solution.

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Example 7

To produce pencils as in Example 3, the leads 11 are impregnated with a polyethyleneimine that has a viscosity from 600 to 1000 m Pa.s. The curing of the reactive adhesive takes place here by the reaction of the isocyanate with the imine groups of the impregnating agent.

Example 8

A saturated solution of polyaminotriazole is used to impregnate the boards 1,2 already provided with grooves 3,4 this applied. After applying the isocyanate as an adhesive component 7, 8 and the insertion of the lead 11, the gluing takes place during the pressing of the glue pieces 12 by the Reaction of the isocyanate with the amino groups of the impregnation agent.

Due to an i. d. Usually taking place carbon dioxide elimination During the "crosslinking reaction, the adhesive proposed according to the invention receives a microporous foam structure.

This, among other things, keeps the hardened layer of the Reaction adhesive elastic and relatively soft within certain limits.

For this reason, the grooves in the boards may be larger than necessary, i. H. in larger tolerance ranges or with larger plus tolerances than before, without disadvantageous, excessively hard adhesive layers to get the lead or between the shaft parts. Due to the high affinity of the proposed reactive adhesive to the shaft material and to the lead on the one hand and the urethane molecules to one another on the other hand the resulting porous adhesive layer always has good or sufficient strength and produces a secure connection between the mine and the shaft material.

- 17th

In addition to wood, plastic or Metal come into consideration.

Likewise, the shafts can also be formed other than from boards or from half-shells glued together. For example, shafts which are preferably made of thermoplastic material are injection-molded or extruded in one piece can be used, in which only the leads are glued with the reactive adhesive proposed according to the invention. Here, too, the adhesive components can be used together or be applied or introduced separately on the mine or in the shaft bore.

Of course, the shafts can also be composed of more than two parts.

Pens or chalks according to the invention can be both exclusively reactive adhesives made from isocyanate and reactive adhesives Have hydrogen-containing compounds, as well as - in addition to different, separately present adhesive systems - Have adhesive layers consisting of adhesive mixtures, the adhesive mixture only one may contain a certain proportion of reactive adhesive.

To set the hardness of the reactive adhesive, in addition to or in addition to an impregnating agent that may be present, the Selection of the reaction component for the isocyanate is of particular importance.

Likewise, the respective isocyanate type, the hardness and the Affect the strength of the adhesive layer.

The proposed reactive adhesive usually consists practically of two components, a (first) "basic component" containing isocyanate and a (second) "reactive component" having reactive hydrogen or reactive hydrogen or functional hydroxyl groups or water or being present directly in this way. .

In the case of blocked prepolymers, the reaction component and the basic component can already be mixed and, if necessary, as aqueous dispersion are present.

In this case, the crosslinking usually only arises through additional heating or the addition of a third one, under certain circumstances. isocyanate-containing, component.

If the adhesive components are present separately, it is closed Note that the mixing ratio between the isocyanate-containing basic component and a functional Hydroxyl-containing reaction component is chosen so that an excess of isocyanate is always present is so that all hydroxyl groups are bound with certainty. The excess isocyanate groups can optionally also react with existing humidity.

Shafts made of metal can, under certain circumstances, be used purely as grips, e.g. B. be designed for thick leads or for chalk, which do not need to be sharpened.

With the pens or chalks according to the invention, except for all writing, painting, Cosmetic pencils or chalks, including those pencils whose leads do not contain any color-releasing substance. In addition to eraser pens, the lead is an eraser strand made of plastic or rubber or the like is glued in a wood or plastic shank, which is also advantageously with the reactive adhesive proposed according to the invention can be produced, including those pens within the scope of the invention whose mine z. B. as a scriber is formed and consists of metal or other hard material, or the mine is a solid substance bound, chemically acting correction mass, z. B. for school ink or similar contains.

In certain cases, leads or chalks can only have a coating layer of reactive adhesive, without the frame to leave the invention. In this case, the coating layer also represents the shaft of the pen.

Claims (1)

Claims Pen or chalk, consisting of a shaft and a lead firmly connected to this, the fixed lead Connection of the mine with the shaft; and, if necessary, the shaft parts with one another, is effected by gluing, characterized in that the adhesive is the product of a polyreaction of an isocyanate with reactive hydrogen-containing compounds is or contains. 2. pen or chalk according to claim 1, characterized in that the adhesive is a polyaddition product Isocyanate with a reactive hydrogen-containing imino, amino, carboxy or hydroxy compound and / or is or contains water. 3. pen or chalk according to claim 1, characterized in that the adhesive is a polycondensation product is or contains reactive isocyanate with water. Pen or chalk according to Claim 2, characterized in that the adhesive is a polyurethane or a reaction product of isocyanate and functional hydroxyl groups is, with the functional hydroxyl groups before the reaction with the isocyanate as a component of the lead or an impregnating agent for the lead or for the shaft material are present. 5. pen or chalk according to claim 2, characterized in that the adhesive consists of an isocyanate and a second, reactive hydrogen-containing component, such as polyaminotriazole, Polyethyleneimine, polycarboxylic acid, polyether polyol, polyester polyol, polyester amide and / or Is or contains polyether amine, formed reaction product 6. pen or chalk according to one of claims 1, 2, 4 or 5, characterized in that the second component has a hydroxyl number of 20 to 400 has. 7. pen or chalk according to claim 1 or 2, characterized in that the adhesive is a '. R. reaction product based on an aqueous plastic dispersion and a blocked isocyanate compound is or contains. 8. pen or chalk according to claim 7, characterized in that the isocyanate compound is a prepolymer is. 9. pen or chalk according to claim 8, characterized in that the isocyanate of the prepolymer is a diphenylmethane diisocyanate is. 10. Pencil or chalk according to one of the preceding Expectations, characterized in that the isocyanate component Einei isocyanate 8-55 wt - has.%. 11 · Pen or chalk according to one of the claims 1 to 6 or 10, characterized in that the isocyanate is a 4,4'-diphenylmethane diisocyanate, a tolylene diisocyanate, a naphthylene-1-5 diisocyanate or a 4,4 ', 4 ^fl- triphenylmethane triisocyanate. l ² pen or chalk according to one of the preceding claims, characterized in that the reaction mixture has a catalyst or a Contains accelerator. 13 pen or chalk according to claim 12, characterized in that the catalyst or the accelerator is an organometallic Compound, a metal salt and / or an amine or a compound with acidic hydrogen is. 14. A method for producing a pen or a chalk according to any one of the preceding claims 1 to 13, characterized in that the isocyanate and any other (s) present Component (s) as an adhesive (7) in the prefabricated grooves (3, 4) made of boards (1, 2) or blanks prepared shaft parts is introduced that the webs (5, 6) of the boards (1, 2) also with it or coated on one or both sides with the adhesive (8) provided for this purpose, that after inserting the leads (11) and assembling the shaft parts or the boards that belong together (1,2) the resulting glue (12) is pressed together, the gluing or curing of the adhesive layers (9,10) takes place and that the boards are then cut and the shafts of the pencils or chalks shaped and, if necessary, painted and sharpened will. _ 4 _ 15. The method according to claim 14 for the production of pencils or chalks according to claim 1, 2, 3, 10, 11, 12 or 13, characterized , that the amount of liquid required for the reaction of the isocyanate in the shaft material, the lead or the impregnation agent for the mine is contained and is withdrawn from it and that the sticking through the reaction of the isocyanate is carried out with water. 16. The method according to claim 14 for the production of pencils or chalks according to claim 1, 2, 4, 6, 10, 11, 12 or 13, characterized in that the shaft material, the lead or the impregnating agent which has hydroxyl groups and that the bonding is due to the reaction of the isocyanate with functional hydroxyl groups he follows. 17. The method according to claim 14 for the production of pencils or chalks according to claim 1, 2, 5, 6, 10, 11, 12 or 13, characterized in that the isocyanate and the second component consist of two separate Containers mixed and introduced as a homogeneous mixture in the grooves and, if necessary, on the adhesive surfaces of the shaft parts is applied and that the bond through the reaction of the isocyanate with the other Component present Polyamxnotriazol, Polyethylene (min, Polyether polyol, polyester polyol, polyester amide and / or Polyetheramine or with a polycarboxylic acid takes place. 18. The method according to claim 14 for the production of pencils or chalks according to claim 1, 2, 7, 8, 9 or 10, characterized in that a dispersion isocyanate system is applied as an adhesive and that the bond is caused by the reaction of the isocyanate with the moisture of the dispersion component he follows. 19. The method according to any one of claims 14 to 18, characterized in, that the compressed glue pieces are first additionally heated, the bonding or the solidification reaction leading to the adhesive takes place.