FI68103C - FOERFARANDE FOER FRAMSTAELLNING AV IMPREGNERADE SLAETA ELLER KRAEPPADE PAPPER I EN PAPPERSMASKIN - Google Patents

Description

χ 68103

A method of making impregnated plain papers or Krep papers in a paper machine

The invention relates to a new method for producing impregnated plain or creped papers in one operation in a paper machine and to the use of papers produced according to this method as a carrier (substrate) for pressure-sensitive adhesive layers (self-adhesive pulps), especially in the production of protective and packaging adhesive tapes.

Impregnated papers are technically used in many ways, for example in the manufacture of cable and insulation papers in the electrical industry, in the manufacture of abrasive papers and valuable wallpaper, in the manufacture of moisture-resistant moldings and door elements in the construction However, the primary and most used impregnated papers are used as a carrier (substrate) for pressure-sensitive adhesive layers (self-adhesive masses), especially in the manufacture of protective and packaging adhesive tape and.

When using impregnated papers as carriers or substrates for pressure-sensitive adhesive layers (self-adhesive pulps), it is quite important that the impregnant holds the paper fibers together so well that the paper has sufficient tear and crack strength. Since such adhesive tapes generally come in commercial rolls and all layers of adhesive in the rolls come into direct contact with the backing paper of the previous layer of adhesive tape, good tear and tear strength is required of the tape when removed from the roll to avoid tearing or splitting. In addition to the cracking strength (cracking resistance), 2 68103 which is very necessary for paper substrates for self-adhesive tapes, the support must also have sufficient strength, elasticity and elongation to allow the tape to be placed on curved and irregular surfaces to form the desired pattern without tearing the tape. In addition, this treatment must achieve heat and water resistance, which is of great importance when used.

In order to produce impregnated papers, it has hitherto been common to impregnate finished papers with good absorbency, such as those made of cellulose, in special impregnation machines, preferably with solutions of aqueous polymers and elastomers or aqueous dispersions (latex) and then dry in a paper web.

The impregnation and finally drying of completely finished papers requires additional work steps, and of all the processing steps, the impregnation of smooth creped papers is the slowest, especially when this work step can usually only be worked at a relatively low flow rate, depending on the length of the drying channel.

In many cases, conventional papermaking methods require very strong wet bonding, which prevents view particles from entering the fibers during impregnation after paper finishing and often results in uneven distribution of particles to the fiber structure.

Experiments have shown that impregnation in a paper machine for the above reasons - whether pulp gluing by means of a rubber dispersion or a gluing press - is not possible due to thermoplasticity and consequent stickiness, as it usually results in web adhesion and staining with hot cylinders and drying felts. Adhesion or entrapment results in tearing of the paper web, which is said to cause severe disturbances in the manufacturing process, especially for thinner papers.

The object of the invention is therefore to avoid the disadvantages which occur both in the adhesion of the paper machine and also in the impregnation and subsequent drying of the finished papers and to develop a method which makes it possible to produce impregnated smooth or creped papers without additional work steps in a paper machine.

It has been found, and must be regarded as a solution to this problem, that this object can be achieved in a simple manner by adding to a pulp or still wet paper a certain amount of a mixture in the form of an aqueous dispersion containing an elastomer or rubber polymer at a certain residual moisture content. in addition to the small amount of paper softener, as well as a small amount of silicone-free, anti-adhesive surfactant. In this case, it is possible to produce impregnated plain or creped papers, in particular for use as a carrier for pressure-sensitive self-adhesive layers, in a single-step paper machine, whereby the paper has the desired properties, while avoiding harmful adhesion of the paper web to hot cylinders and felts. at high speeds and the amount of wet adhesive used can be significantly reduced (up to 50% of the amount otherwise commonly used).

It is therefore an object of the invention to provide a method for producing 68103 impregnated plain or creped papers in a single operation on a paper machine, and is characterized by adding to the fibrous suspension or pulp, prior to sheeting, a commonly used wet adhesive and any conventional adhesives. and / or in addition to dyes, about 1 to 12% by weight, preferably 2 to 4% by weight based on the weight of the dry pulp or paper pulp, a mixture comprising: 0.5 to 0.5% by weight of silicone-free, anti-adhesive, surfactant 89.0 to 95.5% by weight of elastomer or rubber polymer and 2.0 to 6.0% by weight of paper softener, the pulp is formed in a conventional manner on a paper machine - optionally using a creping device intermediate - as a paper web and then treated with a residual water content being 6 to 20% of the remaining amount of the mixture and dried to use said mixture distant so much that the dry paper contains 7-60% by weight of the mixture.

However, it is known to add various additives to pulp or paper by various methods to achieve certain properties, such additives being added to either the fibrous suspension prior to sheeting, which, especially in high speed papermakers, presents difficulties when these substances remain in the slurry and pass through. with water through the sieve-30 compartment must be prevented, or such additives may be already formed on the paper web in a moist or almost dry form. Thus, for example, it is questionable for adhesives to be added either to pulp or to pulp ("pulp gluing") and also to be applied to the surface of a finished paper web ("e.g. glue presses, spraying devices or the like) by means of suitable applicators". Surface sizing ").

On the other hand, with the exception of 5 different methods used in connection with silicones, it is not possible to use the compositions according to the invention containing an anti-adhesive surfactant as impregnating agent in papermaking processes. Rather, there was a prejudice in the expert circles about the use of such mixtures in a papermaking process, because usually anti-adherents as hydrophobic agents significantly interfere with the manufacturing process, even if only in small amounts. Thus, it was surprising and could not be expected by those skilled in the art that the amount of such small anti-adherent surfactants in the impregnating agent mixture would not interfere with the papermaking process itself and even had a beneficial effect when noxious adhesion of the treated paper web to the drying cylinder .

Only in British Patent 922,828, in which the invention relates to the treatment of papers, in particular parchment and parchment papers, with a mixture of silicone rubber and silicone resin to which further substances such as carboxymethylcellulose or epichlorohydride and aliphatic hydride and aliphatic hydride can be added. condensation products, it has been shown that such materials are also used even in the papermaking process. Due to their excellent adhesive-repellent properties, these papers produced by this method can also be used only as release paper or intermediate paper in connection with a variety of sticky substances or self-adhesive pulps, or also as an intermediate carrier for transferable adhesive layers, but not as in the process according to the invention. impregnated papers - as permanent carriers for pressure sensitive adhesive layers. When ordinary paper machines are used in the production of paper, silicones cannot be used because they tend to harden permanently on a screen, felt, etc., and can no longer be removed from said devices.

In addition, it is also not possible to crepe the paper in the presence of silicones 10, since the creping blade will then no longer stick.

Mention should also be made in this connection of DE publication for a process for producing flexible smooth or creped paper having high tear strength and splitting strength, in which, at a certain stage in the production of the paper, namely before the headbox, it is added to the fiber suspension or pulp with other additives. consisting of a small amount of a certain adhesive repellent together with a large amount of synthetic rubber or synthetic resin. This method is concerned with the production of specialty papers which are quite advantageous to use as a carrier for highly adhesive pressure-sensitive adhesive layers with high abrasion and peel strength, and by no means, as in the present application, a method of impregnation and thus to overcome the different difficulties of the task set and its solution, which inevitably results in different types of products.

Organic compounds having one or more long-chain alkyl groups having from 12 to 21 carbon atoms in their molecule (in particular stearoyl or stearyl) are suitable for use as anti-adherent, surfactants in the impregnation process according to the invention. on the other hand, reactive polar groups such as carboxyl, nitrile amino, hydroxyl, ketene or acid anhydride groups.

Examples of such substances according to the invention are:

N, N'-diacyl compounds of polyalkylene amines containing long chain hydrocarbon groups, especially those containing one or more unsaturated (free) secondary amino groups, such as N, N'-distearoyldipropylenetriamine (DiTriDi); 15 Polyvinyl carbamates, e.g.

Polyvinyl N-octadecyl carbamate and Polyvinyl N-pentadesyl carbamate; Triethanolamine monostearyl carbamate ·, Glycerol monostearyl carbamate; 2 0 Pentaerythritol monostearyl carbamate; Trietanoliamiinimonostearaatti; Trietanoliamiinimonopalmitaatti; Trietanolamiinimono monooleate;

glycerol monostearate; Reaction products of stearyl isocyanate with urea or melamine resins or triethanolamine; Low molecular weight hydroxyl group-containing polybutadienes which have been reacted, in whole or in part, with stearyl isocyanate 30, depending on the OH number;

Emulsion polymerization copolymers prepared from long chain hydrocarbon groups containing maleic acid monoamides or maleic acid monoesters and styrene or its derivatives, which may additionally contain reactive constituents with 8 68103 structural groups or carboxyl groups;

Copolymers, made from butadiene and not more than 30% of styrene, containing 2 to 20% of maleic acid monamide or ester in poly-5 form;

Stearic acid complexes with basic chromium chloride (Werner-Komplexe);

Polytetrafluoroethylene 10 According to the invention, the amount of glue-repellent surfactants in the impregnation mixture can be 0.5 to 5% by weight and preferably 1 to 3% by weight, based on 100 parts by weight (solids) of the total amount of the mixture.

Since said substances are sparingly soluble in organic solvents and practically insoluble in water, they are preferably dispersed by means of suitable emulsifiers in water or, if appropriate, in a highly dispersed silicic acid or other conventional finely divided excipients after adsorption and to an aqueous dispersion of a mer or rubber polymer. Suitable emulsifiers are suitable here, in particular mixtures containing non-ionogenic and anionic emulsifiers in a ratio of 1: 1. Examples of these are, on the one hand, aromatic polyglycol ethers, such as, for example, nonylphenol polyglycol ether and, on the other hand, alkyl sulfonates or alkylaryl sulfonates. The elastomer or rubber polymer which may be present in the impregnating composition according to the invention and which constitutes 89-95.5% by weight of its main component, based on 100 parts by weight of the dry matter of the whole composition, may comprise, for example, butadiene. a styrene copolymer having a styrene content of 23 to 55% 03-55%, a butadiene-acrylonitrile-copolymer having a Mooney viscosity of about 40 to 160, preferably 65 to 85, a terpolymer consisting of butadiene, styrene and 5 acrylonitrile., Or acrylic acid butyl ester-acrylic acid copolymer or a mixture thereof, which are generally added in the form of latex or aqueous dispersions. Aqueous acrylate copolymer dispersions containing small amounts of acrylic-10 and / or methacrylic acid and up to 15% acrylonitrile are quite suitable for use. In addition to these, also those which, in addition to butadiene-acrylonitrile and / or acrylic acid esters, also contain polyvinyl acetate, polyvinyl chloride or polyvinyl-15-dichloride as an ingredient, e.g. a mixture containing butadiene-acrylonitrile-co- or terpolymer together with polyvinyl acetate polyurethane latex and polychloroprene dispersions. Relatively small molecule adhesives in the form of a latex can also be added to the butadiene-acrylonitrile or butadiene-styrene copolymers.

Glycols and triethanolamine are quite suitable as paper plasticizers, which form the third main component of the impregnation composition according to the invention and which must be present in the impregnation composition in 2-6% by weight, preferably 3-4% by weight, based on 100 parts by weight of the total mixture solids. Depending on the nature and amount of the additive, this preferably water-soluble component affects the degree of hydrophilic formation in the paper, which is important in the subsequent steps.

To this impregnating composition in the form of an aqueous dispersion according to the invention, which is generally used as a 20-55% and preferably 33-42% dispersion, small amounts of other substances, such as, for example, polyacrylamide, can be added to change its properties. , polyvinyl alcohol or polyvinylpyrrolidone to control the viscosity, and optionally water-soluble urea or melamine-formaldehyde resins which still have free reactive groups, so-called precondensates such as, for example, methylol urea, methyl melamine or methyl ol acrylamide. The choice of each ingredient, which can vary within wide limits, must be made taking into account 10 that the product of the new process must be a relatively soft, flexible paper which is preferably slightly crosslinked in a known manner to provide the necessary flexural rigidity; sufficient strength properties in the longitudinal and width directions. The paper to be used as a carrier in the manufacture of pressure-sensitive adhesive tapes (self-adhesive adhesive tapes for painting and varnishing purposes) must be sufficiently flexible and soft, opaque, as tight as possible to the coating material, solvent and dispersions and must also be permeable.

The first addition amount of the aqueous impregnation dispersion to the fibrous material suspension or pulp, which preferably consists of pure cellulose and preferably has a degree of grinding between 18 and 38 SR, (1-12% by weight and preferably 2-H% by weight based on dry pulp or paper pulp) is carried out. appropriately after grinding.

30 In the manufacture of light papers having a weight of up to about 80 g / m 2, the addition of one portion of the aqueous impregnation dispersion to the pulp prior to sheet formation can be omitted and the entire aqueous impregnation dispersion can be added at a residual water-35 content of 6-20%. .

il 68103

In order to further modify the properties of the paper, small amounts of conventional adhesives such as natural non-resin soap (sodium resin soap) and alum, wax, starch, animal glue, casein and, if desired, a filler such as clay or chalk may be added to the fibrous suspension. salt, and dyes.

A wet adhesive (wet fixative), preferably consisting of melamine-10 or urea-formaldehyde resins containing methylol groups, which have a moisturizing effect on heat, is preferably added after the addition of 0.2-0.5% alum (which activates the fibers and catalyzes the incorporation of the resin into the fibers). in the form before the fiber suspension or paper-15 pulp headbox. In this case, when using the impregnating agent according to the invention, the required amount of wet fixing agent can be reduced by more than half relative to the amount generally used, e.g. from 6.5% to 2.4%, based on the dry pulp or paper pulp.

The exact amounts of substances added to the pulp, as well as the proportions that can be easily determined by simple experiments, depend on the web speed in the wet compartment and thus on the pulp throughput in time-25 units.

In the event that the paper needs to be creped, this can be done with wet rollers using a thin and sharp blade. In this case, the creping step can take place at the earliest at a time after the formation of the sheet, in which case the formed paper web has sufficient strength to withstand the high requirements of this step. The fineness of the creping depends primarily on the strength of the blade: the thinner this is, the finer the creping becomes. In addition, it depends on the temperature of the rollers 35 (creping cylinder), their speed and the position of the blade on the surface of the roll. Instead of wet creping as an intermediate step in the papermaking process, creping can of course also be carried out on the finished paper product after it has been rewetted.

5 After removal from the creping cylinder, the paper web containing additives enters the drying section of the paper machine, where the drying of the paper web takes place by means of strongly heated drying cylinders, whereby steam is generated.

When the residual water content of the paper web is 6-20%, preferably about 8-12%, a suitable amount is applied to the web by means of suitable equipment, e.g. in an adhesive press, such that the completely heat-treated completely dry paper web containing the mixture contains the mixture. 7 to 60% by weight, preferably 15 to 40% by weight, based on dry paper. In this case, it is advantageous to work using a 40% solution of the impregnation mixture at a flow rate of 120 m / min. In this case, for example, 70 g of 20-strength paper is obtained from a plate weighing 50 g + 20 g of impregnant, which corresponds to a impregnant content of about 28.5%.

In the heat treatment, together with the ironing effect between the felts and the highly heated drying cylinders, the gypsum impregnant (from the dispersion, becomes finely divided and anchored together with other high molecular weight adhesives which can be slightly crosslinked by heat due to the fibrous structure. paper using a relatively small amount of rubber, which is otherwise only possible with relatively large amounts of material, while preventing, even at relatively high drying temperatures (115-130 ° C) and high flow rates (above 100 m / min. a track width of 2 m or more), interfering adhesion to hot cylinders and blankets in the drying section and avoiding tearing of the paper web.

According to the disclosed method, impregnated plain or creped papers can be produced in a simple manner, avoiding the additional work steps otherwise required, which can quite advantageously be used as a carrier for conventional pressure-sensitive adhesive layers (self-adhesive pulps), above all mirrors, for packaging tapes.

The invention is further illustrated by the following examples:

Example 1 1000 kg of cellulose containing 690 kg of softwood cellulose (500 kg of highly bleached pine sulphate cellulose, long-fiber, highly absorbent and 190 kg of unbleached pine sulphate cellulose), 280 kg of hardwood cellulose (140 kg birch sulphate cellulose and 140 kg beech sulphate cellulose) and 30 kg hydroxyethylcellulose ("Cellosize", Union 20 Carbide) are ground in a Dutch miller to a degree of grinding of 33 ° SR and diluted with water to a concentration of 0.5%.

A impregnation mixture is prepared from the following substances, in which case a dose of 400 kg per 1000 kg of cellulose, calculated as the amount of solids, is required.

681 03

it

Solid Total (kg) (kg) _ (aqueous dispersion)

Acrylic acid butyl ester-acrylic acid copolymer e ("Butofan DS 3255 X", test product from BASF) - 50% 355.55 711.12

Triethanolamine human monostearate - 10% 13.33 133.33

Phylethylene glycol, molar weight 570-630 10 ("Polydiol 600", Hoechst) 6.67 6.67

Triaethanolamine 6.67 6.67

Defoamer ("Nopco NEW", Nopco Chem.) 0.89 0.89

Melami i ni - formaldehyde and ice condensate 15 ("Maprenal MF 900",

Hoechst) 16.45 16.45 p-toluenesulfonic acid 1% 0.44 44.44

Water, desalted, - 191.55 20 400.00 1111.12

Dispersion solids content: 36%

After grinding, 20 kg of a impregnation mixture containing, based on 100 parts by weight of the total mixture, 25 parts by weight of the whole mixture of 25 parts by weight of elastomer, 3.3% by weight of silicone-free, anti-adhesive surfactant (triethanolamine monostearate) are added to the fibrous suspension. and 3.3% by weight of a paper softener, in the form of a 36.5 kg by weight of a 36% aqueous dispersion, and then a mixture containing 35 kg of urea-formaldehyde resin ("Urecoll KL ", BASF) and 6 kg of aluminum sulphate / sulfuric acid in the form of a 10% aqueous solution with a pH between 2.0 and 3.0.

35 A paper web is then formed from the pulp using a conventional paper machine through a sieve and wet press compartment 15 681 03 (sheet formation, dewatering, drying).

(The filtrate water has a pH between 4.5 and 5.0. At a dry weight of about 38-42%, the web is creped with a creping cylinder made of creping cylinders and steel; the temperature behind the creping cylinder rises from 105 ° to 125 ° C.

With a residual water content of about 8-12% on the paper web, the remainder of the impregnation mixture (380 kg based on solids) is then applied to the paper web by means of an adhesive press in the form of a 36% aqueous dispersion. In the next drying section, the carrier is introduced at a machine speed of about 100 m / min. to a temperature between 90-135 ° C. The residual moisture thus obtained of the impregnated paper is 4.5-5.5%.

Crepe paper having a sheet weight of 100 2 g / m 2 (+2) and an elongation of 15% is obtained, which is excellently suitable as a carrier for the production of self-adhesive pressure-sensitive cover-adhesive tapes.

Example 2 20 As described in Example 1, 70 2 .....

g / m thick impregnated crepe paper for the production of masking tapes: I Application of cellulose 1000 kg of cellulose containing 25 560 kg of pine sulphate cellulose, long fibers, special

absorbent, bleached 200 kg pine sulphate cellulose, unbleached 240 kg eucalyptus cellulose Grinding degree: 19 ° SR

II Wet adhesive (Add before headbox) 3 0 12 kg urea-formaldehyde resin ("Urecoll KL! F, BASF) 0.5 kg alum / sulfuric acid solutions III Plating, dewatering, drying, creping IV With a residual water content of the web of 6-9% addition of said i6 6 81 0 3 impregnation mixture (impregnating agent assembly) by means of an adhesive press.

A Drying and ironing of impregnated crepe paper between the felt and the cylinders after the glue press at temperatures between 105-135 ° C.

Impregnant composition: Total amount (kg) Solid (aqueous dispersant (kg) ___siol___ _

Butadiene acrylonitrile latex 1 0 (‘Synthomer 8155’, Synthomer

Chemie) 50%: sena 80.00 40.00

Plasticizer-free copolymer of acrylic acid esters and vinyl compounds 70.00 35.00,, ("Acronal 500 D", BASF) - 15 as 50%

Dist earoyldipropylene triamine-ni-based (DiTriDi) emulsion -20% 10.00 2.00

Triethanolamine 100% 1.50 1.50

Polyethylene glycol mol. weight 20 570-630 (Polydiol 600, Hoechst) 1.20 1.20

Defoamer ("Mopco NEW", Nopco Chem.) 0.30 0.30

Water, desalted 37.00 200.00 80.00 25 Solids content of dispersion: 40%

The residual moisture of the impregnated paper is adjusted to the given values according to Example 1.

Crepe paper having a basis weight of 70 2 (+ 2) g / m and a tensile strength of 3 5 N / cm at 15% elongation is obtained.

Example 3

In the manner of Example 1, impregnated paper with a heat resistance of up to about 18 ° C is prepared: 35 l Cellulose part 17 681 03 700 kg of pine sulphate cellulose, long fiber, highly absorbent, bleached 200 kg of pine sulphate cellulose, unbleached 5 80 kg acrylic acid copolymer (Basoplast 580 B), (BASF) = 160 kg 50% dispersion 2 kg triethanolamine monostearate

degree of grinding: 2 2 ° SR

II Wet adhesive (Addition before headbox) 10 12 kg of urea-formaldehyde resin ("Urecol KL", BASF) in 10% solution 0,5 kg alum / sulfuric acid III Plating, dewatering, drying IV Residual web at a moisture content of 10-12% 15 ( residual moisture): a impregnating agent mixture (impregnating agent composition) is added, the composition of which is shown below, using an adhesive press V. Drying, crosslinking and ironing of the impregnated paper between the felt and the cylinders after the adhesive press 20 at temperatures between 105-135 ° C.

is 6,810 3

Impregnant composition: Solid Total, (kg) (kg) _ (aqueous dispersion)

Butadiene ene-acrylonitrile · latex 35% with 33% acrylonitrile and 4% methacrylic acid 70.00 200.00 ("Perbunan-N-Latex 3460 M",

Bayer)

Polyvinyl st eary lycarbamate based emulsion - 20% 2.00 10.00

Triethanolamine 1.50 1.50 10 Polyvinyl alcohol low viscosity ("Polyviol M 05/140", Wacker-Chemie) 6.00 6.00

Polyethylene glycol ("Polydiol 600", Hoechst) 1.20 1.20

Defoamer ("Nopco NDW",

Nopco Chem.) 0.30 0.30 81.00 219.00

Dispersion solids content: 37%

Impregnated plain paper with a paper weight of 90 g / m 2 is obtained.

Claims (5)

A process for making impregnated smooth or creped paper in a working phase on a paper machine, wherein, in addition to the usual wetting agent and optionally used ordinary adhesives, fillers and / or coloring agents, a mixture is added to the fiber suspension or pulp prior to sheet formation. (1) a silicone-free, adhesion-preventing surfactant consisting of an organic compound having one or more long-chain alkyl groups, to which the molecular structure of the compound comprises reaction-capable polar groups, such as carboxyl, nitrile, amino, hydroxyl, ketene, or acid anhydride groups, and (2) an elastomeric or rubbery polymer, and the pulp is formed in the usual manner for a paper web on a paper machine, optionally during the interconnection of a crepe device, characterized in that to the pulp is added 1-12 wt. dry fiber or pulp, of a mixture containing: 0.5-5.0% by weight silicone-free, adhesion ratio surfactant, 89.0-95.5% by weight elastomer or rubbery polymer and 2.0-6.0% by weight paper softener, and the pulp is prepared into paper web and this paper web is further processed, where its residual water content is 6-20%. further with such an additional amount of the aforementioned mixture and dried, said mixture being so much obtained that the dry paper contains 7-60% by weight of the mixture. 30 2. A process according to claim 1, characterized in that the mixture is added to the pulp in 2-4% by weight calculated on dry fiber or pulp. 3. A process according to claims 1 and 2, characterized in that the silicone-free, adhesion-preventing, surfactant stain end portion is an organic compound having one or more long-chain alkyl groups of 12-21 carbon atoms.