Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/02—Metal coatings
  • D21H19/08—Metal coatings applied as vapour, e.g. in vacuum
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/52—Cellulose; Derivatives thereof
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/56—Macromolecular organic compounds or oligomers thereof obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H19/58—Polymers or oligomers of diolefins, aromatic vinyl monomers or unsaturated acids or derivatives thereof
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/66—Coatings characterised by a special visual effect, e.g. patterned, textured
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/80—Paper comprising more than one coating
  • D21H19/82—Paper comprising more than one coating superposed
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
  • Y10T428/254—Polymeric or resinous material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31971—Of carbohydrate
  • Y10T428/31993—Of paper

Definitions

• the present invention relates to a paper coated on one side, a process for its production and its use.
• DE-B-1233248 describes a casting process in which a coating composition containing a metallic pigment and organic binder is applied to e.g. a paper web is applied and dried in contact with a heated high-gloss cylinder.
• a paper with a layer produced by the coating process is used for this purpose.
• the layer consists of a Normal temperature non-film-forming synthetic resin binder, the particles of which have a melting point between 71 ° and 99 ° C.
• the layer can also be applied to a base layer which, in addition to filler, contains one of the customary synthetic resin binders.
• a part of the synthetic resin binder to be used in the base layer can also be replaced by natural binders, so that 10 to 30% by weight of the total binder content of the base layer consists of, for example, starch, modified starch, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose and similar substances.
• a paper is known with a top coat applied by means of a coating process, for the manufacture of which a primer is first applied, the pigment composition of which 30% by weight of kaolin and 60% by weight of a polystyrene pigment and the binder composition of which comprises 10 parts by weight of casein and 16 parts by weight of a carboxylated butadiene-styrene latex.
• a mixture of 80 parts by weight of kaolin, 20 parts by weight of calcium carbonate, 10 parts by weight of casein and 8 parts by weight of a butadiene-styrene latex is applied and the applied composition at a temperature of 90 ° C pressed against a chrome painted surface.
• the so-called “direct method”, as described above for DE-B-1233248, is specified and also the “indirect method”, in which the coating composition is applied to the high-gloss cylinder and the dry one before it is dried Paper is brought into contact with the still wet film, which is absorbed by the paper and pulled off the drum.
• the process known from DE-B-2310891 is not the casting process known from DE-A-1233248 (also called the direct method). Rather, with the simultaneous formation of a continuous film from the polymer contained in the coating composition, part of the water is first evaporated and the film formed is shaped against a high-gloss cylinder at a temperature above 100 ° C. under a minimum pressure of 5 kp / cm 2.
• an anti-sticking agent can be added to the coating composition.
• an anti-sticking agent e.g. Sodium carboxymethyl cellulose, methyl cellulose, polyvinyl alcohol and polyvinyl pyrrolidone in amounts up to 10% based on the weight of the main polymer.
• the usual precoatings known from paper production, with and without pigment addition, are provided as the base layer.
• a metallized paper is known from EP-B-98368, in which the layer intended for metallization is shaped under similar process conditions as specified for DE-B-2310891.
• the coating composition contains 5 to 25 parts by weight of film-forming binder, based on 100 parts by weight of pigment, and thus has the pigment / binder ratio of the conventional paper coatings.
• This proposal is intended to eliminate the disadvantage which hitherto existed, which consisted in the fact that the coating surface intended for the metallization first had to be provided with a pre-coating based on organic solvents.
• the object of the present invention is now to make available a paper provided on one side with a coating, using inexpensive coating raw materials, which due to its high gloss and smoothness should be used where a decorative impression is desired.
• the invention sees a special task in the formation of a cover layer which enables direct metallization of the paper, i.e. Permitted without pre-varnishing with a varnish based on organic solvents, so that a paper of the highest smoothness with high gloss and metallic appearance results.
• the invention also intends to provide a paper which, despite the action of water, has a high gloss retention and is therefore - even in the non-metallized state - suitable for producing labels which are bonded with adhesives on an aqueous basis.
• the paper In the metallized state, the paper should be printable using gravure and offset printing, in the non-metallized state using gravure and flexographic printing, and - at least with special inks - in offset printing and should have good printing ink adhesion with mechanical action on the printed surface even in the presence of water.
• Information on the binder content relates to dry weight fractions;
• Information on the pigment content relates to the total binder content (dry weight fractions) of the respective composition.
• the invention also encompasses a method for producing a one-sided coated, high-gloss paper with high smoothness, which can be directly metallized, in which a coating is applied to the base paper, which is formed from one or two superimposed layers and in which a film-forming synthetic resin binder and / or natural binder and mineral pigment is applied to the base paper and dried, and a further composition is applied by means of a coating process the coating formed is applied, for the production of which a further composition is used which contains film-forming synthetic resin binder and natural binder, characterized in that the coating applied to the base paper is satinized after drying and the synthetic resin binder of the further composition has a film-forming temperature ⁇ 40 ° C. and the further composition contains natural binder in an amount of 20 to 60% by weight, based on the total binder content, and optionally the further composition contains up to 5% by weight of mineral pigment t - based on the dry binder content.
• the applied coating is leveled and immediately afterwards fed to a heated high-gloss cylinder and dried in contact with it, the cover layer forming a less porous, closed film layer.
• the process can also be carried out by adding mineral pigment in an amount of up to 5% by weight to the second composition.
• a top layer of higher opacity is thereby achieved, which, however, may be purchased with a lower surface gloss and a reduced surface smoothness.
• a procedure without the addition of mineral pigment in the production of the top layer is therefore particularly preferred.
• a paper according to the invention as claimed in claim 16 is used as a support for a vapor-deposited metal layer, in particular according to claim 12 for the production of labels containing aqueous Adhesives are processed such as bottle labels. Further uses are given by using the non-metallized paper, also as a label to be processed with aqueous adhesives or as decorative paper, metallized or non-metallized, for example as wrapping paper for gifts.
• the film-forming synthetic resin binders to be used to form the top layer have film-forming temperatures of ⁇ 40 ° C., preferably even ⁇ 30 ° C., and are used in the form of aqueous dispersions, preferably based on the polymers and copolymers of acrylic acid esters, methacrylic acid esters, butadiene-styrene, vinyl acetate and vinylidene chloride .
• the same film-forming synthetic resin binders are preferably used for the production of the layers forming the coating, however synthetic resin binders with a higher film-forming temperature may also be used here.
• Cellulose derivatives such as. Serve as natural binders for the production of the coating and the top layer Carboxymethyl cellulose, hydroxyethyl cellulose, preferably casein and starch, modified starch and mixtures of the above-mentioned natural binders.
• the proportion of the natural binder in the coating is preferably not more than 70% by weight, very particularly preferably in a range between 10 and 50% by weight, in each case calculated as dry weight proportions based on the total binder content.
• Chalk, kaolin and titanium dioxide can be used as the mineral pigment in the coating, the total binder content, calculated as dry weight components, based on the pigment component being 10 to 20% by weight.
• Titanium dioxide can preferably be used as the mineral pigment for the top layer to improve the opacity of the paper. However, better results in terms of surface gloss and surface smoothness are achieved without the use of mineral pigment in the top layer, so that it is preferably not added, especially if the paper is to be metallized.
• the cover layer is transparent and consists only of natural binder, synthetic resin binder and residual components of auxiliaries, which may be present in a minor amount in the composition for the production of the cover layer, such as, for example, agents for supporting the detachment of the dried cover layer from the high-gloss cylinder, e.g. B. calcium stearate or optionally one or more of the usual thickening aids, the amount of Total release agents and thickening aids are not more than 10% by weight, based on the total binder content in the top layer.
• a crosslinking aid (wet strength agent) can be present in the top layer.
• the paper according to the invention can be produced particularly inexpensively; the proportion of natural binder can preferably be 32 to 45% by weight. With more than 60% by weight of natural binder, the disadvantage arises that the coating composition has too little solids and the economy is questioned by the high drying effort required. There is also the risk that the water sensitivity of the top layer and thus the loss of gloss will increase.
• the Bekk smoothness of the coating is at least 150 s.
• the coating has a Bekk smoothness in the range from 500 to 3,000 s.
• a coating with a mass per unit area of at least 5 g / m 2 has proven to be necessary to achieve such a smoothness value.
• the air permeability, measured according to Gurley, is preferably the satin paper at max. 9,000 s / 100 ml air.
• the top layer is applied up to a maximum of 10 g / m2, in a preferred embodiment in a basis weight of only 3 to 8 g / m2, preferably up to 6 g / m2.
• the application of the covering layer with such a low mass per unit area forms a further advantage of the present invention in economic terms.
• the cover layer is preferably formed with a gloss in the range from 88 to 98% (gloss measurement according to Lehmann at an angle of 75 degrees).
• the smoothness of the top layer is so high that it cannot be measured with the usual Bekk method.
• the top layer of the paper according to the invention shows a high gloss retention even when exposed to water. This is particularly important if the paper e.g. B. is processed into bottle labels and comes into contact with aqueous adhesives.
• a further improvement of the paper according to the invention is achieved if the water absorption is reduced by means of a wax or paraffin dispersion preparation applied to the back. Such a preparation is preferably applied in a basis weight of 1 to 2.5 g / m2.
• the Cobb value with which the water absorption is determined can be set to a range from 7 to 12 g / m 2 over 60 seconds.
• a reduced water absorption of the back is also advantageous if that Paper according to the invention - metallized or non-metallized - is used as a label to be bonded with aqueous adhesives. It has also proven to be advantageous to use, in such a use, a base paper which has been sized and wet-strengthened and which has a relative wet strength of approximately 20 to 35%. This is particularly advantageous if the paper is used to produce labels that are glued to reusable bottles.
• a raw paper to which 2 to 3% by weight of titanium dioxide has been added as a mass has been found to be particularly suitable for improving the opacity in papers according to the invention which are not to be metallized.
• a wood-free base paper with a basis weight of 59 g / m2 is produced by adding resin and alum, a melamine-formaldehyde resin as wet strength agent and a mixture of kaolin / titanium dioxide to adjust the ash content to a total of 8% by weight.
• the paper is equipped with a paraffin dispersion containing carboxylmethyl cellulose in a mass per unit area of 2.5 g / m 2.
• a layer of the following composition is applied to this base paper to form a coating: 80 parts by weight of kaolin 20 parts by weight of chalk 100 Parts by weight pigment Based on the pigment content, the composition contains: 1.5 parts by weight of carboxylmethyl cellulose 11 parts by weight of a butadiene / styrene-based copolymer applied from aqueous dispersion 0.8 parts by weight of a wet strength agent based on epichlorohydrin.
• the paper web is passed through a supercalender and the coating then has a Bekk smoothness of 865 s.
• the air permeability of the satinized paper is 6,920 s, measured according to Gurley.
• a composition is then applied to this coating using the cast coating process, which is calculated as dry weight parts and is composed as follows: 25 parts by weight of casein 25 parts by weight of a carboxyl group-containing copolymer of vinyl acetate and acrylic acid ester 50 parts by weight of a copolymer based on butadiene-styrene.
• This top layer is formed with a basis weight of 5 g / m2.
• the gloss measurement of the top layer shows (in%): Longitudinal direction: 96 Cross direction: 96.4
• the examination of the ink adhesion according to the applicant's own examination method results in an ink adhesion of 1 for a sample printed with the flexographic printing method after a soak of 10 minutes on a 6-unit scale, in which 1 corresponds to a good value and 6 to a bad value .
• a thin metal layer of high uniformity and with a very high gloss was produced on the cover layer of the paper described in Example 1 by the vacuum evaporation method.
• Layer a is applied in a basis weight of 10 g / m2, layer b in a basis weight of 12 g / m2 to the intermediate dried layer a. After layer b has dried, the paper is satinized in a supercalender and then has one Bekk smoothness of 2,300 s.
• composition for forming the top layer is then applied to the coating via cast coating: 50 parts by weight of casein 25 parts by weight of a carboxyl group-containing copolymer made from vinyl acetate and polyacrylic acid ester 25 parts by weight of a butadiene-styrene copolymer.
• This top layer is applied in a mass per unit area of 3.5 g / m2. After leveling the composition intended to form the cover layer, the paper web is brought into contact with a heated high-gloss cylinder and the composition is dried to form the cover layer. A gloss of 96% is measured.
• Example 1 The procedure is as in Example 1, but in contrast to Example 1, the composition for forming the top layer still contains 5% by weight of titanium dioxide, based on the binder content of the top layer composition. The opacity is significantly improved, but the gloss is about 10% lower than in Example 1.
• Example 4 The procedure is as in Example 4. Instead of titanium dioxide, however, satin white is used, which causes the casein to harden.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Paper (AREA)
• Materials For Medical Uses (AREA)

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Family Applications (1)

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Citations (2)

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• 1990
  • 1990-09-18 DE DE4029491A patent/DE4029491A1/de active Granted
• 1991
  • 1991-08-27 DK DK91915069T patent/DK0549607T3/da active
  • 1991-08-27 AT AT91915069T patent/ATE115664T1/de not_active IP Right Cessation
  • 1991-08-27 US US07/980,800 patent/US5334449A/en not_active Expired - Fee Related
  • 1991-08-27 DE DE59103927T patent/DE59103927D1/de not_active Expired - Fee Related
  • 1991-08-27 FI FI931144A patent/FI931144L/fi not_active Application Discontinuation
  • 1991-08-27 ES ES91915069T patent/ES2065055T3/es not_active Expired - Lifetime
  • 1991-08-27 CA CA 2091904 patent/CA2091904A1/en not_active Abandoned
  • 1991-08-27 EP EP91915069A patent/EP0549607B1/de not_active Expired - Lifetime
  • 1991-08-27 JP JP3514327A patent/JPH06503610A/ja active Pending
  • 1991-08-27 WO PCT/EP1991/001629 patent/WO1992005312A1/de active IP Right Grant

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