GOST R ISO 534-2012 Paper and cardboard. Determination of thickness, density and specific volume from November 14, 2012 –

Whatman paper – premium paper

Whatman paper has a higher density than other types of paper, so it is considered a premium product. There are several standard formats: from A1 to A4 (you can also find whatman paper in A5 format), each of them has its own density – ranging from 120 to 200 g/m².

In addition to such indicators as the weight and density of whatman paper, the uniformity of the paper pulp is also important, which improves the quality of printing. And the high opacity of the sheet allows you to print or draw on it on both sides.

How to determine that what you have in front of you is real, high-quality Whatman paper? First of all, in appearance: this paper is white, thick and smooth. If in doubt, drop a little clean water on the leaf. The drawing paper should not be deformed from it. This is exactly what is used not only for drawing, but also for drawing – with paints, ink or pencil.

Paper weight and GOST indicators

If the density is known, then the weight of a sheet of paper is also easy to determine. For example, an A4 sheet with numbers on an 80 g/m2 package will weigh almost 5 grams. A standard pack of such paper contains 500 sheets, which means the pack weight will be about 2.5 kilograms.

Paper for office printing, books and forms, with a density of 160 g/m² will have values ​​from 800 to 900 kg per cubic meter. Less than 160 – from 750 to 850 kg/m³ In addition to offset paper, whatman paper is also popular. GOST sets its density at 850–950 kg/m³.

The density, hardness, and thickness of the paper may vary depending on your printing needs. Today there are different standards, and choosing all the criteria individually is not difficult.

Questions and answers

Preparing to work as a laminator operator

1. Turn on the laminator and set the preliminary heating temperature to 75-80 °C. The temperature regime must be taken into account when setting the lamination speed: the higher it is, the higher the temperature. 2. Familiarize yourself with the technical specifications and prepare the necessary film. 3. Check that there is no dirt on the pressure shafts. 4. Check whether the prints are completely dry after printing.

It is advisable to wait a day to be completely sure that the paint has hardened. There should be no powder on the sheets. If there is powder on the sheets, take measures to remove it.

5. For thin paper – prepare and adjust the roller for rewinding the product into a roll to align the sheets after lamination to the product format. It is strictly not recommended to work without a reverse winding device if there is a risk of curling of product sheets.

6. Place the film on the laminator and adjust its tension.

7. The tension of the film web should be minimal. Strong tension leads to stretching of the film and curling of the product, while weak tension leads to wave formation, wrinkling when the film is brought to the roller and the possibility of its sticking to the roller.

Product lamination

1. Place the make-up sheets of the run on the work table and run the film through. 2. Turn on the minimum lamination speed. 3. Set the pressure to 3-4 units. 4. When adjusting the pressure on the heating rollers of the laminator, you must remember that if the heating rollers are in a heated state and the lamination process is not carried out, the pressure must be turned off, i.e. the shafts must be separated.

Keeping heated rollers together in such situations can lead to damage and deformation of the rubber of the laminator rollers! 5. Laminate several sheets, release the pressure and stop the laminator. 6. Visually assess the quality of the laminated sheets: the film should not peel off at the fold of the sheet, there should be no bubbles or silvering, the film should not come away from the material.

With good lamination, the film is difficult to tear off from the material even with force. The print must be free of marks, scratches and wrinkles. If necessary, we make corrections for pressure (but not more than the seventh division) and temperature. The choice of optimal lamination modes largely depends on the thickness of the laminated product, climatic conditions in the workshop, and lamination speed. REMEMBER: too high pressure on the rollers, temperature, and tension of the film web lead to defects. 7. After lamination is completed, carefully remove dirt and film residues from the rollers and clean the work area.

Lamination temperature and speed

Determining the ideal temperature requires experience. By the time the film comes into contact with the pressure roller, the film-to-paper adhesion temperature must be reached. If the laminator runs too fast, the film will not adhere to the material. The lamination speed depends on the temperature of the heating roller.

The optimal balance varies for different papers and films. The temperature is also determined by the characteristics of the film itself (manufacturers indicate the temperature in the technical specifications – it ranges from 70 degrees to 105 degrees for matte films and from 70 degrees to 110 degrees for glossy films)

Lamination. Problems and solutions

Problem: Film Wrinkling

Cause: Weak web tension; Solution: Tighten the canvas.

Reason: Incorrect web threading; Solution: Check the web wiring.

Cause: Incorrect installation of the pressure rollers; Solution: Check the installation of the shafts.

Cause: Insufficient temperature; Solution: Wait for the laminator to fully heat up; if necessary, increase the temperature or use a thinner film.

Problem: Paper wrinkles

Cause: The sheet enters the laminator unevenly (the leading edge of the sheet should be parallel to the axis of the laminating rollers); Solution: Smooth out the sheet and reinsert it into the laminator.

Problem: Bubbles under the film

Cause: Weak web tension; Solution: Tighten the canvas.

Cause: Insufficient temperature; Solution: Wait for the laminator to fully heat up; if necessary, increase the temperature or use a thinner film.

Cause: Insufficient lamination pressure; Solution: Increase lamination pressure

Reason: Incorrect web threading; Solution: Check the web wiring.

Cause: Incorrect installation of shafts; Solution: Check how the shafts are installed.

Problem: Regularly recurring defects

Cause: Contamination of the laminating rollers; Solution: Clean the shafts.

Problem: Laminate waviness and print curling

Cause: Excessive heating temperature; Solution: Reduce the heating temperature of the shafts.

Cause: Incorrect installation of shafts; Solution: Check that the shafts are installed correctly.

Cause: High web tension; Solution: Reduce web tension.

Checking the quality of lamination: make several circulation sheets, let them cool for about 10-15 minutes and check the quality of lamination for repeated creasing and folding. The film should not lag behind the paper. If everything is fine, proceed to the process of mass industrial lamination.

Source

Where and how much to buy whatman paper?

So, you know what tasks you need this paper for, you know what the density of whatman paper should be, but where to buy it? Typically at an office supply store or bookstore. Whatman paper is sold at an affordable price – for a sheet of A1 format you will need to pay no more than 20 rubles. Smaller sheets will cost you even less.

Smoothness (roughness)

The geometry of the paper surface is characterized by its smoothness or roughness.

The “surface geometry” of paper is determined not only by micro-irregularities, but also by macro-irregularities. The former are determined by microgeometry, the latter by the distribution of mass over the area.

There is a group of most common methods in which smoothness is measured using air flow.

The most common measurement methods are Bendtsen Sheffield and Parker (roughness). Becca (smoothness).

alt
Bendtsen smoothness tester

The essence of the Beck method is to measure the time required for air of a certain volume to pass into a vacuum chamber between the surfaces of the test sample and a polished glass plate of a certain area, pressed with a certain pressure. Smoothness is measured in seconds. The higher the smoothness, the greater the value of the indicator.

There are no strict relationships between the values ​​of smoothness (roughness) indicators measured by different methods. There is a qualitative relationship between the Beck smoothness and Bendtsen roughness values.

Bendtsen and Sheffield instruments measure the flow of air passing at constant pressure between the surface of the ring and a sheet of paper.

Bendtsen roughness is expressed in ml/min, Sheffield in Sheffield units.

The figures show qualitative relationships between parameters determined by different methods. They make it possible to evaluate the nature of changes in one parameter depending on changes in another and can help in comparing the smoothness and roughness of samples measured by different methods.

The Parker method (PPS) is used to measure the roughness of paper and cardboard under conditions close to those of a printing press. The Parker roughness measurement result is expressed in microns.

What paper is used where?

Paper of different densities is used in different areas. For example, printing requires indicators from 60 to 300 g/m2. This figure is much lower for newsprint – only 45-60 g/m2. Drawing or watercolor paper, paper for certificates and business cards – all these are certain varieties with a specific density, the criteria of which are strictly regulated. And whatman paper even has clear indicators recorded in GOST.

Speaking about whatman paper, it is worth noting that this is the largest paper format used in the field of design and art. It is very popular among people of various professions.

Lamination is easy! [article specially for sheenn]

Post-press and finishing technologies
The end is the crown of the matter. We discuss everything related to cutting, gluing, stitching.

In this article I will look at one simple device that is found in almost every printing house – a laminator or equipment for pressing film. It is necessary to note that for all its apparent simplicity, this equipment and the technological process itself raise many questions and problems for beginners and can be a real disaster when the entire circulation goes into the trash.

Many newcomers come to me with questions: “Help. Scratches. Stripes! . The film peels off. The sheets are curled. “, and sometimes the answers to these questions lie on the surface; you just need to carefully analyze the factors that can influence the occurrence of a marriage. And in this article we’ll talk about them!

All laminators (this article discusses equipment for hot film pressing) are designed in the same way and have no fundamental differences. The process of film pressing is shown schematically in Fig. 1, where a special film with a pre-applied adhesive layer, which is melted on a hot “laminating” roller, is glued to the material under pressure created by the printing cylinder.

Everything seemed simple! But in order for this simple process to go off without a hitch, you need to know and take into account the factors that can affect the quality of the product.

Firstly, the condition of the equipment – the laminating roller and the printing cylinder must be clean and the surface of the cylinders must be perfectly flat and smooth: without chips, scratches or other mechanical damage, otherwise we will see “bubbles”, craters, inclusions on the print .

Tip: To clean the chrome surface of the laminating roller, it is recommended to use alcohol solutions or household FAIRY. To clean the rubber impression cylinder, use either an alcohol solution or products for cleaning dampening rollers in printing machines. I don’t recommend using regular cleaning solutions because of the slow evaporation time, and they stink.

Secondly, the parameters of pressure, temperature, film tension and operating speed must be correctly set on the laminator. The film tension must be adjusted so that the film on the laminating roller is evenly distributed: too high tension leads to film stretching, and too low tension leads to film wavy formation.

The clamping pressure must be experimentally selected taking into account the thickness of the material and film to ensure good adhesion of the film to the printed sheet (in most cases, the pressure on the pressure gauge is kept at 4-5 divisions). Temperature and speed are also selected based on experimental observations and these parameters are interrelated – the speed of operation depends on the temperature of the laminating roller.

If the laminator runs too fast, the adhesive will not have time to activate and the film will not adhere to the printed material. In practice, the temperature of the laminating roller is set in the range of 80–120° (for matte it is less, for glossy it is more).

Thirdly, the film for pressing can be different – they differ not only in thickness (from 24 microns to 250 microns), but also in the quality of both the film itself and the quality of the applied adhesive layer. Some simple tips on how to evaluate the quality of a film: 1.

Pay attention to the quality of winding the film on the sleeve – the film should be wound evenly: without tails along the edges (the end should be smooth), without bumps or waviness. 2. Do not use film with mechanical damage to the roll – broken ends, cuts, dimples and punctures – all this will lead to defective laminated products. 3.

The adhesive layer must be applied evenly over the entire surface of the sheet. Visually assessing such a parameter is very problematic, but there are cases when halos and spots are visible to the naked eye, and this should already be alarming. 4. When further applying UV varnish and foil, care must be taken to use films with a corona (activated) surface.

Fourth, the printing sheets must be suitable for hot film pressing. It is not recommended to use paper with a density of less than 130gsm, tracing paper, or designer papers with a rough texture for laminating. The quality of adhesion is also largely affected by printing ink – do not use prints printed with inks with a high wax content (this also applies to prints from digital machines that use toner with a high oil content).

Prints must be completely dry and the paper must not be too wet, as upon contact with a hot laminated surface, water particles begin to form on the surface of the material, which disrupt adhesion. It is optimal to start the lamination process 24-48 hours after printing.

Tip: For prints that are planned to be laminated, it is better to use powders based on sugar (soluble) or starch. It is not recommended to use silicone-coated powders, because… particles of such powder will always be located on the surface of the paint layer and interfere with film adhesion.

When printing, using WD varnishes on printed prints can either help and improve the quality of lamination, or it can do harm. I highly recommend trying it!

Fifth, before starting work, check the quality of the pressing – make several prints, wait 15 minutes and check the quality of the lamination by folding the print multiple times – the film should not lag behind the paper.

Source

Sampling

When sampling, it is necessary to follow the sequence of operations:

  • from game
    products select units
    products;
  • sheets are selected from product units
    ;
  • sample sheets (samples) are selected and cut from the selected sheets
    ;
  • in accordance with the requirements of standards for specific test methods, samples are cut
    for testing.
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Device from Lorentzen & Wettre for cutting strips for testing paper samples for tearing, breaking and other indicators

Sheets must not have wrinkles or folds and must be flat. They must be cut from undamaged sheets of products. The edges of the selected sheets must be parallel to the machine and cross direction of the paper. The sample sheets should be approximately (300 x 450) mm in size.

When handling sample sheets, care must be taken to protect them from exposure to sunlight, liquids, changes in humidity and other undesirable influences (GOST Sampling for determining average quality).

To bring test conditions into comparable conditions, paper samples are brought to certain standard conditions for humidity and temperature before testing. And the tests themselves are carried out under these conditions. This bringing of samples to standard conditions is called conditioning.

Conditioning conditions are of three types, as indicated in the table. Conditioning conditions at 50% relative humidity are more commonly used. Special conditions are used, for example, when conditioning banknote paper.

Temperature, 0
C
Relative humidity, % Mode characteristics
23±1 50±2 Conditioning conditions for most printed papers
27±1 65±2 For tropical conditions
20±1 65±2 For special conditions

The samples are kept until they reach equilibrium moisture content, which is considered achieved if, with two consecutive weighings of the sample carried out after 1 hour, the last mass differs from the previous one by no more than 0.25%.

When storing and testing samples, the equilibrium humidity should not change (GOST 13523–78. Method of conditioning samples).

Mondi offset paper | formats, prices

Mondi offset paper
– multifunctional cellulose paper with sizing and excellent surface properties for high-quality printing. It is characterized by a high degree of whiteness, opacity, uniform structure, resistance to plucking and the absence of dust separation. Excellent for various methods of printing highly artistic illustration and text publications, visual products and multi-color publications with a long service life (books, reference books, advertising and paper products). Widely used in printing houses for printing full-color book and magazine products, including multicolor publications with artistic content. This printed product contains complex halftone illustrations. It is subject to high requirements for shelf life. Offset paper is the main product the company specializes in. The share of JSC Mondi SYLPK accounts for 37% of the Russian offset paper market
.

Manufacturer:
JSC “Mondi Syktyvkar LPK”

Service station: 00279404-002-2009

Weight:
60, 65, 70, 80, 90, 100, 120, 160, 190, 235 g/m 2

Color:
white

Printing methods:
offset

Certificate of conformity: download

Conclusion about durability:
download

Quality certificate: download

characteristics of offset paper units of measurement values ​​
MAIN FEATURES

Weight

g/m 2

60 – 235

Humidity

%

5 – 7

STRUCTURAL CHARACTERISTICS

Thickness

µm

85 – 190

Bendtsen roughness

ml/min

120 – 800

OPTICAL CHARACTERISTICS

CIE whiteness

%

142 – 148

White D65/10

%

102 – 105

Opacity

%

84 – 91

MECHANICAL CHARACTERISTICS

Longitudinal breaking length

km

4.5

See also: Kotlas offset paper

, Goznak offset paper

, Offset paper Kama

, Offset paper Turinsk

, Offset paper Svetogorsk
, Offset paper

Density and print quality

Paper weight and printing device specifications are closely related. The manufacturer’s instructions for each printer usually indicate the format and recommended density. Marking A4, 64-163 g/m2, for example, means that this type of paper is suitable for this device. Whatman paper with a density higher than permissible will not work – it can even damage the mechanism and damage the printer.

As a rule, standard office printers and copiers use paper in A3 and A4 formats, with an average density of 80 g/m2. It is these indicators that manufacturers focus on when producing printing paper. Each of them produces its own brand, with a guarantee of high quality printing on paper of this brand. For example, products from the domestic brand “Snegurochka” are very popular in our offices.

Density and thickness are not the same thing

When talking about density, many people mean the thickness of the paper, but this is wrong. A thicker sheet of paper of one brand seems denser than another, while their density indicators may be identical.

In fact, thick paper is looser and more porous, it is more susceptible to wear and tear and has a shorter service life. Whereas a thin one with a higher density is more compressed and will last longer. And the ink lies on it more evenly, which is the key to clear, high-quality printing. Therefore, thin paper may not always be bad.

Porosity

Porosity directly affects the absorbency of paper, that is, its ability to accept printing ink, and may well serve as a characteristic of the structure of the paper. Paper is a porous capillary material; In this case, a distinction is made between macro and micro porosity.

Macropores, or simply pores, are spaces between fibers filled with air and moisture. Micropores, or capillaries, are tiny spaces of indeterminate shape that penetrate the top layer of coated papers, as well as spaces formed between filler particles or between them and the walls of cellulose fibers in uncoated papers.

There are also capillaries inside cellulose fibers. All uncoated, lightly compacted papers, such as newsprint, are macroporous. The total pore volume in such papers reaches 60% or more, and the average pore radius is about 0.160.18 microns. Such papers absorb paint well due to their loose structure, that is, a highly developed inner surface.

If we depict the structure of paper in the form of a scale, then at one of its ends there will be macroporous papers consisting entirely of wood pulp, for example, newspaper. The other end of the scale will accordingly be occupied by pure cellulose microporous papers, for example coated ones.

Thus, coated papers belong to microporous, or capillary, papers. They also absorb paint well, but under the influence of capillary pressure forces. Here the porosity is only 30%, and the pore size does not exceed 0.03 microns. The remaining papers occupy an intermediate position.

In fact, this means that when printing on offset paper, both the solvents contained in the paint and the coloring pigments penetrate into the pores, as a result of which the concentration of pigment on the surface is low and it is impossible to achieve rich colors.

Macroporous papers accept paint well, absorbing it as a whole. The paints here are low viscosity. Liquid paint quickly fills large pores, absorbing to a fairly large depth, and excessive absorption can even cause the print to “punch through,” that is, the image will become visible from the back of the sheet.