sheet splitting with a heat seal lamination technique report 71.pdf · a paper sample is laminated...

Sheet Splitting with a Heat Seal Lamination Technique

Marco F.C. Lucisano and Ludmila Pikulik

Innventia Report No.: 71 July 2010

According to Innventia Confidentiality Policy this report is public.

Sheet Splitting with a Heat Seal Lamination Technique Innventia Report No. 71

Acknowledgements

This report is an updated and public version of STFI-Packforsk report CW 220, which was published in 2004 as a result of a common initiative between the Research Clusters “Improved Formation”, “The Engineered Sheet Structure” and the cooperative project “The Effective Surface”.

We wish expresses our gratitude to Mattias Rösberg for skilful experimental assistance, patience and precision. Bo Norman, Daniel Söderberg and Hannes Vomhoff are thanked for insightful discussions.



Table of contents Page

1 Summary ................................................................................................................. 1

2 Introduction ............................................................................................................ 2

3 Experimental ........................................................................................................... 3 3.1 Heat Seal Lamination ................................................................................... 3 3.1.1 Lamination for Optimal Splitting ................................................................................. 3 3.1.2 Plastic-Paper Interactions .......................................................................................... 4 3.1.3 Heat Transfer in a Commercial Heat Seal Laminator ................................................ 6 3.2 Splitting ......................................................................................................... 8

4 Application Examples .......................................................................................... 11 4.1 Fibre Orientation Profiles ............................................................................ 11

4.2 Layer Purity ................................................................................................ 12

5 Conclusions .......................................................................................................... 14

6 References ............................................................................................................ 15

7 Innventia Database information .......................................................................... 17



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1 Summary This report presents a method for paper splitting by heat seal lamination. A paper sample is laminated between two plastic films in a commercial pouch laminator, in which both nip temperature and residence time can be controlled. The laminated sample is then split either freely by hand or at the exit of a nip formed between two metal rollers. Each of the split layers can then be relaminated and split in two new layers. Typically the original sample could be sectioned in layers with a grammage of 2.5–5 g/m2, corresponding to an average of 14 splits from newsprint qualities.

The main advantage of heat seal lamination as a sheet splitting technique is that large samples (up to A4 to A3 in size) can be split. The sample splits can be used for investigations of layer purity in multilayer structures, transverse profiles of fibre orientation as well as in other experimental studies of paper structure.

In this study, we used a commercially available laminator to investigate the potential of the method. We present application examples for different paper qualities and discuss the shortcomings of the commercial lamination unit towards the application to sheet splitting.


Sheet Splitting with a Heat Seal Lamination Technique Innventia Report No. 71 2

2 Introduction Sheet splitting, also known as parallel sectioning of paper, is the art of dividing a paper sample into a number of distinct layers parallel to the plane of the sheet. Parallel splitting of paper is of great practical interest since it enables the measurement of the distribution of composition and structure in the transverse direction of the sample. This conceptually simple operation proves to be extremely tricky and at times impossible. In fact, since a typical paper product has a thickness well under the millimetre scale and the uncollapsed diameter of a single fibre is in the order of 20 µm, the number of “distinct” fibre layers in the thickness direction of a sample is very limited.

The literature reports a number of different methods for parallel splitting of paper: (i) sectioning with sharp razor blades (Pritchard, 1957), (ii) grinding off layers with very fine abrasive material (Hansen, 1951; Dappen, 1951; Östlund et al., 2002), (iii) microtome layering (Browning and Isenberg, 1955; Wood, 1959; Forgacs and Atak, 1961), (iv) adhesive tape splitting (Majewski, 1961; Groen, 1961; Sahlberg, 1965; Larsson & Trollsås, 1966, 1968, 1969; Tanaka, 1986; Jansson, 1999; Lloyd & Chalmers, 2000, 2001; Erkkilä et al.,1998) and (v) the Beloit sheet splitter (Parker and Mih, 1964; Parker & Dobratz, 1965; Kallmes, 1969). Even though these techniques have been used with considerable success, first-hand experimental experience shows that all known methods suffer from a series of practical problems. The most serious issue is the need for a very long learning time or a very experienced operator.

Additionally, sample dimensions are rather limited in most methods, resulting in a low number of splits and restricted in-plane dimensions. Pouch lamination has been mentioned as a innovative and simple technique for sheet splitting (e. g. Danby, 2001; Danby and Zhou, 2003; Rösberg, 2003). Here, paper samples are laminated between two polymeric sheets, which are melt onto the paper surface in a commercially available lamination equipment. Splitting is carried out by separation of the two surfaces, whereupon each layer can be relaminated and split again. This report presents an investigation of heat seal lamination as a new technique for sheets splitting. Additionally, we considered a few possible application examples and assessed the performance of a commercial heat seal laminator for direct application to studies of paper structure.



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3 Experimental This report presents a first assessment of heat seal lamination as a sheet splitting technique. Parallel sectioning of paper with this novel technique takes place in two consecutive phases: (i) heat seal lamination and (ii) the action of splitting the sample in two distinct layers.

3.1 Heat Seal Lamination

3.1.1 Lamination for Optimal Splitting

Lamination is the process of sealing paper between sheets of plastic, using heat and pressure. A paper sheet is sandwiched between two plastic sheets (typically PE, Poly Ethylene, or PET, Poly Ethylene Terephthalate) coated with an adhesive, e. g. EVA (Ethylene Vinyl Acetate). When heat and pressure are applied, the adhesive softens allowing the plastic to adhere to and encase the paper. In order to investigate the effect of laminate thickness on splitting performance, we chose three types of coextruded PET/EVA lamination pouches (Table 1).

Table 1. Physical properties of the lamination pouches. The basis weight was determined by gravimetric measurement on approximately 80 samples.

Total thickness (nominal)

[μm]

PET/EVA

[μm] + [μm]

Grammage ± std. dev.

[g/m2]

100 50 + 50 117 ± 1

125 75 + 50 153 ± 1

250 175 + 75 313 ± 1

The pouch laminator used in our study was a A4-size commercially available unit with controllable hot roll temperature (max 180°C) and lamination speed (280 mm/min – 920 mm/min). The laminator is composed of a pair of heated, rubber-covered rollers mounted on fixed axes, a pair of stationary heated bars, a second set of (cold) rollers and a control system (Figure 1). The temperature signal for temperature control is provided by a surface thermocouple sliding on the metal core of one of the two heated roll.

The actual lamination and splitting process is rather straightforward. Firstly, the plastics, which come in a slightly larger than A4 size, need to be cut to the same width as the sample. A strip of greaseproof paper is inserted at the bottom of the sample to prevent the edge of the pouch from sticking together. The pouch is then inserted through the laminator, which has previously been set for the right temperature and velocity (Figure 1). There are many factors that influence the split quality. The most important of these are (i) the operating temperature, (ii) the running speed (residence time in the hot nip), (iii) the thickness of the plastic layers and (iv) the degree of fibre orientation in



the sample. Yet the operating temperature, running speed and thickness of the sample are interconnected as they all influence the rate of heat transfer to the adhesive layer.

Figure 1. Schematic of the laminator: the paper and lamination pouch are heated first in the nip between two hot rollers, and in the gap formed between two hot bars. A second pair of (cold) rollers guides the laminated paper out of the machine. The while- heated residence time in the machine can be set between 4.5 s and 15.5 s by controlling the laminating speed.

Varying the lamination temperature alters the result of splitting. At low temperatures, there is little melting and the pouch does not adhere well to the paper, resulting in a lack of lamination. The minimum temperature necessary to pull out individual fibers from the paper depends on the thickness of the plastic pouch: approximately 70°C for the 250 µm pouch and 50°C for the 100 µm pouches. However, a much higher lamination temperature is necessary to obtain a complete split: 150°C for the 250 µm thick plastic and 110°C for the 100 µm one. Operating even slightly below these optimal settings produces a ripped and unusable split.

The running speed of the laminator could be varied from a minimum of 280 mm/min to a maximum of 920 mm/min. The aforementioned minimum temperatures for laminations are relative to a velocity of 700 mm/min. Naturally, adjusting the speed also influences the speed quality, as it affects the residence time of the sample. At lower speeds, the residence time at elevated temperature increases, resulting in better adhesion.

3.1.2 Plastic-Paper Interactions

In order to investigate the mode of adhesion between the plastic layer and the surface of the laminated samples, we attempted a microscopic investigation of laminate cross sections (Figure 2A and B). Newsprint, copy paper and liner samples were laminated at different temperatures and lamination velocities, varying the thickness of the lamination pouches. Cross sections were then analyzed with stereo-microscopy and environmental scanning electron microscopy (ESEM). In spite of the numerous samples and operating



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conditions considered in this study, we are unable to present any description of the mode of interaction of the plastic laminate with the surface of the paper web. In fact, we could not observe any systematic trend or general behaviour that could explain the phenomena observed in our microscopy study.

The extent of penetration of the hot melt adhesive into the paper web varied quite significantly between different areas of the laminate. In most cases, we observed that the adhesive remained on the paper surface of the samples (Figure 2A). Yet, areas of the samples could be found where complete penetration was observed; here fibre lumina and some of the interfibre porosity was filled (Figure 2B).

Figure 2. (A) Cross-sectional micrograph of a laminated paper web. (B) Fibre lumina in some regions were filled with the lamination adhesive. (C–D) Web-plastic interface with surface fibres entrapped in the adhesive layer.



Focusing the microscopes on the interface between the paper web and the adhesive layer, we could see regions in which the polymer layer followed the contour of the paper surface (Figure 2C) and single superficial fibres embedded in the plastic laminate (Figure 2D), alternated with regions where we could not observe any close contact between the web and the adhesive.

3.1.3 Heat Transfer in a Commercial Heat Seal Laminator

The single most critical factor for a successful application of heat seal pouch lamination to parallel layering of paper samples is the temperature field in the laminator. Although we chose a top-of-the-line commercially available laminator for our investigation, the use of this unit for splitting purposes was not unproblematic. Here we are going to discuss a few of the shortcomings of our lamination unit towards the application to splitting of paper samples.

It was mentioned previously that the temperature sensor is placed on the metal core of the bottom roller, which means that the temperature indicated by the machine is neither the actual surface temperature of the rollers nor the temperature experienced by the adhesive layer of the lamination pouch. In fact, the temperature experienced at the interface between the paper sample and the plastic is much lower and depends on the plastic thickness (Figure 3). The graph was obtained by laminating type K micro-thermocouples (wire diameter 0.125 mm, response time < 0.1 s, Omega Engineering Inc.) in a pouch and running it through the laminator as a regular plastic laminate. Though the machine was set for and indicated a temperature of 150°C, it was quite obvious that this never occurred. Instead, the thinner plastic experienced a temperature of 130°C, and the thick pouch an even lower 90°C.

Figure 3. Measured temperature profile at the interface between the paper sample and a thin and thick plastic layer. Although the machine set point was 150°C, the surface of the sample never reached this. The maximum temperature experienced inside the thin pouch was 130°C whereas the temperature was 90°C inside the thick pouch.

The best results are obtained when the lamination temperature is even, as this will produce an even split. However, it was noticed during experimentation that a significant



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temperature change occurred within the sample during lamination. This is a problem because at higher temperatures, lamination is much more effective resulting in a greater amount of fibres on the plastic. While this is not necessarily visibly obvious in the individual splits, it can be noticeable on the last obtainable split, which sometimes shows an accumulation of fibres’ in the colder areas. It was therefore concluded that the heat transfer from the core to the surface of the roller was not fast enough to maintain a constant temperature. Running three evenly spaced thermocouples through the machine and noting the maximum temperature reached by each one proved that this was indeed the case. The curves obtained can be seen in Figure 4, which demonstrates the temperature measured by the sensors in the thick plastic as they ran through the machine. There is clearly a rather large difference in the temperature experienced in the sample: while the front of the pouch reached a maximum temperature of 100°C, the last thermocouple only experiences a maximum of around 85°C. This 15°C discrepancy had a negative effect on the uniformity of the splits. In an effort to counteract this occurrence, various methods were tried and the best results were obtained by simply running a full laminated plastic pouch (of 250 mm thickness) through the machine preceding the actual sample. This allowed the initial plastic to absorb most of the excess heat and therefore lower the temperature difference in the test sample. The temperature drop did not disappear entirely but decreased to a 3°C drop between the front and end of the sample (Figure 4).

Figure 4. Graphing temperature variations during lamination. Running the sample straight through there is a 15°C gap between the leading and trailing edge (Blue lines). Under the same conditions, inserting a plastic pouch first decreases this to only about 3°C (Red lines).

A more difficult problem to resolve was the temperature variation along the axis of the rolls. The temperature on the left of the roll is consistently lower than the centre temperature or at the right side (Figure 5A). Though the maximum temperature difference between the left side and the centre is only 8°C, this has a negative effect on the split quality. However, this difference can be somewhat lessened by a longer warm-up period of the machine (Figure 5B). The data for the first graph were collected



immediately after the machine reached 150°C (as indicated on the laminator), whereas the values of the second graph were taken 30 min later. In that case, the largest temperature difference, again occurring between the left side and the centre, was only about 3°C. The longer the machine runs, the smaller the temperature difference.

Figure 5. Temperature variations along the rolls. (A) Immediately after reaching running temperature. The left side of the roller is 8°C colder than in the centre and 5°C colder than the right side. (B) 30 min after reaching running temperature. In this case there is no discernable difference between the right and left side. The maximum temperature difference between the sides and centre is only 3°C.

3.2 Splitting The sheet splitting method consists of two separate steps: lamination and splitting. While the lamination part was done on a commercially available lamination machine, the actual splits were made either freely by hand or on a machine built at Innventia and analogous to that of Minter (1992), consisting of two counter-rotating aluminum cylinder with a diameter of 120 mm. The bottom edge of the plastic is quite easily separated, thanks to the greaseproof paper, and each side is attached to a cylinder with



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tape. As the machine runs, the rollers turn and rip the sample (Figure 6). The rate of revolution of the splitter rollers was kept constant in our study, but we have investigated the effect of the separation between the two rollers by varying the gap from 1 mm to 15 mm. Newsprint and copy paper samples were then split after lamination with both thin and thick plastic. The different roller gaps were rated and compared according to the total number of splits that could be obtained.

Figure 6. Schematic of the splitting machine. The distance between the two rollers is controllable, though the best results are obtained when the cylinders are 8 mm apart.

The newsprint splits were not affected by the variation in roller gap. However, the copy paper in thick plastic (250 µm) gave only 10 splits with a gap of 1 mm and 14 splits with a 8 mm gap, which was chosen as the optimal setting. With larger gaps between the rollers (approximately 15 mm) samples tended to rip and therefore this setting was not considered a valuable option.

An aspect of the splitting process that can influence the quality of the splits is the fibre orientation. For optimal results, it is best to split in the fibre direction, that is to pull the plastic pouch apart in the same way the fibres are aligned. If this is not done, the paper is likely to split not in the middle as it normally does, but rather produces a rip through the sample rendering it unusable for further processing.

In optimal operating conditions, splitting after hot seal lamination gives an excellent uniformity of the local grammage of individual splits. Table 2 presents a map of the local grammage of the first split of a 80 g/m2 copy paper, sampled over a 20-point grid in the plane of the sheet. Here the coefficient of variation of the local grammage was only 3%. While a complete mapping of the local basis weight of all splits obtained from a single paper sample would have provided valuable insights on the accuracy of the method, gravimetric measurements suffered from increasing experimental uncertainty for splits of grammage lower than approximately 10 g/m2, making measurements on thin sheets highly impractical.



Table 1. Mapping the local grammage of a 80 g/m2 copy paper split (here the “light” layer after the first splitting). The average basis weight was 38.5 g/m2 with a coefficient of variation of 3%.

1

(LEFT)

2 3 4

(RIGHT)

A (TOP) 40.3 37.7 37.5 38.1

B 38.4 36.7 36.8 36.7

C 39.4 38.7 39.1 39.3

D 39.9 37.9 39.4 41.2

E (BOTTOM) 38.2 38.2 39.0 38.1

The repeatability of the splitting pattern between different specimens of the same origin was investigated by splitting 10 sheets of a commercial 80 g/m2 copy paper (Rösberg, 2003). The grammage of the second split was still sufficiently high for our gravimetric measurements to be considered reliable. Here we found that the coefficient of variation of the grammage of the second split in a set of ten specimens was 6%, which was considered satisfactory. Unfortunately, the grammage of each individual layer was too low for gravimetric comparison of full sets of split paper. Yet, visual observation of the samples did not show any remarkable difference between the splitting patterns of different specimens of the same origin.



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4 Application Examples Parallel splitting of paper is of great practical interest since it enables the measurement of the distribution of composition and structure in the transverse direction of the sample. The number of layers that a paper can be split into varies depending on its basis weight. Logically, the heavier and thicker the paper, the more splits can be obtained. Regardless of the paper type, the first split consistently separates the sample in two more or less equal parts. Each side can then be laminated a further 5 or 7 times, each split taking off a slight layer of fibres. This can be done until the layer of fibres left is so thin that the adhesion between the plastic is too strong to pull apart. On its own, the plastic is not see-through, but rather has a matte colouring. Therefore, in order to see the fibres better, it is often best to re-laminate each split so that the plastic becomes clear. This also has the advantage of locking the fibres between the plastic so it is impossible for them to be shaken loose.

As an application example for the use of heat seal lamination for splitting, the wire pattern on the surface of paper products was studied in micrographs of the surface layers of the sheet (Figure 7). Here the surface layer of a dyed fine paper sheet was split off the specimen and made available for microscopy studies.

Figure 7. Wire pattern on the surface of a 60 g/m2 sheet with dyed fine paper furnish.

4.1 Fibre Orientation Profiles Once the paper has been sectioned in its thickness direction, a traditional type of structural investigation that can be performed is the study of the transverse fibre orientation profile with techniques analogous to those described by Jansson (1999), Lloyd & Chalmers (2000), Lloyd & Chalmers (2001) (Figure 8).



Figure 8. Transverse fibre orientation profile of a newsprint sample split into 14 layers by heat seal pouch lamination.

4.2 Layer Purity Another application of the heat seal pouch lamination technique for sheet splitting was found in the evaluation of layer purity of multilayer paper webs. Here, 60 g/m2 paper samples were produced on FEX, the pilot paper machine at Innventia, using two fine paper furnishes dyed in red and blue. Paper samples were then split in 10 layers and both sides of all layers were scanned in a commercial flatbed scanner (Figure 9). By classifying pixels in the two colour classes Red and Blue, a transverse profile could be measured, describing the layer purity of the stratified sample (Figure 10).

Figure 9. Study of layer purity in stratified paper webs: example of surface picture of a sample split (Fine paper furnish dyed in red and blue).



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Figure 10. Layer mixing profile across the thickness direction of a stratified sample.



5 Conclusions This report presents an investigation of heat seal pouch lamination as a new technique for sheets splitting. We performed a thorough investigation of the pattern of splitting of different paper products with this method and assessed the performance of a commercial heat seal laminator for direct application to studies of paper structure.

The main advantage of pouch lamination as a sheet splitting technique is that large samples (up to A4 to A3 in size) can be split. Additionally, our study showed that the technique was reliable and gave good repeatability and layer homogeneities. Typically, the original sample could be sectioned in layers with a grammage of 2.5 – 5 g/m2, corresponding to an average of 14 splits from newsprint qualities.

We applied splitting by heat seal lamination to traditional analysis of paper structure and investigated the transverse fibre orientation profile in a newsprint sample and the layer purity of a multiply paper product. In this study, we used a commercially available laminator to investigate the potential of the method. Although the commercial unit was not designed for sheet splitting applications, we found that its shortcomings in this respect could be easily bypassed and a perfectly satisfactory mode of operation could be established.



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6 References Browning, B. L. and Isenberg, I. H. 1955 Study of paper composition by parallel sectioning. TAPPI 38 (10), 602–603.

Danby, R. 2001 Sc print quality influenced by fiber length, fabric structure and machine drainage. In Engineering, Finishing and Converting Conference, Session 31. Atlanta: TAPPI Press.

Danby, R. and Zhou, H. 2003 Numerical evaluation of the printability of paper surfaces. In 89th Annual Meeting, 3A–1. Montreal: PAPTAC.

Dappen, J. W. 1951 Distribution of starch in clay coatings. TAPPI 34 (7), 324–335.

Erkkilä, A.-L., Pakarinen, P. and Odell, M. 1998 Sheet forming studies using layered orientation analysis. Pulp and Paper Canada 99 (1), 81–85.

Forgacs, O. L. and Atak, D. 1961 Distribution of chemical woodpulp and groundwood through the thickness of newsprint. In The Formation and Structure of Paper, vol. 2, pp. 721–737. Oxford: British Paper and Board Manufacturer Association.

Groen, L. J. 1961 Fundamental aspects of filler distribution in paper.In The Formation and Structure of Paper, vol. 2, pp. 697–720. Oxford: British Paper and Board Manufacturer Association.

Hansen, E. 1951 The distribution of filler in paper. TAPPI 34 (4), 180–185.

Jansson, M. 1999 Fiberriktningsanisotropi — variationer i z-led. Master’sthesis, Department of Pulp and Paper Chemistry and Technology, The Royal Institute of Technology, Stockholm, Sweden (In Swedish).

Kallmes, O. J. 1969 Technique for determining the fiber orientation distribution throughout the thickness of a sheet. Tappi Journal 52 (3), 482–485.

Larsson, L. O. and Trollsås, P.-O. 1966 Skiktning av papper med tejp. Report 7:2. Tidningspappersbrukens Forskningslaboratorium, Stockholm (In Swedish).

Larsson, L. O. and Trollsås, P.-O. 1968 A method of studying ink penetration into and ink distribution in the paper in letter-press printing by means of radioactive tracers. Report 2:6. Tidningspappersbrukens Forskningslaboratorium, Stockholm (In Swedish).

Larsson, L. O. and Trollsås, P.-O. 1969 Apparat för skiktning av papper. Report 7:8. Tidningspappersbrukens Forskningslaboratorium, Stockholm (In Swedish).

Lloyd, M. D. and Chalmers, I. R. 2000 Use of an image orientation analysis technique to investigate sheet structural problems during forming. In Annual General Conference, vol. 2, pp. 495–502. Melbourne: APPITA.

Lloyd, M. D. and Chalmers, I. R. 2001 Use of fiber orientation analysis to investigate sheet structural problems during forming. Appita Journal 54 (1), 15–21.

Majewski, Z. J. 1961 Effect of forming processes on sheet structure. In The Formation and Structure of Paper, vol. 2, pp. 749–770. Oxford: British Paper and Board Manufacturer Association.


Sheet Splitting with a Heat Seal Lamination Technique Innventia Report No. 71 16 Minter, S. 1992 Delamination as a sheet splitting method. In Papermakers Conference, vol. 1, pp. 81–84. Atlanta, GA: TAPPI Press.

Östlund, M., Östlund, S., Carlsson, L. A. and Fellers, C. 2002 Experimental determination of residual stresses in paperboard. In Progress in Paper Physics Seminar, pp. 180–183. Syracuse, NY: SUNY-ESF.

Parker, J. D. and Dobratz, T. L. 1965 Method and mechanism for web splitting. U.S. Patent no. 3,182,874.

Parker, J. D. and Mih, W. C. 1964 A new method for sectioning and analyzing paper in the transverse direction. Tappi Journal 47 (5), 254–263.

Pritchard, E. J. 1957 Two techniques for studying the distribution of loading in paper. Proceedings Technical Section BP & BMA 38, 425–438.

Rösberg, M. 2003 Laminat- och splittringsteknik i syfte att bestämma ett pappers svaga skikt samt uppbyggnads i z-led. Tech. Rep. Royal Institute of Technology, Division of Paper Technology (In Swedish).

Sahlberg, C.-R. 1965 Fibernas läge i papperets yta. Svensk Papperstidning 68 (22), 802–803 (In Swedish).

Tanaka, H. 1986 Z-directional distribution of filler starch and aluminium in paper. J. Jpn. Wood Res. Soc. 32 (7), 527–534.

Wood, R. L. 1959 Parallel sectioning of newsprint. Tappi Journal 42 (1), 14–17.



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7 Innventia Database information

Title Sheet Splitting with a Heat Seal Lamination Technique

Author Marco F.C. Lucisano and Ludmila Pikulik

Abstract This report presents a method for paper splitting by heat seal lamination. A paper sample is laminated between two plastic films in a commercial pouch laminator, in which both nip temperature and residence time can be controlled. The laminated sample is then split at the exit of a nip formed between two metal rollers. Each of the split layers can then be relaminated and split in two new layers. Typically the original sample could be sectioned in layers with a grammage of 2.5–5 g/m2, corresponding to an average of 14 splits from newsprint qualities. The main advantage of pouch lamination as a sheet splitting technique is that large samples (up to A4 to A3 in size) can be split. The sample splits can be used for investigations of layer purity in multilayer structures, transverse profiles of fibre orientation as well as in other experimental studies of paper structure.

In this study, we used a commercially available laminator to investigate the potential of the method. We present application examples for different paper qualities and discuss the shortcomings of the commercial lamination unit towards the application to sheet splitting.

Keywords Sheet splitting, lamination, layering, fibre orientation, measurement method, linting

Classification Public

Type of publication Innventia Report

Report number 71

Publication year July 2010



Language English

INNVENTIA AB Box 5604, SE-114 86 Stockholm, Sweden Tel +46 8 676 70 00, Fax +46 8 411 55 18 [email protected] www.innventia.com

INNVENTIA AB is a world leader in research and development relating to pulp, paper, graphic media, packaging and biorefining. Our unique ability to translate research into innovative products and processes generates enhanced value for our industry partners. We call our approach boosting business with science. Innventia is based in Stockholm and in Norway and the U.K. through our subsidiaries PFI and Edge respectively.

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