CN101285281B

CN101285281B - Calendering method of fibre web

Info

Publication number: CN101285281B
Application number: CN2008100917602A
Authority: CN
Inventors: 汤米·万哈拉
Original assignee: Metso Paper Oy
Current assignee: Valmet Technologies Oy
Priority date: 2007-04-12
Filing date: 2008-04-14
Publication date: 2012-04-25
Anticipated expiration: 2028-04-14
Also published as: AT505347A2; FI20070281A; CN101285281A; FI121275B; DE102008016776A1; AT505347A3; FI20070281A0; AT505347B1

Abstract

The invention relates to a method of processing calendaring for a web of fiber (W) in a calender (1). A roller device of the calender is provided with at least two rollers. A roll gap (W) is formed between the rollers, and at least one roller is provided with polymer coatings. An allowed max average surface roughness (Ra) of the surface of the roller (P) which is provided with the polymer coatings in the roller device depends on that: a glossiness that the web of fiber needs on the position of the roller (P) which is provided with the polymer coatings and is positioned on each roll gap (N), and the glossiness of the web of fiber (W, W1) transported into the calender (1). Moreover, the surface average roughness (Ra) of each roller (P) provided with the polymer coatings is less than the allowed max average surface roughness (Ra) determined aiming at each roller (P) provided with the polymer coatings.

Description

The calendering method of web of fiber

Technical field

The present invention relates in calender web of fiber is carried out the method for press polish, have at least two rollers in the roller arrangement of this calender, between these two rollers, be formed with roll gap, and wherein at least one roller is the roller with polymer coating.

Background technology

The factor that acts on the glossiness (Glanz) of paper has a lot., have sufficiently high glossiness here, adopt multiple possible method in the industry hardy in order to ensure paper: as to make the binder content of amount, drier content and the coating of coating contained in the paper be adjustable; The amount that makes polishing agent contained in the coating is transformable; Load of press polish roll gap and heat roller temperature also can be changed; For another example, roughness and the humidity of paper that will carry out the cover paper (Unterlagenpapier) of press polish are adjustable before press polish.Special, in glazing calender, the transporting velocity of paper in the increase of paper glossiness and roll gap quantity, the calender, most pressure and the temperature correlation that is present in heatable hot-rolling in the roller arrangement in roll gap.In the common type of service of glazing calender, heatable roller is arranged alternately with the roller with polymer coating.In glazing calender, be provided with usually 6 to 16 this type of hot-rolling with have the roller of polymer coating.For example, in the what is called optimization load two-wire calender (Optiload-undTwinline-Kalandern) of the applicant's invention, typically be provided with 5 to 12 rollers, wherein 2 to 5 rollers are hot-rollings, and 4 to 7 rollers are the rollers with polymer coating.

Even when the composition and the rolling condition of paper remains unchanged, for different paper kinds, the glossiness that in burnishing process, forms is often with desired inconsistent.Because the influence to the glossiness of paper has multiple different factors, find out reason that paper quality descends and it is controlled very difficulty.

Summary of the invention

The object of the invention just is, searches out the governable process variable that is associated with the paper web multi-roller rolling, and the glossiness of the paper that can guarantee by this process variable in burnishing process, to form keeps evenly.

Before entry into service, polish to the coating of roller, so that this coating has the specific surface roughness that is generally 0.4 μ m to 0.6 μ m with polymer coating.Here, the average deviation Ra on surface is known as surface roughness, as definition among " mechanical drawing 1 & 2 (Maschinenzeichnung 1 & 2) " (the ISBN 952-97096-7-3) of Aimo Pere works.As time goes on; Surface quality with roller of polymer coating can descend; Its roughness since in the web of fiber corrasion of contained coating will increase, in addition, on the surface of web of fiber, will be formed on the depressed position of the vibration that initiation in the roller arrangement do not expect to have.More the time point of roll change can not accurately be confirmed usually, but thinks to change in the suitable time interval determined.

Yet it has been determined that in the rolling condition of the overwhelming majority it is not enough changing the roller with polymer coating according to the present invention, possibly before the time point of real more roll change, just obviously reduce because will carry out the quality of the paper of press polish.

The present invention is the basis with following phenomenon; Promptly; The one or both sides of paper web will polish (poliert) to reach certain glossiness in the multi-roller rolling process, and the surface roughness with roller of polymer coating must remain in certain limits according to paper kind and roll gap.In the past, this situation did not almost receive attention, this be because: to make people can't fully understand it be how to link together with the glossiness of paper to forming the acting parameter diversity of certain glossiness.When the limiting value of the surface roughness of confirming the roller that each has polymer coating based on the paper kind; At first to consider to deliver into the glossiness of the web of fiber in the glazing calender, and will consider to improve the required polishing degree of paper web in the calender roll gap position of confirming.Surface roughness with respective roller (being hot-rolling) of the roller of polymer coating also can be considered when the maximum possible limiting value of the roughness of the roller of confirming to have polymer coating.During this external definite limiting value, can consider that previously mentioned other acts on the factor of paper web glossiness, said factor had both comprised the composition of the paper that glossiness is exerted an influence, and also comprised the burnishing process amount that glossiness is exerted an influence.

Or rather, the present invention relates to a kind of method of in calender, web of fiber being carried out press polish, the roller arrangement of this calender comprises at least two rollers, between said roller, forms roll gap, and at least one in the wherein said roller is the roller with polymer coating.The highest average surface roughness of permission on surface that has the roller of polymer coating in the roller arrangement depends on: web of fiber (W) is in the needed glossiness in position of the roller with polymer coating (P) that is positioned each roll gap place, and the glossiness that delivers into the web of fiber (W, W1) of calender.Each surface average roughness with roller of polymer coating has the highest average surface roughness of the determined permission of roller of polymer coating less than being directed against each.

The present invention most preferably is applicable to the gloss paint papery that contains cellulose and wood pulp, and its Hunter glossiness (Hunter-Glanz) surpasses 20%, preferably surpasses 50%.

At first; When the present invention produces polishing paper and cardboard in glazing calender; Surface roughness to roller with polymer coating is adjusted, still, and when the permission surface roughness of the roller with polymer coating can be higher relatively for the uncoated paper kind; The present invention equally also is applicable to the uncoated paper kind, and this is owing to lower glossiness requirement.

Here, can glazing calender be interpreted as to be used for specific calender that paper and cardboard are carried out press polish that it has roller arrangement, this roller arrangement comprises the parallel rollers of a plurality of stacked location.

Be formed with roll gap between per two stacked rollers, pass the web of fiber surface that calender is carried, in roll gap, handle by the roll gap pressure that is present in the roll gap.In glazing calender; Through rising or the highest at least and/or minimum roller that descends; Open or close roll gap, but the covering that is usually located at the so-called intermediate calender rolls between the highest roller and the minimum roller be extensible/move, with to two stacked rollers between roll gap pressure exert an influence.The roll gap of all glazing calenders can have identical or different roll gap pressure.In addition; Glazing calender can comprise a plurality of devices that usually are associated with the generation of burnishing process and roll gap pressure, as be used for regulating web of fiber surface moisture content (Feuchtigkeitsgehalt) instrument, be used for the heavy device of compensating roller, be positioned at loadshedding equipment that roller end is associated with the adjustment and the supporting arrangement of roller and with burnishing process control be associated at abundant disclosed other device of technical literature.

If paper or cardboard are uncoated paper or cardboard, like the supercalendered paper (SC-Papier) as magazine paper, then the Hunter glossiness of its web of fiber surpasses 20%; If paper or cardboard are coated paper or cardboard, then the Hunter glossiness of its web of fiber surpasses 50%.Boundary between paper and cardboard changes, and every square meter weight of heavier papery will be higher than every square meter weight of light cardboard type in addition.Paper is manufactured to individual layer, and its every square meter weight is at 25g/m ²To 300g/m ²Between.Cardboard is manufactured to multilayer, and its every square meter weight is at 150g/m ²To 600g/m ²Between.

The polishing paper kind had both comprised (the containing wood pulp) paper that contains mechanics material (mechanische Masse), also comprised the coated paper of cellulose.Method of the present invention goes for the paper kind that is rich in the mechanics material is carried out press polish, and this paper kind that is rich in the mechanics material is generally: every square meter weight is about 40g/m ²To 60g/m ²And the Hunter glossiness is that 20% to 50% supercalendered paper, every square meter weight are about 60g/m ²To 80g/m ²And the Hunter glossiness is 50% to 80% but is generally about light weight coated paper of 50% to 65% (LWC-Papier), every square meter weight and is about 70g/m ²To 90g/m ²And the Hunter glossiness is that 65% to 75% middle amount coated paper (MWC-Papier), every square meter weight are about 50g/m ²To 70g/m ²And the Hunter glossiness is that finished coated paper (MFC-Papier:MachineFinished Coated Paper) in 25% to 70% the machine, every square meter weight are about 40g/m ²To 70g/m ²And the Hunter glossiness is that 45% to 55% film coated offset paper (FCO-Papier:Film Coated Offset Paper), every square meter weight are about 100g/m ²To 135g/m ²And the Hunter glossiness surpasses 90% weight coated paper (HWC-Papier).Normally; Method of the present invention go for cellulose, the mechanics content of material is lower than 10% papery; This papery is: wood-free coated paper (WFC-Papier:Woodfree coated paper); Its every square meter weight obviously changes according to the coating number of times, and every square meter weight is about 90g/m ²To 130g/m ²And the Hunter glossiness is 65% to 85%.The paper surface PPS10 roughness (μ m) that obtains by method of the present invention changes between 0.6 to 2.8 along with paper kind difference.

Non-coating supercalendered paper is generally used for printed matter, like magazine and catalogue.Ultralight amount coated paper (ULWC-Papier) or light weight coated paper (light/dab especially) (leicht/leicht gestrichen) can be used for magazine and different catalogues; Coated paper (SMC-Papier), middle piezometric machine-glazed paper and weight calendered paper (moderate strength/be coated with by force) (mittelschwer/stark gestrichen) are first-selected as printing paper and writing paper in the super machine; Wood-free coated paper (not containing wood pulp, coating) is used for promotional literature and magazine, also is used for so-called smooth art paper.Every square meter weight of smooth art paper is at 100g/m ²To 300g/m ²Between change.In some cases, the present invention also can be applicable in the production of the newspaper with frosted face, and its glossiness is about 10, and its roughness is between 3.0 and 4.5.

According to the present invention; The maximal roughness that in glazing calender, has the roller of polymer coating can be definite like this; Confirm the factor that the glossiness to paper exerts an influence according to the paper kind when being initial; For example according to the paper kind and fixed coating content and coating are formed, and confirm the rolling condition of relevant paper kind, the for example humidity of the temperature of hot-rolling, roll gap pressure, transporting velocity and web of fiber.Subsequently, make these conditions keep constant, and web of fiber is carried regular hour section T with (geplanten) actuating speed of setting in calender.In time period T, friction can appear in the roller with polymer coating.When the formation of paper kind glossiness in burnishing process no longer conformed to demand, roughness that will pair roller was controlled, and can directly obtain the permission maximum roughness of each roller in the calender with this.

Because it often is different being arranged in the smoothness of roller arrangement top roll gap and bottom roll gap paper and the forming process of glossiness; So possible is; According to each has the converted paper kind of the roller of polymer coating in the glazing calender roller arrangement, the maximum average roughness Ra of different permissions is measured.At this, its position in roller arrangement is depended in each replacing with roller of polymer coating at interval.

Also can confirm same average surface roughness to the roller that in the glazing calender all have a polymer coating, pair roller is changed in view of the above.If roller will be changed simultaneously, the permission maximum surface roughness that then has the roller of polymer coating must be selected according to the roller with polymer coating that is vulnerable to wear and tear most.The roll gap that in roller arrangement, is positioned at differing heights can also have different roll gap pressure gaps (Walzenspaltdruckprofil) in addition, and the wearing and tearing that on roller, produce thus have nothing in common with each other.

Description of drawings

Then, according to accompanying schematic Fig. 1 and Fig. 2 the present invention is elaborated.

Fig. 1 shows the changing condition of paper glossiness in glazing calender, and it obtains through a series of operation test (Testbetriebsserie).

Fig. 2 schematically shows the glazing calender that uses in the adjustment process in test, be positioned at the calender end through direct observation.

The specific embodiment

In test, paper web W makes every effort to the Hunter glossiness (60% to 75%) that reaches higher and improves the glossiness that reaches about 20 to 30 units through the press polish effect.

In test that Fig. 2 schematically shows is regulated, used so-called optimization load glazing calender, its roller arrangement has nine rollers, and said roller is that roller with polymer coating, one are that both modes of replacing each other of hot-rolling are provided with one.Hot-rolling T is a checker with the roller P with polymer coating like this.Roller P1 to P4 in the roller arrangement is set to, and for the odd number roll gap, hot-rolling T should be arranged on the top of the web of fiber that passes this roll gap conveying, and for the even number roll gap, hot-rolling T should be arranged on the below of this web of fiber.Otherwise; For odd number roll gap N1, N3, N5 and N7; Roller P with polymer coating is arranged on the below of the web of fiber that passes relevant roll gap, and for even number roll gap N2, N4, N6 and N8, the roller P with polymer coating is arranged on the top of this web of fiber.Like this, in roller arrangement, have eight roll gap N, N1-N8, it is that the roller that constituted by roller with polymer coating and hot-rolling is to formed.The highest roller and minimum roller are heatable hot-rollings in the roller arrangement, and the web of fiber (W, W1) with certain glossiness enters into the highest roll gap N, N1, make the paper web W that in calender, carries, the downside of W1 press to the highest hot-rolling T, T1.All roll gap in the roller arrangement are applied with same roll gap pressure.The glossiness of the paper web W1 that carries is 40% Hunter glossiness.

Calendering the paper web and the upper side of the lower surface glossiness is formed through the pressure nip with three different forms of the roll gap.The roll gap pressure that uses is respectively 200,300 and 380kN/m.In Figure 1, the calender in a paper transport in the upper side of the roll gap formed by different Hunter gloss, with different pressure through the line joining the roll gap together in the calender the paper in the transport side of the roll gap formed by the different Hunter gloss solid lines connected places.

Arrive through experimental observation, after the 4th roll gap N, N4, all roll gap pressure that act on the downside of paper make the glossiness that forms not disappear flexibly on the contrary.In the odd number roll gap, the surface roughness of being arranged to roller lower roll, that have polymer coating is 0.8.In the even number roll gap, the surface roughness of being arranged to roller top roll, that have polymer coating is 0.5.Like this, the too coarse roller with polymer coating has stoped the required glossiness of formation on the downside of use paper kind.

Yet what be also noted that is, if this paper kind is required that lower Hunter glossiness is arranged, for example is lower than 55%, and surface roughness Ra=0.8 with roller of polymer coating is always enough.

In addition, from before can also observe the described test, begin to locate just to have formed among roll gap N1, N2 and the N3 this glossiness at calender; Herein; It is about about 50% to 60% that glossiness should be brought up to, and its downside and upper side for paper all is enough, and roughly the same.Thus, at the place that begins of calender, the surface roughness that forms the roller with polymer coating of roll gap N1, N2 and N3 can have higher maximum surface roughness.In contrast, the too coarse surface with roller of polymer coating has hindered back roll gap N4 to N8 and has formed glossiness, and the glossiness that in roll gap N4 to N8, forms should be more than 60%.Usually; For the roller of (gerollten) polymer coating with rolling formation; The surface roughness Ra that it had is less than 0.2, and for the roller of (gegossenen) polymer coating with the formation of casting, the surface roughness Ra that it had is less than 0.4.

Thus, the limiting value of permission maximum surface roughness that has the roller of polymer coating in the calender depends on: roller is positioned beginning of calender roller arrangement or end; And the degree that glossiness need improve in calender.

Noted earlier only is several embodiments of the present invention, and those skilled in the art understand, and the present invention can be achieved with method in the scope of the described technical conceive of claims in many ways.Therefore, when in confirming specific roll gap, having the permission maximum surface roughness of roller of polymer coating, the influence of the preheat roll surface roughness that also can consider to be oppositely arranged.The average surface roughness Ra of new hot-rolling is usually less than 0.2, and the average surface roughness Ra of the hot-rolling of process wearing and tearing is then higher.

Claims

1. the method for in calender (1), web of fiber (W) being carried out press polish, the roller arrangement of this calender comprises at least two rollers, between said roller, is formed with roll gap (N), in said roller, having a roller at least is the roller with polymer coating, it is characterized in that,

For the roller (P) that in this roller arrangement, has polymer coating; Its surperficial the highest average surface roughness of permission (Ra) depends on: this web of fiber (W) is in the needed glossiness in position of the roller with polymer coating (P) that is positioned each roll gap place, and the glossiness that delivers into the web of fiber (W, W1) in this calender (1); And

Each has the surface average roughness (Ra) of the roller of polymer coating less than having the roller the highest average surface roughness of determined permission (Ra) of polymer coating to each.

2. according to the described method of claim 1, it is characterized in that this calender (1) is a glazing calender; This multiroll calender has at least five stacked rollers; In the said roller, there is one to be hot-rolling (T) in per two rollers, has one to be roller (P) with polymer coating.

3. according to the described method of claim 2, it is characterized in that this multiroll calender has at least 8 stacked rollers.

4. according to the described method of claim 2, it is characterized in that this web of fiber (W) is paper web or board web.

5. according to the described method of claim 4, it is characterized in that the paper web of in this calender (1), carrying (W, W1) is the coating paper web that contains wood pulp or cellulose, this paper web reaches the Hunter glossiness above 20% through press polish in said calender.

6. according to the described method of claim 5, it is characterized in that this paper web reaches the Hunter glossiness above 50% through press polish in said calender.

7. according to the described method of claim 5; It is characterized in that; The paper web that carries out press polish is the wood-free coated paper web of finished coated paper web, film coated offset paper web, middle amount coated paper web, weight coated paper web or cellulose in the light weight coated paper width of cloth that contains wood pulp that comprises the mechanics material, the machine, and the Hunter glossiness of wherein said paper web is through surpassing 50% after the press polish.

8. according to the described method of claim 7, it is characterized in that the Hunter glossiness of said paper web is through surpassing 60% after the press polish.

9. according to the described method of one of claim 1-8; It is characterized in that; This roller arrangement comprises that at least one has the roller of polymer coating, and the maximum average surface roughness (Ra) of other roller is inconsistent in the average surface roughness of its maximum possible (Ra) and this roller arrangement.

10. according to the described method of claim 9, it is characterized in that each the highest average surface roughness of permission (Ra) with roller (P) of polymer coating depends on that which roll gap (N) that said roller with polymer coating is positioned in this glazing calender locates.

11. according to the described method of claim 10; It is characterized in that; In the roll gap that this calender begins to locate, the highest average surface roughness of permission (Ra) of roller (P) that has polymer coating in this glazing calender is greater than the highest average surface roughness of permission (Ra) of the roller (P) that in the roll gap of this calender end, has polymer coating.

12. according to the described method of one of claim 1 to 8; It is characterized in that; The roller (P) that in this glazing calender all have polymer coating has the identical the highest average surface roughness of permission (Ra); Wherein, confirm based on the needed glossiness of this web of fiber in the surface roughness (Ra) of the terminal roll gap of this calender roller place, that have polymer coating.

13., it is characterized in that according to the described method of one of claim 1 to 8, cast formation when this polymer coating, the average surface roughness that then has a roller (P) of this polymer coating remain on 0.4 and the maximum the highest average surface roughness of permission between; When this polymer coating is that rolling forms, the average surface roughness that then has a roller (P) of this polymer coating remain on 0.6 and the maximum the highest average surface roughness of permission between.

14. according to the described method of one of claim 1 to 8, it is characterized in that, when the highest average surface roughness of permission (Ra) of the maximum of the roller of confirming to have polymer coating (P), consider the coating characteristic of web of fiber.

15., it is characterized in that said coating characteristic is for forming according to paper kind definite coating content and coating according to the described method of claim 14.

16. according to the described method of one of claim 1 to 8; It is characterized in that; When the highest average surface roughness of permission (Ra) of the maximum of the roller of confirming to have polymer coating (P), the surface roughness of the hot-rolling (T) that consider to be oppositely arranged with said roller with polymer coating.

17. according to the described method of one of claim 1 to 8, it is characterized in that, when the highest average surface roughness of permission (Ra) of the maximum of the roller of confirming to have polymer coating (P), consider the rolling condition of relevant paper kind.

18., it is characterized in that said rolling condition is the humidity of the transporting velocity of web of fiber in the pressure, calender of temperature, the roll gap of hot-rolling and the web of fiber in this calender, carried according to the described method of claim 17.