WO2022079207A1

WO2022079207A1 - Glass sheet arrangement for transport

Info

Publication number: WO2022079207A1
Application number: PCT/EP2021/078532
Authority: WO
Inventors: Pavel WONDRÁK; Michal DVOŘÁČEK; Julie Hubert
Original assignee: Agc Glass Europe; AGC Inc.; Agc Flat Glass North America, Inc.; Agc Vidros Do Brasil Ltda
Priority date: 2020-10-14
Filing date: 2021-10-14
Publication date: 2022-04-21

Abstract

The field of the invention is glass transport, the sheets of glass being disposed on a stillage. The invention describes a special arrangement for safe transport of soft coated glass sheet. The arrangement involves a protective assembly [P] comprising a corrugated cardboard sandwiched between two composite cardboards, one being covered with a kaolin paper type. The arrangement avoid any traces, marks or scratches on the coating.

Description

Glass sheet arrangement for transport

Technical Field

[0001] This patent is related to transport of coated glass articles. The present invention discloses an arrangement of glass sheets package disposed on a stillage. The arrangement is such that soft coating (class C) may be safely transported for quite a long distances without any damage of the coating (scratch or deposition).

Background Art

[0002] Articles such as glass panes or glazing can be fragile, but are also very heavy. Currently for shipment, glass article are leant against inclined parts of a support, known in the trade as a "stillage". The stillage may be made of different material such as metal, plastic or wood and is designed to be charged on a truck.

[0003] Charging a stillage with a coated-glass package means necessary that a first glass sheet should be in direct contact with the stillage. Each glass sheet is moved from the process line in such a way that the coated side of the glass sheet is coming either into contact with the stillage or with an already charged other glass sheets. From the contact between the coating and the stillage, some issues to keep the coating safe exist, particularly when it is a soft coating as a PVD low-e coating. When the coating contact another glass sheet, there is no problem, because some protection, as for example powder, is used.

[0004] The coating may be sensitive to deterioration during transport. Mainly two issues can arise for the quality of the coating. The first one is that mechanical contact may scratch the coating and the second issue is deposition that occurs on the coating during the manipulation when contacting non appropriate material. Deposition may be easily cleanable or not, or not cleanable at all.

[0005] Problems are also to be expected during the unloading of the glass sheets. Moreover, for unloading weight limit, the overall package is divided in some separated packages that are superposed on the stillage. To allow easy unloading of each package, these packages are separated from each other and the kind of separation may also cause problem.

[0006] The current way to skirt any quality issues occurring with sensitive coating contacting the stillage or a separation between two packages, is to use a glass coversheet, so every coating of the charge is contacting another glass sheet which is a safe contact material. A first cover sheet is charged onto the stillage and into contact with it, then the coated glass sheets are deposited on it and all next coatings are thus in contact with the glass surface of the previous coated pane.

[0007] Despite this is a good solution to solve the quality issues explained above, such solution is costly and non-environmental friendly. In fact loading additional heavy glass pane for the transport will increase weight, costs and will leave environmental fingerprint. Moreover, the glass cover sheet is considered as a waste since nor the provider nor the final user has any interest to recover it or reuse it.

[0008] Looking to alternative, we found that it is also known to use cardboard as a protective support for glass to avoid a close contact with the stillage. Unfortunately, when sensitive coating is involved, cardboard alone is responsible for scratch on the coated glass substrate. Scratch is not the only issue, some material difficult to wash may also be transferred to the coated glass sheet.

[0009] To solve scratch problem during glass transportation, paper has been used as interleaving sheet when high smoothness is requested. Those interleaving paper sheets require a good quality as for examples in terms of fine particles content (US20170152633) , resin (US20180305096, W02009008413A1), metallic content (WO2018173572A1 , JP2014118663A), short fibres (WO2018181658A1 ).

[0010] Those papers are used as interleaving paper and have not been tested as a separation between the glass and a stillage. Also they are concerned with scratch problem or deposition problem but they do not give a global solution for both issues. [0011] There is thus still a need for a good solution to protect coated glass panes during long distance transportation without using a loss glass cover sheet. The present invention will now described the application of a coated cardboard on the stillage or as separation, to avoid direct contact between glass coating and stillage or rubber on stillage and to avoid direct contact with cardboard.

Summary of invention

[0012] We have now discovered that transporting sensitive coated glass substrate without using glass cover sheet to avoid damage to the coating is possible if the coated side of the glass contact either another glass surface or a special paper as for example what we here call a kaolin paper type, which will be defined further. Loading is thus made in such a way that the first coated glass is separated from the stillage through a cardboard covered with a special paper on one face. The coated side of the glass sheet is the one contacting the special paper, said special paper covering a composite cardboard. Successive coated glass sheets are disposed over the first one.

[0013] Advantageously the composite cardboard covered with a special paper is part of an assembly, said assembly comprising a corrugated cardboard sandwiched between two composite planar cardboards, one being covered with the special paper, here called the “kaolin paper type”.

[0014] We have found also that advantageously some or all of the composite cardboard edges are rounded to avoid any sharp contact with the coating.

[0015] In a particular embodiment, some supplementary assembly of the invention comprising a cardboard covered with special paper are used as separation between some of the glass sheets of the overall package in such a way that the overall package is divided in some separated smaller packages. The smaller packages allow easy unloading of each package. In this configuration, every coated sides of glass sheets are protected either with a glass sheet or with what we define as a kaolin paper type.

[0016] There are plenty of paper quality depending on its final use, in terms of its composition and surface properties namely depending if it has been coated or not. Paper may be characterized through many different parameters, more particularly its substance (g/m2 ; ISO 536), thickness (pm ; ISO 534), Parker roughness (pm ; ISO 8791-4), Beck smoothness (sec ; ISO 5627). Those properties can vary a lot as for example between a common wrapping bag or a high quality printable paper.

[0017] Kaolin is one of the most extensively used additive in paper industry as filler or coating to improves paper appearance in terms of gloss, smoothness, brightness and mostly its print quality. The quality of kaolin (impurities, particle size and distribution rheology...) will impinge the final paper quality as its porosity, smoothness, impurities. Increasing the amount of kaolin results in a smoother paper with higher porosity.

[0018] We have discovered that the quality of a kaolin coated paper or equivalent (see requested characteristics in table 1) is convenient to be our coated glass protection.

[0019] We have then searched amongst qualities resulting from a kaolin coating which were important for our purpose and we have found that any paper having the following characteristics (see table 1) may be convenient as a contact surface for coated glass sheet transport, to be used for our invention.

[0020] Advantageously the kaolin paper type of the invention is water resistant and is also convenient as a barrier to organic material.

[0021] Table 1 Covering paper characteristics

[0022] The figure 3 illustrates the assembly material [P] to be used as separation between 2 glass sheets or between the coated surface of a glass sheet and the stillage. The assembly [P] comprises the corrugated cardboard [C] sandwiched between composite cardboard [A] and [B], Composite cardboards [A] and [B] are each a superposition of cardboard sheets and filler, resulting in the composite structure. The composite cardboard [A] has one surface which is covered by the so called kaolin paper type, this covered surface being the external one. The cardboard [C] is corrugated. Both composite cardboards [A] and [B] are glued onto the corrugated cardboard [C] in such a way that the corrugated cardboard [C] is sandwiched between the two composite cardboards [A] and [B], Assembly [P] is done to allow the kaolin paper type to appear to one of the external surface of the structure (see figure 3).

[0023] The corrugated cardboard [C] which is part of the assembly [P] allows to protect the glass against shocks during transport and the covering part, which is a kaolin paper type, was an unexpected good solution to avoid any scratch or traces of deposition on the coated surface of the glass sheet.

[0024] Advantageously, the composite cardboard [A] used for the invention has the characteristics described in table 2. More particularly, the composite cardboard [A] is a commercial fully coated white lined chipboard which is FSC certified and 100% recyclable.

[0025] Table 2 Characteristics of the cardboard composite with kaolin paper type

(composite cardboard [A])

[0026] We have found also that advantageously some or all the edges of the composite cardboard [A] are rounded in such a way that no sharp edges are susceptible to scratch the coated glass surface, as for example a PVD low-e coated glass substrate.

[0027] Any kind of conventional stillage for glass transport well known by the man skilled in the art may be used for this invention. The stillage is equipped with a special arrangement for coated glass transport, and this arrangement is such that the coated glass panes are transported without the use of a protective cover glass sheet. [0028] The special arrangement is made by attaching pieces of cardboard assembly [P] onto the stillage where the first glass sheet will be placed. The pieces of cardboard assembly [P] may have different size and I or dimensions depending on the weight to be supported. The kaolin paper type surface is positioned in such a way that it will contact the coated face of the glass sheet. To stabilize the arrangement, the cardboard [B] side is attached to the stillage with a double side tape in order to avoid any other element to come in contact with the sheet of glass and leaving the kaolin paper type side free to contact the coated side of the glass substrate.

[0029] When all pieces of the stillage susceptible to contact the glass sheet have been covered with assembly [P], coated glass sheets are loaded. The first glass sheet is charged in such a way that the coated face contact the kaolin paper type face of the cardboard. A second glass sheet is charged onto the first one in such a way that the coated face of this second glass sheet contact the first glass sheet. The successive following glass sheets are charged in the same way until a maximum weight is reached. The maximum weight of glass loaded depends on the unloading capacity of the final user. When this maximum weight capacity is reached, a new assembly [P] of the invention is placed in such a way that the coating of the first next coated glass sheet will contact the kaolin paper type side.

[0030] In a particular embodiment, the coated glass sheet is part of a laminate. In this particular case, weight of the glass is higher and two possible ways have been investigated. A first possible way to manage the extra weight is to use an assembly of the invention with wider dimension. A second possible way is to decrease the number of coated glass sheets of each package to keep roughly the same weight to be supported by each assembly [P] of the invention.

[0031] When loading of the stillage is completed, the arrangement is charged on a truck and may be safely transported for a long distance.

[0032] The invention is an arrangement for transporting at least one coated glass sheet on a stillage, characterized in that the coated surface of each coated glass sheet placed on the stillage is contacting either an uncoated surface of another glass sheet or a kaolin paper type part of an assembly [P] comprising at least two composite cardboard parts ([A] and [B]) sandwiching a corrugated cardboard [C] and the composite cardboard part [A] being covered with a kaolin paper type.

[0033] The arrangement of the invention is such that said kaolin paper type is any paper characterized by a Beck smoothness, expressed in second and measured following the ISO Norm 5627 which is at most 38 sec, preferably at most 30 sec and more preferably at most 27 sec. Preferably said kaolin paper type is any paper having a pH comprised between 6.0 and 7.4, preferably 6.4 and 7.2 and more preferably 6.5 to 7.0.

[0034] The composite cardboard [A] of the invention has a substance comprised between 270 and 650 g/m2, preferably between 300 and 620 g/m2 and more preferably between 350 and 600 g/m2 and a thickness comprised between 300 and 1000 pm, preferably between 385 and 900 pm and more preferably between 450 and 850 pm.

[0035] The arrangement of the invention is such that at least three edges of the composite cardboard [A] are rounded on the kaolin paper type side. The coated glass sheet to be transported may be monolithic or laminated.

[0036] The arrangement of the invention is such that at least one coated glass sheet contacting a composite cardboard covered with a kaolin paper type is coated by PVD, more particularly is coated with a low-e PVD stack.

Brief description of drawings

[0037] The figures are not at scale to ease the representation. Their meaning is to help the understanding of the invention and they are in no way limiting the scope of the invention.

[0038] Fig.1 Current way for coated glass arrangement on a stillage

[0039] Fig.2 Stillage arrangement corresponding to the present invention

[0040] Fig.3 Assembly of the invention with kaolin paper type surface.

Detailed description of the drawing

[0041] The figure 1 illustrates the current assembly used to transport sensitive coated glass sheets. A first glass sheet with no coating (cover sheet CS) is disposed on the stillage. Then the coated glass sheets (CG) are successively charged with the coated side (film) coming into contact with the first sheet.

[0042] The figure 2 shows the installation of a protection assembly (P) of the invention on the stillage. The kaolin paper type is on the side which will contact the glass sheet (the side away from the stillage). The protection sheet assembly attached on the stillage may have different sizes, for example the ones called below narrow or wide, it could even completely cover the stillage. The size is advantageously so small as possible in order to avoid waste and as big as necessary, in order to be efficient in protecting the coating of the coated glass sheet. As an example, but not limiting the invention, we have tested two different sizes referred as “narrow” or “wide” (see further in the text).

[0043] In a particular embodiment, the “wide” cardboard assembly [P] is 300 mm wide and is able to face the weight of laminated glasses. The “narrow” cardboard assembly [P] is measuring 80 mm wide and is sufficient for monolithic coated glass sheet. The assembly of the invention may be attached to the stillage by any means as for example a double sided tape.

[0044] The figure 3 represents the assembly [P] of the invention. A corrugated cardboard [C] is sandwiched between a composite cardboard of the invention [A] and another cardboard [B], The composite cardboard of the invention [A] is covered by the kaolin paper type of the invention in such a way that the kaolin paper type is on one external surface of the assembly [Pl-

Examples and counter examples of the invention.

[0045] The invention will now be described with some examples but one should understand that the examples here below are by no way to be considered as a limitation of our invention.

[0046] Some tests involving different loading for glass transport on different distances have allowed to demonstrate weaknesses and advantages of the protection systems that may be used while transporting sensitive coated glass sheets. A summary of those preliminary tests are presented in the table 3 here after.

[0047] On a short distance (150 km), cardboard alone only results in cleanable deposition marks but normal cleaning is not sufficient and performing a mechanical cleaning is costly and rises a risk for the coating.

[0048] Problems increase when distance increases. It has been observed that the closer to the stillage the coating was, the stronger marks and traces were.

[0049] From the table below, only examples of the references 8 and 9 are examples of the invention and as can be seen, results after transportation were only correct when a glass cover sheet (example 1) or an assembly [P] conform to the invention (examples 8 and 9) were used.

[0050] Table 3. Examples

[0051] As a conclusion, cardboard assembly covered with kaolin paper type is a good alternative to the heavy glass cover sheet since no scratches nor traces (material transferred from the cardboard to the coating) are observed.

Claims

Claim 1. Arrangement for transporting at least one coated glass sheet on a stillage, characterized in that the coated surface of each coated glass sheet placed on the stillage is contacting either an uncoated surface of another glass sheet or a kaolin paper type side of an assembly [P],

Claim 2. The arrangement of claim 1 wherein the assembly [P] comprises at least two composite cardboard parts ([A] and [B]) sandwiching a corrugated cardboard [C] and the composite cardboard part [A] being covered with a kaolin paper type.

Claim 3. Said kaolin paper type of claim 1 is any paper characterized by a Beck smoothness, expressed in second and measured following the ISO Norm 5627 which is at most 38 sec, preferably at most 30 sec and more preferably at most 27 sec.

Claim 4. Said kaolin paper type of claim 1 is any paper characterized by a pH comprised between 6.0 and 7.4, preferably 6.4 and 7.2 and more preferably 6.5 to 7.0.

Claim 5. The composite cardboard [A] of claim 1 has a substance comprised between 270 and 650 g/m2, preferably between 300 and 620 g/m2 and more preferably between 350 and 600 g/m2.

Claim 6. The composite cardboard [A] of claim 1 has a thickness comprised between 300 and 1000 pm, preferably between 385 and 900 pm and more preferably between 450 and 850 pm.

Claim 7. The arrangement of claim 1 wherein at least three edges of the assembly [P] are rounded on the kaolin paper type side.

Claim 8. The arrangement of claim 1 where at least one coated glass sheet is monolithic.

Claim 9. The arrangement of claim 1 where at least one coated glass sheet is part of a laminated glazing.

Claim 10. The arrangement of claim 1 where at least one coated glass sheet contacting a kaolin paper type is a PVD coated glass sheet.

Claim 11. The arrangement of claim 11 where the at least one PVD coated glass sheet has a low-e PVD coating.