GB1600616A - Coating sheet material with liquids - Google Patents

Coating sheet material with liquids Download PDF

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Publication number
GB1600616A
GB1600616A GB4667977A GB4667977A GB1600616A GB 1600616 A GB1600616 A GB 1600616A GB 4667977 A GB4667977 A GB 4667977A GB 4667977 A GB4667977 A GB 4667977A GB 1600616 A GB1600616 A GB 1600616A
Authority
GB
United Kingdom
Prior art keywords
roll
coating
applicator roll
sheet material
reservoir
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB4667977A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Balfour Beatty PLC
Original Assignee
BICC PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BICC PLC filed Critical BICC PLC
Priority to GB4667977A priority Critical patent/GB1600616A/en
Publication of GB1600616A publication Critical patent/GB1600616A/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05C1/00—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating
    • B05C1/02—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to separate articles
    • B05C1/025—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to separate articles to flat rectangular articles, e.g. flat sheets
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/16—Coating processes; Apparatus therefor

Description

(54) COATING SHEET MATERIAL WITH LIQUIDS (71) We, BICC LIMITED, a British Company, of 21 Bloomsbury Street, London WClB 3QN, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus for coating sheet material with liquids, and especially (but not exclusively) to apparatus for coating discrete sheets of thin flexible metal. An important application is in the application of ight-sensitive coatings to thin metal printing plates. It also relates to coating methods.
Current practice is to use for this application a roll-coater in which the plates are carried by a conveyor through a coating station at which the conveyor is supported by a backing roll while the coating is applied by a grooved or smooth rubber applicator roll supplied with coating material by a transfer roll dipping in a tank containing a supply of the material. With this type of apparatus it is difficult to coat the thinner plates, and moreover the apparatus is restricted to a coating speed of about 0.1 m/s.
For general purpose coating (e.g. for lacquering sheet for the production of cans) higher speeds have been achieved by the use of machines with smooth rubber applicator rolls, but these known machines are unsuitable for coating printing plates because imperfections in the rubber are reflected in the coating and edge effects result in uneven coatings if the substrate consists of discrete sheets.
In accordance with the invention, apparatus for uniformly coating the whole surface of sheet material comprises: an applicator roll of rubber or other resilient material; a rigid backing roll; separate conveyor means for feeding the sheet material into a nip formed between the applicator roll and backing roll, both of which rolls will directly contact respective sides of the sheet material, and for receiving it from the nip; a reservoir for coating material; and means for transferring coating material from the reservoir to the applicator roll; the applicator roll having a textured surface and the apparatus including drive means capable of operating it to advance the sheet material at (but not necessarily only at) a speed in the range 0.2 - 0.5 m/s to give a uniform smooth coating. In many cases a higher speed, possibly up to about 2 m/s, can be achieved.
By a textured surface is meant a surface that is not smooth but is formed with one or more than one projection and/or one or more than one recess distributed over its surface so that the highest parts of the surface can contact the substrate surface and yet leave a substantial amount of the coating material between the substrate and the roll surface. The surface texture of the roll will normally need to be uniform on a large scale, but on a small scale, (determined by the flow properties of the coating material) it may patterned or randomly nonuniform.
Preferably the texture is formed by a fine groove or grooves engraved in the surface of the roll. A single groove extending helically with a short pitch is convenient, but annular or other grooves can be used. Longitudinal grooves are of relatively little value by themselves, but may be useful in conjunction with a groove or grooves extending in another direction. Preferably the roll surface is ground prior to grooving.
The applicator roll may be made of any resilient (rubbery) material that resists the particular coating material; the optimum texture will depend on the particular material. Synthetic rubbers, such as styrenebutadiene rubbers, are very suitable.
The preferred means for transferring coating material from the reservoir to the applicator roll is a transfer roll dipping in the reservoir and rolling on the applicator roll (or on an intermediate transfer roll that does so) but other means can be used such as a doctor blade so positioned on the applicator roll as to form with it a receptacle and means for pumping coating material from the reservoir to the receptacle.
Preferably the apparatus includes a scraper blade for keeping the backing roll free of any substantial amount of coating material.
The apparatus of the invention is capable, under suitable conditions, of applying uniform coatings from side to side and end to end of each discrete sheet, and also coats effectively on continuous web material. The weight of the coating can be finely controlled by varying the texture (e.g. the groove depth). It is much less susceptible to flooding than apparatus with smooth rubber rolls.
The invention will be further described, by way of example, with reference to the accompanying drawing in which: Figure 1 Is a diagram of apparatus in accordance with the invention, and Figure 2 is an enlarged profile of a groove in a roller in the apparatus of Figure 1.
The apparatus shown in Figure 1 is designed for the manufacture of presensitised metal printing plates. A succession of pre-cut metal blanks 1 are advanced by any suitable type of conveyor 2 and pass through a nip formed directly between an applicator roll 3 and a backing roll 4 from which a further conveyor 5 carries them to drying apparatus (not shown).
The applicator roll 3 has a jacket 6 of synthetic rubber, the surface of which is ground and then lathe cut with a shaped stone to form a helical groove of the profile shown in Figure 2. A liquid photoresist is taken from a reservoir 7 by a transfer roll 8 dipping in it, reduced to an even film on the transfer roll by a smoothing roll 9, and applied by the transfer roll 9 to the applicator roll 3. Scraper blades 10, 10 remove any photoresist from the backing roll 4 to prevent any substantial contamination of the underside of the blanks, which would otherwise risk build-up of stale photoresist on the conveyor 5. Rolls 3, 4, 8, 9 are all driven without slip between them.
In a specific example, the applicator roll jacket is of a styrene-butadiene rubber with a Shore A hardness of 45 ; its diameter is 445 mm and it has a single helical groove of the profile shown in Figure 2 with a depth d of 0.125 mm, included angle a 117C and pitch p of 0.50 mm.
This apparatus is suitable for coating at 0.25 mls a photoresist with a viscosity of 10 cP and a solids content of 15% onto printing plates of aluminium, chromium plated steel, or other metal 0.3 mm thick and about 900 mm long by 500 mm wide, to give a uniform coating after removal of solvent about 1 micrometre thick. If a ground smooth rubber roll is substituted for the grooved applicator roll poor coverage results and a maximum dry coating thickness of only 0.3 micrometres can be achieved; there is considerable pattern on the coated sheet resulting from imperfections in the rubber; and the leading edge of the coated plate is very poorly coated and has a margin about 20 mm wide that is unacceptably thickly coated.
WHAT WE CLAIM IS: 1. Apparatus for uniformly coating the whole area of sheet material comprising: an applicator roll of rubber of other resilient material; a rigid backing roll; separate conveyor means or feeding the sheet material into a nip formed between the applicator roll and backing roll, both of which rolls will directly contact sides of the respective sides of the sheet material, and for receiving it from the nip; a reservoir for coating material; and means for transferring coating material from the reservoir to the applicator roll; the applicator roll having a textured surface and the apparatus including drive means capable of operating it to advance the sheet material at a speed in the range 0.2 0.5 m/s to give a uniform smooth coating.
2. Apparatus for uniformly coating the whole area of sheet material comprising: an applicator roll of rubber or other resilient material; a rigid backing roll; separate conveyor means for feeding the sheet material into a nip formed between the applicator roll and backing roll, both of which rolls directly contact respective sides of the sheet material, and for receiving it from the nip; a reservoir for coating material; and means for transferring coating material from the reservoir to the applicator roll; the applicator roll having a surface textured by a fine groove or grooves engraved in the surface of the roll and the apparatus including drive means capable of operating it to advance the sheet material at a speed in the range 0.2 - 0.5 m/s to give a uniform smooth coating.
3. Apparatus as claimed in claim 2 in which the groove is textured by a single fine groove extending helically with a short pitch.
4. Apparatus as claimed in claim 2 or claim 3 in which the surface of the roll was ground prior to grooving.
5. Apparatus as claimed in any one of the preceding claims in which the means for transferring coating materials from the reservoir to the applicator roll is a transfer roll dipping in the reservoir and rolling on the applicator roll or on an intermediate roll that rolls on the applicator roll.
6. Apparatus as claimed in any one of claims 14 in which the means for transferring coating material from the reservoir to the applicator roll comprises a doctor blade so positioned on the applicator roll as to form with it a receptacle and means for pumping coating material from the reservoir to the receptacle.
7. Apparatus as claimed in any one of claim 1-6 including a scraper blade for keeping the backing roll free of any substantial
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (19)

**WARNING** start of CLMS field may overlap end of DESC **. free of any substantial amount of coating material. The apparatus of the invention is capable, under suitable conditions, of applying uniform coatings from side to side and end to end of each discrete sheet, and also coats effectively on continuous web material. The weight of the coating can be finely controlled by varying the texture (e.g. the groove depth). It is much less susceptible to flooding than apparatus with smooth rubber rolls. The invention will be further described, by way of example, with reference to the accompanying drawing in which: Figure 1 Is a diagram of apparatus in accordance with the invention, and Figure 2 is an enlarged profile of a groove in a roller in the apparatus of Figure 1. The apparatus shown in Figure 1 is designed for the manufacture of presensitised metal printing plates. A succession of pre-cut metal blanks 1 are advanced by any suitable type of conveyor 2 and pass through a nip formed directly between an applicator roll 3 and a backing roll 4 from which a further conveyor 5 carries them to drying apparatus (not shown). The applicator roll 3 has a jacket 6 of synthetic rubber, the surface of which is ground and then lathe cut with a shaped stone to form a helical groove of the profile shown in Figure 2. A liquid photoresist is taken from a reservoir 7 by a transfer roll 8 dipping in it, reduced to an even film on the transfer roll by a smoothing roll 9, and applied by the transfer roll 9 to the applicator roll 3. Scraper blades 10, 10 remove any photoresist from the backing roll 4 to prevent any substantial contamination of the underside of the blanks, which would otherwise risk build-up of stale photoresist on the conveyor 5. Rolls 3, 4, 8, 9 are all driven without slip between them. In a specific example, the applicator roll jacket is of a styrene-butadiene rubber with a Shore A hardness of 45 ; its diameter is 445 mm and it has a single helical groove of the profile shown in Figure 2 with a depth d of 0.125 mm, included angle a 117C and pitch p of 0.50 mm. This apparatus is suitable for coating at 0.25 mls a photoresist with a viscosity of 10 cP and a solids content of 15% onto printing plates of aluminium, chromium plated steel, or other metal 0.3 mm thick and about 900 mm long by 500 mm wide, to give a uniform coating after removal of solvent about 1 micrometre thick. If a ground smooth rubber roll is substituted for the grooved applicator roll poor coverage results and a maximum dry coating thickness of only 0.3 micrometres can be achieved; there is considerable pattern on the coated sheet resulting from imperfections in the rubber; and the leading edge of the coated plate is very poorly coated and has a margin about 20 mm wide that is unacceptably thickly coated. WHAT WE CLAIM IS:
1. Apparatus for uniformly coating the whole area of sheet material comprising: an applicator roll of rubber of other resilient material; a rigid backing roll; separate conveyor means or feeding the sheet material into a nip formed between the applicator roll and backing roll, both of which rolls will directly contact sides of the respective sides of the sheet material, and for receiving it from the nip; a reservoir for coating material; and means for transferring coating material from the reservoir to the applicator roll; the applicator roll having a textured surface and the apparatus including drive means capable of operating it to advance the sheet material at a speed in the range 0.2 0.5 m/s to give a uniform smooth coating.
2. Apparatus for uniformly coating the whole area of sheet material comprising: an applicator roll of rubber or other resilient material; a rigid backing roll; separate conveyor means for feeding the sheet material into a nip formed between the applicator roll and backing roll, both of which rolls directly contact respective sides of the sheet material, and for receiving it from the nip; a reservoir for coating material; and means for transferring coating material from the reservoir to the applicator roll; the applicator roll having a surface textured by a fine groove or grooves engraved in the surface of the roll and the apparatus including drive means capable of operating it to advance the sheet material at a speed in the range 0.2 - 0.5 m/s to give a uniform smooth coating.
3. Apparatus as claimed in claim 2 in which the groove is textured by a single fine groove extending helically with a short pitch.
4. Apparatus as claimed in claim 2 or claim 3 in which the surface of the roll was ground prior to grooving.
5. Apparatus as claimed in any one of the preceding claims in which the means for transferring coating materials from the reservoir to the applicator roll is a transfer roll dipping in the reservoir and rolling on the applicator roll or on an intermediate roll that rolls on the applicator roll.
6. Apparatus as claimed in any one of claims 14 in which the means for transferring coating material from the reservoir to the applicator roll comprises a doctor blade so positioned on the applicator roll as to form with it a receptacle and means for pumping coating material from the reservoir to the receptacle.
7. Apparatus as claimed in any one of claim 1-6 including a scraper blade for keeping the backing roll free of any substantial
amount of coating material.
8. Apparatus as claimed in any one of claims 1-7 in which the applicator roll has a surface of synthetic rubber.
9. Apparatus as claimed in any one of claims 1-8 in which the applicator roll has a surface of styrene-butadiene rubber.
10. Apparatus for coating a succession of metal sheets substantially as described with reference to and as shown in Figure 1.
11. Apparatus for coating a succession of metal sheets substantially as described with reference to and as shown in Figures 1 and 2.
12. Apparatus for coating metal blanks to make presensitised printing plates substantially as described with reference to the drawings and the specific example.
13. A method of uniformly coating the whole area of sheet material to give a uniform smooth coating, comprising feeding the sheet material at a speed in the range from 0.2 up to 2 m/s into a nip formed between an applicator roll of rubber or other resilient material having textured surface and a rigid backing roll, both of which rolls directly contact respective sides of the sheet material, receiving it from the nip, and transferring coating material from a reservoir to the applicator roll.
14. A method of uniformly coating the whole area of discrete sheets to give a uniform smooth coating, comprising feeding the sheets in succession at a speed in the range from 0.2 up to 2 m/s into a nip formed between an applicator roll of rubber or other resilient material having textured surface and a rigid backing roll, both of which rolls directly contact respective sides of the sheet material, receiving them from the nip, and transferring coating material from a reservoir to the applicator roll.
15. A method of making presensitised metal printing plates comprising feeding a succession of metal blanks at a speed in the range from 0.2 up to 2 m/s into a nip formed between an applicator roll of rubber or other resilient material having a textured surface and a rigid backing roll, both of which rolls directly contact respective sides of the sheet material, receiving them from the nip, and transferring a liquid photoresist from a reservoir to the applicator roll, thereby applying a uniform coating of the photoresist to the whole area of each blank.
16. a method as claimed in any one of claims 13-15 in which the said speed is in the range from 0.2 up to 0.5 m/s.
17. The use in the method of claim 13 or claim 14 or claim 15 of the apparatus claimed in any one of claims 1-12.
18. Sheet material coated by the apparatus claimed in any one of claims 1-12 or by the method claimed in any one of claims 13-17.
19. A presensitised metal printing plate made by the apparatus claimed in any one of claims 1-12 or the method claimed in any one of claims 13-17.
GB4667977A 1978-05-26 1978-05-26 Coating sheet material with liquids Expired GB1600616A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB4667977A GB1600616A (en) 1978-05-26 1978-05-26 Coating sheet material with liquids

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4667977A GB1600616A (en) 1978-05-26 1978-05-26 Coating sheet material with liquids

Publications (1)

Publication Number Publication Date
GB1600616A true GB1600616A (en) 1981-10-21

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB4667977A Expired GB1600616A (en) 1978-05-26 1978-05-26 Coating sheet material with liquids

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2226574A1 (en) * 2003-09-02 2005-03-16 Gfk-Garment Finish Kay, S.L. Method for the controlled decoration of ready-made clothing, clothing thus obtained and machine required to implement said method
EP2882540A1 (en) * 2012-08-09 2015-06-17 DSM IP Assets B.V. Roll coating process and apparatus

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2226574A1 (en) * 2003-09-02 2005-03-16 Gfk-Garment Finish Kay, S.L. Method for the controlled decoration of ready-made clothing, clothing thus obtained and machine required to implement said method
EP2882540A1 (en) * 2012-08-09 2015-06-17 DSM IP Assets B.V. Roll coating process and apparatus
EP2882540B1 (en) * 2012-08-09 2017-12-27 DSM IP Assets B.V. Roll coating process
US9868130B2 (en) 2012-08-09 2018-01-16 Dsm Ip Assets B.V. Roll coating process and apparatus

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Legal Events

Date Code Title Description
PS Patent sealed
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PE20 Patent expired after termination of 20 years

Effective date: 19980525