CA1095332A - Smash-recoverable printing blanket and method of making same - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A smash-recoverable printing blanket having a substantially uni-form thickness and method of making the same are provided. The blanket comprises a plurality of layers including at least one layer which swells upon being contacted by a liquid. A plurality of microcapsules are dis-posed within the blanket, with the microcapsules containing the liquid.
The microcapsules are ruptured upon smashing the blanket. This releases the liquid contained therewithin against the one layer thereby causing swelling thereof and restoring of the adjacent layer substantially to its original position prior to the smashing, in order to define the uniform thickness. Thus, when the blanket is subjected to excessive compression or shashing, it is self-recovering. In other words, the construction of the blanket is such that it restores itself to its original thickness, without stopping or removing the damaged blanket or stopping the associated printing apparatus or press.

Description

~ 53~

This invent:Lon relates to a printing blanket which is self re-covering after smashing thereof and to a methocl o~ maklng such a blanket.
Printing blankets comprised of a plurality of laminated layers are in wide use throughout industry and are often used in offset llthography ~here the usual Eunction of such a blanket is to transfer printing ink from a printing plate to paper being printed. During the course oE using such a printing blanket in offset l;thography the blanket may be subjected to large compressive forces or smashing. Such smashing is defined as a de-formation of the blanket which causes a substantially permanent reduction in its thickness or gauge. The smashing of such a blanket results in an in-stant deterioration in the quality of the printing and this is due to the fact that the smashed area of the blanket will not transfer printing ink from the plate to the paper in a satisfactory manner.
The usual way of solving the problem of a smashed blanket is to remove such blanket and replace it with a new one. However, there are some instances where it can be determined by inspection that the blanket is not seriously dar~ged and it is possible to restore the smashed area by swel-ling layers ad~oining the smashed area using a suitable solvent. With either of these solutions, it is necessary to stop the printing press and remove the damaged blanket alld this results in substantial material losses but more importantly results in loss of valuable press time.
Printing blankets have been proposed heretofore where efforts have been made to make them sufficiently ~ .

. : .: . :. , :: . : : :

~ S33~
compressible -tha-t -they are no-t d.l~maged by modera-te compressive forces. Further, printing blanke-ts of lamina-ted construc-tion have been proposed tha-t are smash resistarlt.
Elowever, the clesired op-timum si-tua-tion would be -to provide a prin-ting blanke-t and method of making such a blanket which when subjec-ted to excessive compression or smashing is self-recovering, i.e., -the construction of such a blanket is that i-t res-tores i-tsel~ to i-ts original thickness, wi-thou-t stopping and removing -the dar.laged blanke-t or stopping the associa-ted printing appara-tus or press.

Accordingly, i-t is an objec-t of one broad aspect of this invention to provide a smash-recoverable prin-ting blanke~t, i.e., one that is self-recovering af-ter smashing and a method of making such a blanket.
It is an objec-t of another aspec-t of -this inven-tion to provide a simple and economical prin-ting blanke-t par-ticularly adapted to be used in offse-t printing, or the like, which is self-recovering after smashing or excessive compression thereof.
An object of another aspec-t of this invention is -to provide a me-thod of making such a blanket that is self-recovering af-ter smashing.
An object of s-till ano-ther aspec-t of -this inven-tion is the provision of a method of automa-tically restoring -the original -thickness or gauge of a mul-tiple-layer prin-ting blanket.
An object of yet another aspec-t of -this inven-tion is to provide a blanket having a plurali-ty of layers including at least one layer which is adap-ted to expand or swell upon being contac-ted by a liquid and providing con-tainer means wi-th:in -the blanket containing such liquid which are adapted -to release the liquid -~o upon smashing causing swelling and thus restoration of adjacent : ~

. .
.. . . ., , ;
, . j-~. .. .
. : : ,. :
,, .
. ~

i;3~,~

layers and the entlre blanket substantially to its original thickness or gauge.
An ob~ect of still another aspect of this invention i8 to provlde a smash-recoverable printing blanket which has a substantial]y ~miform thickness and has a plurality of layers one or more of which are adapted to be expanded or swollen upon being contacted by liquid means disposed within the blanket with the liquid means being relQased during smashing of the blanket.
An ob~ect of yet another aspect of this invention is to provide a smash-recoverable multiple layer printing blanket having at least one elas-tomeric layer and self acting maans within the blanket for expanding or swelling such elastomeric layer after smashing.
An object of a still further aspect of this invehtion is ,to pro-vide a smash-recoverable multiple layer printing blanket having at least one fabric layer and having self actlng means within the blanket for expanding or swelling such fabric layer thereof after smashing.
According to one broad aspect of this invention, a smash-recovera-ble printing blanket i8 provided having a substantially uniform thickness, the blanket comprising, a plurality of layers including at least one layer which swells upon being contacted by a liquid, and a plurality of micro~ap-sules disposed within the blanket 9 with the microcapsules containing the liquid, the microcapsules being ruptured upon smashing the blanket, thereby to release the liquid contained therawithin against the one layer causing swelling thereof and restoring the adjacent layers substantially to their original positions prior to the smashing, and thereby to define the uniform thickness.
By variants thereof, the microcapsules may be randonly disposed within the ~ne layer , or they may be provided as a thickness thereof ad-~acent the on layer.

,.. .: . .. , . :

: . : .-~ ., ::

i;3~1~
By another varlant, the plurality of layers includes at least another layer which also swells upon bPing con~acted by thc liquid, and the mlcrocapsules are provided as a thickness thereof sandwiched between and against facing surfaces of the one and the other :Layers.
By variations thereof, that one layer may be a fabrlc layer; or it may be an elastomeric layer; or it may be a layer of rubber which swells upon being contacted by a liquid organic solvent and in which the micro-capsules contain that liquid organic solvent; or it may be disposed closely adJacent the bottom layer of the blanket and in which the bottom layer is woven fabric layer.
By another variant, the plurality of layers comprises a facing layer made of a compressible elastomeric material.
By another aspect of this invention, a smash-recoverable printing blanket is provided having a substantially uniform thickness, the blanket comprising, a plurality of layers including a first laycr which swells.upon being contactcd by a first liquid, a plurality of microcapsules provided as a thickness thereof ad~oining the first layer with the microcapsules con-taining the first liquid, a second layer which also swells upon being con-tacted by a second liquid, a plurality of microcapsules disposed a9 a second thickness thereof ad~oining the second layer, with those microcapsules con-taining the second liquid, the microcapsules being ruptured upon smashing of the blanket, thereby to release the liquids contain~d therein against their adjoining layer causing swalling thereof and restoring of adjacent layers substantially to their original positions prior to the smashing and thus to deflne the uniform thickness.
By yet another aspect of thls invention a method is provided for making a smash-recoverable printing blanket having a substantially uniform thickness, thc method ~including the steps of laminating a plurality Qf ~q*~ layers of blanket material includlng at lease one layer which swells upon being contacted by a liquid, and disposing a plurality of microcapsules con-- 4a~-.,", , i: ,- `
: :: .
;., , ::

taining that liquid within the bl.anket closely ad~acent the one layer, the microcapsules being ruptured upon smashlng the blanket, ~hereby tG release the liquid contained therewithin against the one layer causing swelling thereof and rcstoring of adjacent layers substantially to their original posltions prior to the smashing, thus to defirle the uniform thickness.
By variants thereoE, the disposing step may comprise disposing the microcapsules in the one layer and in a random manner; or disposing the microcapsules as a thic~ness thereof adjacent one layeri or disposing the microcapsules having different sizes~
In the accompanying drawings FIG. 1 is a fragmentary cross-sectional view illustrating one exemplary embodiment of a smash-recoverable printing blanket of one aspect of this invention;
FIG. 2 is a view similar to FIG. 1 illustrating such blanket being subjected to smashing forces;
FIG 3 is a fragmentary cross-sectional view illustrating the manner in which a portion of the blanket has self recovered by expanding substantially to its original thickness; .-FIG. 4 is a view similar to the left half portion of FIG. 2 illus-trating another exemplary embodiment of the blanket of another a~pect ofthis invention being sub~ected to smash;
FIG. 5 is a fragmentary view illustrating the self-recovered blanket of FIG. 4;
FIG. 6 is a view similar to FIG. 4 illustrating another exemplary embodiment of the blanket of yet another aspect of this invention;
FIG. 7 ls a view similar to FI&. S illustrating the self-recovered blanket of FIG. 6;
FIG. 8 is a view illustrating another exemplary embodiment of the ~ blanket of still another aspect of this invention prior to smashing thereof;
and ~, ;,; ;, ~ " --: : ~ , ~

.

i33 Z

FIG, 9 is a viaw ~s:Lmilar to FIG. 5 ill~lstrating the self-recov~red blanket o FIG. 8.

`~'` 1 ,~c~

- 5 a -,. ... . . .

: i : ~ . , . ~, , ., , ~ , i33~

ReEerence is now made to FIG. l of the drawings which lllus-trates one exemplary embodiment oE a smLlsh-recoverable pr:intlng blanket of olle aspect of this invention, i.e., a printing blanket which is self recovering after excessive compressioD or smashing thereof. Such blanket is designated generally by the reference numeral 20 and has a substantially unifor~ thicl;ness or gau~e indicated at 21. The blanket 20 is particularly adapted to be used in offset lithographic prlnting although such blanket may be used in other applications. Such blanket is, in essence, self re~
pairing or self recovering and such blanket has integral mealls to be de-lQ scribed in detail subsequently which operates independently and withoutthe attention of an operator of a printing apparatus to assure that the blanket maintains the substantially uniform thickness 21 after being s~lb-Jected to excessive compression or smashing.
The blanket 20 is comprised of a plurality of layers 22, 23, 24, 25, and 26 which are suitably laminated as a ~mitary structure utilizing any technique known in the art. In this example, the layer 22 is in the form of a face layer made of a suitable elastomeric material such as a rubber material of the type com~only used to make offset printing blankets while the layers 23, 24, and 26 are in the form of fabric layers with the layer 26 being the bottom layer or bottom ply of the blan~et 20. The blanket 20 has at least one layer which is adapted to swell upon being contacted by a liquid. In this example such layer is shown as the layer 25 and the s-~el-ling of the layer 25 will be described in detail subsequently.

.. ~ . .............. . .
~, The blanket 20 has a plurality of microcapsules 30 which are dis-posed within the blanket 20. In this example of an aspect oE this inverl-tion such microcapsules 30 are randomly dlsposecl within the layer 25 and contain a liquid 31 which is particularly adapted to cause swelling of the layer 25 and in particular the main matrix portion 32 of such layer once the liquid 31 i9 released from the microcapsules 30 ancl comes into contact with the matrix portion 32 of the layer 25.
The microcapsules 30 are, in essence, miniature containers each having a rupturable or severable outer housing or shell which contains the liquid 31 therewithin. Once -the blanket 20 is subjected to excessive compression or smash as indicated by the force arrows 33 in FIG. 2 of the drawings, the microcapsules 30 which are sub~ected to the excessive com-pressive or smashing forces 33 are ruptured as indicated at 34 in FIG. 2 releasing the liquid 31 therewithin. The released liquid 31 acts upon and causes swelling of its layer 25 and in particular of the matrix portion 32 of such layer 25 with the swelling being indicated at 36 oausing restora-tion of the sdjacent layers of the blanket 2Q substantially to the posi-tions they occupied prior to smashing and restoring the blanket so that it has its original substantially uniform thickness 21.
Other exemplary embodiments of the smash-recoverable printing blanket of other aspects of this invention are illustrated in FiGS. 4-5 ?
6-7. and 8-9 of the drawings. The blanke~s illustrated in FIGS. 4-5, 6-7, and 8-9 are very similar to the blanket 20; therefore~ such blankets will be designated by the reference numerals 20A, 20B, and 20C respectively and representative . .:: :
,~ . :. . :: . --~5332 parts of each blanket wh:Lch are similar to corresponding parts of the blanket 20will be deslgnated in the drawings by the same reEerence nurllerals as in the blanket 20 (whether or not such representative parts are mentLoned in the specification) followed by the letter designation A, B, or C and not described again in detail. ONly those CO~ )onent parts of each blanket 20 will be designated by a new reference numera]. also followed by an associa-ted letter designation and described in detai.l.
The blanket 20A of FIG. 4 has an e].astom2ric face layer 22A, a bottom fabric layer 26A, and fabric layers 23A and 24A disposed between the face layer 22A and the bottom layer 26A. However, it will be seen that the blanket 20A has a ~hickness or coating 37A of microcapsules 30A
adjacent one of the layers and in particular the microcapsules 30A are sandwiched between and against facing surfaces 40A and 41A of the layers 24A and 26A resepctively.
Each of the microcapsules 30A has liquid 31A disposed there-within. Such liquid is such that it causes swelli~g of both layers 24A
and 26A as shown at 42A and 43A in FIG. 5 for the 'layers 24A and 26A
respectively thereby restoring the blanket 20A to ~ts original thickness 21A. The fabric layers 2b~A and 26A are preEerably made of the same material and each of such layers swel.ls in a simil.-r manne:r upon being con-tacted by the liquid 31A forcing adjacent layers o~_twardly away therefrom to restore the blanket 20A to its original thicknec:s 2~A in a similar man-ner as described in connection with the blanket 20_ The blanket 20B of FIGS. 6 and 7 is also comprised - : : ::

533;i~
of a plurality of layers in the form o~ a face layer 22B~ a botto~ fabric layer 26B and a fabric layer 23B ad~oining the face layer 22B. However, instead oE having a fabric layer adjoining the Eabric layer 23B, the blan-ket 20B has an elastomeric layer in the form of a rubber layer 4~1B suitably laminated against the bottom surface of the layer 23B and the layer 44B
has a thickness, layer~ or coating 45B comprised of a plurality of n~cro-capsules 46B each containing a suitable organic solvent 47B within its outer shell. The organic solvent 47B is such that it will cause swelling of the elastomeric layer 44B upon COmin& into contact therewith.
Thus, once the blanket 20B is subjected to compressive or smash-ing forces 33B the microcapsules ~6B are ruptured releasing the organic sol-vent 47B from therewithin causing such organic solvent to come in contact with the bottom portion of the elastomeric rubber layer 44B. The organic solvent 47B acts upon the rubber in layer 44B causing swelling thereof and causing restoration of the adiacent layers substantially to their original position prior to the smashing, thereby to define the uniform thickness 21B.
The blanket 20C of FIGS. 8 and 9 has a plurality of suitably laminated layers which in viewing the blanket in cross-section from top to bottom comprise an elastomeric face layer in the form of a rubber layer 22C, a fabric layer 23C, an elastomeric layer in the form of a rubber layer 50C, and a thickness, layer, o~ coating 51C of microcapsules 46C each con-taining an organic solvent 47C which is particularly adapted to cause swel-ling of the elastomeric layer 50~ upon coming into cOntaCt therewith. The blanket 20C also comprises ,: : ' . . .: -,., :; .

~g~i33~
a fabric layer 24C adjo:ined by a layer or thickness o;E microcapsules 30C
ccntaining a liquid 31C and such blanket 20C has a bottom ply or layer 26C.
The liquid 31C contained in the microcapsules 30C Ls particularly adapted to cause swelling of one or both of the layers 24C and 26C essentially as shown at 53C in FIG. 9.
ThllS, upon subjecting the blanket 20C to compressive or smashing forces the microcapsules 46C are ruptured releasing solvent 47C which causes swelling of the elastomeric rubber layer 50C and simultaneously the microcapsules 30C are ruptured releasing liquid 31C which comes into contact with ~he layers 24C and 26C causing swelling thereof~ The swelling action produced by the released liquid from the two coatings or thicknesses of ruptured microcapsules causes swelling of the layers associated there-with, thereby to cause restoration of such layers substantially to their original positions prior to the smashing and thereby restore the blanket 20C to its substantially ~miform thickness 21C.
The liquid contained in each of the microcapsules 30, 30A, and 30C may be any suitable liquid which produces swelling or expansion of the -fabric layers with which such liquid comes into contact. Similarly, the organic solvent contained in the microcapsules 46B and 46C may be any suitable organic solvent which produces or causes swelling of the rubber layers with whlch such organic solvent comes into contact once the micro-capsules are ruptured.
The face layers 22, 22A, 22B, and 22C of thc blankets 20, 20A, 20B, and 20C respectively may be made of any suitable elastomeric material known in the art for this purpose. In .

;: :, . :
: ; : . ~ .

~ 135332 this example of an aspect of this invention each exemplary blanket is shown with lts face layer made of rubber. It wlll also be appraciated that eacll of the various fabric layers illustrated in connection with the various embodiments of this inven~ion may also be made of any suitable material. Similarly, the elastomeric layers in the form of rubber layers 44B and 50C may be made of any suitable rubber compound or synthetic plastic material. In addition, each of these rubber layers may be reinforced with suitable reinforcing members, stiffenlng fibers, or other suitable means employed in the art for reinforcing purposes.
The microcapsules 30, 30A~ and 30C may be of any suitable si~e and indeed such microcapsules when used in connection with wo~en fabric layers made of conventional natural non-metallic yarn such as cotton, or the like, may be filled with water or a water solution. F~lrther~ the sizes of the microcapsules may be of various sizes within an acceptable range.
For example, such microcapsules 30, 30A and 30C may be in the form of spheres having an outside diameter ranging between 20 and 200 microns.
It will also be appreciated that the microcapsules 46B and 46C
may contain any suitable organic solvent capable of producing swelling of an associated elastomeric ro rubber layer used in a printing blanket and examples of organic solvent which may be used are toluene and buphenyl which are shown to be especially useful in producing expansion or swelling ~-of all types of rubber including though not being limited to natural, neoprene, nitrile, pol~sulfide, butyl, and similar rubbers. It will also be appreciated that the microcapsule~ 46B and 46C may also be in the form of spheres :~

:

53~32 '.

and may range in ~liameter be~ween 20 and 200 microns.
The microcapsules have outer shells which may ,j be made of any suitable po]ymer material used in the process or microencapsulation.
Microcapsules filled with toluene are manufactured and sold by 3M Company, 3M Center, St. Paul, Minnesota 55101.
Microcapsules con-taining aromatic hydrocarbons may also be used and have outer shells made of nitrocellulose.
¦ Water-containing capsules may have a shell material made o~ a suitable vinyl resin. An example of such a vinyl ~ ~:
resin is sold under the registered trademark Elvax 40 by the E. I. DuPont de Nemours and Co., Inc. of Wilmington, Delaware.
Both the water~containing and or~anic-solvent ¦ containing microcapsules may be additionally coated using only suitable process in order to obtain desired properties, e.g , - increased breaking strength as well as solvent and heat resistance.
~ Poly-chloro-p-xylene has been used successfully as ¦ a coatin~ for a variety of microcapsules by the Union Carbîde Corporation, Chemicals and Plastics, 270 Park Ave., New York, ¦ New York, 10017, in a so~called vapor-deposition process.
¦ It will be appreciated that regardless of the I liquid employed in the microca~sules, microcapsules having a broad size range are preferably employed. With microcapsules of different sizes it will be appreciated that the larger microcapsules can be ruptured or severed with lower pressures j than the smaller ones.

! 1?-:~, : . :-:- , .: :

Claims (14)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A smash-recoverable printing blanket having a substantially uniform thickness, said blanket comprising: a plurality of layers including at lease one layer which swells upon being contacted by a liquid; and a plurality of microcapsules disposed within said blanket with said micro-capsules containing said liquid; said microcapsules being ruptured upon smashing said blanket, thereby to release said liquid contained therewithin against said one layer causing swelling thereof, and restoring said adjacent layers substantially to their original positions prior to said smashing, and to define said uniform thickness.

2. A blanket as set forth in claim 1 in which said microcapsules are randomly disposed within said one layer.

3. A blanket as set forth in claim 1 in which said microcapsules are provided as a thickness thereof adjacent said one layer.

4. A blanket as set forth in claim 1 in which said plurality of layers includes at least another layer adapted which swells upon being con-tacted by said liquid; and wherein said microcapsules are provided as a thickness thereof sandwiched between, and against facing surfaces of, said one and said other layer.

5. A blanket as set forth in claim 3 in which said one layer is a fabric.

6. A blanket as set forth in claim 3 in which said one layer is an elastomeric layer.

7. A blanket as set forth in claim 3 in which said one layer is a layer of rubber which swells upon being contacted by said liquid in the form of an organic solvent; and wherein said microcapsules contain said or-ganic solvent.

8. A blanket as set forth in claim 1 in which said one layer is disposed closely adjacent the bottom layer of said blanket; and wherein said bottom layer is a woven fabric layer.

9. A blanket as set forth in claim 3 in which said plurality of layers comprises a facing layer made of a compressible elastomeric material.

10. A smash recoverable printing blanket having a substantially uniform thickness, said blanket comprising: a plurality of layers including a first layer which swells upon being contacted by a first liquid; a plural-ity of microcapsules provided as a thickness thereof adjoining said first layer, with said microcapsules containing said first liquid; a second layer which swells upon being contacted by a second liquid; a plurality of micro-capsules disposed as a second thickness thereof adjoining said second layer, with said microcapsules containing said second liquid said micro-capsules being ruptured upon smashing of said blanket, thereby to release the liquids contained therein against their adjoining layers, causing swel-ling thereof and restoring of adjacent layers substantially to their original positions prior to said smashing, and to define said uniform thickness.

11. A method of making a smash-recoverable printing blanket having a substantially uniform thickness, comprising the steps of: laminating a plurality of layers of blanket material including at least one layer which swells upon being contacted by a liquid; and disposing a plurality of microcapsules containing said liquid within said blanket closely adjacent saod one layer; said microcapsules being ruptured upon smashing said blanket, thereby to release said liquid contained therewithin against said one layer, causing swelling thereof and restoring of adjacent layers substantially to their original positions prior to said smashing, thereby to define said uniform thickness.

12. A method as set forth in claim 11 in which said disposing step comprises disposing said microcapsules in said one layer and in a random manner.

13. A method as set forth in claim 11 in which said disposing step comprises disposing said microcapsules as a thickness thereof adjacent one layer.

14. A method as set forth in claim 13 in which said disposing step comprises disposing said microcapsules having different sizes.