CA1127023A

CA1127023A - Coating composition for release sheets

Info

Publication number: CA1127023A
Application number: CA316,243A
Authority: CA
Inventors: John A. Mattor; Lawrence Price
Original assignee: Scott Paper Co
Current assignee: Warren SD Co
Priority date: 1977-12-23
Filing date: 1978-11-14
Publication date: 1982-07-06
Also published as: JPS5496109A; DE2855397A1; GB2012289A; DE2855397C2; FR2412407B1; FR2412407A1; BE872814A; IT1192623B; IT7869793A0; GB2012289B

Abstract

COATING COMPOSITION FOR RELEASE SHEETS

ABSTRACT OF THE DISCLOSURE
Disclosed is a release sheet having on at least one of its outer surfaces a dried and cured coating composition comprising a release agent, a cross-linkable thermoplastic resin, and a water dispersible organic compound containing polyoxyethylene, polyoxypropylene, or a block copolymer of polyoxyethylene and polyoxypropylene.

Description

~ ~27~23 l l Preparalion o~ such laminates generally involves the use of one or more shee-ts Or corestock in combination with a decorative or print sheet and, if desir ed, a top sheet or overlay. The corestock, if corestock is employed, usually comprises an unbleached krart paper which has been impregnated with a rela-~ive1y inexpensive thermosetting resin such as a phenolic resin, a polyester resin, and the lil<e, which is eàsily cross-linked upon the application of heat and pressure during consolidation.
The decorative or print sheet and the overlay (if used) are both impregnated with a "noble" thermosetting resin (i.e. a resin which is also cross-lin~kable upon the application of the heat and pressure durins~
consolidation, but which exhibits lit~le or no color deterioration upon the application of such heat and pressure and which prevents any strike-through or "bleeding" of the thermosetting resin wsed in the corestock).
Two of the most common "noble" thermosetting resins used to impregnate the decorative or print sheet employed in the preparation of such laminates are urea-formaldehyde resin condensates and melamine-formaldehyde resin condensates, although other resins such as polyester res7ns have also besn employed as "noble" thermosetting resins for the impregnation oF
such sheets.
After consolidation, in those applications where the resulting laminate is intended to be used in a structural application, rather than merely for its decorative effect, the laminate is usually bonded to a substrate material such as plywood, hardboard, particle board, cement-asbestos board, and the like, to give it adclitional strength and rigidity for its intended structural use.
As indicated above, the various laminae employed to îorm the ultimate laminate are consolidated through the simultaneous application of heat and pressure between heated pressure platens. Such presses generally consist of two heavy, heated platens on the top and bottom of the press, with additional heated platens in between to provide the ~ -2-~Z7~;23 1 !

numl~er of oper1in~s clesired in the press. Each openil19 typically inclucles the following ~lem~nts in the following order: a) a heated platen, b) one or more sheets of caul-stock, which are primarily intended to distribute pressure uniformly over the surface of the caul plate, c) a metal caul plate, d) -the opening itself, e) another metal caul plate, f~ one or more sheets of caul stock, and g) another heated platen. The various laminae which will form a laminate are placed together in the oper-ing, sometimes alone and sometimes as a "book" or "pack" of laminates.
In order to prevent the decorative sheet or overlay sheet from adhering to the caul plate, and in some cases to also irnpart desired gtoss or surface texture to the decorative sheet or overlay shee-t, it is customary to employ a release sheet or liner between the print sheet or overlay sheet and the caul plate. The laminae material which is placed against the release sheet is typically an uncured amine for maldehyde resin, such as melamine formaldehyde resin condensate or urea formaldehyde resin condensate. Such materials have a strong tendency to react with and/or adhere to the surface of the release sheet, placing tough requlrements upon the release sheet, which must resist adhering to the laminate.
This ~ifficult requirement is further complicated by the fact that differ ent manufacturers use different laminate materials and difFerent press temperatures and pressures. Furthermore, the variation in heating and cooling cycles occurring from laminate to laminate and edge to center in each laminate, even in a single pressing operation can result' in variable release results.
A particularly satisfactory prior art release coating and release sheet for use with platen pressing of decorative laminates is disclosed in U.S. Patent No. 3,946,135, issued to John O. H. Peterson on March 23, B 1976. This patent, ~ hi~i~hePei~ cor~ at-ed ~-by~ reference, discloses a release coa'ting fa'rmùlation 'comprising a release agent, a monomeric 30 polyhydric alcohol and a cross~linkable thermosetting resin. The .

I -3- l ~12~U23 monomeric polyhydric alcohol cross-links with the cross-link-able thermosetting resin to form a particularly stable surface having a low level of reactance with and/or adhe~ence to laminates used in panel pressing. Elowever, the relea.se sheets coated from the above-described formula are sometimes not entirely satisfactory from a release standpoint for use with all varieties of laminate materials and press conditions.
Also, the release coating formulation, which is coated as an aqueous solution onto a paper substrate, is sometimes difficult to coat because of its low viscosity. Attempts to increase the viscosity by adding conventional thickener materials have generally been unsatisfactory because of their tendency to rapidly cross-link with the other materials in the formulat-ion to increase the coating viscosity very quickly beyond that which is coatable, resulting in an unacceptably short pot life.
SUMMARY OF THE INVENTION
In accordance with one aspect of this invention there is provided a release sheet comprising a substrate having on at least one of its outer surfaces a dried and cured coating composition comprising, in effective amounts for release, a release agPnt, a cross-linkable thermo-setting resin, and a water dispersible organic compound containing polyoxyethylene block having more than 14 repeating units, polyoxypropylene block having more than 4 repeating units; or a block copoiymer of polyoxyethylene and polyoxypropylene.
In accordanc~ with another aspect of this invention there is provided a coating composition comprising, by dry weight per 100 parts of coating, from about 3 to about 30 ,~ 4 parts by dry weight of a release agent, from about 20 parts to abou~ 60 parts by dry weigh-t of a cxoss-linkable thermo-setting resin, and from about 4 parts to about 30 parts by dry weight of a water dispersible organic compound containing S polyoxyethylene, polyoxypropylene, or a block copolymer of polyoxyethylene and polyoxypropylene.
In accordance with another aspect of this invention there is provided in a method of consolidating a plurality of laminae impregnated with thermosetting resin by simultaneously heating and pressing the laminae, the improvement wherein at least one o~ the outer laminae is pressed against ~ release surface of a dried and cured coating composition comprising, in eff~ctive amounts for release, a release agent, a cross-linkable thermosetting resin, and a water dispersible organic compound containing polyoxyethylene, polyoxypropylene, or a block copolymer of polyoxyethylene and polyoxypropylene.
In accordance with another aspect of this invention there is provided in a method of forming a film of resinous material which includes the steps of coating the ilm of resinous material in a flowable state onto a rel~ase surface, drying the resinous film material, and stripping it from the release surface, the improvement wherein the release surface is provided by a dried and cured coating composition compris-ing, in effective amounts for release, a release agent, a cross-linkable thermosetting resin, and a water dispersible organic compound containing polyoxyethylene, polyoxypropylene, or a block copolymer of polyoxyethylene and polyoxypropylene.
By way of added explanation, the present invention in one respect relates to a coating composition for use in the - 4a -preparation o a release coating and release sheet which is particularly useful for panel pressing applications wh~rein decorative laminates are consolidated under heat and pxessure.
In some embodiments, the invention is an improved ~orm of the release coating described and claimed in U.S. Patent No.
3,946,135. The coating composition of the present invention comprises a release agent, a cross-linkable thermosetting resin, and a water dispersible organic compound containing polyoxyethylene, polyoxypropylene or block copolymers of polyoxyethylene and polyoxypropylene. The coating composition is applied to the substrate in an aqueous form, so the organic compound must be water dispersible, and is preferably water soluble. A monomeric polyhydric alcohol is-preferably includ-ed in the coating composition to cross-link with the thermo-setting resin. However, it can be left out in cases wherethe organic compound provides the same function.

- 4b -l~ ~ ~
~L~27~3 The water dispersible organic compound is preferably chosen frorn either Class A -polyoxyethylenated polyoxypropylena-ted ethyler1e diarnine, such as -thc materials sold under the trademark Tetronics; or Class B.-a compound having the formula:

~1 1 ~CH2 C~l O~Cll2-c~l-o~cF
where R1 iS hydrogen or an organic hydrophobe;
R;" R3, and ~ are independently selected from H or CH3-, and where R2, R3, and R4 are all H, more than 50% of the molecular weight of the compound is provided by polyoxyethylene;
X is 0, S, or N;
n = 1 where X is 0 or S, n = 2 where X is N; and a, b, and c are zero or integers, and the sum of a, b, and c is greater than 1. : - ?i One Class B type of organic compound is the type in whiçh R1~ R2~
~/~ R3, and R4 is H, and X is 0 (polyoxyethylene), preferably where a + b +
c is greater than 14 (mol. wt. = 634).
Another Class B type of organic compound is the type in which R1 iS
20 H; R2, R3, R4 is CH3-(polyoxypropylene), and a ~ b + c Is pre~erably less than 25 (mol. wt. ~ 1468), and more preferably greater that 4 (mol.
wt. = 250).
Another Class B type of organic compound is the type in which R1 ' R2 and R4 is H; X is 0; R3 is CH3-; and a; b and c are all integers 25 (block copolymers of polyoxyethylene-polyoxypropylene-polyoxyethylene), preferably where 300 > a ~ c > 9 and 72 > b > 17.
Another Class B type of organic compound is the type in which R1 ' R3 is H; R2, R4 is CH3-; X i~ 0 and a, b, c are all integers (block copolymers of polyoxypt opylene-polyoxyethylene-polyoxypropylene), preFerably where 55 > a + c > 17 and 250 > b > 74.

1~ s ~ 7n23 ll i Another Class B type of organic compou~cl is the type in which R1 is E~ ¦ an organic hydrol~. Examples of such compounds include, but are not iimited to, long-chain carboxylic acid esters of glycerol, polyoxyethylenated long-chain carboxylic acid esters of sorbitol or sor bitan, polyoxyethylt3natecl S fatty acids, polyoxyethylenated polyoxypropylenatecl fatty acids, polyoxye-thyl-enated alkylphenols, and polyoxye-thylenated alcohols.
Some of the above named materials will be recognized as conventional surfactants. The addition of surfactants to release coatings does no-t ~ usually improve release, and in many case is detrimental to release.
10 Furthermore, it will be ,~ ecognized that the quantities desirable for improving release in the present invention are much higher than those quantities normally used in surfactant applications. When used as surfactants, their function is to cause emulsification, lowering of surface tension and the like of aqueous systems, and they are ty,cically 15 used in an amount of about 1%. When they are used in the present invention to improve releas~ characteristics, they are used in a quantity of about 4% to 30% of the coating compound, and as such comprise a substantial art of the coating structure. It should be recognized that some of the above-named materials are commercially obtainable or can be prepared as 20 mixtures of each other and of the same type in varying molecular weights.
Such mixtures are within the scope of the invention.
Thè resulting release sheet is highly useful in panel pressing release applications wherein decorat~ve laminates are consolidated.
They provide significantly improved release under a wide variety of 25 conditions. The coating compositions of the invention exhibit excellent .
stability and pot life. The release sheets prepared therefrom provide very easy release in the pressing of laminates, includ;ng laminates of amine formaldehyde resins, under a wide varie-ty of conditions. These release sheets may be reusablè,`''and they permit excellent control over 30 the gloss and surface texture of the laminates being pressed. Addi~ionally, 1 ~;27;~3 1 ~

the water dispersible oryanic compound provi~les excell~nt viscosity control over the coating mixture wi-thout excessive build up o-f viscosi~y This ;s believed to be due to -the materials having only a few reactive sites even though they are in polymeric ~orm. The present invention is 5 also useful for release coatings u,con which are cast urethanes and polyvinyl chloride resins.
. .

_ The coating compositions of the invention are aqueous coating compositions comprising a release agent, a cross-linkable thermosetting 10 resin, and a water dispersible organic compound containing polyoxyethylene andjor polyoxypropylene. Illustrative of the types of release agents which have been found useful in the coating compositions of the invention - are the Werner type chromiutn complexes of a fatty acid, such as those sold under the trade name "QUILON" by E. 1. duPont de Nemours & Company Inc. of Wiltnir,gton/ Delaware (e.g., QUILON S-the stearic acid complex/
QUILON M or H-the myristic acid complex) and those sold under the tradename "KROMPLEX 75" (a myristic acid chrome chloride complex) by Sun Chemical Co. ' .Illustrative of the types of cross-linkable thermosetting res7ns 20 which are useful in the coating compositions of this invention are urea-ormaldehyde resin condensates, melamine-formaldehyde resin condensates, phenolic resins, and the like. Iilustrative of the types of monotneric, polyhydric alcohols which are used in the preferred embodiments of the present invention are pentaerythritvl, glycerine (glycerol), 1,6 hexanediol, 25 tris-hydroxymethyl nitromethane, tat taric acid (dihydroxysuccinic acid) and the like, alone or in combination with each other.
The amounts of the various components used in the coating composi-tions of this invention are not narrowly critical, as long as they are sufficient to effectively provide release, and preferably range frorn ~ 7 Z;~ ~

about 3 parts by weight (dry) to about 30 parts by weight (dry) of release agent per 1100 parts by weight (dry) of coating, from about 5 parts by weight (dry) to about 50 parts by weight (dry~ of monorneric polyhydric alcohol per 100 parts by weight (clry) o-f coa-l:ing ~if -the 5 r~onomeric polyhydric alcohol is to be included), from about 20 parts by weight (dry) ta about 60 parts by weight (dry) of cross-linkable thermosetting resin per 100 parts ~y weight (dry) of coating, and from about 4 parts, preferably 5 or more, by weight (dry) to about 30 parts by weight (dry) of the water dispersible organic compound per 100 parts by weight (dry) 10 of coating.
In addition to the essential components set forth above, the coating compositions of the present invention may also contain other components such as anti-foam agents, dyes, colorants, and the like.
Release sheets are prepared from the coating compositions of this 15 invention by coating the composition on a suitable base and then heating the resulting coated base until the release coating thereon has been dried and cured. The principal requirement for the substrate or base to be suitable is that it have a relatively smooth surface which resists substantial penetration of the aqueous coating composition into the 20 base. In the case of a cellulosic fibrous substrate such as paper, this requirement is typically met by providing the paper with a base coating which comprises a mineral pigment (e . g . clay) and adhesive (or binder) .
In the case of a metal foil, no base coating will be necessary.
The following examples are intended to further illustrate the 25 invention disclosed and claimed herein, but they are not intended to limit the scope thereof. The release coating formulation of each example was coated with a Meyer rod on a ~3 Ibs . per 3, 300 square feet ream base paper sheet that had been previously coated on both sides with S Ibs. per ream of a convent^nal clay-binder dispersion and further 30 coated on the side upon which the release coating formulation was to be . ., .

l~ Z3 applied witl- 8 Ibs. per rearn of another convenlional clay-binder dispersion. In each example except where otherwise indicatcd, the release coating was applied within 15 minu-tes after mixing and was dried in a circulatin~ air oven for 1 minute at 15~-5 160C. to yield a release coating of approximately 3 Ibs. per3,300 square feet ream.
The general formula for each of the examples was:
Component Parts by Weight (Wet~
. Pentaerythritol at 5.6% (~`o /~ ~7 C'o~Ce~,0~14.3 g.
B lo Resimene 735 (an 80% solution in isopropyl alcohol of a methylated melamine-formaldehyde resin condensate sold by Monsanto Company of St. Louis, Missouri~ 6.0 g.
`p 15 Quilon H (a 50% solution in ~)3l?1 isopropyl alcohol /~/7~ of a Werner-type chr,mic .
chloride complex with myristic acid sold by E. I. DuPont de Nemours and 20 Company, Inc. of Wilmington, Delaware~ 2.4 g.
isopropyl alcohol 0.6 g.

2-ethylhexanol 0.6 g.
Additive water soluble organic compound material under test ~ x Each of the coated and dried examples was tested by the following procedure. A 12 by 12 inch platen press at 280F. and 1200 psi was used for pressing for 10 minutes. The configuration of the stack of materials in the press was, from top to bottom:
1. Hol: platen 2. Conventional release sheet, face down

3. 2-phenolic sheets

4. Melamine-formaldehyde pre-pre~3 sheet

5. The release sheet of the example being tested, face up

6. 1/8 inch thick aluminum caul plate 3a 7. 3/4 inch thick pressed board After pressing, the consolidated ~ larninates were stripped from the release sheet of the example beincl lested and ra1ed as follows:

r6~e ~ J~

~. ~ ~ ~
~Z7~?Z3 Release Value Observed Perfect peeling-type release B Sticking in small spots one or more ¦ corners 5 ¦ C Corner sti~king D Severe corner sticking exterlded alon~
edges ¦ E Total edge and corner sticking ¦ F Partial release only in a few spots 10 ¦ G . Total bonding, no release whatsoever ¦ The test procedure was purposely designed to be sufficiently stringent ¦ to result in very low ratings for the prior art release sheet (the ¦ control) to enable better evaluation of the improved release sheets.
¦ Althouyh the control release sheet performed poorly under this test, it ~5 ¦ is saticfactory for many commercial applications.
¦Example . Amt.g. Releas ~J~ 7 I No - Additive Material ~Wet Wt.) Value V l G
¦ 1. CONTROL --NO ADDITIVE -- F
¦ 2. Polyoxyethylene (Polyox WSR-80 ) .8 A , I mol. wt. = 200,000 ¦ 3. Polyoxyethylene (Po~lyox WSR N-101) .8 A
. ~ol. wt. = 100,000 1 ¦ 4. Polyoxyethylene (Polyox WSR N-10 ) 1.6 A
I mol. wt. = 100,000 25 5. Polyoxyethylene (Polyox WSR N-101) 3.2 A
mol. wt. = 100,000 6. Polyoxyethylene (POE 2002) mol..8 F
wt. = 200

7. Polyoxyethylene (POE 200 ~ mol.1.6 D
wt. = 200

8. Polyoxyethylene (Carbowax~6001)O4 F
mol. wt. = 600

9. Polyoxyethylene (Carbowax 6001).8 . F
mol. wt. = 600 35 10. Polyoxyethylene (Carbowax 6001)1.6 A-B
. mol. wt. = 600 11. Po].yoxyethylene (Carbowax 40001) .~ F
mol. wt. = 4000 ~ t~J~ ,~J~k 10- ` ~

l ~ ~
~ 7 I
¦ 12. Polyoxyc~hylene (Carbowax ~o001) .8 l mol. wt. = 4000 ¦ 13. Polyoxyethylene (Carbowax L~oQol) 1.6 A
I mol. wt. = 4000 5 ¦ 14. Polyoxyethylene (Polyox POE 20Ml) .4 A
I mol. wt. - 20l000 ¦ 15. Polyoxyethylene (Polyox PO~ 20M1) .g A
mol. wt. = 20,000 I 16. Tetraethylene ~lycol, mol. wt. ~ 176 .4 F

10¦ 17. Tetraethylene glycol, mol. wt. = 176 .g F
18. Polyoxyethylenated po~yoxypropylene .4 A
D I glycol (Pluronic~E-35 ) mol. wt. of PPO = 950, + 20 moles EO
l 19. Polyoxyethylenated po~yoxypropylene .8 A
15 1 glycol (Pluronic L-35 ) mol. wt. of PPO = 950, ~ 20 moles EO
20. Polyoxyethylenated po~yoxypropylene .4 A
glycol (Pluronic L-31 ) mol. wt. of I PPO = 950, + 3 moles EO
20 ¦ 21. Polyoxyethylenated po~yoxypropylene .8 C
l glycol (P]uronic L-31 ) mol. wt. of ¦ PPO = 950, + 3 moles EO
22. Polyoxyethylenated po~yoxypropylene 1.6 D
l glycol (Pluronic L-31 ) mol. wt. of 25 ~ PPO = 950, ~ 3 moles EO
¦ 23. Polyoxyethylenated pol~oxypropylene .4 D
, glycol ~Pluronic F-108 ) mol. wt~
I of PPO = 3250, ~ 300 moles EO
¦ 24. Polyoxyethylenated pol~oxypropylene .8 A
30 I glycol (Pluronic F-108 ) mol. wt.
¦ of PPO = 3250, + 300 moles EO
25. Polyoxypropylenated p~lyoxyethylene .4 l glycol (Pluronic 10R5 ) mol. wt.
¦ of PPO = 1000, + 23 moles of EO
35 ¦ 26. Polyoxypropylenated p~lyoxyethylene .8 A
glycol (Pluronic 10R5 ) mol. wt.
of PPO = 1000, ~ 23 moles of EO
27. Polyoxypropylenated p~lyoxyethylene .4 D
l glycol (Pluronic 17R2 ) mol. wt.
40 ¦ of PPO = 1700, ~ 10 moles EO
28. Polyoxypropylenated p~]yoxye~hylene .8 A
glycol (Pluronic 17R2 ) mol. wt.
of PPO = 1700 ~ 10 n;ol~s EO

l f~ k ~

~.r~ ~t~3?~c!~o:i3~'~.~:;t~U~.~,~.~.. '7~.7~ r5`.X~ r~.'n`~3~ 3i~.~L~~^.'3~=C~ r~

~127~Z3 29. Polyoxypropylenated p~lyoxyethylene .4 ~ li glycol (Pluronic lOK8 ~ mol. wt.
of PPO = 1000, -~ 91 moles EO
30. Polyoxypropylenated p~lyoxyethylene .8 A
glycol (Pluronic lOR8 ) mol. wt.
of PPO = 1000, ~ 91 moles EO
31. Polyo~ypropylenated p~ly~xyethylene .4 D
glycol (Pluronic 25R5 ) mol. w~
2500 PPO, 57 moles EO
32. Polyoxypropylenated p~lyoxyethylene .8 A
glycol (Pluronic 25R5 ) mol. wt.
2500 PPO, 57 moles EO
33. N,N'-Po]yoxypropylenated .4 D
ethylenediamine mol. wt., i~
2501-3000 + 1~-17 moles EO
(Tetronic~702 ) 34. N,N'-Polyoxypropylenated .8 A
ethylenediamine mol. wt.
2501-3000 ~ 17 moles EO
tTetronic 702 ) 35. ~N'-Polyoxypropylenated .4 E
ethylenediamine mol. wt.
3501-4000 + 53-61 moles EO
(Tetronic 904~) - -~5 3~. N,N'-Polyoxypropylenated .8 A
ethylenediamine mol. wt.
3501-4000 ~ 5~-61 moles EO
~Tetronic 9~4 ) 37. N~N'-Polyoxypropylenated .4 C
, ethylenediamine mol. wt.
3501-4000 + 3~8-363 moles EO
(Tetronic 908 ) 38. N,N'-Polyoxypropylenated .8 A
ethylenediamine mol. wt.
3501-4000 + 3~8-363 moles EO
~Tetronic 908 ) 7 39. Polyox~propylene ~Polyglycol .4 B
P-1200 ~ mol. wt. 1200 .
40. Polyoxypropylene (Polyglycol 2002) .~ F
mol. wt. 200 41. Polyoxypropylene (Polyglycol 2002) 1.6 D
~ol. wt. 200 42. Polyoxyethylenat~d castor oil .4 C
(~mulphor~EL-719 ) ~0 moles EO
~5 43. Polyoxyethylenated so~bitan .4 monolaurate (Tween~20 ) 20 moles EO

r~ eff ~ ~ ;~
~L~;Z7~Z3 :~

44. Polyoxyethylellat:ed so~i.tan .8 monolaurate ('rween 20 ) 20 moles EO
45. Polyoxycthylerlated sorb~an ,4 monopalmitate (Tween ~0 ) 20 moles EO
46. ~olyoxyethylenated sorb~tan .~ A
monopalmitate (Tween 40 20 moles EO
47. Polyoxyethylenated sgrbitan .4 A
mollooleate (Tween 80 ) 20 moles EO
48. Polyoxyethylenated sgrbitan .8 A
monooleate (Tween 80 ) 20 moles EO
49. Polyoxyethylenated sgrbitan .4 B
monooleate (Tween 81 ) 5 moles EO
50. Polyoxyethylenated sgrbitan .8 A
monooleate (Tween 81 ) 5 moles EO
Sl. Polyoxyethylena5ed sorbitol . .4 laurate (&-1045 ) .
.. 52. Polyoxyethylena~ed sorbitol .8 A-B
laurate (G-1045 ) 53. Polyoxyethylenated sor~itol- .4 B
lanolin esters (G-1471 ) 54. Polyoxyethylenated sor~itol- .8 A
lanolin esters (G-1471 ~
- 30 55. Polyoxyethylenated so~bitol- .4 B
beeswax ester (G-1726 ) 56. Polyoxyethylenated so~bitol ,8 B
beeswax ester (G-1726 ) .
57. Polyoxyethylenated .4 A
polyoxypropy~.enated stearic acid (G-2162 ) 58. Polyoxyethylenated .8 A
polyoxypropy~enated stearic acid ~G-2162 ) 59. Polyoxyethyle~ated stearic .4 B
B acid ~Myrj~45 ) 8 moles EO
60. Polyoxyethyle~ated stearic .8 A
acid (Myrj 45~) 8 moles EO .

~r,~,te ,~7,d,~/C

. . I ~ ~ ~
~27~3 . 3 . I
ol7? 61. Polyo~yethyl.ella~ed ~teari.c .4 /7~ acid (~iyrj 525) 40 moles EO
62. Polyoxyethylc~ated stearic .8 h acid (~Iyrj S2J) 40 moles EO
63. Polyoxyethylena~ed nonylphenol .~ C
(Tergit:olXNP~ moles EO
64. Polyoxyethylencl~cd nonylphenol .8 D
(Tergi.tol NP-14 ) ~ moles EO
65. Polyo~yethylena~ed nonylphenol .4 D
(Tergitol NP-27 ) 7 moles EO
66. Polyoxyethylena~ed nonylphenol .8 B
. ~Tergitol NP-27 ) 7 moles EO
67. Polyoxyethylena~ed nonylphenol .4 C
(Tergitol NP-35 ) 15 moles EO
68~ Polyoxyethylena~ed nonylphenol .8 A
(Tergitol NP-35 ) 15 moles EO
69. Polyoxyethylena~ed nonylphenol .4 C
(Tergitol NP-40 ) 20 moles EO
70. Polyoxyethylena~ed nonylphenol .8 A
(Tergitol NP-40 ) 20 moles EO
71. Polyoxye~hylenated lauryl alcohol .4 A . .
. ~Brij~35 ) 2~ moles EO
72. Polyoxye~hylenated lauryl alcohol .8 A
~Brij 35 ) 23 moles EO .
73. Polyoxye~hylenated stearyl alcohol .8 B
, (Brij 76 ) 10 moles EO
74. Polyoxye,thyle~ated tert-octylphenol .4 A
~~~ (Triton~X-100 ) 9-10 moles EO
75. Same as Ex. No. 2, except Quilon ~ .8 G
~-~w 3~ was replaced with 3.0 g. of Volan (a chrome complex of methacryIic acid) 76. Same as Ex. No. 2,.except Quilon H .8 G
was replaced with p-toluene sulfonic acid 77. Same as Ex. No. 12, except7Quilon H .8 was replaced with Quilon S (a 30%
solution in isopropyl alcohol of a . Werner type chromic chloride complex with stearic acid) 78. Same as Ex. No. 2~ e~cept Resimglle .8 C
735 was replaced with Cymel~303 , ~ f~ ,),0,~

Z7~;:3 79. Same as Ex. No. 12, except Resimene.8 C
735 was repl~ce~ with ~.8 g. of Resimene 975' (urea formaldehyde resin condensate) S 80. Same as Ex. No. 12, except Resimene.8 A
735 was replased wi~h 4.8 g. o~
Resimene X980 (urea fvrma]dehyde resin condensate) 81. Same as Ex. No. 2, except 2-ethyl .8 A
hexanol was replaced with an , additional 0.9 g. of isopropyl alcohol 82. Same as Ex. No. 2, except isopropyl.8 B
alcohol was replaced with an 1~ adclitional 0.9 g. of 2-ethyl hexanol 83. Same as Ex. No. 2, except isopropyl.8 B
. and 2-ethyl hexanol were left out .
84. Same as Ex. No. 12, except .8 A
pentaerythritol was replaced with tris-hydroxymethyl nitromethane 85. Same as Ex. No. 12, except .8 A
. pentaerythritol was replaced with -1.6 gms. of 1,6 hexanediol 86. Same as Ex. No. 12, except .8 A
pentaerythritol was left out 87. ~oating of all Polyox WSR-801 G
88. Same as Ex~ No. 1, except Resimene 0 F
735 was replaced with Resimene 9759 89. Same as Ex. No. 1, except Resimene g 0 . F
735 was replaced with Resimene X980 90. Same as Ex. 85, except carbowax 4000 0 F
was left out 91. Same as Ex. No. 2, except Resimene.8 G
735 was left out 92. Same as Ex. No. 20, except coated .4 2 hours after mixing 93. Same as Ex. No. 21, except coated .8 A
2 hours after mixing 94. Same as Ex. No. 22, except coated1.6 . A
2 hours after mixing . .... ; . l _ _ 1 - Manufactured by Union Carbicle Corp. of N.Y., NoY~

~ @~
llZ7~Z3 2 - Manufactur~d by Dow Ch~m:ical Co. of Midland, MichiKarl 3 - Manufacturcd by Wyandotte Chemical Corp. of Wy~ndotte, Michigan 4 - Ma~ufactured by G~F Corp. o N.Y., N.~.
S - Manufactured by Atlas Chemical Industri.es, Lnc. of Wilming~on, D~laware 6 - Manu~actured by Rohm and ~laas Company of Philadelphia, Pennsylv~nia 7 - Manu~actured by E. I. duPont de Nemours ~ Co. of Wilmington, Delaware 8 - M~nufactured by American Cyanimide 9 - Manufactured by Monsanto Company of St. Louis, Missouri . lll From the above examples it can be seen that a wide variety oF
compounds containing polyoxyethylene and/or- polyoxypropylene significantly 15 improve the release values of the release coating described in ll.S.
Patent No. 3,946,135. For illustration, compare Example No 1 (which represents the release coating of U.S. Patent No. ~,9~,145) with Examples Nos. 2 - 74. As can be seen from the examptes, some materials need be- used in a larger quantity than others to provide the most 20 improved release, and some of the materials are more effective at lower concentration ~see Exs. 43, 47, 57 and 71). Also, it can be seen that higher molecular weights of polyoxyethylene, for exampie 600 or more, provide a greater improvement to release than lower molecular weights.
~See Examples 2-17. ) .41so, it can be seen that examptes of higher 25 molecular weight polyoxypropylene provide greater improvements to release than lower molecular weight examples. However, polyoxypropylene at higher molecular weight becomes water insoluble. Therefore, only a narrow molecular weight range of polyoxypropylene is preferred in the invention, from a molecular weight of about 200 to about 1200, for 30 example. (See Examples 39 - 41;) -Examples 75 - 91 illustrate the results from varying other materiais in the coating formula. Example 86 indicates the ability to leave out . . I ~ ~
l ~ Z3 the monomeric polyhyclric alcohol of ~he formulcl discloscd anci claimecJ in 0.S. Patent No. 3,9~16,135, when using the additive material of the present invention. Coating formulations of the present invention have varying release characteristics dependin0 upon how loncg after beincJ
mixed they were coa-ted on the paper. Examples 92 - 9" illustrate the improvement over the coatin~ mixture of examples 20 - 22 when coatinl 2 hours after mixing.
While the invention has been particularly shown and describecl with reference to preferred embodiments thereof, it is understood that a 10 number of variations and modifica-tions will occur to a person skilled in the art without departincJ from -the spirit and scope of the invention as defined in the appended claims.

,~

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A release sheet comprising a substrate having on at least one of its outer surfaces a dried and cured coating composition comprising, in effective amounts for release, a release agent, a cross-linkable thermo-setting resin, and a water dispersible organic compound containing polyoxyethylene block having more than 14 repeating units, polyoxypropylene block having more than 4 repeating units; or a block copolymer of polyoxyethylene and polyoxypropylene.

2. The release sheet according to claim 1, wherein said water dispersible organic compound provides from about 4% to about 30% by weight of the coating composition.

3. The release sheet according to claim 2, wherein said release agent is a Werner-type complex of fatty acid with chromic chloride.

4. The release sheet according to claim 2, wherein said coating composition further includes a monomeric polyhydric alcohol.

5. The release sheet according to claim 1, wherein said water dispersible organic compound is either:

Class A. polyoxyethylenated polyoxypropylenated ethylenediamine;
or Class B. a compound having the formula:

where R1 is hydrogen or an organic hydrophobe;
R2, R3 and R4 are independently selected from H or CH3-, and where R2, R3 and R4 are all H, more than 50% of the molecular weight of the compound is provided by polyoxyethylene X is O, S or N, n = 1 where X is O or S, n = 2 where X is N, and a, b or c are zero or integers, and the sum of a, b and c is greater than 1.

6. The release sheet according to claim 5, wherein said water dispersible organic compound provides from about 4% to about 30% by weight of the coating composition.

7. The release sheet according to claim 6, wherein the release agent is a Werner-type complex of fatty acid with chromic chloride.

8. The release sheet according to claim 7, wherein said coating composition further comprises a monomeric polyhydric alcohol.

9. The release sheet according to claim 8, wherein said water dispersible organic compound provides more than 5% by weight: of the coating composition.

10. The release sheet according to claim 5, wherein said water dispersible organic compound is a Class B compound.

11. The release sheet according to claim 10, wherein the water dispersible organic compound is selected from the group consisting of:
polyoxyethylene, polyoxypropylene, polyoxyethylenated long-chain carboxylic acid esters of glycerol, polyoxyethylenated long-chain carboxylic acid esters of sorbitol or sorbitan, polyoxyethylenated fatty acids, polyoxyethyl-enated polyoxypropylenated fatty acids; polyoxyethylenated alkylphenols, polyoxyethylenated alcohols, and polyoxyethylenated polyoxypropylene glycols.

12. The release sheet according to claim 10, in which R1, R2, R3 and R4 is H, and X is O.

13. The release sheet according to claim 12, in which a + b + c is greater than 14.

14. The release sheet according to claim 10, in which R1 is H;
R2, R3, R4 is CH3-; and a + b + c is less than 25.

15. The release sheet according to claim 14, in which a + b + c is greater than 4.

16. The release sheet according to claim 10, in which R1, R2 and R4 is H;
X is O;
R3 is CH3-; and a, b, and c are all integers.

17. The release sheet according to claim 16, in which 300 > a + c > 9; and 72 > b > 17.

18. The release sheet according to claim 10, in which R1, R3 is H;

R2, R4 is CH3-;
X is O; and a, b and c are all integers.

19. The release sheet according to claim 18, in which 55 > a + c > 17; and 250 > b > 4.

20. The release sheet according to claim 10, in which R1 is an organic hydrophobe.

21. The release sheet according to claim 10 wherein the cross-linkable thermosetting resin is selected from the group consisting of melamine-formaldehyde resin condensates and urea-formaldehyde resin condensates.

22. The release sheet according to claim 1, wherein said coating composition is coated on a paper web having a base coat of pigment and adhesive.