KR20160061257A - Fluorosilicone oleophobic low adhesion anti-wetting coating - Google Patents

Abstract

According to the present invention, an inkjet print head comprises a front surface having a polymeric coating including an oleophobic graft polymer. The polymer includes a cross-linked fluorine elastomer and a perfluorinated fluorosilicone grafted to the cross-linked fluorine elastomer. The polymeric coating has an ink contact angle of at least 45 degrees and a slip angle of less than 35 degrees. The coating or film of the oleophobic graft polymer has excellent thermal stability.

Description

FLUOROSILICONE OLEOPHOBIC LOW ADHESION ANTI-WETTING COATING < RTI ID = 0.0 >

Embodiments disclosed herein relate to coatings applied to printing device elements. In particular, the embodiments disclosed herein relate to an oleophobic, anti-wetting coating that can be applied to the front of a printhead.

In a typical solid ink printhead structure, the printer has a nozzle plate with a jet arrangement to eject ink from the jet stack. In some printhead systems, the nozzle plate and jet stack are composed of plates of stainless steel, but recently these components have been replaced by flexible polymeric layers such as polyimide. In some cases, the polyimide film may be combined with an open plate of stainless steel Wet coating, and then the array of openings is ground in the polyimide film with a laser.

Drooling of the nozzles, wetting and attachment of the ink at the front of the printhead, resulting in missed ejection and misdirection leading to poor image quality. When the pressure inside the print head exceeds a certain pressure, the ink drops due to overdischarge of the nozzles. Performance can be improved if the nozzles can maintain high pressure without spilling ink. Wetting occurs when the front of the printhead is wet after printing. This ink remaining on the print head blocks the nozzles leading to missing nozzles and printing in the wrong direction. Figure 1 shows a photograph of this contaminated printhead.

One way to solve these problems is to apply an active cleaning blade system. The system purges the ink from the printhead and then wipes the ink from the front with a wiper blade. Ink purging typically occurs when the system detects a missed shot and the ink freezes, solidifies, or shrinks after the power is turned off and air enters the system. After removing the contaminants, trapped air, and cleaning the nozzles with ink purging, the wipers wipe the front.

In connection with wiper blade systems, a variety of anti-wetting coatings are used to improve performance. Current coatings have good thermal and ink stability, but do not have the mechanical robustness desired for such coatings, especially when used in connection with wiper blade systems. Other problems arise due to coating stability in printhead manufacturing conditions.

Figure 1 is a front view of a contaminated printhead.
2 is a side view of the printhead assembly.
Figure 3 is a side view of an intermediate structure in the printhead assembly manufacturing process of Figure 2 according to the embodiments disclosed herein.
Figure 4 is a side view of another intermediate structure in the printhead assembly manufacturing process of Figure 2 in accordance with the embodiments disclosed herein.
Figure 5 is a side view of yet another intermediate structure in the printhead assembly manufacturing process of Figure 2 in accordance with the embodiments disclosed herein.
6 shows the graft synthesis path.
Figure 7 shows a thermogravimetric analysis (TGA) profile of an exemplary oleophilic graft polymer according to embodiments disclosed herein. According to TGA analysis, the coating is thermally stable to about 330 ° C without weight loss.

Embodiments disclosed herein provide thermally stable, mechanically robust, low adhesion coatings based on oleophobic grafted polymers made by crosslinking crosslinked fluoroelastomers with perfluorofluorosilicone and grafting. The oleophilic graft polymers exhibit desirable and / or complementary combination properties for polyurethane based coatings. In embodiments, oleophobic graft polymers that are applied as coatings are particularly useful in high definition (HD) piezo printhead applications where the coating is applied to the front of the printhead. The coating or film of the oleophobic graft polymer disclosed herein exhibits a high ink contact angle of 45 degrees or more and a low slip angle of less than 35 degrees and has excellent thermal stability.

 In addition, such coatings exhibit minimal thickness and weight loss at temperatures above 290 DEG C and are suitable for use in stringent printhead assembly conditions. Coatings employing the oleophobic graft polymers disclosed herein are rigid and have a long quality life even with continuous exposure to melt at about < RTI ID = 0.0 > 140 C < / RTI > Often grafted polymer coatings can be applied to solid ink, pigmented ink, and UV ink, show good performance at high overspray pressures, and have easy cleaning and self-cleaning properties. Finally, the oleophobic graft polymers are formed with the coatings required by simple coating techniques such as flow coating, die extrusion coating, spin coating, draw bar coating, slot-die coating and are advantageous for printhead manufacture. These and other advantages will be apparent to those skilled in the art.

In some embodiments, the coating is comprised of an oleophobic graft polymer, which has a fluorine elastomer crosslinked with an aminosilane crosslinker and a fluorine silicone segment fluorosilicone grafted onto a crosslinked fluoroelastomer.

As used herein in connection with graft polymers, the term " oleophobic " refers to graft polymer properties that reject oil, hydrocarbons, and more generally organic compounds, particularly non-polar organic compounds. The oleophobicity imparts anti-wetting properties that exclude wetting by solvent-based, solid ink jet based, and other pigmented and UV curable ink compositions. Owingness provides good contact angle and slip angle properties to the coating, and performance is exerted at high excess drool pressures.

As used herein, the term " graft polymer " refers to a chemical combination of two or more prepolymers. Grafts appear to be in polymeric crosslinked form. For example, the graft polymers disclosed herein can be prepared by the reaction of a pre-fluoroelastomer with a pre-fluoro silicone, and the fluoro silicone has a functional group capable of graft covalently bonding with the fluoroelastomer. Optionally, the aminosilane crosslinker covalently bonds the fluoroelastomer and the fluorosilicone. In embodiments, the crosslinking agent that crosslinks the fluoroelastomer performs a dual role in providing a graft attachment point that bonds the fluorine silicone.

As used herein, the term " fluoroelastomer " refers to any material that is generally divided into elastomers and contains a significant amount of fluorine. Fluorine elastomers are high thermal stability, nonflammable, and corrosion resistant fluorine-containing rubber-like synthetic polymers, typically co-polymers / ternary interpolymers. In embodiments, the fluoroelastomer (FE) contains at least about 65 percent fluorine. In embodiments, the fluorine content is from about 50 to about 90 percent, or from about 60 to about 100 percent. Exemplary commercial fluorine elastomers generally have a fluorine content of from about 66 to about 70 percent.

Currently known and available fluoroelastomers include copolymers of vinylidene fluoride and hexafluoropropylene, ternary copolymers of vinylidene fluoride, propylene hexafluoride and tetrafluoroethylene, and alternating copolymers of propylene and tetrafluoroethylene . These fluoroelastomers are commercially available under the VITON (TM) (Dupont), DYNEON (TM), FLUOREL (TM) (3M), AFLAS (TM) (3M), and TECNOFLON (TM) (Solvay Solexis) product grades. Such fluoroelastomers exhibit excellent solvent resistance and oil resistance and also have a relatively high temperature resistance in comparison with the corresponding non-fluoroelastomers. In embodiments, the fluoroelastomer (FE) is a polymer comprising monomer units selected from the group consisting of vinylidene fluoride, ethylene tetrafluoride, propylene hexafluoride, perfluorinated methyl vinyl ether, and combinations thereof. In some of these embodiments, the fluoroelastomer is a ternary copolymer of vinylidene fluoride, ethylene tetrafluoride, and propylene hexafluoride.

In embodiments, the molecular weight of the fluoroelastomer (FE) is from about 50,000 to about 70,000 daltons as measured by gel permeation chromatography. In embodiments, the fluoroelastomer is selected based on the tensile strength. In some such embodiments, the tensile strength of the fluoroelastomer is from about 15 mPa to about 25 mPa, or from about 20 mPa to about 25 mPa, or from about 22 mPa to about 25 mPa, as measured according to standard ASTM D412C. In embodiments, fluoroelastomers are selected according to their ability to participate in the crosslinking chemistry disclosed herein.

As used herein, fluorine silicon refers to silicone polymers having substantial degrees of fluorine substituents and may be any fluorinated oligomers, homopolymers, or copolymers. Fluorosilicone shows comparable chemical stability and compatibility with fluoroelastomers. In embodiments, the fluorine silicon is an alkoxysilane-terminated silicone and the average molecular weight is from about 10 daltons to about 10,000 daltons. Fluorine silicon is selected from those having solvent refining properties similar to fluoroelastomers, but capable of bonding with silanol. The fluorine silicone component is also selected to provide good abrasion resistance to the oleophilic graft polymer. Abrasion resistance is particularly useful in printhead systems that use wiper blades that continue to contact the coating during use.

The non-pseudopolymer may be combined with a content limited to the fluoroelastomer by a crosslinking method using functional groups of such polymers similar to the amine or trimethoxy functional groups in the aminosilane crosslinking agent. In one embodiment, the fluoroelastomers extend sologelated interpenetrating networks by reaction with alkoxy-terminated fluorine silicon having aminosilanes. The fluorine silicon segments used in these grafts are as follows.

The terminal alkoxysilane groups provide chemical moieties for the downstream Graft chemistry by the embodiments disclosed herein. The graft chemical structure of the alkoxysilane group is achieved with a material having a hydroxyl group, such as an organic alcohol or silanol. Silanol binders provide siloxane products (Si-O-Si), such as the olefinic graft polymers described herein. Linker (L) applied to Formula II compounds consists of any substituted or unsubstituted C ₁ -C ₆ alkyl, including alkyl fluorides, such as perfluorinated alkyl. The linker L further comprises a fluorine silicon backbone at the terminal oxygen, or, in some embodiments, any competitive organic functionalities attached to the terminal silicon or terminal carbon atom. Non-limiting functionalities of attached linker L include silanes such as alkoxysilanes and / or chlorosilanes; Silanol; Carboxylic acid; Amine; Carbamates; ester; ether; And others.

The R groups of the alkoxysilane moiety (Si (OR) ₃ ) may be the same or different. R includes substituted methyl, ethyl, n-propyl, or isopropyl including substitution with fluorine. R is also hydrogen. In some embodiments, R is hydrogen after the hydrolysis step in preparing the grafted chemical structure. In formula II, m, n, and o are integers that are selected based on the target molecular weight, as described above. In embodiments, m and o are integers from 2 to 8. In embodiments, n is an integer from 2 to 4.

In embodiments herein, the oleophilic graft polymer described herein is a compound of formula II:

II

        Wherein FE is a fluoroelastomer,

        FS is fluorine silicon,

        L is a linker,

        m, n, and o are independently integers from 1 to 10;

Each of R ¹ and R ² is independently optionally fluorinated C ₁ -C ₆ alkyl,

R ³ and R ⁴ are independently optionally fluorinated C ₁ -C ₆ alkyl or optionally fluorinated C ₁ -C ₆ alkoxy. In embodiments, m and o are independently integers of from 3 to 8 and n is an integer of from 1 to 10. In embodiments, as described above, linker L comprises C ₁ -C ₆ alkyl having a functional group end capable of covalently bonding to the terminal hydroxyl group of fluorine silicon.

Any C ₁ -C ₆ alkyl or C ₁ -C ₆ alkoxy is linear or branched. In embodiments, these groups are optionally substituted, including substitution of a halogen other than fluorine, such as chlorine or bromine. It will be appreciated by those skilled in the art that all fluorine silicon sites are not actually substituted, as in structure I, since structure I is polymerizable. Thus, in embodiments, the printhead coating disclosed herein may comprise a mixture of structure I and structure III:

III

Each group in the formula is defined as above. In embodiments, Structure III is small and is present at less than about 10%, or less than about 5%, or less than about 1% by weight of the coating composition. In some embodiments, the compound of Structure III, when present, has hidden silanol groups. For example, they may be substituted with alkoxy groups when treated with an alkylating agent.

The compound of formula II is composed of fluoroelastomer (FE) and fluorine silicone (FS) as described above. The two polymers are bonded with a crosslinker aid. The crosslinking agent is first used to crosslink the fluoroelastomer. In embodiments, the fluoroelastomer is crosslinked to the amino functionalized silane. In embodiments, the amino-functionalized silane also provides a graft-coupling point for fluorine silicon as indicated in structure I. In embodiments, the amino-functionalized silane can have a terminal bond of a polysiloxane having 3-aminopropyltrimethoxysilane (AO800, UCT, Bristol, Pa.) (Or siloxane when n = 1 in structures I and III) . It will be appreciated by those skilled in the art that the crosslinking agent itself may not be essential, but may have a high degree of fluorination.

In some embodiments, there is provided a process for making an oleophobic graft polymer comprising: crosslinking a fluoroelastomer to an amino functionalized silane; and grafting the alkoxysilane-terminated fluoroelastomer to a crosslinked fluoroelastomer. In some of these embodiments, the oleophilic graft polymer produced by this method consists of the compound of structure I above. In embodiments, crosslinking is carried out in the presence of alkoxysilane-terminated fluorine silicon. Crosslinking fluoroelastomers having hydrogen atoms in the backbone is expected to result in dehydrofluorination of the fluoroelastomers as indicated in step 1 of the following reaction path 1. An unsaturated fluoroelastomer intermediate and a protonated amino functionalized cross-linking agent are produced from the hydrogen dehydrofluoride. Regeneration of the amine with base (Step 2) and addition of amine to the unsaturated bond in succession (Step 3) yields a crosslinked fluoroelastomer which is grafted with perfluorinated silicon. Grafting (step 4) is accomplished by hydrolysis of the alkoxy groups of the cross-linking agent and / or the alkoxysilanes of the alkoxy silane-terminated fluorine silicon, and the compounds of structure I are provided.

Step 1: (Dehydrofluorination)

Step 2: (Regeneration of amines)

Step 3: (amine addition to double bond)

Route 1: Crosslinking reaction of fluoroelastomer using aminofunctionalized fluorosilicone as a crosslinking agent and perfluorinated fluorosilicone end of alkoxysilane.

As noted above, the fluoroelastomer crosslinking step is carried out in the presence of perfluorinated fluorosilicone. In some such embodiments, the ratio of the amino-functionalized silane to the alkoxy silane-terminated perfluorinated silicon is from about 0.5: 1 to about 3: 1, or from about 1: 1 to about 2: 1. In some embodiments, the ratio is about 1.5: 1. In some embodiments, the amino-functionalized silane content for the fluoroelastomer is from about 2 pph to about 10 pph. In some embodiments, the amino-functionalized crosslinker attachment to the perfluorinated fluorosilicone can be performed prior to the fluoroelastomer crosslinking. Any of the above processes may be performed with a catalyst aid and the reactions may optionally proceed at an elevated temperature. Typically, the reactions proceed in an organic solvent, such as methyl isobutyl ketone (MIBK). In embodiments, the reactions proceed in a one-pot reaction, without isolating the chemical intermediates. In embodiments, the reaction products are used as direct coatings with or without any type of purification.

In some embodiments, there is provided an inkjet printhead comprising a front face having a polymer coating, wherein the polymer coating comprises an oleophobic graft polymer that is comprised of a crosslinked fluoroelastomer and fluorosilicone grafted to the fluoroelastomer do. In some of these embodiments, the oleophilic graft polymer comprises a compound of structure I.

The ink contact angle of a satisfactory oleophobic coating should be greater than about 40 degrees over the life of the coating to maintain a drool pressure specification of about 4 inches, and a larger contact angle is advantageous. Also, the front coating has a low slip angle to ideally facilitate easy / self-cleaning features, thereby reducing the overall or low maintenance cost, high engine reliability and operating cost of the printhead cartridge. The low slip angle is a measure of low ink adherence and means that the ink is wiped from the surface without leaving ink residue around the nozzle. Any ink residue around the nozzle breaks the ink meniscus and fogs at pressures below the specified value. Also, any coating ideally retains this characteristic even after severe press press assembly conditions, e.g., about 290 DEG C and 350 PSI for 30 minutes. In some embodiments, the ink contact angle of the polymer coating is at least about 50 degrees and the ink slip angle is less than about 30 degrees. In addition, the polymer coating used for the front of the printhead is stable at 290 캜 and 350 psi, which is advantageous for manufacture.

Wet print head front coat of an ink jet printhead configured to jet the oleophobic low adhesion surface ink disclosed herein onto a recording medium. Any suitable recording medium may be used, such as, for example, XEROX® 4024 paper, XEROX® Image Series paper, Courtland 4024 DP paper, ruled notebook paper, bond paper, silica coated paper such as Sharp Company silica coated paper, JuJo paper, Hammermill laser print paper, And other, transparent materials, fabrics, textile products, plastics, polymer films, inorganic substrates such as metals and wood, and others.

In some embodiments, the printhead is configured with a front surface having an oleophobic adhesive coating comprising an oleophobic adhesive polymer on the surface, wherein the drop droplets of the ultraviolet gel ink or solid ink are in contact with the surface coat This is about 50 degrees or more. In some embodiments, the contact angle is about 55 degrees, or about 65 degrees or more. In one embodiment, there is no upper limit for the contact angle between the droplets of the ultraviolet gel ink or the solid ink and the surface coating. In another embodiment, the contact angle is less than about 150 degrees, or less than about 90 degrees. The larger the ink contact angle, the higher the overspray pressure. The overspout pressure is related to the aperture plate performance to prevent ink flow from the nozzle as the ink tank (reservoir) pressure increases. In some embodiments, the coating provides low adhesion and a high contact angle to the ultraviolet curable gel ink and solid ink, which preferably acts on the overspray pressure. In some embodiments, the coatings of the present invention provide a low slip angle of less than about 30 degrees. In some embodiments, the slip angle is less than about 25 degrees. In some embodiments, the slip angle is greater than about 1 degree. The contact angle is almost independent of the droplet size. However, the contact angle is measured by dispensing 5-10 microliters of UV ink or solid ink drops onto the surface coating. The slip angle is measured by dispensing 7-12 microliters of UV ink or solid ink drops on the surface coating.

In embodiments described herein, the oleophobic adhesive coating is thermally stable and can be applied at elevated temperatures, such as from about 180 ° C to about 325 ° C, and a high pressure of from about 100 psi to about 400 psi, for an extended period of 15 times, Provides a low slip angle of from about 1 degree to about 30 degrees and a high contact angle of from about 45 degrees to about 150 degrees after exposure for two hours. In one embodiment, the oleophobic adhesive coating is thermally stable even after about 30 minutes of exposure at about 290 DEG C, about 350 psi. High density piezo printhead assembly requires high temperature, high pressure adhesive bonding steps. It is desirable that the face coating will withstand these high temperature and high pressure conditions. The stability of the oleophobic low adhesion surface coatings described herein at high temperature and high pressure can be applied in current printhead manufacturing processes.

When coated on the front of an inkjet printhead, the oleophobic low-adhesion surface coating exhibits a sufficiently low adhesion to the ink ejected from the inkjet printhead, and thus the ink droplets in the oleophobic adhesive coating are printed in a simple self- Slides on the head. Contaminants such as dust, paper particles and the like, which are sometimes found in the front of the inkjet printhead, are removed from the front of the inkjet printhead by sliding the ink drop. The oleophobic low adhesion printhead face coating provides a self-cleaning, no-fouling inkjet printhead.

The oleophobic adhesive coating, as used herein, refers to an ink that is ejected from an inkjet printhead when the contact angle between the ink and the oleophobic adhesive coating is, in one embodiment, greater than about 50 degrees, or greater than about 55 degrees Quot; sufficiently low wettability ".

The oleophobic adhesive coatings disclosed herein may be used in any suitable ink jet printer such as continuous ink jet printers, thermal on demand (DOD) ink jet printers, and ink jet printheads of solvent based low adhesion printhead frontcoat of piezo DOD ink jet printers . As used herein, the term " printer " encompasses any device that performs a print output function for any purpose, such as a digital copier, book reader, facsimile, all-in-one, and the like.

The oleophobic low-adhesion coatings disclosed herein can be used to provide an oleophobic printhead front for an inkjet printhead for ejection of any suitable ink such as a water-based ink, a solvent ink, a UV-curable ink, a dye sublimation ink, It is used as a coating. An exemplary inkjet printhead suitable for use with the oleophobic adhesive coatings disclosed herein is shown in Fig.

2, an inkjet printhead 20 in accordance with an embodiment of the present invention includes a support brace 22, a nozzle plate 24 coupled with the support brace 22, and an oleophobic adhesive coating, Adhesive low-adhesion coating 26.

The support brace 22 is formed of any suitable material, such as stainless steel, and has openings 22a formed therein. The openings 22a communicate with an ink source (not shown). The nozzle plate 24 is formed of any suitable material such as polyimide and has nozzles 24a formed therein. The nozzles 24a are communicated with the ink source through the openings 22a so that the ink source ink is ejected from the printhead 20 through the nozzles 24a to the recording medium.

In the illustrated embodiment, the nozzle plate 24 is joined by the support brace 22 and the intervening adhesive 28. The adhesive 28 is provided as a thermoplastic adhesive and is melted in the process of joining the nozzle plate 24 to the support brace 22. Typically, the nozzle plate 24 and the oleophobic adhesive coating 26 are also heated during the bonding process. Depending on the thermoplastic adhesive, the bonding temperature is from about 180 캜 to about 325 캜.

Conventionally oily low adhesive coatings can be degraded in a typical bonding process or in other high temperature, high pressure processes of inkjet printhead assembly. However, the oleophobic adhesive coating 26 disclosed herein exhibits a sufficiently low adhesion and high contact angle to the ink, which is marked with a low slip angle even after being heated to the bonding temperature. The oleophobic low adhesion coating 26 provides a self-cleaning, non-contaminated ink jet printhead 20 having a high overspout pressure. Due to the oleophobic adhesive coating 26, which has a desirable surface property such as a low slip angle and a high contact angle and a significant resistance to degradation after exposure at elevated temperatures, the inkjet printhead has a self- And can be assembled in high temperature and high pressure processes. An embodiment of the ink-jet printhead forming process is described with reference to Figs. 2-5.

Referring to FIG. 3, an inkjet printhead, such as an inkjet printhead 20, is fabricated by forming an oleophobic low adhesion coating, such as an oleophobic low adhesion coating 26, The substrate 32 may be formed of any suitable material, such as polyimide.

In one embodiment, the oleophobic adhesive coating 26 is formed by first applying a reaction mixture comprising at least one fluoroelastomer and at least one fluorosilicone compound, as described above to the substrate 32. After the reaction mixture is applied to the substrate 32, the reactants are reacted to form an oleophobic adhesive coating 26. The reactants are reacted, for example, by curing the reaction mixture.

In one embodiment, the reaction mixture is applied to the substrate 32 by any suitable method such as die compression coating, dip coating, spray coating, spin coating, flow coating, stamp printing, and blade techniques. The reaction mixture is sprayed using an air atomizing device such as an air brush or an atomizing air / liquid atomizer. The air atomizing apparatus is mounted on an automated reciprocating apparatus which uniformly moves to cover the surface of the substrate 32 with a uniform amount of the reaction mixture. The use of doctor blades is another technique that can be applied to apply the reaction mixture. In the flow coating, the programmed dispenser is applied to apply the reaction mixture.

4, the substrate 32 is joined to the opening brace 22 via an adhesive 28 to obtain the structure shown in Fig. In one embodiment, the adhesive 28 is bonded to the substrate 32 after being bonded to the opening brace 22. In another embodiment, the adhesive 28 is bonded to the opening brace 22 after being bonded to the substrate 32. In another embodiment, the adhesive 28 is simultaneously bonded to the substrate 32 and the opening brace 22.

In embodiments in which the adhesive 28 is provided as a thermoplastic adhesive, the thermoplastic adhesive is melted at the bonding temperature and bonding pressure at which the oleophobic coating 26 is exposed to bond the adhesive 28 to the substrate 32 and the opening brace < (22). In one embodiment, the bonding temperature is at least about 290 ° C. In one embodiment, the bonding temperature is at least about 310 ° C. In another embodiment, the bonding temperature is at least about 325 ° C. In one embodiment, the bonding pressure is at least about 100 psi. In one embodiment, the bonding pressure is at least about 300 psi.

After bonding the substrate 32 to the open brace 22, the open brace 22 in the patterning process is applied as one or more masks to extend the openings 22a into the adhesive 28 as shown in Figure 2 . The opening brace 22 is also applied as a mask in one or more patterning processes for forming the nozzles 24a in the substrate 32 to form the nozzle plate 24 as shown in Fig. One or more patterning processes also applied to the formation of the nozzles 24a are applied to the formation of the nozzle openings 26a in the oleophobic adhesive coating 26 such that the nozzle openings 26a are aligned with the nozzles 24a, . In one embodiment, the openings 22a extend into the adhesive 28 in a laser flux patterning process or the like. In one embodiment, the nozzles 24a and nozzle openings 26a are formed in the substrate 32 and the oleophobic adhesive coating 26, respectively, in a laser flux patterning process or otherwise.

Synthesis of oleophilic graft polymer (A) .

Referring to FIG. 6, the fluoroelastomer is dissolved in a ketone solvent at 40 (Part A) and is referred to as fluoroelastomer. On the other hand, the alkoxysilane terminated fluorine silicon and amino cross-linker are mixed overnight at 42 (Part B) and are referred to as adhering silicon. After both solutions are prepared, fluorine silicone is slowly added to the fluoroelastomer at 44 and the catalyst is added. In one embodiment, the catalyst is MgO / CaO. The mixture is then mixed for 2 hours and applied to the polymer substrate used as the printhead at 46. In one embodiment, the coating is drawn directly onto the polyimide. It can also be applied by flow coating. The solvent is evaporated and the polymer film is then oven-cured at 48 ° C for 24 hours at 450 ° F. It may also be cured under other curing conditions.

Properties of the Process In an embodiment, 17.5% fluoroelastomer (TECNOFLON.RTM. FKM (P959), Solvay Specialty Polymers, Alpharetta, GA) dissolved in methyl isobutyl ketone (MIBK) and about 1 pph FC4430 A solution of AKF 290 (Wacker) was prepared. Surfactants appear to provide compatibility between the fluoroelastomer and the release layer / oil applied to the fuser and prevent pinhole / fish eye defects. Next, an amino crosslinking agent and alkoxy silane end fluorine silicone at a molar ratio of 1.5: 1 in MIBK were mixed and stirred overnight. In this example, three different samples were prepared. (1) Crosslinking agent: and fluorine silicone (0.86 mM: 0.57 mM) (2) Crosslinking agent: and fluorine silicone (1.71 mM: 1.13 mM) Silicon (2.56 mM: 1.70 mM). After 16-18 h, Part B was added to Part A at 44 and mixed. Part B was added to Part A, the 9% MgO / CaO stock solution in the MIBK mixture in the sol state was added and the mixture was agitated vigorously for 5 minutes using a devil shaker and the product mixture The polyimide substrate was coated with Druuba. Cured at room temperature overnight, transferred to an oven at 218 ° C and held for 4 hours.

Owing Graft Polymer Properties : According to the TGA decomposition profile in air as shown in Fig. 7, the coating is stable up to 330 占 폚. The surface properties of the coatings on the ink were evaluated. The results are shown in Table 1 below.

Coating material Thickness and weight loss after 30 min at 290 ° C The surface characteristic contact angle, CA, and slip angle SA for the solid ink (degrees) Initial (after) Stacking (290 ˚C / 350 PSI / 30 min) Lamination + Inking at 140 ˚C for 2 days Fluorosilicone - Fluorine Silicone Graft 3-5% 68 (18-20) 68 (31) 67 (25) Existing Coatings Approximately 50% 71 (10) 68 (15) 60 (20)

As can be seen in the table, the surface properties are compared to the existing control coatings. These coatings maintained a high contact angle even after 290 ° C / 350 PSI with a Teflon coverlay, which is a stacking condition simulating the compression bonding cycle applied in the print head assembly process. The laminated coating also maintained a high contact angle with the molten CYMK ink after 2 days at < RTI ID = 0.0 > 140 C. < / RTI > The slip angle was slightly higher than the control, but it was judged that the ink slipped cleanly on the surface and was low enough to allow easy cleaning during use. It is also expected that such exemplary oleophilic graft polymers will have desirable mechanical robustness for long term performance of such coatings. These coatings can be seen to scale up with flow coatings and achieve flow coating with these graft polymers.

According to the TGA decomposition profile in air, the coating is stable up to 330 ° C. The surface properties of the coatings to the inks were evaluated and the results are presented in Table 1 above. These coatings maintained a high contact angle even after 290 ° C and 350 PSI with Teflon® coverlay, a lamination condition simulating the compression bond bonding cycle applied in the print head assembly process. Also, the laminated coatings maintained a high contact angle even after two days of fusing with the solid ink at 140 ° C. The slip angle was slightly higher than the control, but it is easy to clean. When the test coupons were extruded after ink research, the ink slipped cleanly and no ink residue was observed in the coating.

Fluorine elastomers - fluorosilicone graft coatings are thermally stable, mechanically robust, oleophobic, low adhesion coatings. These compositions have a very different chemical composition from other coatings used in the art. The coating has thermal stability while having a high ink contact angle and low slippage. No ink is observed on the film surface after curing. The coating also exhibits little thickness and weight loss after exposure to 290 < 0 > C.

The fact that such a coating can maintain the desired surface properties while having very high thermal stability and no oil at all is an attractive option as an anti-wet coating in the field of high precision piezoelectric printing.

Claims (10)

An ink jet printhead having a front face with a polymer coating, wherein the polymer coating comprises an oleophobic graft polymer,
Crosslinked fluoroelastomers; And
And fluorine silicon grafted to the crosslinked fluorine elastomer. The inkjet printhead of claim 1, wherein the oleophilic graft polymer has a structure of formula (II)

II
Wherein FE is fluoroelastomer;
FS is perfluorinated fluorine silicone;
L is a linker;
m, n, and o are integers from 1 to 10;
R ¹ and R ² are each independently substituted or unsubstituted C ₁ -C ₆ alkyl,
R ³ and R ⁴ are independently optionally and independently fluorinated C ₁ -C ₆ alkyl or optionally optionally fluorinated C ₁ -C ₆ alkoxy. The inkjet printhead of claim 1, wherein the ink contact angle of the polymer coating is at least about 45 degrees. 2. The inkjet printhead of claim 1, wherein the polymer coating is stable at 290 DEG C and 350 psi. A method of forming an oleophobic graft polymer coating on a printhead,
Crosslinking the fluoroelastomer with the amino functionalized silane;
Grafting an alkoxysilane-terminated fluorine silicone to the crosslinked fluoroelastomer to form an oleophobic graft polymer; And
And coating the oleaginous graft polymer on the front side of the printhead. 6. The process of claim 5, wherein the oleophilic graft polymer has a final structure of formula (II).

II
Wherein FE is fluoroelastomer;
FS is perfluorinated silicon fluoride;
L is a linker;
m, n, and o are integers from 1 to 10;
Each of R ¹ and R ² is independently optionally and independently fluorinated C ₁ -C ₆ alkyl,
R ³ and R ⁴ are independently optionally and independently fluorinated C ₁ -C ₆ alkyl or optionally optionally fluorinated C ₁ -C ₆ alkoxy. 6. The method of claim 5, wherein the crosslinking is performed in the presence of the alkoxysilane-terminated fluorine silicon. An inkjet printhead comprising a front face having a polymer coating, wherein the polymer coating comprises a structure of formula (II):

II
Wherein FE is fluoroelastomer;
FS is fluorine silicon;
L is a linker;
m, and o are independently an integer from 3 to 8;
n is an integer from 1 to 10;
R ¹ and R ² are each independently substituted or unsubstituted C ₁ -C ₆ alkyl,
R ³ and R ⁴ are independently optionally and independently fluorinated C ₁ -C ₆ alkyl or optionally optionally fluorinated C ₁ -C ₆ alkoxy. 9. The inkjet printhead of claim 8, wherein the linker L comprises C ₁ -C ₆ alkyl terminated with a functional group capable of covalently bonding to the terminal hydroxyl functionality of the fluorine silicone. The method of claim 8, wherein the fluoroelastomer (FE) is a polymer comprising monomer units selected from the group consisting of vinylidene fluoride, ethylene tetrafluoride, propylene hexafluoride, perfluorinated methyl vinyl ether, head.

Images