KR20010013348A - Bonding system in an inkjet printer pen and method for providing the same - Google Patents

Abstract

An inkjet printer pen structure is provided that includes a flexible circuit (26) having a plurality of conductors (28) formed on a first surface electrically connected to a plurality of contact pads (29) located on a second surface of the flexible circuit; a body (12) adapted to store and dispense ink; and a bonding system prepared from a latently curable composition located between the first surface of the flexible circuit and the body. The bonding system operably attaches the conductors on the flexible circuit to the body. Also provided is a method for providing such a bonding system in an inkjet printer pen.

Description

A bonding system in an inkjet printer pen and a method for providing the same

Inkjet printer pens generally include (1) ink reservoirs and ink dispensing mechanisms that can hold various valves, springs, foams, bags, etc., which facilitate ink handling and facilitate dispensing ink from the body during printing. A flexible circuit for transmitting electrical signals from an inkjet printer to a printer chip to volatilize and eject ink onto a recording medium, generally paper, and (3) a position between the flexible circuit and the body Thereby tightly coupling the flexible circuit to the body and protecting the flexible circuit from unnecessary exposure to corrosive printing inks. The printer chip may be in any form, and is essential for printing by an actual inkjet printer pen.

Inkjet printer pens generally include a small metal or plastic ink holding container attached to a flexible circuit. This flexible circuit electrically connects the printer chip to the driver electronics in the inkjet printer where the inkjet pen is located. This flexible circuit is attached to the print head to transfer current from the printer to the printer chip.

Plastics commonly used in the manufacture of inkjet pen bodies include polyphenylene oxides, polysulfones, polyesters, liquid crystal polymers (LCPs), polyether-ether-ketones (PEEKs), polyetherimides (PEIs), phenolic materials, Nylon and other thermoset or thermoplastic working materials.

The above-described flexible circuits are generally thin about 1 mil to about 3 mil (0.025 mm to 0.075 mm) polymer film, such as polyimide film, on which a plurality of patterns of copper or gold plated copper traces or conductors are molded. It is. For example, the flexible circuit material consists of a polyimide film (UPLIX, Ic Composites Inc. of Wilmington, Delaware, USA) having a thickness of about 0.05 mm. In addition, a plurality of gold traces and conductors are also formed on the surface of the film. Such gold plated copper conductors are typically 0.033 mm thick and are generally provided on only one side of the polyimide film. However, this conductor may be an intersection line passing through the polyimide film and terminating on the opposite side.

An inkjet printer pen rapidly heats a small amount of ink to vaporize the ink and eject it through one of the plurality of orifices to print an ink spot on a recording medium such as a paper sheet. Generally, at least one orifice is arranged linearly in the nozzle member. When ink is ejected from each orifice in the proper order, characters or other images are printed on the recording medium as the printer chip moves relative to the recording medium. This medium is generally moved each time the printer chip moves along the medium. The heated inkjet printer is high speed without making a sound when ink touches the recording medium. The printer offers high quality printing and is compact and affordable.

The current provided from the printer's external power source for printing a single ink spot is passed through a given thin film resistor. The resistor is then heated to alternately overheat adjacent thin layers of ink in the vaporization chamber, causing explosive vaporization, which in turn ejects ink through the connected orifices onto the recording medium.

The bonding material used to attach the flexible circuit to the inkjet pen body must have good adhesion to the body and sometimes be strong and rigid to withstand continuous immersion in hot inkjet inks. The ink may be a curable hot melt (thermoplastic) solvent or an aqueous medium or a mixture of solvents with an aqueous medium such as alcohol and water. The most widely used carrier liquids for inks are solvents, aqueous media and mixtures thereof. The main types of components used in the ink formulations are as follows.

additive Usage Colorants (dyes or pigments) Marker Buffer Colorant stabilization Binder Fastness to water and light; Pigment Immobilization to Substrate Water or organic solvent Solvent or carrier Biocides / Fungicides Prevent ink disassembly and nozzle clogging Penetrant Improved drying and moisture fastness Absorbent Prevention of drying in nozzle Fixative Improved Burn Durability Surfactants Improved wettability of printed substrates

Aqueous inks used in printing on paper are more restrictive in composition than organic solvent inks. In high temperature inkjet printing, the ink must be able to withstand the high temperatures formed for vaporization of the ink. The pH of the ink can vary widely from about 4 to about 11 and can be strong corrosive.

The coupling between the flexible circuit and the pen body is provided for two purposes: to maintain physical contact between the flexible circuit and the printer chip conductors and to coat the conductor to protect the conductor from contact with corrosive ink. When the bonding material used to bond the flexible circuit to the pen body is attacked by the ink, the flexible circuit is detached and / or lifted from the pen body, causing the ink to contact the conductive circuit, resulting in electrical shorts between the conductors and other electrical Cause disability. In addition, if the bonding material fails to form a complete film and protects the circuit from chemical attack of the ink, it may cause an electrical short or a bad signal. All of these problems can cause the inkjet printer pen to stop working. Therefore, in the manufacture of this pen, it is sometimes desirable that the bonding material be tacky enough to exhibit sufficient initial adhesion and that the pen can be handled without leaving the flexible circuit. The way of clamping the part in order not to leave the flexible circuit is unlikely or may add additional steps, costs and time to the manufacturing process.

Some of the bonding methods for attaching flexible circuits to currently used pen bodies are using double-sided pressure sensitive adhesive (PSA) tape or thermoplastic bonding films. These PSA tapes and thermoplastic films are tacky at room temperature or at high temperatures, but today are more advanced printing inks, i.e. used at high temperatures and contain strong corrosive solvents or auxiliary solvents and generally have a pH in the range of about 4 to about 11, more generally It does not provide the adhesion or ink resistance protection required for printing inks ranging from about 6 to about 8.

Solutions to the shortcomings of such PSAs and uncured thermoplastic systems can be obtained through cured or thermoset bonding materials that provide improved chemically resistant bonds and protective films after curing.

However, some cured film techniques have the disadvantage of not being able to obtain adequate strength in handling prior to initiation of curing. In addition, some cured bonding films generally require longer curing times than are required for the high speed, high throughput production lines normally used for assembly of pens. Many cured compounds generally require about 10 minutes to about 90 minutes per unit. More generally, however, the preferred total bond time is on the order of 1 to 4 seconds. Other ultraviolet (UV) free radical cure chemistry / technologies, which typically have a short cure time, typically only about a few seconds, are required for the inkjet pen because UV cured light does not approach the bonding film in non-assembled and / or assembled structures. Not used for the purpose In addition, the bonding film irradiation before bonding of the components is impossible because the bonding film can be cured before the components are joined together. In the case of the free radical curing chemistry described above, stopping exposure to ultraviolet light generally stops curing, and it is not impossible or practical to continue to be exposed to ultraviolet light during the curing cycle.

In addition, the aforementioned bonding films are generally made of high molecular weight materials that do not generally flow at room temperature and thus do not provide adequate wettability (a phenomenon known as "tenting") between extremely spaced lead or conductors. Thus, films made of high molecular weight materials do not adequately coat small, extremely spaced conductors and traces, and thus do not protect against the corrosiveness of the ink and provide undesirable conductivity between conductors on flexible circuits as described above. do.

Accordingly, coupling systems and couplings for coupling flexible circuits to pen bodies in inkjet pens that are reversible for various inkjet pen manufacturing processes and provide a barrier between the ink in the ink reservoir of the pen body and the conductors on the flexible circuit. A method is required.

The present invention relates to an inkjet printer pen structure.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings illustrating preferred embodiments and the following detailed description.

1 is a perspective view of an inkjet printer pen 10.

FIG. 2 is an exploded perspective view showing the back side of the flexible circuit 26 of FIG. 1 with one coupling system 30 described herein.

3A, 3B, and 3C are cut along the lines A-A of FIG. 2 showing the coupling of the flexible circuit 26 to the pen body 12 using the coupling system 30 described herein. Cross section view.

FIG. 3D is a partial cross-sectional view showing the system 30 of FIG. 3C coupled to the ink reservoir 12.

4 is a partial cross-sectional view of another embodiment of the coupling system described in the present invention.

Detailed description of preferred embodiments

The inkjet printer pen described in the present invention includes a bonding system made of a latent curable composition that couples a flexible circuit to an inkjet pen body. The latent curable composition has a curing mechanism that can be cured at room temperature, provides sufficient open time to bond parts / substrates well, and can be stimulated by external influences such as radiation exposure such as ultraviolet light or visible light.

Generally, the binding system is made of a latent curable composition, which is a polymer (including oligomer) composition that is activated upon exposure to radiation to cure. Curing, as used herein, means that the polymer in the composition is present or begins to form (crosslink) bonds between the formed polymer chains, the polymer chains are stretched to increase molecular weight, or crosslinking and stretching occurs simultaneously. Once curing is initiated, the composition has an "open time" as described above. Thus, the latent curable composition continues to cure even after the inkjet printer pen member is mated without being continuously exposed to radiation. The open time is preferably about 24 hours or less, more preferably about 6 hours or less, most preferably about 5 minutes to about 30 minutes. After the open time, the latent curable composition is in a state that cannot be softened easily, which is referred to herein as " completely cured ".

The binding system is preferably self-fastening. That is, it may be pressure sensitive or melt flowable. For example, the bonding system can be made of a latent curable composition that is melt flowable that softens to wet the surface disposed by application of heat and / or pressure. This bonding system joins two surfaces upon cooling. Bonding systems made from a melt flowable latent curable composition have excellent handleability that can be used in various assembly processes for making inkjet printer pens. In addition, the latent curable composition of melt flow retains an initial bond strength that allows the parts to mate together during the assembly process prior to curing. For example, some preferred fully cured bonding systems have an overlap shear strength of at least 100 psi (0.69 MPa) and about 2 to 3 piw (0.35 to 0.53 kN) when tested for materials used to make flexible circuits and inkjet printer pen bodies. / m) of 90 ° peel strength.

The melt flowable material used in the bonding system of the present invention may be thermoplastic or thermoset. The melt flowable material can be a copolymer, a graft copolymer, a permeable network and mixtures thereof.

If the bonding system made of the latent curable composition is melt flowable, the latent curable composition is preferably heated on a flexible circuit until it is tacky. Bonding systems made from a latent curable and melt flowable composition may be made from a combination of both thermoplastic polymer material components and thermoset material components, or from both components. The latent curable composition comprises a melt flowable material selected from the group consisting of epoxy / acrylate, epoxy / polyester, epoxy / polycaprolactone and mixtures thereof.

In a preferred embodiment, the latent curable composition useful in the bonding system in the inkjet pen of the present invention is an epoxy containing material that provides the maximum strength and resistance of the composition (i.e. heat and chemical resistance), a polyester component that quickly enhances the degree of ginger, It is preferable to include a photoinitiator that cures the composition upon exposure to radiation and a hydroxyl-containing material that imparts flexibility to the latent curable composition and / or retards the rate of cure, and more preferably substantially consists of the components. good. Such bonding systems have improved physical properties such as improved heat resistance and improved chemical resistance in inkjet printer environments.

One example of a latent curable melt flowable composition is an epoxy / polyester hotmelt composition described in European Patent Publication 0620259 (George et al.). The composition is latent cured upon exposure to radiation to provide a high strength material with good adhesion to the pen body substrate. In this composition, the epoxy containing material is a thermosetting component and the polyester is a thermoplastic polymer material. For example, if the radiation used is ultraviolet light, its wavelength range is 200 to 800 nm and the dosage is about 50 milli Joules to about 1000 milli Joules. The latent curable composition preferably comprises a hydroxyl containing material that imparts flexibility and toughness to the composition. Preferred polyesters for the epoxy / polyester materials are solid at room temperature, preferably with a number average equivalent in the range of about 7500 to about 200,000, more preferably in the range of about 10,000 to about 50,000, most preferably in the range of about 15,000 to about 30,000. It is good to be.

Epoxy-containing materials

Epoxy-containing materials useful in the compositions of the invention include one or more oxirane rings that are polymerizable by ring opening Is an organic compound having Such materials, commonly referred to as epoxides, include monomeric epoxides and polymeric epoxides and may be aliphatic, cycloaliphatic or aromatic. Generally, this material has an average of at least two epoxy groups per molecule (preferably having more than two epoxy groups per molecule). Polymer epoxides include linear polymers with terminal epoxy groups (eg diglycidyl ethers of polyoxyalkylene glycols), polymers with oxirane unit backbones (eg polybutadiene polyepoxides) and polymers with side chain epoxy groups (eg , Glycidyl methacrylate polymer or copolymer). The weight average molecular weight of the epoxy containing material may range from 58 to about 100,000 or more. In addition, mixtures of various epoxy-containing materials can be used in the latent curable composition of the present invention. The "average" number of epoxy groups per molecule is the number of epoxy groups in the epoxy containing material divided by the total number of epoxy molecules present.

Useful epoxy containing materials include cyclohexene oxide groups, such as epoxycyclohexanecarboxylate, typically 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy- 2-methylcyclohexylmethyl-3,4-epoxy-2-methylcyclohexane carboxylate and bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate. More detailed examples of useful epoxides of this nature are illustrated in US Pat. No. 3,117,099.

Another epoxy containing material particularly useful in the practice of the present invention includes glycidyl ether monomers represented by the formula:

Wherein R 'is alkyl or aryl and n is an integer from 1 to 6. Examples include glycidyl ethers of polyhydric phenols obtained by reacting an excess of chlorohydrin such as epichlorohydrin (e.g., 2,2-bis- (2,3-epoxypropoxyphenol) propane) with a polyhydric phenol. have. Examples of another epoxide of this kind that can be used in the practice of the present invention are described in US Pat. No. 3,018,262.

Epoxy-containing materials that can be used in the present invention include many commercially available materials. Specifically, available epoxides include octadecylene oxide, epichlorohydrin, styrene oxide, vinyl cyclohexene oxide, glycidol, glycidyl methacrylate, diglycidyl ether of bisphenol A (e.g. shells). Products sold under the trade names EPON 828, EPON 1004 and EPON 1001F sold by the Chemical Company under the trade names DER-332 and DER-334 under the Dow Chemical Company, and diglycidyl ethers of bisphenol F (e.g. ARALDITE GY281), vinylcyclohexene dioxide (e.g., ERL 4206 from Union Carbide Corp.), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexene carboxylate (e.g., ERL-4221 from Union Carbide Corp.), 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane metadioxane (e.g., ERL-4234 from Union Carbide Corp.), bis (3,4-epoxycyclohexyl) Adipate (e.g. uni Carbide cope ERL-4299), dipentene dioxide (e.g. Union Carbide cope ERL-4269), epoxidized polybutadiene (e.g. OXIRON 2001 from FMC Cop), silicone resins containing epoxy functional groups, epoxy silanes [example , Beta- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and gamma glycidoxypropyltrimethoxy silane available from Union Carbide], flame retardant epoxy resins (e.g., brominated bisphenols available from Dow Chemical Company) Type epoxy resin, DER-542), 1,4-butanediol diglycidyl ether (e.g., ARALDITE RD-2 from Ciba-Geigy), hydrogenated bisphenol A-epichlorohydrin epoxy resin (e.g., shell chemicals) The company EPONEX 1510) and polyglycidyl ethers of phenolformaldehyde novolacs (eg, DEN-431 and DEN-438 from Dow Chemical Company).

Polyester

Useful polyesters include hydroxyl and carboxyl terminations that are amorphous or semicrystalline. In particular, hydroxyl end products are preferred. "Amorphous" means a material that has a glass transition temperature but does not exhibit a crystalline melting point measurable with a differential scanning calorimeter (DSC). The glass transition temperature is below the decomposition temperature of the photoinitiator (described below), with a temperature not higher than about 120 ° C. is preferred. By "semicrystalline" is meant a polyester component exhibiting a crystalline melting point in DSC measurements, preferably having a maximum melting point of about 150 ° C.

In general, if a latent curable composition that cures under ambient conditions is desired, the glass transition temperature of the polyester component is preferably lower than ambient temperature, preferably less than about 20 ° C. As the glass transition temperature of the polyester component increases, the composition may need to be thermally cured and radiation cured.

The polyester preferably has a Brookfield viscosity in excess of 10,000 millipascals at 121 ° C. Viscosity is related to the equivalent of the polyester component. Further, preferred polyester components are those having a number average equivalent weight of about 7500 to 200,000, more preferably about 10,000 to 50,000, and most preferably about 15,000 to 30,000.

Polyester components useful in the present invention include reaction products of dicarboxylic acids (or diester equivalents thereof) and diols. Diacids (or diester equivalents thereof) are saturated aliphatic acids having 4 to 12 carbon atoms (linear, branched or cyclic materials having 5 to 6 atoms in the ring) and / or 8 to 8 carbon atoms. 15 aromatic acids. Examples of suitable aliphatic acids include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12 dodecanediic acid, 1,4-cyclohexanedicarboxylic acid, 1,3 -Cyclopentanedicarboxylic acid, 2-methylsuccinic acid, 2-methylpentanediic acid, 3-methylhexanediic acid, and the like. Suitable aromatic acids include terephthalic acid, isophthalic acid, phthalic acid, 4,4'-benzophenone dicarboxylic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4'-diphenylether dicarboxylic acid, 4,4'-diphenylthioether dicarboxylic acid and 4,4'-diphenylamine dicarboxylic acid. It is preferable that the structure which exists between both carboxyl groups in such diacid contains only carbon and hydrogen. In particular, it is more preferable that it is a phenylene group. It is also possible to use any combination of the diacids described above.

Diols include branched diols, linear diols and cyclic aliphatic diols having 2 to 12 carbon atoms, examples of which include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butanediol , 1,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 1,6-hexanediol, 1,8-octanediol, cyclobutane-1,3-di (2 ' Ethanol), cyclohexane-1,4-dimethanol, 1,10-decanediol, 1,12-dodecanediol and neopentyl glycol. As the long-chain diol, poly (oxyalkylene) glycol or the like in which the alkylene group contains 2 to 9 carbon atoms (preferably 2 to 4 carbon atoms) may be used. It is also possible to use any combination of the diols described above.

Commercially available hydroxyl terminated polyester materials include various saturated linear semicrystalline copolyesters from Hums America Inc. such as DYNAPOL S1358, DYNAPOL S1227, DYNAPOL S1229, DYNAPOL S1401, DYNAPOL S1228, and DYNAPOL S1402. Useful saturated linear amorphous copolyesters also include DYNAPOL S1313, DYNAPOL S1421 and DYNAPOL S1420 from Hums America Inc.

Photoinitiator

Photoinitiators useful in the compositions of the present invention are cationic and include three types. That is, aromatic iodonium complex salt, aromatic sulfonium complex salt, and metallocene salt. Useful aromatic iodonium complex salts are described in more detail in US Pat. No. 4,256,828. Preferred aromatic iodonium complex salts are diaryl iodonium hexafluorophosphate and diaryl iodonium hexafluoroantimonate. Useful aromatic sulfonium complex salts are also disclosed in US Pat. No. 4,256,828. Preferred aromatic sulfonium complex salts are triaryl substituted salts such as triphenylsulfonium hexafluoroantimonate. Useful metallocene salts are described in more detail in US Pat. No. 5,089,536. One example of a useful salt is Cp (xylene) Fe ⁺ SbF ₆ ⁻ . The metallocene salt can be activated by visible light or black light. Sulfonium salts can be activated upon exposure to medium pressure mercury ultraviolet light. In any case, the epoxy can cure through heat.

Useful aromatic iodonium complex salts are those represented by the formula:

Wherein Ar ¹ and Ar ² are aromatic groups having 4 to 20 carbon atoms and are selected from the group consisting of phenyl, thienyl, furanyl and pyrazolyl groups. Z is oxygen; sulfur; [Where R is aryl (6-20 carbon atoms, such as phenyl) or acyl (2-20 carbon atoms, such as acetyl, benzoyl, etc.); Carbon to carbon bonds; or Wherein R ₁ and R ₂ are selected from hydrogen, alkyl radicals of 1 to 4 carbon atoms and alkenyl radicals of 2 to 4 carbon atoms. m is 0 or 1 and X is a halogen-containing complex anion selected from tetrafluoroborate, hexafluorophosphate, pentafluorohydroxyantimonate, hexafluoroarsenate and hexafluoroantimonate .

Ar ¹ and Ar ² aromatic groups may optionally have one or more fused benzo rings (eg, naphthyl, benzothienyl, dibenzothienyl, benzofuranyl, dibenzofuranyl, and the like). Aromatic groups may also be substituted with one or more nonbasic groups that are substantially non-reactive with the epoxide and hydroxyl functional groups if desired.

Useful aromatic iodonium complex salts are described in more detail in US Pat. No. 4,256,828. Preferred aromatic iodonium complex salts are diaryl iodonium hexafluorophosphate and diaryl iodonium hexafluoroantimonate.

Aromatic iodonium complex salts useful in the compositions of the present invention are those that are photosensitive only in the ultraviolet region of the spectrum. However, these salts can be photosensitized by spectra in the vicinity of ultraviolet light and in the visible range by photosensitizers of known photodegradable organic halogen compounds. Examples of such photosensitizers include aromatic amines and colored aromatic polycyclic hydrocarbons.

Suitable aromatic sulfonium complex salt photoinitiators for use in the compositions of the present invention may be represented by the formula:

Wherein R ₃ , R ₄ and R ₅ are the same or different, provided that at least one of these groups is aromatic. This group may be selected from aromatic moieties having 4 to 20 carbon atoms (eg, substituted and unsubstituted phenyl, thienyl and furanyl) and alkyl radicals having 1 to 20 carbon atoms. The term "alkyl" also includes substituted alkyl radicals (eg, substituents such as halogen, hydroxy, alkoxy, aryl). It is preferable that R <_3> , R <_4> and R <_5> are each aromatic. Z, m and X are all as described above for the iodonium complex salt.

When R ₃ , R ₄ or R ₅ are aromatic groups, they may optionally have one or more fused benzo rings (eg, naphthyl, benzothienyl, dibenzothienyl, benzofuranyl, dibenzofuranyl, etc.). . In addition, these aromatic groups may be substituted with one or more nonbasic groups that are substantially non-reactive with the epoxide and hydroxyl functional groups if desired.

As the triaryl substituted salt, for example, triphenylsulfonium hexafluoroantimonate is preferable. Useful sulfonium complex salts are described in detail in US Pat. No. 4,256,828.

Aromatic sulfonium complex salts useful in the present invention are inherently photosensitive only in the ultraviolet region of the spectrum. However, depending on the selector of the photosensitizer as disclosed in US Pat. No. 4,256,828, it may also be photosensitized by spectra in the vicinity of the ultraviolet and in the visible range.

Useful metallocene salts can be represented by the formula:

[(L ¹ ) (L ² ) M ^p ] ^{+ q} Y _r

In the formula, M ^p represents a metal selected from Cr, Mo, W, Mn, Re, Fe and Co,

L ¹ is 1 or 2 ligands that provide π electrons which may be the same or different ligands selected from substituted and unsubstituted η ³ -allyl, η ⁵ -cyclopentadienyl and η ⁷ -cycloheptatrienyl, η ⁶ - represents an aromatic compound, and 3 to 8 π have a 2 to 4 fused rings which can provide each e compound in the valence shell of M ^p-benzene and substituted η ⁶ - η ⁶ is selected from benzene compound ,

L ² is 1 to 3 ligands or bonds that provide an even number of sigma electrons, which may be the same or different ligands selected from carbon monoxide or nitrosonium,

Provided that the total electron charge provided to M ^p by L ¹ and L ² + the ionic charge of the metal M ^p must be such as to provide a positive residual total charge q to the complex salt,

q is the residual charge of the complex ion, an integer of 1 or 2,

Y is AsF ₆ ^-, SbF ₆ ^- and SbF ₅ OH ^-, and halogen-containing complex anion selected from,

r is an integer of 1 or 2, the number of anion ions required to neutralize the charge q on the cationic ion.

Useful metallocene salts are described in detail in US Pat. No. 5,089,536. This metallocene salt can be used with reaction accelerators such as oxalate esters of tertiary alcohols.

Useful commercial photoinitiators include FX-512, an aromatic sulfonium complex (3M, St. Paul, Minn.), UVI-6974, an aromatic sulfonium complex (Union Carbide Corp.), and IRGACURE 261, a metallocene complex. Gaigi products), cationic photoinitiators CD-1010, CD-1011 and CD-1012. The photoinitiator is preferably cationic, more preferably 50% by weight triaryl sulfonium hexafluoroantimonate (CD-1010 from Sartomer) in polypropylene carbonate.

Hydroxyl-containing material

The latent curable composition preferably further comprises a hydroxyl containing material. The hydroxyl containing material may be any liquid or solid organic material having at least one, preferably at least two, and most preferably about three hydroxyl functional groups. The hydroxyl containing organic material should be free of other "active hydrogen" containing groups such as amino moieties and mercapto moieties. In addition, the hydroxyl containing organic material should be substantially free of thermally or photolytically unstable groups that do not release volatile components or degrade the material when exposed to actinic radiation upon curing or at temperatures below about 100 ° C. The organic material preferably comprises two or more primary or secondary aliphatic hydroxyl groups (ie, hydroxyl groups are bonded directly to non-aromatic carbon atoms). This hydroxyl group may be located at the terminal or may be a side group of a polymer or copolymer. The number average equivalent of the hydroxyl-containing material is preferably about 31 to 2250, more preferably about 80 to 1000, and most preferably about 80 to 350.

Representative examples of suitable organic materials having one hydroxyl functional group include alkanols, monoalkyl ethers of polyoxyalkylene glycols and monoalkyl ethers of alkylene glycols.

Representative examples of useful monomeric polyhydroxy organic materials include alkylene glycols (eg, 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 2-ethyl-1,6-hexanediol, bis ( Hydroxymethyl) cyclohexane, 1,18-dihydroxyoctadecane and 3-chloro-1,2-propanediol), polyhydroxyalkanes (e.g. glycerin, trimethylolethane, pentaerythritol and sorbitol) and Other polyhydroxy compounds such as N, N-bis (hydroxyethyl) benzamide, 2-butene-1,4-diol, castor oil and the like.

Representative examples of useful polymer hydroxyl-containing materials include polyoxyalkylene polyols (eg, glycols and triols of polyoxyethylene and polyoxypropylene having an equivalent weight of 31 to 2250 for diols and 80 to 350 equivalents for triols) Polytetramethylene oxide glycols of various molecular weights, hydroxyl-terminated polyesters and hydroxyl-terminated polylactones.

Useful commercially available hydroxyl-containing materials include POLYMEGs (QO Chemicals Inc., West Lafayette, Ill.), Such as polytetramethylene oxide glycol, such as POLYMEG 650, 1000 and 2000; TERATHANEs, which are polytetramethylene oxide glycols (produced by E.I Dupont de Numur and Company, Wilmington, Delaware), such as TERATHANE 650, 1000 and 2000; Polytetramethylene oxide glycol, POLYTHF from BASF Corp .; BUTVARs which are polyvinyl acetal resins (Monsanto Chemical Company, St. Louis, MO), such as BUTVAR B-72A, B-73, B-76, B-90 and B-98; TONEs, which are polycaprolactone polyols (Union Carbide Corp., Denver, Conn.) Such as TONE 0200, 0210, 0230, 0240 and 0260; DESMOPHEN's (Miles Inc., Pittsburgh, Pa.), Saturated polyester polyols, such as DESMOPHEN 2000, 2500, 2501, 2001KS, 2502, 2505, 1700, 1800, and 2504; RUCOFLEXs from Lukkov, New York, USA, saturated polyester polyols such as S-107, S-109, S-1011 and S-1014; VORANOL 234-630 (trimethylol propane) from Dow Chemical Company, Midland, Michigan; Dow Chemical Company's VORANOL 230-238 (glycerol polypropylene oxide adduct); SYNFACs (Milliken Chemical, Spartanburg, SC, USA) which are polyoxyalkylated bisphenol A, such as SYNFAC 8009, 773240, 8024, 8027, 8026 and 8031; ARCOLs (Arco Chemical Company, Newtown Square, Pennsylvania), which are polyoxypropylene polyols, such as ARCOL 425, 1025, 2025, 42, 112, 168, and 240.

The amount of hydroxyl-containing organic materials used in the compositions of the present invention may vary depending on the compatibility of the epoxy-containing and polyester components with the hydroxyl-containing materials, the equivalents and functional groups of the hydroxyl-containing materials, and the physical properties desired for the final cured composition. The same factors can vary over a wide range.

Hydroxyl-containing materials are particularly useful for adjusting the flexibility of latent curable compositions useful in the present invention. As the equivalent of the hydroxyl containing material increases, the flexibility of the latent curable composition correspondingly increases, resulting in a loss of cohesive strength. Likewise, decreasing the equivalent weight loses flexibility, but consequently the cohesive strength may increase. Thus, the equivalent of hydroxyl-containing material is chosen such that the two properties are properly balanced according to the particular application. For example, to adjust the flexibility of the binding system, the latent curable composition preferably comprises polyoxyethylene glycol and triols having an equivalent weight of about 31 to 2250 for glycols and an equivalent weight of 80 to 350 for triols. More preferred are polyoxypropylene glycols and triols having an equivalent weight of about 31 to 2250 for glycols and an equivalent weight of about 80 to 350 for triols.

The polyether polyols added to the latent curable compositions useful in the bonding system included in the inkjet printer pen of the present invention are particularly preferred for adjusting the curing rate of the composition by radiation exposure. Increasing the amount of polyether polyols may delay the curing reaction for a time sufficient to bond the substrate that is not radiopaque. The effect becomes even more pronounced when the glass transition temperature of the polyester component is less than about 20 ° C.

Polyether polyols (ie, polyoxyalkylene polyols) useful for adjusting the cure rate include polyoxyethylene and polyoxypropylene having a hydroxyl equivalent weight of about 31 to 2250 for diols and an equivalent weight of about 80 to 350 for triols. Glycols and triols, as well as polytetramethylene oxide glycols and polyoxyalkylated bisphenol As of various weight average molecular weights. Preferred hydroxyl containing materials are glycerol polypropylene oxide adducts such as VORANOL 230-238, commercially available from Dow Chemical Company.

additive

An additive may be added to the latent curing composition of the present invention. Optionally, tackifiers, fillers, adjuvants, adhesion enhancers, plasticizers, compatibilizers, and mixtures thereof, up to 50% of the total weight of the composition (based primarily on epoxy-containing materials, polyester components, photoinitiators, and optional hydroxyl-containing materials) It can be included as. As fillers, for example, silica, glass, clay, talc, pigments, colorants, glass beads or bubbles or polymer expanded or unexpanded beads or bubbles, glass fibers or ceramic fibers, etc. may be added to reduce the weight or cost of the composition. have. It is also possible to add additives to adjust the viscosity and to further strengthen. Tackifiers such as rosin (eg rubber rosin, deoiled rosin, wood rosin), modified rosin (eg polymerized rosin, hydrogenated rosin, disproportionated rosin), rosin esters, hydrocarbon resins, polymerized terpenes, pure monomers Resins, hydrogenated hydrocarbons, and reinforcing resins may be added to the latent curable composition to enhance self-fastening. One preferred tackifier is a terpene phenol copolymer sold under the tradename ARAKAWA 2130 by Arakawa Chemical Industries Limited, Chicago, Illinois, USA. Preferred additives and amounts of additives do not adversely affect the curing process.

The latent curable composition comprises from 2 to 95 parts by weight of epoxy-containing material and correspondingly from 98 to 5 parts by weight of the polyester component per 100 parts by weight in total. More preferably, the latent curable composition of the present invention preferably contains 2 parts by weight to 80 parts by weight of epoxy-containing material, and 98 parts by weight to 20 parts by weight of the corresponding polyester component. Most preferably, the latent curable composition of the present invention preferably contains 2 parts by weight to 60 parts by weight of epoxy-containing material, and 98 parts by weight to 40 parts by weight of the corresponding polyester component. Increasing the amount of epoxy-containing material relative to the polyester component generally results in a latent curable composition having higher final strength and heat resistance but lower flexibility, forming ginger and viscosity. In addition, increasing the amount of polyester component generally results in a latent curable composition having a lower final strength, such as shear or peel adhesion and higher heat resistance but higher viscosity, flexibility and ginger strength. Thus, the relative amounts of the two components are adjusted according to the desired properties of the final composition.

The photoinitiator is added in an amount of about 0.1 to 4 weight percent based on the mixed weight of the epoxy containing material and the polyester component. Increasing the amount of photoinitiator may increase the cure rate, but it may be necessary to coat the latent curable composition with a thinner layer to avoid cure occurring only at the surface. In addition, increasing the amount of photoinitiator may reduce the required amount of energy exposure. The amount of photoinitiator depends on the curing rate of the desired composition, the intensity of the radiation source and the thickness of the composition.

The relative amount of hydroxyl containing organic material added to the composition is determined by the ratio of the number of hydroxyl groups to the number of epoxy groups in the latent curable composition. This ratio ranges from about 0: 1 to about 1: 1, more preferably from about 0.1: 1 to about 0.8: 1, most preferably from about 0.1: 1 to about 0.7: 1. It is good. More hydroxyl-containing materials may increase the flexibility of the latent curable composition, but consequently lose cohesive strength. If the hydroxyl containing material is a polyether polyol, the increase will slow down the curing process.

How to manufacture a joining system

The latent curable compositions of the present invention are prepared by mixing effectively under stirring until the components are sufficiently melt blended without raising thermal decomposition under elevated temperatures sufficient to liquefy each component in a suitable container, preferably a container that is not actinically permeable. Each component may be added simultaneously or sequentially, but it is preferred to first combine the epoxy-containing material with the polyester component and then add the hydroxyl-containing material, optional additives, and then the photoinitiator.

One method of preparing the latent curable composition includes adding solid and liquid epoxy-containing materials and a solid polyester resin to the metal container and melting the viscous liquid at about 280-320 ° F. (138-160 ° C.). do. Melting can be carried out using hot plates, ovens or other types of heating vessels. A tackifier is added to the mixture thus heated. Next, hydroxyl-containing material and wax (e.g., microcrystalline polypropylene wax used as nucleating agent available under the trade names UNILIN 700 and UNILIN 550, a petroleum product in Tulsa, Oklahoma, USA) were added, and the homogeneous mixture was Mix until obtained to obtain a heated mixture. Thus, once a homogeneous mixture is obtained, a photoinitiator is added and stirred and mixed again. The latent curable composition thus heated is coated with a film or after cooling to room temperature and then coated. The latent curable composition heated during the mixing should not be exposed to ultraviolet light as much as possible to prevent premature activation of the curing system. This is generally done in a hood and / or room with overhead light removed and the mixing vessel shielded from unwanted radiation exposure.

In one method, the latent curable composition is heated to 350-400 ° F. (177-205 ° C.) as described above. Preferably, the latent curable composition is preferably in the form of a film, and any one of several methods may be used to coat the molten composition with a film. For example, die slot extrusion, hot rod or hot knife coating, or hot coating rod methods. The preferred method used to coat the film is to use the hot rod method. The method basically involves placing a heated metal rod on the heated metal bed to adjust the orifice to about 8-10 mils (0.20 mm to 0.25 mm). Through this orifice or slot a thin support of a certain length, such as paper or plastic, is placed and coated thereon with a latent curable composition. Such a thin support, generally 3 mil (0.075 mm) to 5 mil (0.13 mm) thick, is placed in the slot between the heating rod and the bed, leaving 5 mil (0.13 mm) of opening. This remaining 5 mil (0.13 mm) opening provides space for the 5 mil (0.13 mm) thick film of the latent curable composition to be coated. The actual coating is to place or pour the molten latent curable composition onto the support and then stretch the paper or plastic support through a hot rod / hot bed orifice to produce a 5 mil (0.13 mm) coating of the latent curable composition on the support. Forming. Tensile velocities should generally be about 3 to 4 feet (0.9 m to 1.2 m) per minute to provide a smooth, uniform high temperature coating on the support. This 5 mil (0.13 mm) latent curable composition film is cooled to around room temperature in about 5 to 15 seconds and the molten latent curable composition is converted to a substantially tack free film.

If the support on which the adhesive is coated is a siliconized paper or plastic film, the cooled latent curable composition film may be used as a film without a support that can separate and bond both sides together. If the support on which the latent curable composition is coated is a surface that is not peel coated, such as a polyester film, the latent curable composition film cannot be separated and the resulting combination of the latent curable composition and polyester film can be used in the bonding system. have. As such, the single-side coated support may be further processed to place the self-fastening material on the surface of the support opposite the latent curable composition. The self-fastening material may be pressure sensitive or melt flowable and, if melt flowable, may be latent curable or latent curable, such as the opposite side. Thus, the resulting three-layered joining system can be used to join both sides together.

In addition, when the bonding system made from the latent curable composition is melt flowable, the method of the present invention comprises disposing a latent curable latent curable composition on a pen body substrate and heating the composition sufficiently soft to bond to the substrate. Include. When the composition is heated, it is first softened and mated to the surface of the substrate, thus removing the air trapped by this flowing material. As the heating cycle continues to further heat the composition, the composition becomes tacky and sufficiently wets the surface to bond to the surface. In some applications, the composition will melt flow to conceal defects, surface defects and / or fill gaps. However, when the melt flowable latent curable composition is disposed on a substrate at room temperature, the composition is preferably tack free.

Bonding systems made from latent curable compositions are preferably substantially tack free at ambient temperatures for machine handleability reasons. However, if the bonding system is tacky or pressure sensitive at room temperature, the bonding system may be protected from dust and other contaminants by a release liner or liner before being used for transport through a high speed assembly device. However, for any composition, at least one release liner is highly desirable for most manufacturing processes to provide a support for a latent curable composition.

The total thickness of the pre-cured bonding system (including the layered structure described above) is generally from about 0.5 mil (0.013 mm) to about 40 mil (1.0 mm), preferably from about 2 mil (0.05 mm) to about 5 mil (0.13 mm). It is good to be thickness. The coupling system can be manufactured in continuous length, if desired, forming a roll up to thousands of feet (609 m) in length and 72 inches (1800 mm) in width. In addition, all methods of making the binding system should be carried out with substantially minimal exposure to UV or UV containing radiation to block activation of the photoinitiator to prevent premature curing of the latent curable composition. Generally, about 1 hour of exposure to indirect fluorescence is stable and will not activate the photoinitiator. The coating sheet or roll described above is preferably stored in a low temperature dark room prior to bonding.

Substrate bonding

Generally, a latent curable composition is coated on a single substrate, such as a flexible circuit or inkjet pen body, and once coated, is exposed to a radiation source to initiate curing of the epoxy containing material. The epoxy containing material is assumed to be cured or crosslinked by the epoxy containing material itself, the hydroxyl containing material, and to some extent by the polyester component, but is not limited to this theory. First, it is preferable to coat the flexible circuit with a latent curable composition.

The bonding of the flexible circuit to the pen body is preferably carried out by attaching a film of the latent curable composition to the flexible circuit present on the surface with the plurality of conductors (ie, the gold plated copper trace face). This can be done by cutting the film of the latent curable composition into the desired precise shape and placing the thus shaped film in a flexible circuit. The film is then pressed with a heated shoe to melt the latent curable composition resulting in the composition flowing between the trace and the conductor to bond to the flexible circuit surface. As a result, the latent curable composition will cover and block the entire surface of the flexible circuit. In general, between a heated shoe or thermother and a latent curable composition film, a release coating of silicone or silicone rubber or paper sold under the trade name TEFLON is placed so that the molten latent curable composition adheres undesirably to the heated shoe. Or do not combine. The bonding temperature used to bond the latent curable composition is generally between about 180 ° F. and about 320 ° F. (about 82 ° C. to about 160 ° C.). The pressure is generally about 5 to about 20 pounds per square inch of bond area (about 34.5 kPa to 138 kPa) and the residence time (the time that the latent curable composition and the hot shoe stay in contact) is about 3 to about 5 seconds. . Of course, the temperature of the hot shoe can be higher, but in this case shorten the contact / bond time. Suitable temperature, pressure and time conditions are determined by the flow properties and optimum properties desired for the final bond.

The latent curable composition not only binds but also protects. As a protective function, the latent curable composition protects the brittle conductor from ink, humidity, external attack of conductive shorts and other undesirable external influences on gold plated copper conductors.

Curing of the latent curable composition is initiated upon exposure of the composition to any source of radiation, preferably actinic radiation (ie radiation having a wavelength in the ultraviolet or visible spectral region) and then continues for a period of time. Suitable radiation sources include mercury, xenon, carbon arcs, tungsten filament lamps, the sun and the like. Most preferred is ultraviolet light, specifically ultraviolet light from a medium pressure mercury arc lamp. The exposure time may range from less than about 1 second to more than 10 minutes depending on the amount and type of reactant involved, the radiation source, the distance from the radiation source, and the thickness of the cured composition (total energy exposure of about 0.2 joules per square centimeter (J / cm 2). Time to deliver)).

In addition, the composition can be cured upon electron beam radiation exposure. The dosage required is generally from less than 1 megarad to more than 100 megarad. The rate of cure tends to increase with increasing amount of photoinitiator during a given light exposure or irradiation. In addition, the curing rate increases with increasing radiation intensity or electron dosage.

Particularly preferred is a latent curable composition comprising a hydroxyl containing material that retards the rate of curing when joining two radiopaque substrates together. When the latent curable composition is coated on the pen body and the composition is irradiated with radiation, the second substrate, such as a latent curable composition, may be applied at any time during the open time until the latent curable composition is sufficiently cured to be unable to bond to the substrate. A flexible circuit can be coupled to the first substrate. The second substrate is within the open time, preferably within about 24 hours, more preferably within about 8 hours, most preferably within about 5 minutes to about 30 minutes from the time the latent curable composition is exposed to radiation. It is good to cover it. That is, the composition remains uncured enough to allow the second substrate to bond for a period of time (open time) after being irradiated (also, a high glass transition temperature polyester component such as a glass transition temperature of 20 ° C. Similar effects can be obtained by using the above components).

The second substrate, such as the pen body, is generally joined by heat, pressure, or heat and pressure (eg, a hot press, a heated nip roller or a heat laminator). Typical conditions for covering the pen body are from about 250 ° F. to about 300 ° F. (from about 121 ° C. to about 300 ° F.) with or without pressure application of about 5 pwi to about 25 piw (about 0.88 kN / m to about 4.4 kN / m). 149 ° C.) at a temperature of about 1 second to about 5 seconds. Laminator pressures are useful above about 200 kilopascals (kPa). As another method, one or both sides of the freestanding film may be irradiated, and then the film may be disposed between both substrates, and then the film may be bonded to both substrates using heat, pressure or heat and pressure. Alternatively, if one of the substrates is radiolucent, the two substrates are joined together and the latent curable composition is irradiated through the transparent substrate.

The curing process is initiated once the latent curable composition is exposed to radiation. After exposure to radiation, the latent curable composition may be tacky or tacky for a period of time that becomes virtually tacky. Preferably, curing within ambient conditions within about 48 hours, more preferably within about 24 hours, depending on the intensity of the radiation source, the radiation exposure time, the concentration of the photoinitiator, and the concentration of the hydroxyl-containing component added to the latent curable composition. good. If it is desired to cure only under ambient conditions, the glass transition temperature of the polyester component should be below ambient temperature, preferably below about 20 ° C.

The time to reach full cure can be accelerated by post-curing the composition with heat such as the use of an oven. Post cure time and temperature may vary depending on the glass transition temperature of the polyester component, the concentration of the photoinitiator, radiation exposure conditions, and the like. Typical postcuring conditions range from 5 to 15 minutes at about 50 ° C. to about 1 to 2 minutes at temperatures of up to about 100 ° C. Acceleration of curing can also be achieved when heat and pressure are used to bond both substrates together, such as when using a heat press, a heat laminator or a heated nip roller. In the case of the latent curable composition which has a polyester component whose glass transition temperature is about 20 degreeC or more as a main component, it is preferable to use heat besides radiation in order to harden a composition.

Referring to FIG. 1, reference numeral 10 generally shows an inkjet printer pen incorporating one aspect of the present invention. The inkjet printer pen 10 includes a pen body 12, such as a printer chip 20 and a flexible circuit 26 made using Tape Automated Bonding (TAB).

The specific structure of the printer chip 20 is not critical in this application, and various kinds of printer chips, such as those having a nickel nozzle plate, can be used in the present invention.

One side (or front side) of the flexible circuit 26 includes a plurality of contact pads 29. The printer pen 10 allows the contact pads 29 present on the front surface of the flexible circuit 26 (opposite side of the recording medium not shown) to be operatively connected to the printer to transmit print signals. It is mounted in a printer (not shown). In order to access the conductor from the front of the flexible circuit 26 a hole must be formed through which the end of the conductor is exposed through the front of the flexible circuit 26. The exposed ends of the conductors are then plated with gold, for example, to create the contact pads 29 shown in front of the flexible circuit 26.

2 is a perspective view showing the back side of the flexible circuit 26 separated from the printer pen 10. The second surface (or back side) of the flexible circuit 26 includes a plurality of conductors 28 electrically connected to the front surface of the flexible circuit 26 and at which ends contact pads 29 are made.

As described above, the backside of the flexible circuit 26 on which the conductors 28 are formed comprises a coupling system 3 made of the latent curable composition described above. The coupling system 3 coats and insulates the conductor 28 to protect the coating of the conductor present on the flexible circuit 26 from ink exposure and potential shorts. The coupling system 30 is preferably manufactured by attaching a latent curable composition to the back side of the flexible circuit 26 on which the conductor 28 is formed. More preferably, the bonding system 30 is formed of a latent curable composition that is self-fastening.

Prior to forming the bonding system 30 on the flexible circuit 26, the latent curable composition may be provided in a film that is die cut or punched in a form that matches the area of the flexible circuit 26 to be joined. If the latent curable composition comprises a melt flowable material, the film is temporarily softened using heat and pressure prior to lamination on the backside (on the conductor) of the flexible circuit 26 to adhere to the flexible circuit 26. By improving this, the conductor 28 can be appropriately formed. In the case where the latent curable composition includes a pressure-sensitive material, the use of only light heat and / or pressure can enhance the adhesion to the flexible circuit 26, so that the conductor 28 can be properly coated.

3A, 3B, and 3C show more details of the coupling circuit 30 stacked on the flexible circuit 26 and conductor 28 shown in FIG. 2. 3A to 3C are cut along the line A-A in FIG. The coupling system 30 aligns with respect to the flexible circuit 26 and adheres properly onto the flexible circuit 26 upon applying pressure with or without heat.

Attaching the coupling system to the conductor 28 on the flexible circuit 26 allows the resulting flexible circuit stack to be attached to the pen body. The attachment of the flexible circuit laminate to the pen body is performed using a heated pressure pad. In this process, the self-fastening function of the latent curable composition causes the composition to soften and adhere to the plastic pen body. Exposure of this latent curable composition to radiation begins to bind to the pen body as shown in FIG. 3D.

4 relates to another embodiment of the coupling system 30 described in the present invention. In this aspect, the bonding system includes a support layer 30c having a first surface and a second surface. The support layer 30c is preferably made of a chemically and thermally stable material, and in particular, the support layer 30c more preferably contains polyester. The self-fastening layer 30a is disposed on the second surface and the latent curable composition film 30b is disposed on the first surface. In manufacture, the self-fastening layer covers one surface of a preferred substrate, such as a flexible circuit. Heat, pressure or heat and pressure are applied to secure the structure to the flexible circuit 26. The structure attached to the flexible circuit is exposed to radiation and the pen body 12 is secured to the latent curable composition at any point in the open time of the latent curable composition. The self-fastening layer can be melt flowable, pressure sensitive or melt flowable and pressure sensitive as described above. The self-fastening layer can be provided as a continuous layer or a pattern coated layer. One advantage of using such a structure is that the support layer provides some strength to the structure during the manufacturing process. Suitable pressure sensitive materials are neoprene rubber, nitrile rubber, styrene-butadiene rubber, natural rubber with suitable amount of hydrogenated rosin, phenolic resin, polyterpene resin, polyethylene, ethylene-vinyl acetate copolymer, polyamide resin, It is preferably selected from the group consisting of acrylic polymers and mixtures thereof. If the self-fastening material used is pressure sensitive, a substrate, such as a flexible circuit, can be stored after attaching to the first surface of the support at any point before curing.

In the above, the coupling system which reduced the possibility of the electrical short circuit which arises when the conductor in a flexible circuit comes into contact with ink in the inkjet printer pen structure was demonstrated, and the method of providing this coupling system was demonstrated. The exact shape and size of the headland pattern depends on the type of printer chip design used.

Those skilled in the art will recognize that various modifications and changes of the present invention are possible without departing from the scope and spirit of the present invention, and the present invention is not limited by the above-described exemplary embodiments.

Summary of the Invention

The present invention provides a method and coupling system for coupling a flexible circuit to a pen body in an inkjet printer pen. This bonding system and bonding method create a bond by a bonding system made of a latent curable composition. The term "latent curable" described herein refers to the selective stimulation or initiation of the curing of the system upon exposure to radiation, such as ultraviolet or visible light, thereby initiating a transition step where complete curing is in the presence of radiation after exposure to radiation. It can happen regardless. The binding system is preferably self-fastening.

As used herein, the term "self-fastening" means that the bonding system may be melt flowable or pressure sensitive. This “melt flowability” means that the bonding system is substantially tack free at room temperature but softens first to conform when the composition is heated, and becomes tacky and sufficiently wetted to bond to the surface when the bonding system continues to be heated. After the bonding system is bonded to the surface, the melt fluidity, i.e., maintains the thermoplastic, flows again upon reheating, or may be thermoset, which no longer flows upon reheating, or part of the bonding system begins to cure or crosslink. It becomes thermosetting, and the other part can maintain thermoplasticity. As used herein, the term "decompression" refers to a gradual permanent tack at room temperature, and generally adheres to a variety of different surfaces, even if simply pressed below a pressure equivalent to the hand or finger force without activation by solvents or heat. It means.

As a first aspect of the present invention, an inkjet printer pen structure includes: a flexible circuit in which a plurality of conductors formed on a first surface are electrically connected to a plurality of contact pads on a second surface; A body made to store and dispense ink; And a coupling system made of a latent curable composition located between the body and the first surface of the flexible circuit and operatively attaching the flexible circuit to the body.

The coupling system between the pen body and the flexible circuit in the inkjet printer pen described in the present invention provides many advantages. This coupling system provides sufficient work or open time after curing is initiated upon exposure to radiation to allow matching to the desired part. As used herein, “open time” means the time from the initial exposure of the latent curable composition to radiation until the latent curable composition is sufficiently cured to the extent that no further binding occurs effectively. During the open time, the latent curable composition continues to cure even after the inkjet printer pen member is mated without continuing exposure to radiation. Once curing is complete, sufficient crosslinking and / or chain extension is formed to block the ink from attacking the conductors of the flexible circuit. It is also desirable that the bonding system is self-fastening to exhibit adhesive properties prior to initiation of curing by exposure to radiation and to reduce the likelihood of misalignment of the inkjet printer pen parts prior to complete curing. As a result, the bonding system and method for producing an inkjet printer pen described in the present invention are particularly useful for various manufacturing processes with high throughput.

The bonding system is preferably made of a latent curable composition comprising an epoxy containing material that provides the ultimate strength and resistance (ie, chemical and thermal resistance) of the bonding system in an inkjet printer environment. In particular, the latent curable composition preferably comprises an epoxy containing material, a polyester component, an effective amount of a photoinitiator and a hydroxyl containing material, more preferably an epoxy containing material, a polyester component, an effective amount of a photoinitiator and a hydroxyl containing material. It is good to be configured. In addition, the binding system can cure even at room temperature if first activated by a photoinitiator.

The binding system is preferably self-fastening, which means that the binding system can be pressure sensitive or melt flowable. In one aspect, the latent curable composition is preferably melt flowable for use in various manufacturing / assembly processes.

In another embodiment, the bonding system comprises a carrier having a first major surface and a second major surface; A self-fastening film provided on the first major surface of the carrier; And a latent curable composition provided on the second major surface of the carrier. The carrier is preferably a film made of a material which is thermally stable and chemically stable, more preferably this film comprises a polyester. The self-fastening film includes a pressure sensitive material or a melt flowable material.

The latent curable composition can be exposed to radiation either before or after the composition is fastened to the flexible circuit. The latent curable composition may be first fastened to the pen body and then exposed to radiation or first fastened to the flexible circuit. In either case, the fastening step may include applying pressure and / or heat to the composition provided in the inkjet pen body or the flexible circuit. In addition, the use of a transparent pen body allows the latent curable composition to be applied to a flexible circuit or pen body and the remaining parts attached to the latent curable composition, and then the latent curable composition can be exposed to radiation through the transparent pen body. Thus, the fastening of the latent curable composition to the pen body or flexible circuit occurs prior to radiation exposure.

The areas of electrical contact between the flexible circuits, the area between the inkjet pen body and adjacent or other conductors on the flexible circuits are preferably coated with a bonding system that is protected from ink shorting the conductors or adjacent conductors. The properties of bonding systems made from latent curable compositions are advantageous because they can be readily used in a variety of manufacturing processes because the clamping of the mated parts and the continuous radiation exposure are not required prior to completion of curing.

Such features and advantages of the invention are described in detail below.

Claims (29)

A flexible circuit having a plurality of conductors formed on the first surface electrically connected to the plurality of contact pads present on the second surface; A body manufactured to store and dispense ink; And a bonding system made of a latent curable composition located between the body and the first surface of the flexible circuit and operatively attaching a conductor on the flexible circuit to the body. The inkjet printer pen structure of claim 1, wherein the latent curable composition comprises an epoxy containing material, a polyester, a hydroxyl containing material, and an effective amount of photoinitiator. The inkjet printer pen structure of claim 2, wherein the latent curable composition comprises a hydroxyl-containing epoxy to epoxy-containing material in a weight ratio of about 0.1: 1 to about 0.7: 1. The inkjet printer pen structure of claim 1, wherein the latent curable composition is self-fastening. The inkjet printer pen structure of claim 1, wherein the bonding system comprises a film about 0.2 mm to about 0.025 mm thick. The support of claim 1, wherein the bonding system is a support having a first major surface and a second major surface, a self-fastening layer provided on the first major surface of the support, and a latency provided on the second major surface of the support. An inkjet printer pen structure comprising a curable composition. The inkjet printer pen structure of claim 1, wherein the bonding system further comprises a pressure sensitive material. The inkjet printer pen structure of claim 4, wherein the latent curable composition is melt flowable. 3. The inkjet printer pen structure of claim 2, wherein the photoinitiator is selected from the group consisting of aromatic iodonium complex salts, aromatic sulfonium salts, metallocene salts, and mixtures thereof. The photoinitiator of claim 2, wherein the photoinitiator is selected from the group consisting of diarylionium hexafluorophosphate, diarylionium hexafluoroantimonate, triaryl substituted salts, metallocene salts and mixtures thereof. Inkjet printer pen constructions. The inkjet printer pen structure of claim 2, wherein the hydroxyl containing material has at least two hydroxyl functionalities. The method of claim 7, wherein the pressure sensitive material is synthetic rubber, natural rubber with an effective amount of hydrogenated rosin, phenolic resin, polyterpene resin, polyethylene, ethylene / vinyl acetate copolymer, polyamide resin, acrylic resin and the like Inkjet printer pen structure, characterized in that selected from the group consisting of a mixture of. The inkjet printer pen structure of claim 6, wherein the self-fastening layer comprises a pressure sensitive material. The inkjet printer pen structure of claim 6, wherein the self-fastening layer is melt flowable. The inkjet printer pen structure of claim 6, wherein the support layer comprises polyester. Coating a latent curable composition on a flexible circuit surface having a conductor on the surface, Exposing the latent curable composition to radiation for a time sufficient to initiate cure, Contacting the latent curable composition to a body made to store and dispense ink, and Forming a coupling system between the flexible circuit and the body to operatively attach the flexible circuit to the pen body via the coupling system. Including a method of providing a bonding system in the inkjet printer pen. 17. The method of claim 16, wherein the latent curable composition comprises an epoxy containing material, a polyester, a hydroxyl containing material and an effective amount of photoinitiator. 17. The method of claim 16, wherein the bonding system is self-fastening. 19. The method of claim 18, wherein the latent curable composition is melt flowable. 19. The method of claim 18, wherein the bonding system further comprises a pressure sensitive material. 20. The method of claim 19, wherein the latent curable composition further comprises an epoxy-acrylate, an epoxy-polyester, an epoxy-polycaprolactone, and mixtures thereof. 18. The method of claim 17, wherein the photoinitiator is selected from the group consisting of aromatic iodonium salts, aromatic sulfonium salts, metallocene salts, and mixtures thereof. 18. The photoinitiator of claim 17, wherein the photoinitiator is selected from the group consisting of diarylionium hexafluorophosphate, diarylionium hexafluoroantimonate, triaryl substituted salts, metallocene salts, and mixtures thereof. Method of providing a bonding system in an inkjet printer pen. 18. The method of claim 17, wherein the hydroxyl containing material has at least two hydroxyl functional groups. The pressure sensitive material according to claim 20, wherein the pressure sensitive material is synthetic rubber, natural rubber having an effective amount of hydrogenated rosin, phenolic resin, polyterpene resin, polyethylene, ethylene / vinyl acetate copolymer, polyamide resin, acrylic resin and the like A method of providing a binding system for an inkjet printer pen, characterized in that it is selected from the group consisting of a mixture of: 17. The method of claim 16, wherein the bonding system is a film about 0.2 mm to about 0.025 mm thick. 20. The method of claim 19, further comprising applying heat and / or pressure to the latent curable composition. An inkjet printer comprising the inkjet printer pen according to claim 1. A printer system comprising a computer operatively connected to the inkjet printer of claim 28.