TWI478979B - Conductive resin composition - Google Patents

Description

Conductive resin composition

The present invention relates to a conductive resin composition, and more particularly to a conductive resin composition which can obtain a cured product having excellent electrical resistance and heat stability.

The screen paste used in the prior art is printed on a printed wiring board to form a conductive paste for a conductive circuit pattern. In the adhesive resin formed of a thermosetting resin or a thermoplastic resin, metal powder such as silver or copper is added or dispersed. Or carbon black, graphite-like carbon conductive powder. In order to meet the characteristics of conductivity, printability, adhesion, solder heat resistance, high temperature heat resistance, moisture resistance, thermal shock resistance, and abrasion resistance, the conductive paste has been proposed as various resin components and conductive powders.

A thermosetting resin which is known as a binder is, for example, a resol type phenol resin. The resol type phenol resin has excellent heat resistance, and when used in a conductive paste, it shrinks in volume by self-condensation, and as a result, it is expected to increase the contact area between the added conductive powders, and to reduce the electric resistance and to conduct good electrical conductivity. Sex. In addition, since the price is low, and it has excellent adhesion, mechanical properties, electrical properties, and the like in addition to heat resistance, it is widely used not only as a binder but also as a molding material, an adhesive, and a coating agent for various substrates. Patent Document 1 discloses that a resin composition containing a resol type phenol resin is used as a binder resin for a conductive paste.

On the other hand, the resole type phenol resin is required to further improve the printability, and to improve the brittleness, storage stability, and the like of the cured coating film.

Further, regarding the excellent adhesion, flexibility, and abrasion resistance, a binder resin obtained by addition reaction of a compound having a hydroxyl group and a polyisocyanate compound has been proposed. For example, Patent Document 3 and 4 disclose a conductive paste containing a polyester polyol, an isocyanate compound, and a conductive powder.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Publication No. 5-194822

Patent Document 2: JP-A-2006-100081

Patent Document 3: JP-A-2006-302825

In recent years, in order to further improve the heat resistance of a binder resin using a resol type phenol resin, to improve resin characteristics, and to develop a novel binder resin, a resol type phenol-added isocyanate compound has been tried.

However, in this case, due to the condensation reaction of the co-preserved resol type phenol itself and the addition reaction with the isocyanate compound, it is difficult to control the reaction system, so that the properties of the cured product obtained by increasing the electric resistance value and the welding heat resistance are obtained. The problem of the bias value.

Therefore, an object of the present invention is to provide a conductive resin composition containing a conductive powder, a resol type phenol resin, and an isocyanate compound, and a cured product having stable physical properties can be obtained.

The inventors of the present invention have found that it is possible to carry out a reaction under a specific temperature condition, and it is possible to carry out a reaction with one of the above-mentioned problems in order to solve the above-mentioned problems, and it has been found that a resin which is preferentially subjected to a resol-type phenol resin-type condensation reaction affects boiling resistance and the like When the isocyanate addition reaction is preferentially carried out, the resin property is hardly adversely affected, and the physical properties can be stabilized. Further, the present invention can be accomplished by inhibiting the condensation reaction of a resol type by a pyrazole compound.

In other words, the conductive resin composition of the present invention contains (A) a resol type phenol resin, (B) a pyrazole compound, (C) an isocyanate compound, and (D) a conductive powder.

In the conductive resin composition of the present invention, the (B) pyrazole compound is preferably 3,5-dimethylpyrazole. The above (C) isocyanate compound is preferably a blocked isocyanate.

Moreover, the conductive resin composition of the present invention contains (A) a resol type phenol resin, (F) a pyrazole block isocyanate compound, and (D) a conductive powder. The above (F) pyrazole block isocyanate compound is preferably a 3,5-dimethylpyrazole block of a trimer of 1,6-hexamethylene diisocyanate.

The conductive resin composition of the present invention more preferably contains (E) a polyvinyl acetal resin.

Further, in the conductive resin composition of the present invention, the (D) conductive powder is preferably one or more of carbon black and graphite.

The cured conductive resin of the present invention is characterized in that the conductive resin composition is cured.

Moreover, the conductor circuit pattern of the present invention is characterized in that the conductive resin cured product is used.

The present invention can provide a conductive resin composition containing a conductive powder, a pyrazole compound, a resol type phenol resin, and an isocyanate compound, and can obtain a cured product having a stable physical property.

Form of implementing the invention

The conductive resin composition of the present invention is characterized by comprising (A) a resol phenol resin, (B) a pyrazole compound, (C) an isocyanate compound, and (D) a conductive resin composition of the conductive powder. Further, it is characterized by comprising (A) a resol type phenol resin, (F) an isocyanate compound which is a pyrazole block, and (D) a conductive resin composition of the conductive powder.

Each component will be specifically described below.

Further, in the present invention, the resins mean (A), (B), (C), (D), (E) and (F).

<(A) resole type phenol resin>

In the present invention, the (A) resole type phenol resin can be used as any of the binder resins previously used in the conductive paste. Further, it can be modified by an alkoxy group or the like. The molecular weight of the resole type phenol resin (A) is not particularly limited, and the weight average molecular weight MW is preferably from 500 to 5,000.

The resol type phenol resin can be obtained, for example, by methylolating a phenol compound with formaldehyde under a base, and under a acidic condition or heating to cause a condensation reaction to gel and harden.

The raw material of the resol type phenol resin is a phenol compound such as phenol, m-cresol, o-cresol, p-cresol, p-tert-butylphenol, p-ethylphenol, 2,3-di Methyl phenol, 2,5-xylenol, m-ethyl phenol, 3,5-xylenol, m-methoxy phenol, bisphenol A, bisphenol F, and the like. Preferred in terms of hardenability and heat resistance are bisphenol A, phenol, m-cresol, m-ethylphenol, 3,5-xylenol, and m-methoxyphenol.

The above-mentioned formaldehydes, such as formaldehyde, para-formaldehyde or trioxane, may be used alone or in combination of two or more. The obtained methylol group is preferably such that the aromatic ring has 1.0 or more per one core.

The amount of the (A) phenol resin-based phenol resin to be added is preferably from 10 to 55% by mass, more preferably from 20 to 45% by mass, based on the solid content of the resin in the composition. When the addition amount of the resol type phenol resin is less than 10% by mass, the characteristics such as solder heat resistance and high-temperature heat resistance necessary for the conductor pattern are lowered, and when it exceeds 55% by mass, the boiling resistance and the bendability are improved. It is not appropriate to have adverse effects such as printability. Further, the (A) resol type phenol resin preferably has a formaldehyde content of 0.1% or less and has excellent environmental properties.

<(B)pyrazole compound>

Although the reason is not clear, when the pyrazole compound is present in the resin composition, the condensation reaction of the resol type phenol resin can be suppressed, and the reaction of the resin composition containing the resol type phenol resin and the isocyanate compound can be suppressed. The physical properties of the hardened material are stabilized. The pyrazole compound may be contained in the resin composition alone or in the form of a block agent of an isocyanate compound as described below.

In the present invention, (B) pyrazole compounds such as unsubstituted pyrazole, 3-methylpyrazole, 4-methylpyrazole, 5-methylpyrazole, 3-pentylpyrazole, 3,5-di Any one or more of the 3, 4, and 5 positions of the pyrazole ring such as methylpyrazole, 3-chloropyrazole, and 3,4-dibromopyrazole are an alkyl group having 1 to 5 carbon atoms, a halogen atom, and benzene. A pyrazole substituted with a thiol group or an ethyl hydrazide group. These may be one or two or more substituents on the pyrazole ring. The pyrazole compound is preferably an unsubstituted pyrazole, an alkyl-substituted pyrazole, and one or more pyrazole compounds selected from the above derivatives, and the balance between thermal dissociation and thermal stability for the block agent is particularly Preferably it is 3,5-dimethylpyrazole.

The amount of the pyrazole compound to be added is preferably from 1 to 35 mass%, more preferably from 10 to 30 mass%, based on the solid content of the resole type phenol resin. When the amount of the pyrazole compound added is less than 1% by mass, the self-condensation of the resol phenolic resin cannot be sufficiently suppressed under the curing conditions of the present invention, and when it exceeds 35% by mass, the reactivity of more than necessary is suppressed, and the film properties are lowered. It is not appropriate.

<(C) Isocyanate Compound>

In the (C) isocyanate compound of the present invention, any one of the adhesive resins previously used for the conductive paste can be used. Such isocyanate compounds are, for example, aliphatic isocyanate compounds, aromatic isocyanate compounds, terminal isocyanate prepolymers obtained from isocyanate compounds and polyhydroxy compounds or polyamine compounds, and polymers having a high molecular weight isocyanate group.

The amount of the isocyanate compound to be added is preferably from 20 to 80% by mass, more preferably from 35 to 75% by mass, based on the solid content of the resin in the solid content. When the amount of the isocyanate compound added is less than 20% by mass, the boiling resistance is lowered, and when it exceeds 80% by mass, the properties such as solder heat resistance and high-temperature heat resistance are lowered.

The above aliphatic isocyanate compound such as 1,6-hexamethylene diisocyanate (HDI or HMDI), isophorone diisocyanate (IPDI), methylcyclohexane 2,4-(2,6)-diisocyanate (hydrogenated TDI), 4,4'-methyl bis(cyclohexyl isocyanate) (hydrogenated MDI), 1,3-(isocyanate methyl)cyclohexane (hydrogenated XDI), norbornene diisocyanate (NDI), Lysine diisocyanate (LDI), trimethylhexamethylene diisocyanate (TMDI), dimer acid diisocyanate (DDI), N,N',N"-tris(6-isocyanate, hexamethylenemethyl) Biuret and the like.

The above aromatic isocyanate compound is, for example, tolyl diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI) or the like.

The above terminal isocyanate prepolymer, and a low molecular weight polyhydroxy compound for producing a polymer such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, Hexamethylglycol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, polyethylene glycol, polypropylene glycol, polyethylene adipate, propylene glycol adipate, and the like.

Further, from the viewpoint of the single liquefaction and the lifespan, the isocyanate compound is preferably a blocked isocyanate which is blocked by a known blocking agent (blocking agent). Blocking agents such as alcohols, n-propanol, isopropanol, t-butanol, isobutanol, alcohols, phenyl alcohol, chlorohydrin, cresol, xylenol, p-nitrophenol, etc. Alkylphenols such as phenol, pt-butylphenol, p-sec-butylphenol, p-sec-aminophenol, p-octylphenol, p-nonylphenol, 3-hydroxypyridine, 8 - a basic nitrogen-containing compound such as hydroxyquinoline or 8-hydroxyquinaldine; a reactive methene compound such as diethyl malonate, ethyl acetate or ethyl acetonate; acetamide or acrylamide; An imidazole such as an acid amide such as aniline, succinimide succinate, samarium imide such as maleimide, 2-ethylimidazole or 2-ethyl-4-methylimidazole a ketone or an aldehyde oxime of an internal amide such as 2-pyrrolidone or ε-caprolactam, acetone oxime, methyl ethyl ketone oxime, cyclohexanone oxime, acetaldehyde oxime, etc. , heavy sulfites, etc. These block agents may be used alone or in combination of two or more.

<(D) Conductive Powder>

In the present invention, the (D) conductive powder can be used as any of the adhesive resins previously used in the conductive paste. Conductive powder such as metal powder of gold, silver, copper, platinum, palladium alloy, furnace black, hot carbon black, channel black, acetylene black, carbon black such as carbon black, graphite, carbon black and graphite The carbon powder of the mixture, carbon nanotube or the like is preferably a mixture of carbon black, graphite, carbon black and graphite.

(D) The content of the conductive powder is preferably 70 to 95% by mass, more preferably 75 to 90% by mass, based on the solid content of the composition, when it is a metal powder, and when it is a carbon powder, the composition is The solid content is preferably 35 to 65 mass%, more preferably 45 to 55 mass%. When the amount of addition is less than the above range, sufficient conductivity cannot be obtained, and when it is more than the above range, the mechanical strength of the cured film is lowered.

<(E) Polyethylene acetal resin>

The present invention may contain (A) resol type phenol resin, (B) pyrazole compound, (C) isocyanate compound, and (D) conductive powder in view of dispersibility and printing characteristics of the conductive powder. Or a resin composition, or a conductive resin composition containing (A) a resol type phenol resin, (F) a pyrazole block isocyanate compound, and (D) a conductive powder, preferably another Contains (E) polyethylene acetal resin. (E) The polyvinyl acetal resin may be any of those previously used for the adhesive paste of the conductive paste. (E) A polyvinyl acetal resin is obtained by acetalizing a polyvinyl alcohol resin with an aldehyde.

The above aldehyde is not particularly limited, and examples thereof include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, hexanal, heptaldehyde, 2-ethylhexanal, cyclohexanal, furfural, benzaldehyde, and 2-methylbenzaldehyde. And 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxyphenol, m-hydroxybenzaldehyde, phenylacetaldehyde, β-phenylpropanal, etc., preferably butyraldehyde. These aldehydes may be used alone or in combination of two or more.

Commercially available polyethylene acetal resin product names such as Yersley BL-1, BL-1H, BL-2, BL-2H, BL-5, BL-10, BL-S, BM-1, BM- 2. BM-S, BH-3, BX-1, BX-2, BX-5, BX-55, BX-L, BH-3, BH-S, BM-S, KS-3Z, KS-5, KS-5Z, KS-8, KS-23Z (above is Sekisui Chemical Industry Co., Ltd.), electro-chemical butyral 4000-2, 5000A, 6000C, 6000EP (above is the electric chemical industry (stock) system). Further, these resins may be used alone or in combination of two or more.

The amount of the polyethylene acetal resin to be added is preferably from 1.5 to 20% by mass, more preferably from 3 to 15% by mass, based on the solid content of the resin in the composition. When the amount of addition is less than 1.5% by mass, effects such as dispersibility of the conductive powder and printing characteristics are not obtained, and when the amount is more than 20% by mass, the heat resistance of the coating film such as solder heat resistance is lowered.

<(F) Isocyanate compound blocked by pyrazole>

In the conductive resin composition of the present invention, (F) an isocyanate compound in which a pyrazole block is blocked, and an isocyanate compound is blocked by a pyrazole compound. The isocyanate compound is exemplified as the above (C) isocyanate compound, and the pyrazole compound is exemplified as the above (B) pyrazole compound. When the conductive resin composition of the present invention contains (F) a pyrazole block-isocyanate compound, the (B) pyrazole compound may not be contained.

The amount of the (F) isocyanate compound to be added to the pyrazole block is preferably from 25 to 85% by mass, more preferably from 40 to 80% by mass, based on the solid content of the resin in the composition.

<Other ingredients>

The conductive resin composition of the present invention may contain other components in addition to the above components. As other components such as a solvent, an antifoaming agent, a thixotropic agent, a coupling agent, an antioxidant, a dispersing agent, a leveling agent and the like, any of the known ones can be used.

<Conductive resin cured product>

The cured conductive resin of the present invention is obtained by curing the above-mentioned conductive resin composition. The hardening method is preferably heat hardening. The hardening temperature is preferably from 100 to 200 ° C, more preferably from 120 to 180 ° C. Moreover, the conductor circuit pattern of the present invention is a material having the cured conductive resin of the present invention on the printed wiring board. The conductor circuit pattern of the present invention can be obtained by applying the conductive resin composition of the present invention to a known printed wiring board by screen printing or the like, followed by curing.

<Method for Producing Conductive Resin Hardened Article>

The method for producing a conductive cured product of the present invention preferably comprises heating (A) resol type phenol resin, (B) pyrazole compound, (C) isocyanate compound, and (D) conductive at 100 to 200 ° C. A method of hardening a conductive resin composition of powder. The components of the conductive resin composition are as described above. Further, the above other components may be contained. The hardening temperature is more preferably from 120 to 180 °C. The heating method is not particularly limited, and any method known as a batch type oven, a hot air circulation type drying oven, or a far infrared ray conveying oven can be used.

Example

The invention will now be described more specifically by way of examples. Also, "parts" means no part of the mass.

(Reference example 1)

After adding 8.8 parts by weight of the basic catalyst shown in the following Table 1 to 100 parts by mass of the solid component of the resol type phenol resin, the time from the heating at 150 ° C to the gelation time (gel time) was measured. . The gelation was confirmed by visual observation, and the results are shown in Table 1 below.

(Reference example 2)

After adding 3,5-dimethylpyrazole which is one of the components (B) of the present invention to the resole type phenol resin as shown in the following Table 2, the time from the heating at 150 ° C to the gelation time was measured. (gel time). The gelation was confirmed by visual observation, and the results are shown in Table 1 below. Further, the relationship between the solid content ratio of the resol type phenol resin and 3,5-dimethylpyrazole and the gel time is shown in Fig. 1 .

(Examples 1 to 6, Comparative Examples 1 to 5)

The conductive resin composition (conductive paste) (Examples 1 to 6 and Comparative Examples 1 to 5) was prepared by mixing and dispersing each component in a three-seat roll mixer as shown in the following Table 3. The units in Table 3 are parts by mass.

*1: Regal Chemicals Co., Ltd. makes the Legit PL-5208 (NV=60%)

*2: Benzene BM-S butyl carbitol produced by Sekisui Chemical Industry Co., Ltd.

Acetate grade resin (NV=20%)

*3: methyl ethyl ketoxime adduct of 1,6-hexamethyl-diisocyanate (HDI) terpolymer (NV=70%)

*4: BI-7982 manufactured by Baxenden Co., Ltd. (NV=70%)

※5:3,5-dimethylpyrazole

*6: Captured carbon black EC-300J by Lion King Co., Ltd.

*7: SP-20 made by Japan Black Lead Co., Ltd.

*8: Bujichi 20 acetate (butyl carbitol acetate) manufactured by Kyowa Fermentation Chemical Co., Ltd.

The printed wiring board produced from the obtained conductive paste was subjected to volume resistance, adhesion, tape peeling resistance, solder heat resistance, boiling resistance, and pencil hardness test by the following evaluation test methods. The results are shown in Table 4 below.

(1) Volume resistance value

Each of the conductive pastes of the above Examples 1 to 6 and Comparative Examples 1 to 5 was applied onto a copper circuit portion of a glass epoxy substrate on which an electrode was formed by a screen printing method to form a pattern film having a width of 1 mm × 100 mm. . Next, it was heat-hardened at 150 ° C for 30 minutes in a hot air circulating drying oven. Then, the resistance value (R) of the obtained cured film was measured by a milliohm fast tester (3540 mΩ HiTESTER manufactured by HIOKI Co., Ltd.), and the volume resistivity was calculated. When the volume resistance value is measured, the thickness (t) of the conductive molded body is measured using a Saf encoder, and the correct line width (w) and length (l) of the conductive molded body based on the reflected light are measured using an optical microscope, and then measured based on the measurement. The value is calculated from the equation "ρ=R‧w‧t/l". In the formula, ρ is the volume resistivity (Ω ‧ cm), R is the resistance value (Ω), w is the width (cm), t is the thickness (cm), and l is the length (cm). Further, the volume resistance value is preferably small.

(2) Adhesiveness and tape peeling resistance

With the screen printing method of the above (1), a copper foil surface of a glass epoxy copper laminate is formed into a 15 mm × 15 mm pattern film, and then heat-hardened. After 100 squares of 1 mm × 1 mm were formed on the obtained cured film using a cutter, the number of squares remaining on the substrate when the upper coating film was peeled off with a transparent tape was examined, and the adhesion (JIS K5400-8.5) was evaluated. It is better to have more residual squares. Further, the tape peeling resistance was evaluated by attaching a scotch tape to the obtained cured film, peeling the tape so as to be 90° with respect to the coating film, and visually confirming the adhering matter of the tape. The evaluation criteria are as follows.

○: Scotch tape is completely free of attachments

×: Scotch tape has attachments

(3) Solder heat resistance

The printed wiring board produced in the above (1) was immersed in a solder bath at 260 ° C for 19 seconds, and then the resistance value of the cured film after the treatment was measured by a milliohm fast tester (3540 mΩ HiTESTER manufactured by HIOKI Co., Ltd.). The rate of change was calculated from the calculated volume resistance value based on the volume resistance value before the treatment. Further, the rate of change after the welding treatment is preferably smaller.

(4) boiling tolerance

The printed wiring board produced in the above (1) was immersed in boiling water for 2 hours, and then the resistance value of the cured film after the boiling treatment was measured by a milliohm rapid tester (3540 mΩ HiTESTER manufactured by HIOKI Co., Ltd.) to calculate the rate of change. Further, the rate of change after the welding treatment is preferably smaller.

(5) Pencil hardness

According to the test method of JIS K5600-5-6, the pencil hardness tester is used to indicate the highest hardness of the coating film without injury when the load is 1 kg. The pencil used was Mitsubishi Hayany (Mitsubishi Pencil Co., Ltd.).

It was confirmed from the above Comparative Examples 1 and 2 that the addition of the pyrazole compound inhibits the condensation of the resol phenol resin and affects the coating film properties. Further, from Comparative Examples 3 to 5, in the system of the mixed resole phenol resin and the isocyanate compound, the composition ratio of the isocyanate compound was increased to improve the boiling resistance, but the rate of change in resistance after the welding treatment was increased. This is caused by the self-condensation of the resol resin at the same time as the addition reaction with the isocyanate compound at the time of thermosetting, and the hydroxyl group required for the addition reaction is reduced to leave the isocyanate compound, which is expected to affect the soldering treatment. It is also presumed that one of the factors is that the self-condensation of the resol resin causes the mesh density of the crosslinked structure formed during thermal curing to be light, thereby lowering the heat resistance. However, in Examples 1 to 3, since 3,5-dimethylpyrazole was added, it was confirmed that the rate of change in electrical resistance after the welding treatment can be reduced. It is presumed that it is known from the above Reference Examples 1 and 2 that the gelation time can be alleviated when the resole phenolic resin coexists with 3,5-dimethylpyrazole, so that the self-condensation of the resol phenolic resin can be suppressed during thermosetting. Further, Examples 4 to 6 using an isocyanate compound of 3,5-dimethylpyrazole as a block agent were also confirmed to have excellent solder heat resistance. Thus, it has been found that the cured film formed using the conductive resin composition (conductive paste) of the present invention has excellent solder heat resistance and boiling resistance, and has high conductivity and adhesion to a substrate, and is therefore suitable for use. A circuit for forming a printed wiring board.

Fig. 1 is a graph showing the relationship between the solid content ratio of a resol type phenol resin and 3,5-dimethylpyrazole and gel time.

Claims (11)

A conductive resin composition comprising (A) a resol type phenol resin, (B) a pyrazole compound, (C) an isocyanate compound, and (D) a conductive powder, the aforementioned (A) A The blending amount of the phenol resin type phenol resin is 10 to 55% by mass based on the solid content of the resin solid content in the composition, and the amount of the (B) pyrazole compound blended is a solid content. The conversion is 1 to 35% by mass based on the solid content of the resole type phenol resin, and the blending amount of the (C) isocyanate compound is based on the solid content of the resin solid content in the composition. Say, it is 20~80% by mass. The conductive resin composition of claim 1, wherein the (B) pyrazole compound is 3,5-dimethylpyrazole. The conductive resin composition according to claim 1 or 2, wherein the (C) isocyanate compound is a blocked isocyanate compound. The conductive resin composition of claim 1, wherein (E) a polyvinyl acetal resin is further contained. The conductive resin composition of the first aspect of the invention, wherein the (D) conductive powder is at least one of carbon black and graphite. A conductive resin composition comprising (A) a resol resin type phenol resin, (F) a pyrazole block isocyanate compound, and (D) a conductive powder, the (A) resol type The blending amount of the phenol resin is 10 to 55% by mass based on the solid content of the resin solid content in the composition, and the amount of the (F) isocyanate compound to be mixed with the pyrazole block is solid. Composition conversion, relative to composition The solid content of the resin is 25 to 85% by mass. The conductive resin composition of claim 6, wherein the (F) isocyanate compound is a 3,5-dimethyl group of a trimer of 1,6-hexamethylene diisocyanate. Pyrazole block. The conductive resin composition of claim 6, wherein (E) a polyvinyl acetal resin is further contained. The conductive resin composition of the sixth aspect of the invention, wherein the (D) conductive powder is at least one of carbon black and graphite. A cured resin of a conductive resin obtained by hardening a conductive resin composition according to any one of claims 1 to 9. A conductor circuit pattern characterized by using a conductive resin cured material as in claim 10 of the patent application.