JP2001049070A - Acrylic binder resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition good in processability and workability and excellent in printing properties by admixing a specific amount of an acrylic polymer obtained by copolymerization of a monomer mixture with a specific amount of an organic solvent containing a specific amount or more of an aromatic hydrocarbon-containing alcohol having a boiling point of a specific temperature or higher. SOLUTION: This binder resin composition comprises 100 parts by mass of an acrylic polymer (A) obtained by copolymerization of a monomer mixture and 150-2,000 parts by mass of an organic solvent (B) containing at least 50 mass % of an aromatic hydrocarbon-containing alcohol having a melting point of at least 200 deg.C such as benzyl alcohol, or the like. The component A is obtained by copolymerizing the monomer mixture comprising 65-100 mass % of at least one alkyl (meth)acrylate, 0-5 mass % of an unsaturated carboxylic acid and 0-10 mass % of a hydroxy group-containing (meth)acrylate and other copolymerizable monomers. The composition gives pyrolysis residue of 0.5 mass % or less under a baking condition of heating up to 450 deg.C at a temperature rising rate of 10 deg.C/min in the air or in an inert atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic solvent-based acrylic binder resin composition, and more particularly, to a low solid content, high viscosity, no stringiness, and excellent handling workability. Also, the present invention relates to an acrylic binder resin composition showing good baking properties with few residues due to thermal decomposition.

[0002]

2. Description of the Related Art Conventionally, there has been known a method in which a conductor or a ceramic molded body is produced by dispersing a metal or an inorganic filler in a binder, producing a pattern or a molded body, and then thermally decomposing the binder component by firing. Have been. The binder component used in this method is necessary to retain the workability during molding and to prevent the filler from being damaged during transfer, and to thermally decompose the filler before sintering it before it becomes the final product. To be removed. Therefore, it is necessary for the binder to have good thermal decomposability and to satisfy workability in each processing as the performance required for the binder. As each processing method, there are a screen printing method, a method of forming a slurry into a sheet shape using a doctor plate or the like, and a processing method using a dipping method.

[0003] In particular, in applications used for screen printing and dipping, it is necessary to minimize the amount of a binder component contained in order to increase the filling rate of a filler component to be sintered. Therefore, the binder component is a solvent-based binder resin in which a butyral resin or ethyl cellulose is dissolved in an organic solvent to obtain high viscosity that satisfies screen suitability and dip suitability with a low solid content as much as possible. Had been.

[0004]

However, in addition to the above-mentioned requirements, components used in recent electronic materials include fillers that can be fired at a low temperature, such as glass powder, from fillers of a high-temperature firing type such as alumina. When sintering a low-temperature sintering type filler or sintering in an inert atmosphere (reducing atmosphere) to prevent oxidation of the metal filler, sludge is generated as sintering failure with the above butyral resin or ethyl cellulose resin binder. However, there is a problem that the characteristics of the completed ceramic or metal conductor are deteriorated. In order to solve the drawbacks of the conventional binder, an acrylic resin binder using an acrylic resin having a good firing property has been proposed. For example, a copolymer of isopropyl methacrylate and 2-ethylhexyl methacrylate and a methacrylic ester having a hydroxyl group at the β-position or the α-position (JP-A-10-167736) can be mentioned. However, those containing an acrylic resin as a main component improve the thermal decomposability, but it is necessary to increase the molecular weight of the copolymer in order to develop a high viscosity like screen printing, and stringing caused by the high molecular weight is required. Due to this phenomenon, printability or dip coating suitability could not be satisfied.

[0005] The present invention has been made to solve the above-mentioned problems, and an acrylic binder resin excellent in sinterability can exhibit high viscosity characteristics at a low solid content, and has no stringiness and has good workability and workability. The present invention provides an acrylic binder resin composition having good properties and excellent printability and dip coating suitability.

[0006]

Means for Solving the Problems The present inventors have made intensive studies on the above problems, and as a result, by using a specific organic solvent, it is possible to exhibit high viscosity characteristics at a low solid content and without stringing. The present invention was found to have good workability in various processing methods, and to have good calcination properties, and to have thermal decomposition properties that do not leave sludge.

[0007] That is, the present invention provides at least one (a-1) 6 selected from alkyl (meth) acrylate monomers.
5 to 100% by mass, unsaturated carboxylic acid monomer (a-2)
A monomer mixture containing 0 to 5% by mass, 0 to 20% by mass of a hydroxy group-containing (meth) acrylate monomer (a-3) and 0 to 10% by mass of other copolymerizable monomers (however, Is 100% by mass) and an organic solvent containing an aromatic hydrocarbon-containing alcohol having a boiling point of 200 ° C. or higher in an amount of 50% by mass or more based on 100 parts by mass of an acrylic polymer (A) obtained by copolymerizing the same. B) 15
It is characterized by containing 0 to 2000 parts by mass. Here, as the aromatic hydrocarbon-containing alcohol of the organic solvent (B), benzyl alcohol is desirable from the viewpoint of improving stringing of the acrylic binder resin composition,
The weight average molecular weight of the acrylic polymer (A) is from 100,000 to 800,000 from the viewpoint of coating workability and stringiness improvement, and further up to 450 ° C at a rate of 10 ° C / min in the atmosphere and / or in an inert atmosphere. Is preferably 0.5% by mass or less.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The polymer component of the acrylic binder resin composition of the present invention is a monomer mixture containing the following components (a-1) to (a-4) (however, the total of the monomers is 100
% By weight). However, (a-2), (a-3) and (a-4) can be appropriately selected and used as needed. (A-1): at least one kind (65 to 100% by mass) selected from alkyl (meth) acrylate monomers (a-2): unsaturated carboxylic acid monomer (0 to 5% by mass) (a- 3): Hydroxy group-containing (meth) acrylate monomer (0 to 20% by mass) (a-4): Other copolymerizable monomer (0 to 10% by mass)

[0009] At least one selected from (a-1) alkyl (meth) acrylate monomers exhibits good baking properties by containing at least 65% by mass, and more preferably at least 70% by mass. is there. As the component (a-1), alkyl (meth) acrylate having 1 to 6 carbon atoms is preferable in terms of thermal decomposability, and specific examples include methyl (meth) acrylate, ethyl (meth) acrylate, and n- Butyl (meth) acrylate,
Mono (meth) acrylates such as i-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are exemplified. These monomers may be used in combination of two or more to obtain a desired glass transition temperature (Tg).

(A-2) When the content of the unsaturated carboxylic acid monomer is set to 5% by mass or less, the dispersion stability of the filler dispersed in the binder can be improved, and at the same time, good thermal decomposability at the time of firing is obtained. Obtainable. More preferably, it is in the range of 0.1 to 2% by mass. Specific examples include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, 2-methacryloyloxyethyl hexahydrophthalate, 2-meracryloyloxyethyl phthalate, 2-methacryloyloxyethyl maleate, 2-methacryloyloxyethyl succinate and the like,
One type or a mixture of two or more types can be used.

(A-3) When the content of the (meth) acrylate containing a hydroxyl group is 20% by mass or less, a binder can be provided with a viscosity increasing effect, and good thermal decomposability at the time of firing can be obtained. Can be improved in dispersion stability. More preferably, it is in the range of 0.1 to 10% by weight or less. Specific examples include hydroxy (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypropyl (meth) acrylate, and the like.

[0012] (a-4) Other copolymerizable monomers can be copolymerized in a range of 10% by weight or less as long as the sinterability is not reduced. Specific examples include styrene, α-methylstyrene, acrylonitrile, acrylamide, methacrylamide, diethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth)
Acrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, trimethylolpropane tri (meth) acrylate, polybutylene glycol dimethacrylate,
Examples include 1,6 hexanediol dimethacrylate, 1,3 butylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, and vinyl acetate.

[0013] The organic solvent (B) used in the acrylic binder of the present invention must contain at least 50% by mass of an aromatic hydrocarbon-containing alcohol having a boiling point of 200 ° C or higher.

[0014] By containing 50% by mass or more of an aromatic hydrocarbon-containing alcohol having a boiling point of 200 ° C or more, a high viscosity can be imparted to the varnish when the polymer is dissolved, and stringing at a high viscosity characteristic of an acrylic polymer. The coating workability during screen printing or dip coating can be improved. Preferably, it is a range containing 60% by mass or more.

[0015] Specific examples include benzyl alcohol, phenylpropylene glycol, cresol and the like, with benzyl alcohol having the highest effect of suppressing stringiness being particularly preferred.

Further, the content of the organic solvent (B) needs to be 150 to 2000 parts by mass with respect to 100 parts by mass of the acrylic polymer. When the amount of the organic solvent (B) is 150% by mass or more, the acrylic polymer can be uniformly dissolved to impart fluidity, and when the amount is 2000% by mass or less, a good high viscosity can be exhibited. . More preferably, it is in the range of 300 parts by mass to 900 parts by mass.

The organic solvent (B) other than the aromatic-containing alcohol having a boiling point of 200 ° C. or higher is not necessarily required to have a boiling point of 200 ° C. or higher as long as it satisfies printability, stringiness and high viscosity. It is preferable to use one having a temperature of 150 ° C. or higher.

Specific examples include terpineol, dihydroterpineol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether. Ethyl ether acetate, diethylene glycol monobutyl ether acetate, 2,2,4-trimethyl 1,3-
Pentadiol monoisobutyrate, isophorone, 3-
Methoxybutyl acetate, aromatic or aliphatic hydrocarbons having a boiling point of 150 ° C. or higher, butyl lactate, dibutyl phthalate, phthalic acid esters such as dioctyl phthalate or dibutyl adipate, plasticizers such as adipic acid ester such as dioctyl adipate, and the like, At least one of the above solvents can be used as a mixture.

The molecular weight of the acrylic polymer is preferably in the range of 100,000 to 800,000 in terms of mass average molecular weight in order to satisfy the performance of screen printing and dip coating and no stringing. By setting the mass average molecular weight to 100,000 or more, it becomes possible to develop a viscosity at which coating workability at the time of screen printing or dip coating becomes good. Performance tends to be obtained. More preferably 150,000-7
It is in the range of 10,000. For applications where a high viscosity is to be exhibited at a low solid content, the high molecular weight may be used. For applications where the viscosity is not desired to be increased, the desired viscosity can be obtained by setting the molecular weight low.

[0020] The acrylic binder resin of the present invention is characterized in that there is little thermal decomposition residue such as sludge even in an atmosphere in the atmosphere and / or in an inert atmosphere.
It is possible to reduce the thermal decomposition residue under heating conditions up to 450 ° C. at a heating rate of min to 0.5% by mass or less.

The conventionally used ethyl cellulose resin or butyral resin has a problem that a large amount of residue called sludge is generated at a low temperature of 450 ° C. or less, and further sludge is generated at a low temperature of 450 ° C. or less. Therefore, there was a disadvantage that it could not be used for parts requiring high-purity quality for electronic materials and the like, but the acrylic binder resin composition of the present invention did not have such disadvantages, and was used for electronic materials and the like. It can be used for parts requiring high purity quality. Further, it is suitable for a metal filler in which an oxidation reaction proceeds by heat, a metal oxide which is apt to undergo thermal degradation, a phosphor, and the like. Here, the inert atmosphere is often nitrogen, but may be a mixed gas of oxygen and nitrogen.
In addition, a gas such as helium, neon, or argon is used.

<Production Method> Examples of the method for producing the acrylic binder resin composition of the present invention include well-known methods such as solution polymerization, suspension polymerization, and emulsion polymerization. In solution polymerization, a monomer is polymerized in a solvent, so that a binder resin can be obtained simultaneously with the completion of the polymerization. In the suspension polymerization, in order to polymerize a monomer suspension in water, a bead polymer is dissolved in a solvent to produce a binder resin. In emulsion polymerization,
In order to polymerize the monomer emulsified in water in micelles, the polymer in an emulsified state is separated by precipitation or the water content is dried by a spray drier, and the obtained polymer is dissolved in a solvent to produce a binder resin.

<Usage Method> The filler powder used by using the acrylic binder resin composition obtained according to the present invention is not limited to oxides such as alumina, zirconia, titanium oxide and barium titanate, as well as alumina nitride and nitride. Silicon, nitride such as boron nitride, metals such as copper, silver, nickel, etc., silica powder such as low melting point glass powder, cathode ray and PD
Examples include various phosphors used for P and the like. These inorganic powders are not particularly limited as long as they are formed of a binder resin composition and can be used to decompose the binder resin composition by firing, and can be used for various inorganic powders. The mixing ratio of the ceramic powder and the binder resin composition can be 3 to 30 parts by mass of the solid content of the binder resin composition with respect to 100 parts by mass of the ceramic powder, but differs depending on the specific gravity of the ceramic. It is not limited to the above range. If necessary, a plasticizer, a dispersing aid, and an antifoaming agent may be added. The coating method includes screen printing or dip coating for high viscosity applications, and a doctor blade method or cast method for low viscosity applications.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. In the examples, “parts” indicates “parts by mass”, and “%” indicates “% by mass”. In addition, the evaluation method in an Example is as follows.

<Acid value> mg number of KOH (mg KOH / g) required to neutralize 1 g of acrylic polymer (solid content).

<Firing property> The obtained acrylic binder resin was dried, a sample amount of 10 to 20 mg was placed on an aluminum dish, and evaluated by TG (thermal loss analysis). The atmosphere was heated from room temperature to 450 ° C. at a rate of 10 ° C./min in air, then cooled to room temperature, and the state of the residue was observed. ◎: There was no black or gray residue on the aluminum plate, and it was completely decomposed. Heat loss rate of 99.9% or more ：: There was no black or gray residue on the aluminum dish, and it was completely decomposed. Heat loss rate 99.5% to 99.9% or more Δ: Black or gray residue was present on the aluminum dish, and poor decomposition products were observed. Heat loss rate 97% to 99.5% x: Black or gray residue was present on the aluminum dish, and poor decomposition products were observed. Heat loss rate of 97% or less

<Stringiness> Using a No. 4 rotor having a B-type viscosity, the viscosity was measured while changing the number of revolutions during the measurement. Although the number of rotations varies depending on the viscosity region, the viscosity was measured with the ratio of the number of rotations being 10 times, and the viscosity ratio (thixotropic property) was calculated. For example, in a high viscosity region, a viscosity ratio of 0.3 rpm to 3 rpm (0.3 / 3 rpm), and in a low viscosity region, 0.6 rpm
The viscosity ratio (0.6 / 6 rpm) between pm and 6 rpm was measured and the following evaluation criteria were used. Viscosity ratio: less than 1.5 Stringing property × Viscosity ratio: 1.5 to 2 Stringing property △ Viscosity ratio: 2 or more Stringing property ○

Example 1 600 parts of pure water and 1.8 parts of polyvinyl alcohol (80% of saponification degree, polymerization degree of 1700) were dissolved in a 2-liter separable flask capable of heating and cooling, and sodium sulfate 1 247 parts of methyl methacrylate, 95 parts of benzyl methacrylate, 2-
A monomer mixture of 38 parts of hydroxyethyl methacrylate, 1.3 parts of n-dodecylmercaptan, and 0.8 parts of azobisisobutyronitrile was charged, and the mixture was vigorously stirred at 350 rpm to form a suspension, and the temperature was raised to 75 ° C. The reaction was carried out for 5 hours to complete the polymerization. The obtained suspension was dehydrated and dried to obtain a beaded polymer (A1). 100 parts of the obtained polymer (A1) was placed in a 2-liter three-necked flask, and 140 parts of benzyl alcohol and 93 parts of terpineol 93 were added.
Then, the mixture was dispersed in the mixture, heated to 80 ° C. and dissolved for 3 hours to produce an acrylic binder resin composition (C1).

[Examples 2 to 9] In the same manner as in Example 1,
Various acrylic binder resin compositions (C2 to C9) shown in Tables 1 and 2 were obtained.

[0030]

【table 1】

[0031]

[Table 2]

The symbols in the table are as follows. iBMA: isobutyl methacrylate nBMA: n-butyl methacrylate MMA: methyl methacrylate EMA: ethyl methacrylate BzMA: benzyl methacrylate SMA: stearyl methacrylate

Various evaluations of the obtained binder resin are shown in Table 1.
And Table 2. All of the binder resin compositions of Examples 1 to 9 had good sintering properties, and those having few residues were obtained. In addition, when the organic solvent contained benzyl alcohol in an amount of 50% or more, good thixotropy was exhibited, and good resistance to stringiness was observed.

In the same manner as in Example 1, various acrylic binder resin compositions shown in Table 3 were obtained. Various evaluations of the obtained binder resin composition are as shown in Table 3.

[0035]

[Table 3]

Since the binder resin composition of Comparative Example 1 did not use benzyl alcohol at all, the stringing resistance was poor. In the binder resin composition of Comparative Example 2, the content of benzyl alcohol in the solvent (B) was as low as 30%, and the stringiness was poor. The binder resin composition of Comparative Example 3 contained as much as 10% by mass of methacrylic acid, which is the component (a2) of the acrylic polymer, and had good stringing properties, but had a large firing residue and reduced thermal decomposability. The binder resin composition of Comparative Example 4 is an organic solvent containing a polymer obtained by copolymerizing 30% by mass of 2-hydroxyethyl methacrylate, which is the component (a3) of the acrylic polymer, with 60% of an aromatic-containing alcohol having a boiling point of 200 ° C. or lower. In this case, the amount of 2-hydroxyethyl methacrylate was large, so that there was a large amount of sintering residue, the thermal decomposability was reduced, and the anti-stringiness was poor. In Comparative Example 5, a binder resin composition was produced by using ethyl cellulose ("Ethyl Cellulose HE Type" manufactured by Dow Chemical Company) instead of the acrylic resin. The stringiness was good, but the firing residue was poor.

[0037]

As described in detail above, the acrylic binder resin composition of the present invention achieves both high viscosity and anti-stringing performance, which cannot be obtained with the conventional acrylic binder resin. And has good thermal decomposition properties. This makes it possible to impart various coating and processing operability when used as a binder resin requiring high viscosity at a low solid content, and can be used as a binder resin for low-temperature firing. The effect of the invention is remarkable. In particular, by using benzyl alcohol, the balance of exhibiting the viscosity increasing effect and good thermal decomposability is improved, and stringing is less likely to occur even at high viscosity, which makes it more suitable for screen printing or dip coating. Furthermore, even when firing at a low temperature of 450 ° C. or less, the amount of pyrolysis residue is reduced, so that it can be used for parts requiring high purity quality such as for electronic materials.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C09D 11/10 B22F 3/02 M 5G301 H01B 1/22 C04B 35/00 108 F-term (Reference) 4G030 GA14 PA21 4J002 BC041 BF021 BG041 BG071 BG091 BG131 BH021 EC016 GT00 4J039 AD10 BC07 BC13 BC29 BE12 CA04 CA07 EA48 GA10 4J100 AB02S AB03S AJ02Q AJ08Q AJ09Q AL03P AL04P AL04S AL08 AL09SCA04 AL10SAL04 CA09 CA33 DA03 5G301 DA03 DA06 DA10 DD01 DD02

Claims (4)

[Claims] Claims 1. An alkyl (meth) acrylate monomer selected from the group consisting of at least one (a-1) of 65 to 100% by mass, an unsaturated carboxylic acid monomer (a-2) of 0 to 5% by mass,
Hydroxy group-containing (meth) acrylate monomer (a-
3) By copolymerizing a monomer mixture containing 0 to 20% by mass and (a-4) 0 to 10% by mass of other copolymerizable monomers (however, the total of all monomers is 100% by mass) 15 parts of an organic solvent (B) containing 50% by mass or more of an aromatic hydrocarbon-containing alcohol having a boiling point of 200 ° C. or more based on 100 parts by mass of the obtained acrylic polymer (A).
An acrylic binder resin composition containing 0 to 2,000 parts by mass. 2. A boiling point of 200 contained in the organic solvent (B).
The acrylic binder resin composition according to claim 1, wherein the aromatic hydrocarbon-containing alcohol at a temperature of not less than ° C is benzyl alcohol. 3. The acrylic binder resin composition according to claim 1, wherein the weight average molecular weight of the acrylic polymer (A) is from 100,000 to 800,000. 4. The thermal decomposition residue under baking conditions by heating up to 450 ° C. at a heating rate of 10 ° C./min in an atmosphere in the atmosphere and / or in an inert atmosphere is 0.5% by mass or less. The acrylic binder resin composition according to claim 1, wherein: