JP2007056127A - Resin composition for adhesion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for adhesion having excellent adhesive strength especially to metal. <P>SOLUTION: The resin composition for the adhesion is characterized as comprising a polyvinyl butyral resin (A), a polyvinyl butyral resin (B), a resol type phenol resin (C) and a metal compound (D). The polyvinyl butyral resin (A) has ≤30 mPa s solution viscosity at 20°C when the solid concentration is regulated to 10 wt.% by using a mixed solvent of ethanol/toluene at 1/1 (weight ratio) thereof. The polyvinyl butyral resin (B) has ≥500 mPa s solution viscosity at 20°C when the solid concentration is regulated to 10 wt.% by using the mixed solvent of ethanol/toluene at 1/1 (weight ratio) thereof. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an adhesive resin composition that is particularly excellent in adhesion to metals.

  Conventional phenolic resins used in adhesive resin compositions include resol type phenolic resins having reactive crosslinking groups such as methylol groups and dimethylol groups in the molecule, and novolac type phenolic resins containing crosslinking agents such as hexamethylenetetramine. It has been known. In order to increase the adhesive strength, it has been proposed to use these phenolic resins, polyvinyl butyral resins and epoxy resins in combination as an adhesive resin composition (see, for example, Patent Document 1), but sufficient adhesive strength. Cannot be obtained, and further improvements are required.

JP 2001-081432 A (page 2-3)

  In view of such a situation, an object of the present invention is to provide an adhesive resin composition excellent in adhesive strength, particularly adhesive strength to metal.

  As a result of intensive studies to solve the above problems, the present inventor has obtained an adhesive resin composition containing two kinds of polyvinyl butyral resins having specific solution viscosities and further containing a resol type phenolic resin and a metal compound. It has been found that the adhesive strength can be remarkably improved by using it, and the present invention has been completed.

  That is, the present invention relates to a polyvinyl butyral resin (A) having a solution viscosity at 20 ° C. of 30 mPa · s or less when the solid content concentration is adjusted to 10% by weight using a mixed solvent of ethanol / toluene = 1/1 (weight ratio). ), Polyvinyl butyral resin (B) having a solution viscosity of 500 mPa · s or higher when the solid content is adjusted to 10% by weight using a mixed solvent of ethanol / toluene = 1/1 (weight ratio), resol type The present invention provides an adhesive resin composition comprising a phenol resin (C) and a metal compound (D).

  The adhesive resin composition according to the present invention is excellent in adhesive strength and is particularly suitable for metal bonding applications.

  The polyvinyl butyral resin used in the present invention is a polyvinyl butyral having a solution viscosity at 20 ° C. of 30 mPa · s or less when the solid content concentration is adjusted to 10% by weight using a mixed solvent of ethanol / toluene = 1/1 (weight ratio). Solution viscosity at 20 ° C. when the resin (A) (A) and ethanol / toluene = 1/1 (weight ratio) mixed solvent are used to adjust the solid content concentration to 10% by weight. Is used in combination with a polyvinyl butyral resin (hereinafter abbreviated as a high-viscosity material) (B) of 500 mPa · s or more. When each of these is used alone, or when a polyvinyl butyral resin having a solution viscosity different from that of the low-viscosity body (A) and the high-viscosity body (B) is used alone or in combination, the obtained adhesive resin When the composition is used, sufficient adhesive strength cannot be obtained. The solution viscosity measured here is a value measured using a rotational viscometer (BM type). As a particularly preferred polyvinyl butyral resin, the solution viscosity is 10 to 25 mPa · s as the low-viscosity body (A), and the solution viscosity is 600 to 3000 mPa · s as the high-viscosity body (B).

  The mixing ratio (weight ratio) of the low-viscosity body (A) and the high-viscosity body (B) is that the low-viscosity body (A) / high-viscosity body (B) is obtained from the point that a resin composition having better adhesive strength can be obtained. = It is preferable that it is the range of 3/7-7/3.

  As a use ratio of the low-viscosity body (A) and the high-viscosity body (B), the total of the low-viscosity body (A) and the high-viscosity body (B) with respect to 100 parts by weight of the resol type phenol resin (C) described later. The amount is preferably 2.5 to 30 parts by weight.

  Examples of the resol type phenol resin (C) used in the present invention include those obtained by reacting phenols and aldehydes as raw materials in the presence of a catalyst described later. The phenols are not particularly limited, and examples thereof include phenols, alkylphenols such as bisphenol A, bisphenol F, cresol, xylenol, ethylphenol, butylphenol, and octylphenol, polyhydric phenols such as resorcin and catechol, and halogens. Phenol, phenylphenol, aminophenol and the like. In addition, these phenols are not limited to one type, and two or more types can be used in combination.

  Examples of the aldehydes include formaldehyde such as formaldehyde, paraformaldehyde, and trioxane, acetaldehyde, and the like.

  Examples of the catalyst include sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, sodium carbonate, ammonia, triethylamine, hexamethylenetetramine and the like. The catalyst may be used alone or in combination of two or more. Among these, it is preferable to use ammonia resole synthesized using ammonia as a catalyst from the viewpoint of excellent adhesive strength when the obtained adhesive resin composition is used. The addition amount of the catalyst is not particularly limited, but is preferably 0.02 to 0.2 in terms of molar ratio with respect to phenols used as a raw material.

  As the form of the resol type phenol resin (C), any of solid, aqueous solution, solvent solution, aqueous dispersion and the like can be used. From the viewpoint of excellent workability of the resulting adhesive resin composition, methanol, ethanol A solvent solution such as methyl ethyl ketone (MEK) or acetone is preferred.

  The metal compound (D) used in the present invention is not particularly limited, and various compounds can be used. Among these, a divalent metal salt is preferable. Examples of these are nickel nitrate, zinc nitrate, nickel chloride, nickel acetate, nickel carbonate, nickel sulfate, nickel naphthenate, nickel sulfamate, nickel oxalate, nickel hydroxide, zinc phosphate, zinc oxide, dihydrogen phosphate. Manganese etc. are mentioned, and these can be used alone or in combination of two or more. Among these, nickel nitrate and zinc nitrate are preferable because they have good solubility, act on the metal on the bonding surface, and have excellent bonding strength between the bonding resin composition and the metal.

  As a use ratio of the metal compound (D), 0.1 part by weight with respect to 100 parts by weight of the resol type phenol resin (C) from the viewpoint of excellent adhesive strength when the obtained adhesive resin composition is used. It is preferable that

  In addition, the adhesive resin composition of the present invention includes an aminosilane such as 3-aminopropyltrimethoxysilane and a silane such as epoxysilane such as 3-glycidoxypropyltrimethoxysilane within the range not impairing the effects of the present invention. Additives such as coupling agents and surfactants may be added. These can be used alone or in admixture of two or more. Although it does not specifically limit as usage-amount, It is preferable that it is 0.1-5 weight part with respect to 100 weight part of the said resol type phenol resin (C).

  An epoxy resin (E) can be added to the adhesive resin composition. The epoxy resin (E) is not particularly limited, and various types can be used. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, biscresol F type epoxy resin, bisphenol S type epoxy resin, bifunctional epoxy resin such as t-butylcatechol type epoxy resin, phenol novolac, etc. Type epoxy resins, cresol novolak type epoxy resins, p-tert-butylphenol novolak type epoxy resins, nonylphenol novolak type epoxy resins and the like, and polyvalent aliphatic epoxy resins include, for example, soybean oil And polyglycidyl ethers of vegetable oils such as castor oil, and polyvalent alkylene glycol type epoxy resins include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexa Modified epoxy modified with a compound capable of imparting flexibility such as diol, glycerin, erythritol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, a condensate of trimethylolpropane and epihalohydrin, and carboxyl group-containing rubber. Resins etc. are mentioned, These can be used alone or in combination of two or more. Among these, a bifunctional epoxy resin having an epoxy equivalent of 400 to 1000 g / eq is preferable because it is excellent in adhesive strength with a metal of the obtained adhesive resin composition, and industrial availability is easy. A bisphenol A type epoxy resin is particularly preferred, and is a modified polyphenol obtained by acetalizing a polyhydric phenol (x1) and a polyvalent vinyl ether (x2) from the viewpoint of excellent workability and excellent adhesive strength. It is particularly preferable that the epoxy resin is a liquid epoxy resin obtained by converting the compound (d) into glycidyl ether.

  Examples of the polyhydric phenols (x1) include dihydroxybenzenes such as hydroquinone, resorcin, catechol, and substituents thereof; 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,4- Dihydroxynaphthalenes such as dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, and substituents thereof; bis (4-hydroxyphenyl) methane (bisphenol F), 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 2,2-bis (3-methyl-4-hydroxyphenyl) propane (bisphenol C), 1,1-bis (4-hydroxyphenyl) cyclohexane (Bisphenol Z), 1 1,1-bis (4-hydroxyphenyl) -1-phenylethane (bisphenol AP), bis (4-hydroxyphenyl) sulfone (bisphenol S) and bisphenols such as those substituents containing products thereof. Examples of substituents in these substituent-containing products include alkyl groups, aryl groups, cycloalkyl groups, alkoxy groups, alkoxycarbonyl groups, acyl groups, and halogen atoms.

  Among these polyhydric phenols (x1), dihydric phenols are preferable because a low-viscosity epoxy resin can be obtained even if the vinyl ether modification rate is increased.

  The polyvalent vinyl ethers (x2) are not particularly limited as long as they are compounds containing more than one vinyl ether group in one molecule. For example, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol diester Vinyl ether, Tetraethylene glycol divinyl ether, Polyethylene glycol divinyl ether, Propylene glycol divinyl ether, Dipropylene glycol divinyl ether, Tripropylene glycol divinyl ether, Tetrapropylene glycol divinyl ether, Polypropylene glycol divinyl ether, Polytetramethylene glycol di Divinyl ethers containing (poly) oxyalkylene groups such as vinyl ether; Divinyl ether, triglycerol divinyl ether, 1,3-butylene glycol divinyl ether, 1,4-butanedidiol divinyl ether, 1,6-hexanediol divinyl ether, 1,9-nonanediol divinyl ether, 1,10- Divinyl ethers having an alkylene group such as decanediol divinyl ether, neopentyl glycol divinyl ether, and hydroxypivalate neopentyl glycol divinyl ether; trimethylolpropane trivinyl ether, ethylene oxide-modified trimethylolpropane trivinyl ether, propylene oxide-modified trimethylolpropane Trivinyl ethers, trivalent vinyl ethers such as pentaerythritol trivinyl ether, pentaerythritol Le tetra ether, pentaerythritol ethoxy tetra vinyl ether, tetravalent vinyl ethers such as ditrimethylolpropane tetra ether; dipentaerythritol hexa (penta) vinyl polyvalent vinyl ethers and the like.

  Among the polyvalent vinyl ethers (x2), divinyl ethers are preferable because a low-viscosity epoxy resin can be obtained even if the vinyl ether modification rate is increased. Divinyl ethers may be selected appropriately in consideration of the desired properties of the resulting epoxy resin. Among these, divinyl ethers containing a polyoxyalkylene group and divinyl ethers having an alkylene group are preferable.

  The method for the acetalization reaction is not particularly limited as long as it follows the reaction conditions of the aromatic hydroxyl group and the vinyl ether group. For example, the polyhydric phenols (x1) and the polyvalent vinyl ethers (x2 The modified polyhydric phenols (d) can be obtained by heating with stirring and mixing. In this case, an organic solvent and a catalyst can be used as needed. The organic solvent that can be used is not particularly limited, but aromatic organic solvents such as benzene, toluene, xylene, ketone organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, Alcohol-based organic solvents such as isopropyl alcohol and normal butanol can be used, and may be appropriately selected in consideration of properties such as the raw materials used and the solubility of the product, reaction conditions, economy, and the like. The amount of the organic solvent is preferably 5 to 500% by weight based on the raw material weight.

  As for the catalyst, the reaction proceeds normally even in a non-catalytic system, but depending on the type of raw material used, the desired properties of the resulting modified polyphenols (d), the desired reaction rate, etc. A catalyst may be used. The type of the catalyst is not particularly limited as long as it is a catalyst usually used for the reaction of a hydroxyl group and a vinyl ether group. For example, inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, toluenesulfonic acid, Methanesulfonic acid, xylenesulfonic acid, trifluoromethanesulfonic acid, oxalic acid, formic acid, trichloroacetic acid, trifluoroacetic acid and other organic acids, aluminum chloride, iron chloride, tin chloride, gallium chloride, titanium chloride, aluminum bromide, gallium bromide Lewis acids such as boron trifluoride ether complex and boron trifluoride phenol complex can be used, and the addition amount can be in the range of 10 ppm to 1 wt% with respect to the total weight of the raw material. However, in the catalyst addition system, it is necessary to select the type, addition amount, and reaction conditions so as not to cause a vinyl group nucleus addition reaction to the aromatic ring.

  The reaction conditions between the aromatic hydroxyl group and the vinyl ether group are usually room temperature to 200 ° C., preferably 50 to 150 ° C., and may be heated and stirred for about 0.5 to 30 hours. In this case, in order to prevent the self-polymerization of vinyl ethers, the reaction in an oxygen-containing atmosphere is preferable. The progress of the reaction can be traced by measuring the residual amount of the raw material using gas chromatography, liquid chromatography or the like. When an organic solvent is used, it is removed by distillation or the like. When a catalyst is used, it is deactivated with a deactivator if necessary, and then removed by washing with water or filtering. However, in the case of an organic solvent or catalyst (including a deactivated catalyst residue) that does not adversely affect the epoxidation reaction in the next step, there is no need for purification.

  The reaction ratio of the polyhydric phenols (x1) and the polyvalent vinyl ethers (x2) in the above reaction is not particularly limited, but is combined with the types of the raw polyhydric phenols (x1) and the polyvalent vinyl ethers (x2). Further, it may be determined according to the desired vinyl ether modification rate of the modified polyphenols (d) to be obtained, physical properties such as molecular weight, hydroxyl equivalent, and the acetal conversion rate depending on the reaction conditions.

  While adding or adding an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide to the dissolved mixture of the modified polyphenols (d) obtained above and epihalohydrin such as epichlorohydrin or epibromohydrin, 20 The epoxy resin (D) which can be used suitably by this invention can be obtained by making it react at -120 degreeC for 1 to 10 hours. The added amount of epihalohydrin is usually in the range of 0.3 to 20 equivalents relative to 1 equivalent of hydroxyl group in the raw material modified polyphenols (d).

  As the alkali metal hydroxide, an aqueous solution thereof may be used. In that case, the aqueous solution of the alkali metal hydroxide is continuously added to the reaction system, and water and epihalohydrin are continuously added under reduced pressure or normal pressure. May be distilled off, and the liquid may be further separated to remove water and the epihalohydrin to be continuously returned to the reaction system.

  Further, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, trimethylbenzylammonium chloride or the like is added to a dissolved mixture of the modified polyphenols (d) and epihalohydrin as a catalyst at 50 to 150 ° C. for 1 to 5 hours. A method of adding a solid or aqueous solution of an alkali metal hydroxide to the halohydrin etherified product of the phenol resin obtained by the reaction and reacting again at 20 to 120 ° C. for 1 to 10 hours to dehydrohalogenate (ring closure) may be used. .

  Furthermore, alcohols such as methanol, ethanol, isopropyl alcohol and butanol, ketones such as acetone and methyl ethyl ketone, ethers such as dioxane, aprotic polar solvents such as dimethyl sulfone and dimethyl sulfoxide, etc. are used in order to facilitate the reaction. It is also possible to carry out the reaction by adding.

  After the epoxidation reaction product is washed with water or without washing with water, epihalohydrin and other added solvents are removed at 110 to 250 ° C. under a pressure of 10 mmHg or less under reduced pressure. After completion of the reaction, the produced salt is removed by filtration, washing with water, etc., and an epoxy resin can be obtained by distilling off a solvent such as toluene and methyl isobutyl ketone under heating and reduced pressure.

As a use ratio of the epoxy resin (E), 2 to 20 parts by weight with respect to 100 parts by weight of the resol type phenol resin (C) from the viewpoint of excellent adhesive strength when the obtained adhesive resin composition is used. It is preferable that
The application of the adhesive resin composition of the present invention is not particularly limited as long as it is for adhesion, and is particularly suitable for metal adhesion such as a steel plate, steel material, aluminum, and stainless steel material. In general, the metal bonding process is a degreasing process with a solvent and an alkaline degreasing solution, followed by an etching process with an acid, an adhesive is applied, pre-dried at 60 to 120 ° C., and heat treated with a high-temperature press at 180 to 280 ° C. However, the adhesive resin composition of the present invention is characterized in that it exhibits excellent adhesive strength even without this etching step treatment, and can simplify the bonding step.

  The present invention will be specifically described below with reference to examples. In addition, all parts and% in the examples represent parts by weight and% by weight.

Synthesis example 1
To a 4-neck 2 liter flask equipped with a stirrer, a condenser, a thermometer and a dropping funnel, 750 g of phenol and 898 g of 40% aqueous formaldehyde solution were added and stirring was started. After adding 14.1 g of 25% aqueous ammonia as a catalyst and reacting at 80 ° C. for 5 hours, dehydration under reduced pressure was performed. After dehydration, the temperature was raised to 90 ° C., 200 g of methanol was added to adjust the nonvolatile content to 50%, and a resol type phenol resin (C-1) solution was obtained.

Synthesis example 2
To a 4-neck 2 liter flask equipped with a stirrer, a condenser, a thermometer and a dropping funnel, 750 g of phenol and 898 g of 40% aqueous formaldehyde solution were added and stirring was started. After adding 7.5 g of 48% aqueous sodium hydroxide as a catalyst and reacting at 80 ° C. for 3 hours, dehydration under reduced pressure was performed. After dehydration, the temperature was raised to 90 ° C., 200 g of methanol was added to adjust the nonvolatile content to 50%, and a solution of a resol type phenol resin (C-2) was obtained.

Synthesis example 3
A flask equipped with a thermometer and a stirrer was charged with 228 g (1.00 mol) of bisphenol A and 172 g (0.85 mol) of triethylene glycol divinyl ether (manufactured by ISP: trade name Rapi-Cure DVE-3) at 120 ° C. The temperature was raised for 1 hour and the temperature was raised, and the mixture was further reacted at 120 ° C. for 6 hours to obtain 400 g of a transparent semi-solid modified polyhydric phenol (d-1).

  In a flask equipped with a thermometer, a dropping funnel, a condenser, and a stirrer, 400 g of the modified polyphenols (d-1) obtained above (hydroxyl equivalent 364 g / eq.), 925 g of epichlorohydrin (10 mol), n -185 g of butanol was charged and dissolved. Thereafter, the temperature was raised to 65 ° C. while purging with nitrogen gas, and then the pressure was reduced to an azeotropic pressure, and 122 g (1.5 mol) of a 49% aqueous sodium hydroxide solution was added dropwise over 5 hours. Stirring was then continued under these conditions for 0.5 hour. During this time, the distillate distilled azeotropically was separated with a Dean-Stark trap, the aqueous layer was removed, and the reaction was conducted while returning the organic layer to the reaction system. Thereafter, unreacted epichlorohydrin was distilled off under reduced pressure. 1000 g of methyl isobutyl ketone and 100 g of n-butanol were added to the crude epoxy resin thus obtained and dissolved. Further, 20 g of a 10% aqueous sodium hydroxide solution was added to this solution and reacted at 80 ° C. for 2 hours. Then, washing with 300 g of water was repeated three times until the pH of the washing solution became neutral. Next, the system was dehydrated by azeotropic distillation, and after microfiltration, the solvent was distilled off under reduced pressure to obtain 457 g of a transparent liquid epoxy resin (E-1). The epoxy equivalent was 462 g / eq, and the viscosity was 12000 mPa · s (25 ° C., Canon Fenceke method).

Examples 1-8
Resol type phenol resins (C-1) and (C-2) obtained in Synthesis Examples 1 and 2, and polyvinyl butyral resin shown below, commercially available metal compounds, epoxy resin obtained in Synthesis Example 3, and commercially available products The following epoxy resins were mixed at a blending ratio shown in Table 1 to obtain an adhesive resin composition. Using this, it was applied to an etching acid-treated or untreated steel plate, dried at 120 ° C. for 30 seconds, hot-pressed at 250 ° C. for 4 minutes, and then subjected to a tensile shear test according to JIS K-6850. The results are shown in Table 1.

Low-viscosity polyvinyl butyral resin (A): 20 when SREC BL-10 (manufactured by Sekisui Chemical Co., Ltd., ethanol / toluene = 1/1 (weight ratio) mixed solvent is adjusted to 10% by weight. Solution viscosity at 11 ° C. 11 mPa · s)
High-viscosity polyvinyl butyral resin (B): 20 when SREC BH-3 (Sekisui Chemical Co., Ltd., ethanol / toluene = 1/1 (weight ratio) mixed solvent is adjusted to 10% by weight. Solution viscosity at 2 ° C. 2150 mPa · s)
Metal compound: Nickel nitrate (Wako Pure Chemical Industries, Ltd.)
Zinc nitrate (Wako Pure Chemical Industries, Ltd.)
Epoxy resin: EPICLON 4050 (Dainippon Ink Chemical Co., Ltd., bisphenol A type epoxy resin, epoxy equivalent 940 g / eq, softening point 98 ° C.)
Comparative Examples 1-4
Using the resol type phenolic resin (C-1) obtained in Synthesis Example 1, polyvinyl butyral resin, epoxy resin, and solvent were mixed at a blending ratio shown in Table 2, and adhesive properties were measured in the same manner as in the Examples. The results are shown in Table 2.

  Polyvinyl butyral resin: ESREC BH-S (manufactured by Sekisui Chemical Co., Ltd., ethanol / toluene = 1/1 (weight ratio) solution concentration at 20 ° C. when the solid content concentration is adjusted to 10% by weight 250 mPa・ S)

Claims (8)

Polyvinyl butyral resin (A) having a solution viscosity at 20 ° C. of 30 mPa · s or less when the solid content concentration is adjusted to 10% by weight using a mixed solvent of ethanol / toluene = 1/1 (weight ratio), ethanol / toluene = A polyvinyl butyral resin (B) having a solution viscosity at 20 ° C. of 500 mPa · s or more when a solid content concentration is adjusted to 10% by weight using a 1/1 (weight ratio) mixed solvent, a resol type phenol resin (C), and An adhesive resin composition comprising a metal compound (D). The adhesive resin composition according to claim 1, wherein a weight ratio (A) / (B) of the polyvinyl butyral resin (A) and the polyvinyl butyral resin (B) is 3/7 to 7/3. The adhesive resin composition according to claim 1, wherein the resol type phenol resin (C) is ammonia resol. The adhesive resin composition according to claim 1, wherein the metal compound (D) is nickel nitrate and / or zinc nitrate. Furthermore, the resin composition for adhesion | attachment in any one of Claims 1-4 containing an epoxy resin (E). The adhesive resin composition according to claim 5, wherein the epoxy resin (E) is a bifunctional epoxy resin having an epoxy equivalent of 400 to 1000 g / eq. The epoxy resin (E) is a liquid epoxy resin obtained by glycidyl etherification of a modified polyhydric phenol (d) obtained by acetalizing a polyhydric phenol (x1) and a polyvalent vinyl ether (x2). The adhesive resin composition according to claim 6. The adhesive resin composition according to claim 7, wherein the polyhydric phenols (x1) are dihydric phenols, and the polyvalent vinyl ethers (x2) are divinyl ethers.