JP2001011411A - Composition for adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compsn. for an adhesive for adhesion between or among an inorg. materials and an org. polymers, especially a one liquid type compsn. for an adhesive, suitable for adhesion between base materials largely different in their coefficients of thermal expansion and impact resistance, etc., e.g. a luminescence tube of a fluorescent light (made of glass) and a substrate part (made of an org. polymer) or a base of the tube, and exerting its adhesive force by curing with heat, and a bonded product therewith. SOLUTION: This compsn. for an adhesive is prepared by mixing an acrylic resin (A) having an unsaturated bond in its branched chain, which is prepared from an acrylic resin having an epoxy group in its branched chain, and a fatty acid, acrylic acid, or methacrylic acid, and a radical-polymerizable epoxy resin oligomer (B) having an unsaturated bond, which is prepared from an epoxy resin and acrylic acid, methacrylic acid, a hydroxyalkyl acrylate, a hydroxyalkyl methacrylate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition for bonding an inorganic substance and an organic polymer compound to each other or to each other, and particularly to the bonding of substrates having greatly different coefficients of thermal expansion and impact resistance. An object of the present invention is to provide a suitable one-component adhesive composition which is cured by heating to exhibit an adhesive force and a bonded article bonded using the composition.

[0002]

2. Description of the Related Art Adhesion between inorganic substances such as glass, iron, aluminum alloys and magnesium alloys and organic polymer compounds such as polyester resin, nylon resin, noryl resin, polyolefin resin, etc. is based on the surface polarity and heat resistance of both substrates. , Thermal expansion coefficient, impact resistance, etc. are very difficult.

[0003] Conventionally, as an adhesive for bonding an inorganic substance and an organic polymer compound, an epoxy resin-based adhesive having a high adhesive force and a low material selectivity has been widely used. However, many of the conventional epoxy resin adhesives have extremely high adhesive strength, but are poor in workability because they are of two or more liquid types. In addition, since such adhesives are very hard and inflexible, substrates having significantly different coefficients of thermal expansion and impact resistance (eg, glass and polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), etc.) )
In the case where is bonded, a substrate having lower impact resistance (glass in the above example) may be easily broken by a slight impact. Furthermore, since epoxy resins are generally mutagenic, workers are susceptible to dermatitis such as rash and swelling during the preparation stage of mixing the main agent and the curing agent, during the bonding operation, etc., and there is a problem in safety and hygiene. .

On the other hand, as an adhesive for bonding an arc tube (glass) of a fluorescent lamp and a base portion (organic polymer compound), an acrylic resin having a hydroxyl group and / or a carboxyl group, a radical polymerizable unsaturated oligomer ( An adhesive comprising a polyester diacrylate, a polyurethane diacrylate, an epoxy diacrylate, etc., a radical polymerization initiator and a silane coupling agent is disclosed (JP-A-8-157796 and JP-A-9-004447). When this adhesive is used in a closed system, it is not hindered from curing by air, and foams during curing to show an appropriate adhesive strength. It does not cure at all and foams and does not show sufficient adhesive strength. Further, since this adhesive is hard and very brittle, it is difficult to maintain the adhesive strength for a long time.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an adhesive composition for adhering an inorganic substance and an organic polymer compound to each other or to each other, and particularly to a base material having greatly different coefficients of thermal expansion and impact resistance. Suitable for bonding between each other, for example, between a luminous tube (glass) of a fluorescent lamp and a base portion (organic polymer compound) or a base portion. And a bonded article bonded using the same.

[0006]

Means for Solving the Problems As a result of intensive studies in view of the above objects, the present inventors have found that an acrylic resin (A) having an unsaturated bond derived from a fatty acid, acrylic acid or methacrylic acid in a side chain, and an unsaturated bond The composition for an adhesive containing the radical polymerizable epoxy resin oligomer (B) having
It is useful for bonding inorganic substances to organic polymer compounds, particularly for bonding fluorescent lamps, bulb-type fluorescent lamps, etc. to arc tubes (glass) and bases (organic polymer compounds) or bases. Even when applied to substrates with greatly different impact properties,
The present inventors have found that one of the substrates can maintain good adhesive strength without being easily broken by an impact, and arrived at the present invention.

That is, the adhesive composition of the present invention comprises an acrylic resin (A) having an unsaturated bond in the side chain, which is prepared from an acrylic resin having an epoxy group in the side chain and a fatty acid, acrylic acid or methacrylic acid. A radical polymerizable epoxy resin oligomer (B) having an unsaturated bond, which is prepared from an epoxy resin and acrylic acid, methacrylic acid, hydroxyalkyl acrylate, hydroxyalkyl methacrylate, etc., is uniformly mixed at room temperature. .

The acrylic resin (A) having an unsaturated bond in the side chain and the radical polymerizable epoxy resin oligomer (B) are preferably in a weight ratio of 5/95 to 80/20, more preferably in a weight ratio of 10/90 to 60/20. Mix at 40.

The adhesive composition of the present invention has an oxygen content of 0.05 to 0.05% based on the total volume of the acrylic resin (A) and the radical polymerizable epoxy resin oligomer (B) having an unsaturated bond in the side chain. It is characterized in that it is 20% by volume, preferably 5 to 15% by volume.

The fatty acid used in the present invention may be a mixture of a plurality of fatty acids. In this case, the mixture preferably contains 10 to 60 mol% of a fatty acid having a conjugated double bond,
It is more preferably contained in an amount of up to 50 mol% from the viewpoint of the curability and adhesive strength of the adhesive.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The adhesive composition of the present invention comprises an acrylic resin having an unsaturated bond in the side chain, which is prepared from an acrylic resin having an epoxy group in the side chain and a fatty acid, acrylic acid or methacrylic acid. A) and a radically polymerizable epoxy resin oligomer (B) having an unsaturated bond prepared from an epoxy resin and acrylic acid, methacrylic acid, hydroxyalkyl acrylate, hydroxyalkyl methacrylate and the like. Hereinafter, each component, the adhesive composition and its application will be described in detail.

[1] Acrylic resin having unsaturated bond in side chain (A) The acrylic resin of the present invention having unsaturated bond in side chain (A)
Synthesizes an acrylic resin having an epoxy group in the side chain by copolymerizing an epoxy group-containing unsaturated monomer and other radically polymerizable unsaturated monomers, and a fatty acid,
It is prepared by adding acrylic acid or methacrylic acid.

An acrylic resin having an epoxy group in a side chain is prepared by using an organic solvent such as toluene, xylene, ethyl acetate (EAC), butyl acetate, or n-butyl alcohol (BAL) to obtain α,
Using an organic azo polymerization initiator such as α'-azobisisobutyronitrile (AIBN) and an organic peroxide polymerization initiator such as benzoyl peroxide at a polymerization temperature of 40 to 150 ° C, the epoxy group-containing initiator is not used. It can be synthesized by solution polymerization of a saturated monomer and a radical polymerizable unsaturated monomer. The polymerization method is not limited to this.Emulsion polymerization or dispersion polymerization using water as a medium may be used, but if it is synthesized by solution polymerization, it becomes easy to introduce an unsaturated bond to an epoxy group in a side chain in a later step,
preferable.

The acrylic resin having an epoxy group in the side chain has an epoxy equivalent of 300 to 3,500, preferably 500 to 3,000. If the epoxy equivalent is less than 300, the storage stability of the adhesive tends to deteriorate. If the epoxy equivalent exceeds 3500, the adhesive is likely to foam in the bonding step, and the adhesive strength may be reduced.

Examples of the epoxy group-containing unsaturated monomer include glycidyl acrylate and glycidyl methacrylate (GM).
A), 3,4-epoxycyclohexylmethyl methacrylate and the like, or a mixture thereof can be used.

The radically polymerizable unsaturated monomer copolymerized with the epoxy group-containing unsaturated monomer includes an alkyl ester of acrylic acid or methacrylic acid (eg, methyl acrylate, ethyl acrylate, propyl acrylate,
Butyl acrylate (BA), cyclohexyl acrylate,
2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, methyl methacrylate (MMA), ethyl methacrylate, propyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, methacrylic acid
2-ethylhexyl, lauryl methacrylate, stearyl methacrylate, etc., acrylic acid or hydroxyalkyl ester of methacrylic acid (alkyl group having 6 or less carbon atoms, for example, 2-hydroxyethyl acrylate, acrylic acid
2-hydroxypropyl, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-methacrylic acid
Adducts of hydroxypropyl, 4-hydroxybutyl methacrylate and the like with ε-caprolactone or γ-butyrolactone, acrylates or methacrylates of polyglycol (for example, polyethylene glycol monoacrylate,
Polypropylene glycol monoacrylate, polytetramethylene glycol monoacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, polytetramethylene glycol monomethacrylate, etc.), styrene (SM), substituted maleimides (eg, phenylmaleimide, cyclohexylmaleimide, etc.) are used. It is possible. These may be used plurally at the same time.

The acrylic resin (A) having an unsaturated bond in the side chain is prepared by charging an acrylic resin having an epoxy group in the side chain and a fatty acid, acrylic acid or methacrylic acid into a reaction vessel, and then setting an appropriate reaction temperature (50 to 150). C), and reacted until the acid value of the reaction product becomes 0 to 20 mg KOH. If the reaction is stopped in a state where the acid value exceeds 20 mg KOH, the storage stability of the adhesive may deteriorate. To facilitate this reaction, tetraethylammonium chloride and tetrabutylammonium bromide (TBAB)
It is preferred to use a catalyst such as a phase transfer catalyst, such as, for example, an amine such as triethylamine. Also, in order to prevent polymerization of fatty acids, acrylic acid or methacrylic acid, and to prevent thickening and gelling during the reaction, p-methoxyphenol (MEHQ), t-butylcatechol, dilauroylthiodipropionate It is preferable to add an antioxidant such as (DLTP).

The fatty acid, acrylic acid or methacrylic acid is used in an amount of 0.5 to 1.2 molar equivalents relative to the epoxy group-containing unsaturated monomer.
Preferably, 0.6 to 1.0 molar equivalent is used. If the amount is less than 0.5 molar equivalent, the adhesive is susceptible to polymerization inhibition by air, and sufficient adhesive strength may not be obtained. When used in excess of 1.2 molar equivalents, fatty acids, acrylic acid or methacrylic acid may remain unreacted and the storage stability of the adhesive may deteriorate.

The fatty acid used in the present invention may be a mixture of a plurality of fatty acids. In this case, the mixture preferably contains 10 to 60 mol% of a fatty acid having a conjugated double bond,
It is more preferably contained in an amount of up to 50 mol% from the viewpoint of the curability and adhesive strength of the adhesive. Although many synthetic fatty acids and natural fatty acids can be used as fatty acids, natural fatty acids such as soybean fatty acids, rapeseed fatty acids, corn fatty acids, and tall fatty acids are preferred.

[2] Radical Polymerizable Epoxy Resin Oligomer (B) The radical polymerizable epoxy resin oligomer (B) having an unsaturated bond of the present invention comprises an epoxy resin and acrylic acid, methacrylic acid, hydroxyalkyl acrylate, methacrylic acid. It is prepared by charging a hydroxyalkyl ester or the like into a reaction vessel and reacting at 50 to 150 ° C. with stirring. At this time, it is preferable to use an organic solvent such as toluene or xylene because the viscosity of the reaction system can be reduced. Further, in order to shorten the reaction time, it is preferable to use a phase transfer catalyst such as tetraethylammonium bromide and tetrabutylammonium bromide (TBAB), and a catalyst such as amines such as triethylammonium, and acrylic acid, methacrylic acid and hydroxy acrylate. It is preferable to use an antioxidant (polymerization inhibitor) such as p-methoxyphenol (MEHQ) or t-butyl catechol in order to suppress polymerization of alkyl esters, hydroxyalkyl methacrylates, and the like.

As the epoxy resin, those described on pages 961 to p970 of "Chemical Products of 13599" (Kagaku Kogyo Nippo, 1999) can be used. The epoxy equivalent of the epoxy resin is preferably from 100 to 2,000. Epoxy equivalent is 1
If it is less than 00, the adhesive tends to be hard and brittle, and 20
If it exceeds 00, the heat resistance of the adhesive, the impact resistance of the joint, etc. may be deteriorated.

[3] Adhesive Composition The adhesive composition of the present invention comprises an acrylic resin (A) having an unsaturated bond in a side chain and a radically polymerizable epoxy resin oligomer (B) uniformly at room temperature. It is manufactured by mixing.

In the adhesive composition of the present invention, the weight ratio of the acrylic resin (A) having an unsaturated bond in the side chain to the radical polymerizable epoxy resin oligomer (B) is 5/95 to 80.
/ 20, more preferably 10/90 to 60/40. The amount of the acrylic resin (A) having an unsaturated bond in the side chain is 5% by weight based on the total weight of the acrylic resin (A) having an unsaturated bond in the side chain and the radical polymerizable epoxy resin oligomer (B). If the amount is less than the above range, the composition may be susceptible to curing inhibition by air (oxygen), and the adhesive strength may decrease. On the other hand, if it exceeds 80% by weight, the adhesiveness to the organic polymer substrate tends to be slightly weak.

Acrylic resin having an unsaturated bond in the side chain (A) and radical polymerizable epoxy resin oligomer (B)
When mixing, fillers (eg, titanium dioxide, calcium carbonate, talc, silica fine powder, glass powder, glass beads, etc.), reinforcing fibers (eg, glass fibers, carbon fibers, etc.), phenolic or polyphenolic antioxidants ( For example, p-methoxyphenol (MEHQ), t-butylcatechol, etc.), a silane coupling agent (eg, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, etc.), and an organic solvent (eg, toluene, xylene, Ethyl acetate (EAC), butyl acetate, isopropyl alcohol, n-butyl alcohol (BAL)
Etc.), tackifiers for promoting adhesion, rubbers (eg, chloroprene rubber, isobutylene rubber, etc.), pigments (eg, titanium oxide, calcium carbonate, etc.), and other compounds generally contained in adhesives. Good.

In order to control the curability of the composition, an azo-based polymerization initiator such as α, α′-azobisisobutyronitrile (AIBN) and an organic peroxide-based polymerization initiator such as benzoyl peroxide are used. Etc. may be added. These polymerization initiators are 0.005 to acrylic resin (A) having an unsaturated bond in the side chain.
It is preferable to add 〜2% by weight.

The adhesive composition of the present invention is used in an amount of 0.05 to 20% by volume, preferably 5 to 20% by volume, based on the total volume of the acrylic resin (A) having an unsaturated bond in the side chain and the radical polymerizable epoxy resin oligomer (B). Contains ~ 15% oxygen by volume. If the oxygen content is less than 0.05% by volume, the storage stability of the adhesive in summer may deteriorate. On the other hand, if it exceeds 20% by volume, the curability tends to deteriorate. The oxygen content was determined by first placing 800 g of the adhesive in a 1 L round can, replacing the voids with nitrogen, sealing tightly, stirring with a ball mill for 1 day, leaving it to stand for 1 hour, removing the lid, and removing the oxygen concentration meter “OM- The sensor part of "511E" (manufactured by Komei Rika Kogyo Co., Ltd.) was inserted into the gap of the can and measured. Generally, the measurement is performed in this manner. However, simply, after opening the container containing the adhesive, the sensor portion of the oxygen concentration meter may be immediately inserted into the gap of the container to perform the measurement.

[4] Application of the adhesive composition The inorganic material to which the adhesive composition of the present invention can be applied includes:
Glass, aluminum alloy, iron, magnesium alloy and the like can be mentioned. As the organic polymer compound, a polyester resin (eg, polyethylene terephthalate (PE)
T), polybutylene terephthalate (PBT), etc.), polyamide resins (eg, nylon 6, 66 nylon, aramid resin, etc.), polyolefin resins (eg, polypropylene resin (PP), polystyrene resin (PS), acrylonitrile)
-Styrene-butadiene resin (ABS) and the like). The adhesive composition of the present invention exhibits particularly excellent adhesive properties in bonding glass to polyethylene terephthalate resin (PET) or polybutylene terephthalate resin (PBT). That is, even when the adhesive composition of the present invention is applied to a fragile substrate such as glass, good adhesive strength can be maintained without the glass being damaged by impact.

[0028]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 A mixed solvent of ethyl acetate (EAC) and n-butyl alcohol (BAL) (weight ratio EAC / BAL = 80/20) was used as a solvent, and methyl methacrylate (MMA), styrene (SM), acrylic Butyl (BA), polypropylene glycol monomethacrylate ("PP-1000" manufactured by NOF CORPORATION, molecular weight 350) and glycidyl methacrylate (GMA) as MMA / SM / BA / PP-1
000 / GMA = 45/10/30/5/10 weight ratio, α,
Acrylic resin with epoxy group in the side chain using α'-azobisisobutyronitrile (AIBN) as a polymerization initiator (solid content
60% by weight and an epoxy equivalent of 1420) were synthesized.

To this resin solution, tetrabutylammonium bromide (TBA 2% by weight based on the solid content) was added.
B) 0.8 mol equivalent of soybean fatty acid (having a conjugated double bond) to 1% by weight of p-methoxyphenol (MEHQ), 0.5% by weight of dilauroylthiodipropionate (DLTP) and glycidyl methacrylate (GMA) 20 mole% fatty acids
Was added, and the mixture was reacted at 100 ° C. for 7 hours to prepare an acrylic resin having an unsaturated bond in a side chain. The acid value of the obtained fatty acid-modified acrylic resin (acrylic resin having an unsaturated bond in a side chain) was 0.2 mg KOH. In addition, α,
α′-azobisisobutyronitrile (AIBN) was added at 0.5% by weight based on the solid content.

A bisphenol A-type epoxy resin diacrylate (radical polymerizable epoxy resin oligomer) obtained by adding acrylic acid to a bisphenol A-type epoxy resin (epoxy equivalent: 180) was added to the fatty acid-modified acrylic resin / weight ratio. Bisphenol A type epoxy resin diacrylate = 20/80, and 0.01% by weight of p-methoxyphenol (MEHQ) based on the total weight of fatty acid-modified acrylic resin and bisphenol A type epoxy resin diacrylate was added. And mixed until uniform. Subsequently, under a vacuum, the oxygen content of the composition was adjusted to 8% by volume with respect to the total volume of the fatty acid-modified acrylic resin and the bisphenol A type epoxy resin diacrylate to produce a composition for an adhesive.

Example 2 An acrylic resin having an unsaturated bond in the side chain was prepared in the same manner as in Example 1 except that acrylic acid was used instead of soybean fatty acid. The acid value of the obtained acrylic acid-modified acrylic resin (acrylic resin having an unsaturated bond in a side chain) is 0.1.
It was 0 mg KOH.

In addition, "Aronix M-210" (EO modified diacrylate of bisphenol A, Toagosei Co., Ltd.)
Was added so that the weight ratio became acrylic acid-modified acrylic resin / Aronix M-210 = 40/60, followed by stirring and mixing until uniform. Subsequently, the composition for an adhesive was manufactured by adjusting the oxygen content of the composition to 10% by volume based on the total volume of the acrylic acid-modified acrylic resin and Aronix M-210 under vacuum.

Example 3 An adhesive composition was prepared in the same manner as in Example 2 except that the operation for removing air was omitted. The oxygen content of this composition was 28% by volume based on the total volume of the acrylic acid-modified acrylic resin and Aronix M-210.

Example 4 Adhesion of the adhesive composition of Example 2 with 1% by weight of γ-glycidoxypropyltrimethoxysilane and 120% by weight of calcium carbonate (pigment) based on the solid content, respectively. A pharmaceutical composition was produced.

Comparative Example 1 Acrylic resin having no unsaturated bond in the side chain (Toray Industries, Inc.)
Cotax LH-614, acid value 5.3mg KOH, hydroxyl value
58.5 mg KOH), epoxy diacrylate ("V # 540" manufactured by Osaka Organic Chemical Industry Co., Ltd., bisphenol A diepoxyacrylic acid adduct, molecular weight 480) and α, α'-azobisisobutyronitrile (AIBN) Cotax LH-614 / V # 54
The mixture was uniformly mixed at a weight ratio of 0 / AIBN = 60/40/1 to produce an adhesive composition.

The luminous tube (glass) of a bulb-type fluorescent lamp and a substrate (polybutylene terephthalate resin (PBT)) are adhered to each of the compositions produced as described above, and the adhesive strength and the impact resistance of the glass are measured. evaluated. Table 1 shows the results. The test method and evaluation criteria are as follows. Adhesive strength: cylindrical arc tube with rounded tip (glass)
After applying an adhesive between the substrate and the substrate (polybutylene terephthalate resin (PBT)), the substrate is cured by heating at 140 ° C. for 5 minutes. With the base part up and the arc tube part down, attach a 1kg weight to the arc tube with a 5cm long thread, release the weight at a stretch with the thread stretched on the vertical extension, Was loaded. ○ It is firmly adhered and does not peel off. Pass. △ Somewhat loose, but not peeling. Pass. × Easy peeling. Fail Impact resistance: After applying an adhesive between the arc tube (glass) and the substrate (polybutylene terephthalate resin (PBT)), heat and cure at 140 ° C for 5 minutes. This was gently dropped from a height of 30 cm on the floor where the sponge cushion was pulled, and it was examined whether the glass was broken. ○ The glass does not break. Pass. △ The glass is not damaged, but a part of the adhesive is chipped off. Pass. × The glass is broken. failure

As can be seen from Table 1, when the adhesive composition of Comparative Example 1 was used, sufficient adhesive strength was not exhibited, and the impact resistance of the bonded glass was inferior. The product showed good results in both adhesive strength and impact resistance. Thus, the adhesive composition of the present invention is suitable for bonding substrates having greatly different coefficients of thermal expansion and impact resistance.

[0039]

As described in detail above, the adhesive composition of the present invention has an acrylic resin (A) having an unsaturated bond derived from a fatty acid, methacrylic acid or acrylic acid in the side chain, and an unsaturated resin. A one-component adhesive composition that contains a radically polymerizable epoxy resin oligomer (B) and is cured by heating to exhibit adhesive strength. It shows excellent adhesive properties in bonding an arc tube (glass) such as a lamp to a base portion (organic polymer compound) or a base portion.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 4J027 AA01 AA02 AE02 AE03 AE04 AJ08 CA08 CA12 CA14 CA18 CA19 CA29 CA34 CA36 CA38 CD09 4J040 FA231 FA232 FA261 FA262 JA12 JB02 LA06 MA01 MA02 MA05 MA10 NA17 NA19

Claims (6)

[Claims] 1. An adhesive composition comprising an acrylic resin (A) having an unsaturated bond derived from a fatty acid, acrylic acid or methacrylic acid in a side chain, and a radically polymerizable epoxy resin oligomer (B). . 2. The adhesive composition according to claim 1, wherein the acrylic resin (A) has an unsaturated bond in the side chain.
Is a composition for adhesives obtained by adding a fatty acid, acrylic acid or methacrylic acid to an acrylic resin having an epoxy group in a side chain. 3. The adhesive composition according to claim 1, wherein the radical polymerizable epoxy resin oligomer (B) is an epoxy resin containing acrylic acid, methacrylic acid, hydroxyalkyl acrylate or hydroxyalkyl methacrylate. An adhesive composition characterized by adding an ester. 4. The adhesive composition according to claim 1, wherein the weight of the acrylic resin (A) having an unsaturated bond in the side chain and the weight of the radically polymerizable epoxy resin oligomer (B). The composition for an adhesive, wherein the ratio is from 5/95 to 80/20. 5. The composition for an adhesive according to claim 1, wherein the acrylic resin (A) having an oxygen content having an unsaturated bond in the side chain and the radical polymerizable epoxy resin oligomer ( B) 0.05-20 for the total capacity
% By volume. 6. The adhesive composition according to claim 1, wherein the fatty acid is a mixture of a plurality of fatty acids, and contains 10 to 60 mol% of a fatty acid having a conjugated double bond. An adhesive composition comprising: